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000
FXUS65 KCYS 031148
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
548 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 540 AM MDT SUN MAY 3 2015

A WEAK COLD FRONT WILL PUSH ACROSS AREAS TO THE EAST OF THE
LARAMIE RANGE THIS MORNING TURNING WINDS TO THE NORTH AND
NORTHEAST. GUSTS TO 20-25 KTS WILL BE POSSIBLE OVER THE NEBRASKA
PANHANDLE FROM LATE THIS MORNING THROUGH THE AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP IN AREAS ALONG INTERSTATE
80 (RWL TO SNY) BY THIS AFTERNOON. SIMILAR TO YESTERDAY...BRIEF
HEAVY RAIN AND GUSTY WINDS WILL BE POSSIBLE WITH THESE STORMS. LOW
CLOUDS WILL FORM ALONG THE SOUTHERN LARAMIE RANGE AND CHEYENNE
RIDGE BY EARLY MON MORNING.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 031148
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
548 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 540 AM MDT SUN MAY 3 2015

A WEAK COLD FRONT WILL PUSH ACROSS AREAS TO THE EAST OF THE
LARAMIE RANGE THIS MORNING TURNING WINDS TO THE NORTH AND
NORTHEAST. GUSTS TO 20-25 KTS WILL BE POSSIBLE OVER THE NEBRASKA
PANHANDLE FROM LATE THIS MORNING THROUGH THE AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP IN AREAS ALONG INTERSTATE
80 (RWL TO SNY) BY THIS AFTERNOON. SIMILAR TO YESTERDAY...BRIEF
HEAVY RAIN AND GUSTY WINDS WILL BE POSSIBLE WITH THESE STORMS. LOW
CLOUDS WILL FORM ALONG THE SOUTHERN LARAMIE RANGE AND CHEYENNE
RIDGE BY EARLY MON MORNING.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC




000
FXUS65 KCYS 031148
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
548 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 540 AM MDT SUN MAY 3 2015

A WEAK COLD FRONT WILL PUSH ACROSS AREAS TO THE EAST OF THE
LARAMIE RANGE THIS MORNING TURNING WINDS TO THE NORTH AND
NORTHEAST. GUSTS TO 20-25 KTS WILL BE POSSIBLE OVER THE NEBRASKA
PANHANDLE FROM LATE THIS MORNING THROUGH THE AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP IN AREAS ALONG INTERSTATE
80 (RWL TO SNY) BY THIS AFTERNOON. SIMILAR TO YESTERDAY...BRIEF
HEAVY RAIN AND GUSTY WINDS WILL BE POSSIBLE WITH THESE STORMS. LOW
CLOUDS WILL FORM ALONG THE SOUTHERN LARAMIE RANGE AND CHEYENNE
RIDGE BY EARLY MON MORNING.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC




000
FXUS65 KCYS 031148
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
548 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 540 AM MDT SUN MAY 3 2015

A WEAK COLD FRONT WILL PUSH ACROSS AREAS TO THE EAST OF THE
LARAMIE RANGE THIS MORNING TURNING WINDS TO THE NORTH AND
NORTHEAST. GUSTS TO 20-25 KTS WILL BE POSSIBLE OVER THE NEBRASKA
PANHANDLE FROM LATE THIS MORNING THROUGH THE AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS WILL DEVELOP IN AREAS ALONG INTERSTATE
80 (RWL TO SNY) BY THIS AFTERNOON. SIMILAR TO YESTERDAY...BRIEF
HEAVY RAIN AND GUSTY WINDS WILL BE POSSIBLE WITH THESE STORMS. LOW
CLOUDS WILL FORM ALONG THE SOUTHERN LARAMIE RANGE AND CHEYENNE
RIDGE BY EARLY MON MORNING.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC


  [top]

000
FXUS65 KRIW 030910
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

THE SHOWERS ASCT WITH A WEAK SOUTHERN STREAM VORT LOBE THAT WAS OVER
THE GREAT BASIN EARLIER THIS EVENING WILL ONLY PRODUCE SOME BRIEF
SPRINKLES OR LIGHT SHOWERS IN SOUTHWEST WY THIS MORNING. IN THE
MEANTIME...A COOL FRONT EJECTING FROM A NORTHERN STREAM SHORTWAVE
WITH THE ASCT VORT MAX TRACKING EAST ALONG THE MONTANA CANADIAN BORDER
WILL BE DROPPING DOWN ACROSS NORTHERN WYOMING AND APPEARS THAT IS
HAS REACHED AS FAR SOUTH AS WRL. THIS FRONT WILL GET LODGED UP
AGAINST THE CONTINENTAL DIVIDE TODAY THUS KEEPING THE BEST
INSTABILITY AND INVERTED V SOUNDINGS ALONG AND WEST OF THE DIVIDE
AS SOMEWHAT MORE STABLE AIR DRIFTS IN BEHIND THE FRONT EAST OF THE
DIVIDE TODAY. HAVE MENTION OF SCATTERED THUNDERSTORMS WITH SMALL HAIL
AND GUSTY WINDS WEST OF THE DIVIDE AND A FEW SHOWERS WITH ISOLD
THUNDER WITH GUSTY WINDS EAST. MONDAY WILL FEATURE MORE WIDESPREAD
THUNDERSTORM ACTIVITY WITH LIFTED INDICES DOWN TO MINUS 3 IN SOME
AREAS. WRF QPF INDICATES RELATIVELY STRONG AND MORE FOCUSED
CONVECTIVE INDUCED PRECIP ALONG AND WEST OF THE DIVIDE MONDAY
COMPARED TO THE MORE WIDESPREAD LIGHTER SHOWERS ASCT WITH PROBABLE
VIRGA SHOWERS THAT IT APPEARS TO BE INDICATING FOR THIS AFTERNOON.
TUESDAY SHOULD BE EVEN MORE ACTIVE AS FAR AS CONVECTION GOES GIVEN
THE ANTICIPATED UPSTREAM STRONG CLOSED LOW MAKING LANDFALL ONTO
THE PAC NW/BRITISH COLUMBIA COAST ALONG WITH AN ARM OF LOWER
PRESSURE EXTENDING EAST SOUTHEAST INTO WY. IN FACT THE GFS
INDICATES AN H7 CIRCULATION OVER PATHFINDER RESERVOIR TUESDAY WITH
THE EURO SHOWING A WEAKER LOW BUT NO DISCERNIBLE H7 CIRCULATION
OVER JOHNSON COUNTY TUE. NEGATIVE LIFTED INDICES AND WEAK CAPES
COUPLED WITH THE H7 CIRCULATION SHOULD RESULT IN QUITE AN ACTIVE
CONVECTIVE DAY TUE/TUE EVE. TEMPERATURES WILL NOT FLUCTUATE MUCH
THROUGH TUE.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

SYNOPSIS...A TROUGH OF LOW PRESSURE OVER THE WESTERN U.S. WILL BRING
COOLER CONDITIONS WITH CHANCES OF SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH SATURDAY.  THE SYSTEM AND WILL LIFT INTO THE HIGH
PLAINS ON SUNDAY WITH DECREASING CHANCES OF SHOWERS.

DISCUSSION...MEDIUM RANGE MODELS HAVE SHOWN GOOD OVERALL AGREEMENT
AND RUN-TO-RUN CONSISTENCY OVER THE LAST 36 HOURS IN THE DEVELOPMENT
OF TROUGH ACROSS THE WESTERN U.S. WEDNESDAY THROUGH FRIDAY.   THE
TWO WEATHER MAKERS DURING THIS PERIOD ARE A SUB-TROPICAL UPPER LOW
NEAR 30N/140W AND A NORTHERN STREAM UPPER LOW NEAR 50N/150W. THE
SUB-TROPICAL LOW WILL GET KICKED INTO THE SW U.S. ON MONDAY AND
LIFT NNE ACROSS THE CENTRAL HIGH PLAINS INTO STRONG DOWNSTREAM
RIDGE ON WEDNESDAY. THIS SYSTEM WILL BRING INCREASING SHOWERS AND
THUNDERSTORMS UP FROM THE SOUTH ON WEDNESDAY...HOWEVER THE
HEAVIEST AND MOST WIDESPREAD PRECIPITATION IS EXPECTED EAST OF THE
AREA...ALONG AND EAST OF THE STORM TRACK.

NORTHERN STREAM UPPER LOW WILL DIG SOUTH ALONG THE WEST COAST
WEDNESDAY AND THURSDAY...ROUGHLY ALONG 120W.  THERE MAY BE SOMEWHAT
OF A BREAK IN PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY BETWEEN
THE TWO SYSTEMS...THE FIRST UPPER LOW OUT OF THE SUB-TROPICS LIFTING
INTO THE NORTHERN PLAINS THURSDAY MORNING.  UPPER LOW ALONG THE WEST
COAST IS EXPECTED TO CUTOFF FROM THE FLOW THURSDAY AND THEN SLOWLY
WOBBLE EASTWARD ACROSS THE GREAT BASIN FRIDAY AND SATURDAY.
UPSTREAM PACIFIC TROUGH IS FORECAST TO MOVE INTO THE EASTERN
PACIFIC...ACROSS 140W AROUND 00Z SATURDAY...AND ACT AS THE KICKER
FOR THE GREAT BASIN LOW THAT IS EXPECTED TO ACCELERATE OUT OF
NORTHERN UTAH NE ACROSS WYOMING INTO THE HIGH PLAINS SATURDAY NIGHT
AND SUNDAY.  NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED
ACROSS MUCH OF THE AREA THURSDAY AFTERNOON THROUGH SATURDAY OUT
AHEAD OF THE UPPER LOW...THE BEST CHANCE FOR HEAVIER PRECIPITATION
ON FRIDAY NIGHT AND SATURDAY FROM SOUTHEAST INTO CENTRAL WYOMING.
SNOW LEVELS ARE EXPECTED TO BE BETWEEN 7KFT AND 8KFT ACROSS MOST OF
THE AREA THURSDAY THROUGH SATURDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A WEAK COLD FRONT WILL STALL OUT ALONG THE DIVIDE LATER THIS
MORNING. THIS WILL RESULT IN A NORTHERLY TO EASTERLY SURFACE FLOW
TODAY INTO TONIGHT.  ALTHOUGH BOUNDARY LAYER MOISTURE WILL INCREASE
IN WAKE OF THE FRONT EARLY THIS MORNING...LOW CLOUDS ARE NOT
EXPECTED. THE AIR MASS WILL BE RELATIVELY STABLE FOR MUCH OF THE
DAY...BUT WILL BEGIN TO BECOME SLIGHTLY UNSTABLE AFTER 21Z SUNDAY
WITH PEAK HEATING AND SOME CONVECTION IS POSSIBLE ESPECIALLY CLOSER
TO THE DIVIDE. WILL MENTION VCTS AT KLND AND KCPR...BUT ONLY HAVE
VCSH AT TERMINALS FARTHER NORTH. THIS CONVECTION SHOULD WEAKEN BY
AROUND 03Z MONDAY...BUT SOME ISOLATED ACTIVITY COULD LINGER PAST 06Z
MONDAY. VFR CONDITIONS ARE EXPECTED...EXCEPT FOR BRIEF MVFR/IFR
CONDITIONS NEAR CONVECTION.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

A SLIGHTLY UNSTABLE ATMOSPHERE WITH ADEQUATE MOISTURE WILL ALLOW FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
AREA...MAINLY IN THE AFTERNOON AND EVENING. INVERTED V
SOUNDINGS...STEEP LAPSE RATES AND COOL TEMPERATURES ALOFT SUGGEST
STRONG OUTFLOW WINDS TO 45 KTS...AND SMALL HAIL WILL BE THE MAIN
HAZARDS. ENOUGH COVERAGE TO MENTION VCTS AT ALL TERMINALS DURING THE
AFTERNOON AND EVENING. THE CONVECTION WILL WEAKEN BY AROUND 03Z
MONDAY...BUT SOME ACTIVITY COULD LINGER PAST 06Z MONDAY. VFR
CONDITIONS ARE EXPECTED EXCEPT FOR BRIEF MVFR/IFR CONDITIONS
POSSIBLE NEAR ANY CONVECTION.

&&

.FIRE WEATHER...

WESTERLY ZONAL FLOW WILL BE OVER THE AREA THROUGH TODAY WITH WEAK
LOW PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND
SUBTROPICAL MOISTURE MOVING UP FROM THE GREAT BASIN IN THE
SOUTHERN BRANCH OF THE FLOW. DIURNALLY DRIVEN SCATTERED SHOWERS
WITH ISOLATED THUNDERSTORMS REFORMING LATE THIS MORNING AND
INCREASING THROUGH THE AFTERNOON WILL RESULT. CLOUD COVER AND SCATTERED
PRECIPITATION WILL HAVE A COOLING EFFECT TODAY. WITH MODERATE
FLOW ALOFT AND CONVECTIVE CELLS MOVING 25 TO 30 MPH...WIND GUSTS
TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS ALONG WITH SMALL HAIL.
THE COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE
THIS AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW
ALOFT GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED THIS AFTERNOON.
THESE MAINLY LATE DAY THUNDERSTORMS ARE EXPECTED TO PERSIST
THROUGH AT LEAST TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LIPSON
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...LIPSON








000
FXUS65 KRIW 030910
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

THE SHOWERS ASCT WITH A WEAK SOUTHERN STREAM VORT LOBE THAT WAS OVER
THE GREAT BASIN EARLIER THIS EVENING WILL ONLY PRODUCE SOME BRIEF
SPRINKLES OR LIGHT SHOWERS IN SOUTHWEST WY THIS MORNING. IN THE
MEANTIME...A COOL FRONT EJECTING FROM A NORTHERN STREAM SHORTWAVE
WITH THE ASCT VORT MAX TRACKING EAST ALONG THE MONTANA CANADIAN BORDER
WILL BE DROPPING DOWN ACROSS NORTHERN WYOMING AND APPEARS THAT IS
HAS REACHED AS FAR SOUTH AS WRL. THIS FRONT WILL GET LODGED UP
AGAINST THE CONTINENTAL DIVIDE TODAY THUS KEEPING THE BEST
INSTABILITY AND INVERTED V SOUNDINGS ALONG AND WEST OF THE DIVIDE
AS SOMEWHAT MORE STABLE AIR DRIFTS IN BEHIND THE FRONT EAST OF THE
DIVIDE TODAY. HAVE MENTION OF SCATTERED THUNDERSTORMS WITH SMALL HAIL
AND GUSTY WINDS WEST OF THE DIVIDE AND A FEW SHOWERS WITH ISOLD
THUNDER WITH GUSTY WINDS EAST. MONDAY WILL FEATURE MORE WIDESPREAD
THUNDERSTORM ACTIVITY WITH LIFTED INDICES DOWN TO MINUS 3 IN SOME
AREAS. WRF QPF INDICATES RELATIVELY STRONG AND MORE FOCUSED
CONVECTIVE INDUCED PRECIP ALONG AND WEST OF THE DIVIDE MONDAY
COMPARED TO THE MORE WIDESPREAD LIGHTER SHOWERS ASCT WITH PROBABLE
VIRGA SHOWERS THAT IT APPEARS TO BE INDICATING FOR THIS AFTERNOON.
TUESDAY SHOULD BE EVEN MORE ACTIVE AS FAR AS CONVECTION GOES GIVEN
THE ANTICIPATED UPSTREAM STRONG CLOSED LOW MAKING LANDFALL ONTO
THE PAC NW/BRITISH COLUMBIA COAST ALONG WITH AN ARM OF LOWER
PRESSURE EXTENDING EAST SOUTHEAST INTO WY. IN FACT THE GFS
INDICATES AN H7 CIRCULATION OVER PATHFINDER RESERVOIR TUESDAY WITH
THE EURO SHOWING A WEAKER LOW BUT NO DISCERNIBLE H7 CIRCULATION
OVER JOHNSON COUNTY TUE. NEGATIVE LIFTED INDICES AND WEAK CAPES
COUPLED WITH THE H7 CIRCULATION SHOULD RESULT IN QUITE AN ACTIVE
CONVECTIVE DAY TUE/TUE EVE. TEMPERATURES WILL NOT FLUCTUATE MUCH
THROUGH TUE.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

SYNOPSIS...A TROUGH OF LOW PRESSURE OVER THE WESTERN U.S. WILL BRING
COOLER CONDITIONS WITH CHANCES OF SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH SATURDAY.  THE SYSTEM AND WILL LIFT INTO THE HIGH
PLAINS ON SUNDAY WITH DECREASING CHANCES OF SHOWERS.

DISCUSSION...MEDIUM RANGE MODELS HAVE SHOWN GOOD OVERALL AGREEMENT
AND RUN-TO-RUN CONSISTENCY OVER THE LAST 36 HOURS IN THE DEVELOPMENT
OF TROUGH ACROSS THE WESTERN U.S. WEDNESDAY THROUGH FRIDAY.   THE
TWO WEATHER MAKERS DURING THIS PERIOD ARE A SUB-TROPICAL UPPER LOW
NEAR 30N/140W AND A NORTHERN STREAM UPPER LOW NEAR 50N/150W. THE
SUB-TROPICAL LOW WILL GET KICKED INTO THE SW U.S. ON MONDAY AND
LIFT NNE ACROSS THE CENTRAL HIGH PLAINS INTO STRONG DOWNSTREAM
RIDGE ON WEDNESDAY. THIS SYSTEM WILL BRING INCREASING SHOWERS AND
THUNDERSTORMS UP FROM THE SOUTH ON WEDNESDAY...HOWEVER THE
HEAVIEST AND MOST WIDESPREAD PRECIPITATION IS EXPECTED EAST OF THE
AREA...ALONG AND EAST OF THE STORM TRACK.

NORTHERN STREAM UPPER LOW WILL DIG SOUTH ALONG THE WEST COAST
WEDNESDAY AND THURSDAY...ROUGHLY ALONG 120W.  THERE MAY BE SOMEWHAT
OF A BREAK IN PRECIPITATION WEDNESDAY NIGHT INTO THURSDAY BETWEEN
THE TWO SYSTEMS...THE FIRST UPPER LOW OUT OF THE SUB-TROPICS LIFTING
INTO THE NORTHERN PLAINS THURSDAY MORNING.  UPPER LOW ALONG THE WEST
COAST IS EXPECTED TO CUTOFF FROM THE FLOW THURSDAY AND THEN SLOWLY
WOBBLE EASTWARD ACROSS THE GREAT BASIN FRIDAY AND SATURDAY.
UPSTREAM PACIFIC TROUGH IS FORECAST TO MOVE INTO THE EASTERN
PACIFIC...ACROSS 140W AROUND 00Z SATURDAY...AND ACT AS THE KICKER
FOR THE GREAT BASIN LOW THAT IS EXPECTED TO ACCELERATE OUT OF
NORTHERN UTAH NE ACROSS WYOMING INTO THE HIGH PLAINS SATURDAY NIGHT
AND SUNDAY.  NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED
ACROSS MUCH OF THE AREA THURSDAY AFTERNOON THROUGH SATURDAY OUT
AHEAD OF THE UPPER LOW...THE BEST CHANCE FOR HEAVIER PRECIPITATION
ON FRIDAY NIGHT AND SATURDAY FROM SOUTHEAST INTO CENTRAL WYOMING.
SNOW LEVELS ARE EXPECTED TO BE BETWEEN 7KFT AND 8KFT ACROSS MOST OF
THE AREA THURSDAY THROUGH SATURDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A WEAK COLD FRONT WILL STALL OUT ALONG THE DIVIDE LATER THIS
MORNING. THIS WILL RESULT IN A NORTHERLY TO EASTERLY SURFACE FLOW
TODAY INTO TONIGHT.  ALTHOUGH BOUNDARY LAYER MOISTURE WILL INCREASE
IN WAKE OF THE FRONT EARLY THIS MORNING...LOW CLOUDS ARE NOT
EXPECTED. THE AIR MASS WILL BE RELATIVELY STABLE FOR MUCH OF THE
DAY...BUT WILL BEGIN TO BECOME SLIGHTLY UNSTABLE AFTER 21Z SUNDAY
WITH PEAK HEATING AND SOME CONVECTION IS POSSIBLE ESPECIALLY CLOSER
TO THE DIVIDE. WILL MENTION VCTS AT KLND AND KCPR...BUT ONLY HAVE
VCSH AT TERMINALS FARTHER NORTH. THIS CONVECTION SHOULD WEAKEN BY
AROUND 03Z MONDAY...BUT SOME ISOLATED ACTIVITY COULD LINGER PAST 06Z
MONDAY. VFR CONDITIONS ARE EXPECTED...EXCEPT FOR BRIEF MVFR/IFR
CONDITIONS NEAR CONVECTION.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

A SLIGHTLY UNSTABLE ATMOSPHERE WITH ADEQUATE MOISTURE WILL ALLOW FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
AREA...MAINLY IN THE AFTERNOON AND EVENING. INVERTED V
SOUNDINGS...STEEP LAPSE RATES AND COOL TEMPERATURES ALOFT SUGGEST
STRONG OUTFLOW WINDS TO 45 KTS...AND SMALL HAIL WILL BE THE MAIN
HAZARDS. ENOUGH COVERAGE TO MENTION VCTS AT ALL TERMINALS DURING THE
AFTERNOON AND EVENING. THE CONVECTION WILL WEAKEN BY AROUND 03Z
MONDAY...BUT SOME ACTIVITY COULD LINGER PAST 06Z MONDAY. VFR
CONDITIONS ARE EXPECTED EXCEPT FOR BRIEF MVFR/IFR CONDITIONS
POSSIBLE NEAR ANY CONVECTION.

&&

.FIRE WEATHER...

WESTERLY ZONAL FLOW WILL BE OVER THE AREA THROUGH TODAY WITH WEAK
LOW PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND
SUBTROPICAL MOISTURE MOVING UP FROM THE GREAT BASIN IN THE
SOUTHERN BRANCH OF THE FLOW. DIURNALLY DRIVEN SCATTERED SHOWERS
WITH ISOLATED THUNDERSTORMS REFORMING LATE THIS MORNING AND
INCREASING THROUGH THE AFTERNOON WILL RESULT. CLOUD COVER AND SCATTERED
PRECIPITATION WILL HAVE A COOLING EFFECT TODAY. WITH MODERATE
FLOW ALOFT AND CONVECTIVE CELLS MOVING 25 TO 30 MPH...WIND GUSTS
TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS ALONG WITH SMALL HAIL.
THE COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE
THIS AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW
ALOFT GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED THIS AFTERNOON.
THESE MAINLY LATE DAY THUNDERSTORMS ARE EXPECTED TO PERSIST
THROUGH AT LEAST TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LIPSON
LONG TERM...AEM
AVIATION...WM
FIRE WEATHER...LIPSON









000
FXUS65 KCYS 030910
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 030910
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 030910
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 030910
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 AM MDT SUN MAY 3 2015

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 300 AM MDT SUN MAY 3 2015

STARTING OFF THIS MORNING...SURFACE ANALYSIS SHOWING A FRONTAL
BOUNDARY LAYING WEST TO EAST ACROSS NORTHERN WYOMING...VERY SLOWLY
MOVING SOUTH THIS MORNING. LOOKS TO LAY ALONG THE LARAMIE RANGE BY
18Z OR SO TODAY WITH NORTHEASTERLY WINDS BEHIND THE FRONT FOR
AREAS EAST OF THE LARAMIE RANGE. MEANWHILE...THE UPPER LEVEL LOW
THAT HAS BEEN SENDING US PIECES OF ENERGY THE PAST COUPLE DAYS
CONTINUES OVER THE DESERT SOUTHWEST.

BEST FOCUS FOR SHOWERS AND THUNDERSTORMS TODAY LOOKS TO BE WEST
AND SOUTH OF THIS FRONT...BASICALLY ALONG AND WEST OF THE LARAMIE
RANGE. BUT IT AL DEPENDS ON WHERE THIS FRONT ULTIMATELY ENDS UP BY
EARLY AFTERNOON. SHOULD IT HAPPEN TO TAKE A LITTLE LONGER TO GET
TO THE LARAMIE RANGE...SHOWERS AND STORMS COULD BE FURTHER EAST.

A LITTLE MORE UNSTABLE TODAY OVER YESTERDAY WITH NAM SHOWING A
POCKET OF 850MB CAPE AROUND 1000 J/KG NEAR LARAMIE OVER TO
SARATOGA AND 700MB CAPES AROUND 600 J/KG. LIFTED INDICES NEAR
-4C...SO DO BELIEVE THE STRONGEST STORMS WILL BE IN THIS AREA.
LOCATIONS BEHIND THE FRONT WILL MOST LIKELY EXPERIENCE COOLER
TEMPERATURES IN THE NORTHEAST FLOW...SO DID NOT STRAY TOO MUCH
FROM THE LOW CHANCE POPS WE HAD GOING EAST OF I-25. DID INCREASE
POPS THOUGH OUT WEST AS MODELS ARE IN GREAT AGREEMENT WITH THE
LARAMIE RANGE...CARBON AND ALBANY COUNTIES SEEING DECENT RAINFALL
THIS AFTERNOON.

SHOWERS AND THUNDERSTORMS COULD LAST INTO THE LATE EVENING HOURS
TONIGHT WITH THE FRONTAL BOUNDARY IN THE AREA AND FAIRLY GOOD
UPSLOPING WINDS.

SOME DIFFERENCES IN GFS AND ECMWF ON WHAT IS GOING TO HAPPEN
MONDAY. BOTH ARE SHOWING SOME ENERGY MOVING NORTH FORM THE DESERT
SOUTHWEST TO INTERACT WITH THE STALLED FRONTAL BOUNDARY. GFS KEEPS
HIGHER POPS WEST...WHILE ECMWF SHOWS THE SOUTH LARAMIE RANGE AND
POINTS SOUTH SEEING MOST OF THE POPS. WENT MORE WITH THE ECMWF/NAM
SOLUTION WITH THE HIGHER POPS ACROSS THE SOUTH AND EAST.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN MAY 3 2015

THE MODELS ARE STILL SHOWING A RATHER UNSETTLED EXTENDED PERIOD.
ON WED THE SHORTWAVE TROUGH WILL BE LOCATED OVER CENTRAL NEBRASKA.
GOOD LLVL MOISTURE IS INDICATED BY THE GFS WITH DEWPOINTS IN THE
MID 40S TO LOW 50S ACROSS THE PLAINS AND PW VALUES ARE QUITE HIGH
FOR EARLY MAY (0.75-1.0 INCHES). WITH MORE SUNSHINE ON WED
COMPARED TO PREVIOUS DAYS...THERE WILL BE BETTER INSTABILITY. SO
SCATTERED TO NUMEROUS SHOWERS AND TSTMS WILL DEVELOP BY WED
AFTN...SOME WITH HEAVY RAIN. WHILE THE MODELS YESTERDAY WERE
SHOWING A BRIEF BREAK IN THE PRECIP ON THURS...THIS IS REALLY NO
LONGER THE CASE. AN UPPER LOW WILL BE CUT OFF ACROSS NORTHERN
CALIFORNIA WITH EAST TO SOUTHEAST WINDS ACROSS THE CWA. THE GFS
INDICATES ANOTHER AFTN OF DECENT CAPE (600-800 J/KG) SO DID RAISE
POPS SOME INTO THE 30-40 PERCENT RANGE BY THURS EVENING. IT WILL
LIKELY BECOME EVEN WETTER AS WE HEAD INTO FRI. THE UPPER LOW MOVES
EASTWARD INTO THE GREAT BASIN ON FRI WITH UPPER LEVEL DIFFLUENCE
INCREASING ACROSS SOUTHEAST WY. THERE IS ALSO GOOD LLVL
UPSLOPE WITH A SFC HIGH OVER THE NORTHERN PLAINS...SO THE
POTENTIAL EXISTS FOR SOME PRETTY HIGH RAINFALL AMOUNTS FROM FRI
AFTN INTO SAT. BOTH THE GFS AND ECMWF SHOW WIDESPREAD QPF AMOUNTS
OF 0.5-1.5 INCHES. WILL ALSO HAVE TO MONITOR THE POTENTIAL FOR
SOME STRONG TO SVR STORMS AS THE EVENT DRAWS CLOSER...ALTHOUGH AT
THIS TIME THE THREAT LOOKS MARGINAL WITH LIMITED INSTABILITY (MORE
OF A STRATIFORM EVENT WITH EMBEDDED CONVECTIVE CELLS).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SUN MAY 3 2015

DAILY CHANCES FOR WETTING RAINS FOR MOST LOCATIONS AS A COLD FRONT
MOVE SOUTH OUT OF MONTANA AND STALLS NEAR THE LARAMIE RANGE. THIS
FRONT WILL INTERACT WITH ENERGY FROM A DISTURBANCE OVER THE FOUR
CORNERS AREA AND WILL FOCUS SHOWERS AND THUNDERSTORMS ACROSS
SOUTHEAST WYOMING. COOLER TEMPERATURES AND WETTING RAINS WILL AID
IN ONGOING GREENUP OF FUELS...SO NO FIRE WEATHER CONCERNS ARE
ANTICIPATED THROUGH MUCH OF THE UPCOMING WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC


  [top]

000
FXUS63 KUNR 030800
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
200 AM MDT SUN MAY 3 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 145 AM MDT SUN MAY 3 2015

WATER VAPOR SHOWS PRIMARILY ZONAL FLOW THROUGH THE NRN PLAINS WITH
UPPER TROF TRAVERSING SCNTRL CANADA. AT THE SFC...TROF IS PUSHING
THROUGH THE ERN DAKOTAS WITH HIGH BUILDING THROUGH MT INTO THE WRN
DAKOTAS. RADAR RETURNS SHOW A FEW -SHRA OVER SERN MT/SWRN ND.

TODAY...SFC HIGH WILL CONTINUE BUILDING SEWD PRODUCING BREEZY NLY
WINDS AND COOLER TEMPS FOR OUR CWFA. AS BL WINDS TURN MORE NE/E
LATER THIS AFTN...A FEW -SHRA/-TSRA POSSIBLE OVER NERN WY AND THE
BLKHLS ALTHOUGH INSTABILITY WILL BE LIMITED. BETTER CHANCE FOR
PCPN COMES TONIGHT ACROSS OUR WRN ZONES AS UPPER LEVEL DIVERGENCE
INCREASES IN RESPONSE TO DEPARTING JET STREAK OVER ND.

MONDAY...PCPN CHANCES WILL CONTINUE INTO THE MRNG BEFORE UPPER
ENERGY DEPARTS. SE WINDS INCREASE DURING THE DAY AS SFC HIGH
SHIFTS INTO THE UPPER MIDWEST AND LEE TROF DEVELOPS OVER MT/WY.
COULD SEE SOME ADDITIONAL SHRA/TSRA DEVELOP LATE IN THE DAY ACROSS
OUR FAR SRN ZONES AS SHORT WAVE EJECTS NEWD FROM A DESERT SW LOW.
HIGHS MOSTLY IN THE 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 145 AM MDT SUN MAY 3 2015

UPPER FLOW BECOMES SOUTHWESTERLY TUESDAY AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. A STRONG DISTURBANCE WILL
EJECT INTO THE CENTRAL/NORTHERN PLAINS...BRINGING INCREASING CHANCES
FOR PRECIPITATION. GFS AND ECM ARE STILL SHOWING MUCH OF THE PRECIP
BEGINNING TUESDAY NIGHT...WITH AROUND AN INCH OF QPF FOR MANY
LOCATIONS ACROSS WRN SD BY THURSDAY NIGHT. CYCLONIC FLOW WILL KEEP
CHANCES OF SHOWERS AND THUNDERSTORMS AROUND THROUGH NEXT
WEEKEND...AND BOTH MODELS ARE SHOWING THE MAIN UPPER LOW BECOMING
NEGATIVELY TILTED NEXT SATURDAY JUST W/SW OF THE CWA. IF THIS PANS
OUT...THIS MAIN SYSTEM COULD BRING ANOTHER INCH OR MORE OF QPF.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL BE NEAR TO SLIGHTLY
ABOVE AVERAGE...IN THE 60S TO LOWER 70S.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 145 AM MDT SUN MAY 3 2015

VFR CONDITIONS WILL PERSIST THROUGH EARLY THIS
AFTERNOON. -SHRA/-TSRA WILL DEVELOP LATER THIS AFTERNOON OVER THE
HIGHER TERRAIN AND THEN OVER NORTHEAST WY/SOUTHWEST SD TONIGHT WITH
LOCAL MVFR CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...POJORLIE



000
FXUS63 KUNR 030800
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
200 AM MDT SUN MAY 3 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 145 AM MDT SUN MAY 3 2015

WATER VAPOR SHOWS PRIMARILY ZONAL FLOW THROUGH THE NRN PLAINS WITH
UPPER TROF TRAVERSING SCNTRL CANADA. AT THE SFC...TROF IS PUSHING
THROUGH THE ERN DAKOTAS WITH HIGH BUILDING THROUGH MT INTO THE WRN
DAKOTAS. RADAR RETURNS SHOW A FEW -SHRA OVER SERN MT/SWRN ND.

TODAY...SFC HIGH WILL CONTINUE BUILDING SEWD PRODUCING BREEZY NLY
WINDS AND COOLER TEMPS FOR OUR CWFA. AS BL WINDS TURN MORE NE/E
LATER THIS AFTN...A FEW -SHRA/-TSRA POSSIBLE OVER NERN WY AND THE
BLKHLS ALTHOUGH INSTABILITY WILL BE LIMITED. BETTER CHANCE FOR
PCPN COMES TONIGHT ACROSS OUR WRN ZONES AS UPPER LEVEL DIVERGENCE
INCREASES IN RESPONSE TO DEPARTING JET STREAK OVER ND.

MONDAY...PCPN CHANCES WILL CONTINUE INTO THE MRNG BEFORE UPPER
ENERGY DEPARTS. SE WINDS INCREASE DURING THE DAY AS SFC HIGH
SHIFTS INTO THE UPPER MIDWEST AND LEE TROF DEVELOPS OVER MT/WY.
COULD SEE SOME ADDITIONAL SHRA/TSRA DEVELOP LATE IN THE DAY ACROSS
OUR FAR SRN ZONES AS SHORT WAVE EJECTS NEWD FROM A DESERT SW LOW.
HIGHS MOSTLY IN THE 60S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 145 AM MDT SUN MAY 3 2015

UPPER FLOW BECOMES SOUTHWESTERLY TUESDAY AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. A STRONG DISTURBANCE WILL
EJECT INTO THE CENTRAL/NORTHERN PLAINS...BRINGING INCREASING CHANCES
FOR PRECIPITATION. GFS AND ECM ARE STILL SHOWING MUCH OF THE PRECIP
BEGINNING TUESDAY NIGHT...WITH AROUND AN INCH OF QPF FOR MANY
LOCATIONS ACROSS WRN SD BY THURSDAY NIGHT. CYCLONIC FLOW WILL KEEP
CHANCES OF SHOWERS AND THUNDERSTORMS AROUND THROUGH NEXT
WEEKEND...AND BOTH MODELS ARE SHOWING THE MAIN UPPER LOW BECOMING
NEGATIVELY TILTED NEXT SATURDAY JUST W/SW OF THE CWA. IF THIS PANS
OUT...THIS MAIN SYSTEM COULD BRING ANOTHER INCH OR MORE OF QPF.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL BE NEAR TO SLIGHTLY
ABOVE AVERAGE...IN THE 60S TO LOWER 70S.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 145 AM MDT SUN MAY 3 2015

VFR CONDITIONS WILL PERSIST THROUGH EARLY THIS
AFTERNOON. -SHRA/-TSRA WILL DEVELOP LATER THIS AFTERNOON OVER THE
HIGHER TERRAIN AND THEN OVER NORTHEAST WY/SOUTHWEST SD TONIGHT WITH
LOCAL MVFR CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...POJORLIE




000
FXUS65 KCYS 030553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1153 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...ZF
FIRE WEATHER...SML




000
FXUS65 KCYS 030553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1153 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1148 PM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH MUCH OF THE TAF PERIOD. WINDS WILL
GENERALLY BE LESS THAN 15 KTS OVERNIGHT BUT WILL INCREASE SOME BY
LATE MORNING SUNDAY. ANOTHER ROUND OF SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER 18Z ON SUNDAY. MVFR CIGS
MAY DEVELOP BY LATE SUNDAY EVENING AT CYS.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...ZF
FIRE WEATHER...SML



000
FXUS63 KUNR 030523
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1123 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1121 PM MDT SAT MAY 2 2015

VFR CONDITIONS WILL PERSIST THROUGH EARLY SUNDAY AFTERNOON.
-SHRA/-TSRA WILL DEVELOP LATER SUNDAY AFTERNOON OVER THE HIGHER
TERRAIN AND THEN OVER NORTHEAST WY/SOUTHWEST SD SUNDAY NIGHT WITH
LOCAL MVFR CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON




000
FXUS63 KUNR 030523
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1123 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1121 PM MDT SAT MAY 2 2015

VFR CONDITIONS WILL PERSIST THROUGH EARLY SUNDAY AFTERNOON.
-SHRA/-TSRA WILL DEVELOP LATER SUNDAY AFTERNOON OVER THE HIGHER
TERRAIN AND THEN OVER NORTHEAST WY/SOUTHWEST SD SUNDAY NIGHT WITH
LOCAL MVFR CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



000
FXUS65 KRIW 030510
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A WEAK COLD FRONT WILL PUSH SOUTH ACROSS THE AREA...STALLING OUT
ALONG THE DIVIDE BY AROUND 15Z SUNDAY. IN WAKE OF THIS
FRONT...EXPECT A NORTHERLY TO EASTERLY SURFACE FLOW THRU SUNDAY
EVENING. ALTHOUGH BOUNDARY LAYER MOISTURE WILL INCREASE IN WAKE OF
THE FRONT...LOW CLOUDS ARE NOT EXPECTED SUNDAY MORNING. THE AIR MASS
WILL BE RELATIVELY STABLE FOR MUCH OF THE DAY...BUT WILL BEGIN TO
BECOME SLIGHTLY UNSTABLE AFTER 21Z SUNDAY WITH PEAK HEATING AND SOME
CONVECTION IS POSSIBLE ESPECIALLY CLOSER TO THE DIVIDE. WILL MENTION
VCTS AT KLND AND KCPR...BUT ONLY HAVE VCSH AT TERMINALS FARTHER
NORTH. THIS CONVECTION SHOULD WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ISOLATED ACTIVITY COULD LINGER PAST 06Z MONDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

A SLIGHTLY UNSTABLE ATMOSPHERE WITH ADEQUATE MOISTURE WILL ALLOW FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
AREA...MAINLY SUNDAY AFTERNOON AND EVENING. INVERTED V
SOUNDINGS...STEEP LAPSE RATES AND COOL TEMPERATURES ALOFT SUGGEST
STRONG OUTFLOW WINDS AND SMALL HAIL WILL BE THE MAIN HAZARDS. ENOUGH
COVERAGE TO MENTION VCTS AT ALL TERMINALS DURING THE AFTERNOON AND
EVENING. THE CONVECTION WILL WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ACTIVITY COULD LINGER PAST 06Z MONDAY.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...WM
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 030510
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A WEAK COLD FRONT WILL PUSH SOUTH ACROSS THE AREA...STALLING OUT
ALONG THE DIVIDE BY AROUND 15Z SUNDAY. IN WAKE OF THIS
FRONT...EXPECT A NORTHERLY TO EASTERLY SURFACE FLOW THRU SUNDAY
EVENING. ALTHOUGH BOUNDARY LAYER MOISTURE WILL INCREASE IN WAKE OF
THE FRONT...LOW CLOUDS ARE NOT EXPECTED SUNDAY MORNING. THE AIR MASS
WILL BE RELATIVELY STABLE FOR MUCH OF THE DAY...BUT WILL BEGIN TO
BECOME SLIGHTLY UNSTABLE AFTER 21Z SUNDAY WITH PEAK HEATING AND SOME
CONVECTION IS POSSIBLE ESPECIALLY CLOSER TO THE DIVIDE. WILL MENTION
VCTS AT KLND AND KCPR...BUT ONLY HAVE VCSH AT TERMINALS FARTHER
NORTH. THIS CONVECTION SHOULD WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ISOLATED ACTIVITY COULD LINGER PAST 06Z MONDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

A SLIGHTLY UNSTABLE ATMOSPHERE WITH ADEQUATE MOISTURE WILL ALLOW FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
AREA...MAINLY SUNDAY AFTERNOON AND EVENING. INVERTED V
SOUNDINGS...STEEP LAPSE RATES AND COOL TEMPERATURES ALOFT SUGGEST
STRONG OUTFLOW WINDS AND SMALL HAIL WILL BE THE MAIN HAZARDS. ENOUGH
COVERAGE TO MENTION VCTS AT ALL TERMINALS DURING THE AFTERNOON AND
EVENING. THE CONVECTION WILL WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ACTIVITY COULD LINGER PAST 06Z MONDAY.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...WM
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 030510
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A WEAK COLD FRONT WILL PUSH SOUTH ACROSS THE AREA...STALLING OUT
ALONG THE DIVIDE BY AROUND 15Z SUNDAY. IN WAKE OF THIS
FRONT...EXPECT A NORTHERLY TO EASTERLY SURFACE FLOW THRU SUNDAY
EVENING. ALTHOUGH BOUNDARY LAYER MOISTURE WILL INCREASE IN WAKE OF
THE FRONT...LOW CLOUDS ARE NOT EXPECTED SUNDAY MORNING. THE AIR MASS
WILL BE RELATIVELY STABLE FOR MUCH OF THE DAY...BUT WILL BEGIN TO
BECOME SLIGHTLY UNSTABLE AFTER 21Z SUNDAY WITH PEAK HEATING AND SOME
CONVECTION IS POSSIBLE ESPECIALLY CLOSER TO THE DIVIDE. WILL MENTION
VCTS AT KLND AND KCPR...BUT ONLY HAVE VCSH AT TERMINALS FARTHER
NORTH. THIS CONVECTION SHOULD WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ISOLATED ACTIVITY COULD LINGER PAST 06Z MONDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

A SLIGHTLY UNSTABLE ATMOSPHERE WITH ADEQUATE MOISTURE WILL ALLOW FOR
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
AREA...MAINLY SUNDAY AFTERNOON AND EVENING. INVERTED V
SOUNDINGS...STEEP LAPSE RATES AND COOL TEMPERATURES ALOFT SUGGEST
STRONG OUTFLOW WINDS AND SMALL HAIL WILL BE THE MAIN HAZARDS. ENOUGH
COVERAGE TO MENTION VCTS AT ALL TERMINALS DURING THE AFTERNOON AND
EVENING. THE CONVECTION WILL WEAKEN BY AROUND 03Z MONDAY...BUT SOME
ACTIVITY COULD LINGER PAST 06Z MONDAY.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...WM
FIRE WEATHER...C.BAKER










000
FXUS65 KCYS 022328
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
528 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 525 PM MDT SAT MAY 2 2015

VFR CONDITIONS OUTSIDE OF THUNDERSTORMS. CONVECTION SHOULD WEAKEN
AFTER SUNSET WITH ONLY A FEW LINGERING SHOWERS AND STORMS THROUGH
03Z SUN. BRIEF MVFR CIGS/VSBYS ARE STILL POSSIBLE BENEATH HEAVIER
PRECIPITATION CORES. OTHERWISE...EXPECT SCATTERED TO BROKEN CLOUD
COVERAGE AROUND 10-15K FEET AGL OVERNIGHT. SHOWERS AND STORMS ARE
EXPECTED ONCE AGAIN ON SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...CLH
FIRE WEATHER...SML




000
FXUS65 KCYS 022328
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
528 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 525 PM MDT SAT MAY 2 2015

VFR CONDITIONS OUTSIDE OF THUNDERSTORMS. CONVECTION SHOULD WEAKEN
AFTER SUNSET WITH ONLY A FEW LINGERING SHOWERS AND STORMS THROUGH
03Z SUN. BRIEF MVFR CIGS/VSBYS ARE STILL POSSIBLE BENEATH HEAVIER
PRECIPITATION CORES. OTHERWISE...EXPECT SCATTERED TO BROKEN CLOUD
COVERAGE AROUND 10-15K FEET AGL OVERNIGHT. SHOWERS AND STORMS ARE
EXPECTED ONCE AGAIN ON SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...CLH
FIRE WEATHER...SML



000
FXUS65 KCYS 022328
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
528 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 525 PM MDT SAT MAY 2 2015

VFR CONDITIONS OUTSIDE OF THUNDERSTORMS. CONVECTION SHOULD WEAKEN
AFTER SUNSET WITH ONLY A FEW LINGERING SHOWERS AND STORMS THROUGH
03Z SUN. BRIEF MVFR CIGS/VSBYS ARE STILL POSSIBLE BENEATH HEAVIER
PRECIPITATION CORES. OTHERWISE...EXPECT SCATTERED TO BROKEN CLOUD
COVERAGE AROUND 10-15K FEET AGL OVERNIGHT. SHOWERS AND STORMS ARE
EXPECTED ONCE AGAIN ON SUNDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...CLH
FIRE WEATHER...SML



000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON



000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON




000
FXUS63 KUNR 022320
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
520 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 517 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA WITH LOCAL MVFR CIGS/VSBYS WILL DISSIPATE OVER
SOUTH CENTRAL SD THIS EVENING. A FEW SHOWERS MAY BRUSH NORTHWEST
SD OVERNIGHT. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH
SUNDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...HELGESON




000
FXUS65 KCYS 022202
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
402 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...SML




000
FXUS65 KCYS 022202
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
402 PM MDT SAT MAY 2 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM MDT SAT MAY 2 2015

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER SOUTHEAST WYOMING
THIS AFTERNOON WITH SOME ACTIVITY MAKING ITS WAY INTO THE FAR
SOUTHERN NEBRASKA PANHANDLE. MOST OF THIS ACTIVITY HAS BEEN ON THE
WEAK SIDE WITH ONE STRONGER STORM NEAR PINE BLUFFS EARLIER THIS
AFTERNOON.

FOR THE REST OF THIS AFTERNOON AND EVENING A FEW MORE SHOWERS AND
THUNDERSTORMS WILL BE FOUND ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA BUT NOT ANTICIPATING ANYTHING SEVERE. COULD SEE ONE
OR TWO MORE STRONGER STORMS WITH SOME SMALL HAIL...BUT WITH
INCREASING CIRRUS BLOW OFF AND THE BOUNDARY LAYER STABILIZING FROM
PREVIOUS CONVECTION THE POTENTIAL FOR STRONGER STORMS WILL WANE
OVER THE NEXT FEW HOURS. MOST SHOWER ACTIVITY WILL DIE OFF BY MID
EVENING BUT A FEW SHOWERS COULD LINGER LATER INTO THE NIGHT.

MORE SHOWER AND THUNDERSTORM ACTIVITY WILL AGAIN OCCUR SUNDAY
AFTERNOON. COVERAGE SHOULD OVER A GREATER EXTENT AND WILL SPREAD
INTO NORTHERN PORTIONS OF THE FORECAST AREA. AGAIN THE POTENTIAL
FOR SEVERE THUNDERSTORMS WILL BE MINIMAL BUT NOT IMPOSSIBLE.
MAINLY LOOKING AT SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WITH GUSTY WINDS AND SMALL HAIL WITH SOME STRONGER THUNDERSTORMS.

MODELS HAVE TRENDED COOLER WITH UPSLOPE EASTERLY FLOW MONDAY.
COULD BE A SOGGY DAY INTO THE PLAINS WITH STRATIFORM RAIN IN THE
MORNING. MAIN CHANCES FOR AFTERNOON THUNDERSTORMS WILL BE WEST OF
THE LARAMIE RANGE BUT ANY BREAKS IN LOW CLOUD ACROSS THE PLAINS
WOULD ALLOW FOR QUICK DESTABILIZATION...LEADING TO A FEW AFTERNOON
THUNDERSTORMS. SEVERE THUNDERSTORMS ARE NOT LIKELY BUT SOME
STRONGER THUNDERSTORMS WILL BE POSSIBLE WEST OF THE LARAMIE RANGE
WITH GUSTY WINDS AND SMALL HAIL THE MAIN THREATS.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 337 PM MDT SAT MAY 2 2015

STILL LOOKS LIKE AN UNSETTLED PATTERN NEXT WEEK AS ACTIVE
SOUTHWEST FLOW PERSISTS ACROSS THE INTERMOUNTAIN WEST AHEAD OF A
DIGGING WEST COAST TROUGH. THIS WILL RESULT IN SHOWER/THUNDERSTORM
CHANCES ALL WEEK. INITIAL VORT EJECTING FROM PARENT SHORTWAVE OVR
NEW MEXICO WILL LIFT NORTHEAST THRU THE CWA. ITS CURRENT
TRAJECTORY SUGGESTS THAT WRN NE PANHANDLE SITES BE IN THE BEST
POSITION TO SEE AFTERNOON SHOWERS/STORMS. CLOUD-COVER SHOULD BE
PRETTY THICK OTHERWISE...WHICH WILL KEEP CONVECTIVE DEPTH SHALLOW
AND WEAK. THE PARENT SHORTWAVE WILL LIFT TO NR THE CO/NE/KS TRIPLE
POINT BY MIDDAY WEDNESDAY... SETTING THE STAGE FOR YET ANOTHER
ROUND OF WK CONVECTION. THAT SHORTWAVE DEPARTS SWIFTLY WEDNESDAY
NT. BOTH THE GFS/ECMWF ARE TRYING TO RESOLVE WEAK VORTS LIFTING
NORTH ONCE AGAIN IN SOUTHWEST FLOW FOR THURSDAY. HARD TO TIME THE
LOCATION AND STRENGTH OF THOSE THIS FAR OUT...BUT STILL NEED TO
KEEP CONVECTIVE CHANCES GOING. WRN US LONGWAVE TROUGH INCHES
CLOSER TO THE FOUR CORNERS FOR FRI/SAT WHICH WILL CONTINUE THE
AFTERNOON/EVENING THUNDERSTORM THREAT. DEPENDING ON TIMING THAT
THIS OCCURS...MAY NEED TO KEEP AN EYE ON SEVERE WEATHER THREAT OUT
THAT DAY. OTHERWISE...SEVERE CONCERNS WILL BE MITIGATED BY THICKER
CLOUD-COVER AND RELATIVELY COOL PBL CONDITIONS. THAT SAID...HIGH
TEMPERATURES WILL OSCILLATE BETWEEN UPPER 50S AND 60S OVR LOWER
ELEVATIONS THRU THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 314 PM MDT SAT MAY 2 2015

UNSETTLED WEATHER WILL BE THE MAIN STORY THROUGH THE UPCOMING WEEK
WITH SHOWERS AND ISOLATED THUNDERSTORMS NEARLY EVERY DAY. AN UPPER
LEVEL TROUGH WILL BE IN PLACE ACROSS THE WESTERN CONUS THROUGH THE
WEEK. COVERAGE AND STRENGTH OF SHOWERS AND THUNDERSTORMS WILL VARY
FROM DAY TO DAY AND WILL LARGELY DEPEND ON SMALLER DISTURBANCES
WHICH MAY MOVE ACROSS THE AREA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...SML



000
FXUS65 KRIW 022048
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
248 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
BRIEF MVFR CONDITIONS COULD IMPACT THE SOUTHERN AND WESTERN AIRPORTS
AS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MOVE THROUGH THROUGH
THE EARLY EVENING HOURS. A PACIFIC TROUGH WILL MOVE THROUGH
WESTERN AND CENTRAL WYOMING THIS EVENING COMBINING WITH
SUBTROPICAL MOISTURE MOVING NORTH AND EAST FROM THE GREAT BASIN.
THE COMBINATION WILL PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET...AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH
06Z SUNDAY. THE HIGHER MOUNTAINS WILL BE OBSCURED LOCALLY WITH
THE HEAVIER SHOWERS AND THUNDERSTORMS. THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY AIRPORT FOR
LOWER CEILINGS AND VISIBILITY.  ANOTHER PACIFIC TROUGH WITH MORE
MOISTURE COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED
CLOUDS AND SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS
FROM 15Z TO 18Z SUNDAY WITH ISOLATED THUNDERSTORMS AFTER 18Z.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER







000
FXUS65 KRIW 022048
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
248 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
BRIEF MVFR CONDITIONS COULD IMPACT THE SOUTHERN AND WESTERN AIRPORTS
AS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MOVE THROUGH THROUGH
THE EARLY EVENING HOURS. A PACIFIC TROUGH WILL MOVE THROUGH
WESTERN AND CENTRAL WYOMING THIS EVENING COMBINING WITH
SUBTROPICAL MOISTURE MOVING NORTH AND EAST FROM THE GREAT BASIN.
THE COMBINATION WILL PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET...AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH
06Z SUNDAY. THE HIGHER MOUNTAINS WILL BE OBSCURED LOCALLY WITH
THE HEAVIER SHOWERS AND THUNDERSTORMS. THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY AIRPORT FOR
LOWER CEILINGS AND VISIBILITY.  ANOTHER PACIFIC TROUGH WITH MORE
MOISTURE COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED
CLOUDS AND SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS
FROM 15Z TO 18Z SUNDAY WITH ISOLATED THUNDERSTORMS AFTER 18Z.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS65 KRIW 022048
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
248 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
BRIEF MVFR CONDITIONS COULD IMPACT THE SOUTHERN AND WESTERN AIRPORTS
AS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MOVE THROUGH THROUGH
THE EARLY EVENING HOURS. A PACIFIC TROUGH WILL MOVE THROUGH
WESTERN AND CENTRAL WYOMING THIS EVENING COMBINING WITH
SUBTROPICAL MOISTURE MOVING NORTH AND EAST FROM THE GREAT BASIN.
THE COMBINATION WILL PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET...AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH
06Z SUNDAY. THE HIGHER MOUNTAINS WILL BE OBSCURED LOCALLY WITH
THE HEAVIER SHOWERS AND THUNDERSTORMS. THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY AIRPORT FOR
LOWER CEILINGS AND VISIBILITY.  ANOTHER PACIFIC TROUGH WITH MORE
MOISTURE COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED
CLOUDS AND SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS
FROM 15Z TO 18Z SUNDAY WITH ISOLATED THUNDERSTORMS AFTER 18Z.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER







000
FXUS65 KRIW 022048
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
248 PM MDT SAT MAY 2 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

SOUTHERLY PUSHES OF MOISTURE WILL BRING AFTERNOON SHOWERS AND
THUNDERSTORMS THE NEXT FEW DAYS UNDER A INCREASINGLY SOUTHWEST FLOW.
COVERAGE OF STORMS WILL INCREASE THROUGH THE AFTERNOON...WITH SOME
OF THE BEST COVERAGE ANTICIPATED ACROSS SOUTHWESTERN WYOMING. AN
AREA OF LOW PRESSURE IS STILL EXPECTED TO IMPACT THE PACIFIC
NORTHWEST TUESDAY AFTERNOON...HELPING TO KEEP SHOWER ACTIVITY ACROSS
THE AREA EARLY NEXT WEEK

THIS AREA OF LOW PRESSURE WILL DIVE SOUTH THROUGH THE WEEK...LANDING
OVER THE DESERT SOUTHWEST BY THURSDAY EVENING. THIS WILL LEAVE A
STRONG SOUTH-SOUTHWESTERLY FLOW ACROSS THE AREA THROUGH MUCH OF NEXT
WEEK...AGAIN ENCOURAGING SHOWER AND THUNDERSTORM ACTIVITY.

THE MOVEMENT OF THE AREA OF LOW PRESSURE VARIES A BIT DEPENDING ON
WHICH MODEL IS USED TO DICTATE ITS PATH...THOUGH BOTH MODELS
EVENTUALLY PUSH THE SYSTEM NORTH OVER NORTHERN UTAH BY SATURDAY
MORNING. STORM COVERAGE RELATING TO THIS SYSTEM DRASTICALLY
INCREASES THROUGH SATURDAY AFTERNOON AND EVENING....WITH BASICALLY
THE ENTIRETY OF THE FORECAST AREA INCLUDED IN FORECASTED STORM
COVERAGE. THE OVERALL ADVANCEMENT OF THIS SYSTEM WILL DRAG SOME
COOLER TEMPERATURES ACROSS THE FORECAST AREA. HOWEVER...TEMPERATURES
WILL GENERALLY REMAIN SEASONABLY MILD THROUGH THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
BRIEF MVFR CONDITIONS COULD IMPACT THE SOUTHERN AND WESTERN AIRPORTS
AS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MOVE THROUGH THROUGH
THE EARLY EVENING HOURS. A PACIFIC TROUGH WILL MOVE THROUGH
WESTERN AND CENTRAL WYOMING THIS EVENING COMBINING WITH
SUBTROPICAL MOISTURE MOVING NORTH AND EAST FROM THE GREAT BASIN.
THE COMBINATION WILL PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET...AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH
06Z SUNDAY. THE HIGHER MOUNTAINS WILL BE OBSCURED LOCALLY WITH
THE HEAVIER SHOWERS AND THUNDERSTORMS. THE COVERAGE IS NOT
EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY AIRPORT FOR
LOWER CEILINGS AND VISIBILITY.  ANOTHER PACIFIC TROUGH WITH MORE
MOISTURE COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED
CLOUDS AND SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS
FROM 15Z TO 18Z SUNDAY WITH ISOLATED THUNDERSTORMS AFTER 18Z.

&&

.FIRE WEATHER...

ZONAL FLOW WILL BE OVER THE AREA THROUGH SUNDAY WITH WEAK LOW
PRESSURE TROUGHS IN THE NORTHERN BRANCH OF THE FLOW AND SUBTROPICAL
MOISTURE MOVING UP FROM THE GREAT BASIN IN THE SOUTHERN BRANCH
OF THE FLOW.  DIURNALLY DRIVEN SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS WILL RESULT LASTING INTO THE MID EVENING HOURS
AND REFORMING LATE SUNDAY MORNING AND INCREASING THROUGH THE
AFTERNOON. CLOUD COVER AND SCATTERED PRECIPITATION WILL HAVE A
COOLING EFFECT WITH SLIGHT COOLING TONIGHT AND GREATER COOLING
ON SUNDAY.  WITH MODERATE FLOW ALOFT AND CONVECTIVE CELLS MOVING
25 TO 30 MPH...WIND GUSTS TO 45 MPH WILL ACCOMPANY THE THUNDERSTORMS
ALONG WITH SMALL HAIL. MOUNTAIN AREAS ABOVE 9500 FEET SHOULD SEE
SOME LIGHT SNOW/GRAUPEL...ESPECIALLY THIS EVENING.  THE COVERAGE
OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO INCREASE SUNDAY
AFTERNOON. WITH STRONG CONVECTIVE MIXING AND MODERATE FLOW ALOFT
GOOD OR BETTER SMOKE DISPERSAL IS EXPECTED SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS63 KUNR 022022
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
222 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA ARE EXPECTED THROUGH THIS EVENING...MAINLY
ACROSS CENTRAL SD. MVFR CONDITIONS WILL BE POSSIBLE NEAR TSRA.
OTHERWISE VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...13




000
FXUS63 KUNR 022022
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
222 PM MDT SAT MAY 2 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 222 PM MDT SAT MAY 2 2015

UPPER LEVEL SHORTWAVE TROUGH NOW TRAVERSING THE NORTHERN PLAINS
WITH AN ASSOCIATED SFC TROUGH EXTENDING SOUTH ACROSS THE EASTERN
FA. DIURNAL HEATING COUPLED WITH SUFFICIENT LL MOISTURE WILL
CONTINUE TO SUPPORT ML CAPES IN EXCESS OF 1000 J/KG ALONG AND
AHEAD OF THE TROUGH...WITH ISOLD SHRA/TS EXPECTED THROUGH EVENING
THERE. A FEW STRONG STORMS WITH SMALL HAIL AND GUSTY WINDS WILL BE
POSSIBLE IN THIS PULSE ENV WITH NEGLIGIBLE DEEP LAYER SHEAR. UPPER
LEVEL JET STREAM WILL SLIDE SE ACROSS ND WITH A HIGH CENTERED WEAK
FGEN RESPONSE DEVELOPING LATE TONIGHT ACROSS THE FAR NW. HAVE
INCLUDED A LOW POP FOR THIS. OTHERWISE...DRY WX EXPECTED ACROSS
THE MAJORITY OF THE FA TONIGHT.

SUNDAY...LL FLOW WILL VEER N-E THROUGH THE DAY WITH UPSLOPE
CONVERGENT FLOW DEVELOPING OVER NE WY AND THE WESTERN BH BY
AFTERNOON. DIURNAL HEATING WILL SUPPORT WEAK INSTABILITY OVER THIS
AREA...ALLOWING ISOLD/SCT SHRA/TS WITH THE BEST CHANCES OVER THE
HIGHER TERRAIN OF THE WESTERN BH. BETTER CHANCES FOR PRECIP WILL
DEVELOP OVER THE WESTERN HALF OF THE FA SUNDAY NIGHT AS DEEPER
MOISTURE TRANSPORT ENSUES PER THE EJECTING SW CONUS UPPER LOW.
LINGERING LL BAROCLINIC ZONE IN PLACE OVER THE REGION WITH A GRAZING
NORTHERN STREAM IMPULSE WILL PROVIDE SUFFICIENT LIFT AND FORCING.
HENCE...HAVE INCREASED POPS TO HIGHER CHANCE FOR THIS AREA...WITH
THE BEST CHANCE BEING LATE SUNDAY NIGHT WITH POTENTIAL ADDED LIFT
FROM A PASSING UPPER JET STREAK. OTHERWISE..COOLER CONDS CAN BE
EXPECTED WITH HIGHS IN THE 60S NW HALF...WITH 70S SCENTRAL SD.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS ALSO
THROUGH TUESDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP
TROUGH DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO
SHOW A STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN
PLAINS WHICH WOULD BRING INCREASING CHANCES FOR
PRECIPITATION...BUT THE TIMING HAS BECOME A LITTLE FASTER INTO THE
TUE NIGHT TO WED NIGHT TIME FRAME. GFS AND ECM ARE SHOWING AROUND
AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD. NOW BOTH MODELS
ARE SHOWING THE MAIN UPPER LOW BECOMING NEGATIVELY TILTED NEXT
SATURDAY JUST W/SW OF THE CWA. IF THIS PANS OUT...THIS MAIN SYSTEM
COULD BRING ANOTHER INCH OR MORE OF QPF.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 222 PM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA ARE EXPECTED THROUGH THIS EVENING...MAINLY
ACROSS CENTRAL SD. MVFR CONDITIONS WILL BE POSSIBLE NEAR TSRA.
OTHERWISE VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...13



000
FXUS65 KCYS 021823
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1223 PM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...CAH
FIRE WEATHER...GCC




000
FXUS65 KCYS 021823
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1223 PM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...CAH
FIRE WEATHER...GCC



000
FXUS65 KCYS 021823
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1223 PM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...CAH
FIRE WEATHER...GCC




000
FXUS65 KCYS 021823
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1223 PM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1222 PM MDT SAT MAY 2 2015

A VFR AVIATION PERIOD UPCOMING INTO SUNDAY MORNING. THERE IS A
SLIGHT POSSIBILITY FOR A BRIEF PERIOD OF MVFR IN -SHRA/-TSRA THIS
AFTERNOON...BUT AM NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH/VCTS
TO THE TAFS AT THIS TIME. WINDS WILL VARY BETWEEN WEST AND
SOUTHWEST THROUGH THE PERIOD...WITH PERHAPS A FEW EXTRA GUSTS THIS
AFTERNOON AND/OR EARLY EVENING IN ANY ERRANT -SHRA/-TSRA. ANY
CONVECTION CHANCE WILL DISSIPATE WITH SUNSET.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...CAH
FIRE WEATHER...GCC



000
FXUS65 KRIW 021805
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1205 PM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z AND HELP
PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET...
AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH 03Z SUNDAY. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON. ANOTHER PACIFIC TROUGH WITH MORE MOISTURE
COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED CLOUDS AND
SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS FROM 15Z TO
18Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 021805
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1205 PM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z AND HELP
PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET...
AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH 03Z SUNDAY. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON. ANOTHER PACIFIC TROUGH WITH MORE MOISTURE
COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED CLOUDS AND
SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS FROM 15Z TO
18Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN







000
FXUS65 KRIW 021805
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1205 PM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z AND HELP
PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET...
AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH 03Z SUNDAY. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON. ANOTHER PACIFIC TROUGH WITH MORE MOISTURE
COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED CLOUDS AND
SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS FROM 15Z TO
18Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN








000
FXUS65 KRIW 021805
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1205 PM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z AND HELP
PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET...
AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS WITH WIND GUSTS TO 45KTS THROUGH 03Z SUNDAY. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON. ANOTHER PACIFIC TROUGH WITH MORE MOISTURE
COMING UP FROM THE GREAT BASIN WILL PRODUCE INCREASED CLOUDS AND
SHOWER ACTIVITY IN THE SOUTHWEST AND WESTERN MOUNTAINS FROM 15Z TO
18Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN







000
FXUS63 KUNR 021726
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1126 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

WATER VAPOR SHOWS UPPER TROF WORKING THROUGH THE PAC NW INTO THE
NRN ROCKIES EARLY THIS MRNG. AT THE SFC...AN ASSOCIATED LEE TROF
IS PUSHING INTO ERN MT/ERN WY SUPPORTING SLY BL FLOW OVER THE
CWFA.

TODAY...UPPER TROF WILL CONTINUE ITS EWD PROGRESSION...WITH SFC
TROF ADVANCING THROUGH THE WRN DAKOTAS DURING THE AFTN. MOISTURE
POOLING ALONG/AHEAD OF THIS SFC TROF WILL RESULT IN A CORRIDOR OF
NEAR 1000J/KG MLCAPE EXTENDING NWD INTO CNTRL SD. OVERALL MOISTURE
WILL BE RATHER SCANT AND MID LVL WINDS RELATIVELY LIGHT...SO
PROBABLY NOT MORE THAN A FEW PULSE TYPE STRONG STORMS IN THE LATE
AFTN/EARLY EVE. TEMPS WILL BE VERY WARM TODAY GIVEN THERMAL RIDGE
PASSING OVERHEAD...AND BEHIND THE SFC TROF DEEP MIXING AND VERY
DRY AIR WILL RESULT IN MINIMUM RELATIVE HUMIDITIES OF 10 TO 15
PERCENT...AND POSSIBLY IN THE SINGLE DIGITS OVER PARTS OF NERN WY.

SUNDAY...HIGH PRESSURE WILL BUILD INTO THE WRN DAKOTAS WITH
NOTICEABLY COOLER TEMPS AND BREEZY N/NE WINDS EXPECTED. SOME LATE
DAY STORMS POSSIBLE IN NERN WY AND THE BLKHLS GIVEN STEEP LO LEVEL
LAPSE RATES AND WEAK CYCLONIC FLOW ALOFT. BETTER CHANCE FOR
SHRA/TSRA ACRS NERN WY AND FAR WRN SD LATE SUNDAY NIGHT AS AREA
COMES UNDER INFLUENCE OF RIGHT REAR QUAD OF JET STREAK OVER ND.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 218 AM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS
EXPECTED MONDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH
DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A
STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS AND ECM
ARE SHOWING AROUND AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE END
OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1126 AM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA ARE POSSIBLE THIS AFTERNOON AND
EVENING...MAINLY ACROSS CENTRAL SD. MVFR CONDITIONS WILL BE
POSSIBLE NEAR TSRA. OTHERWISE VFR CONDITIONS EXPECTED THROUGH THE
FORECAST PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 218 AM MDT SAT MAY 2 2015

VERY WARM TEMPS COMBINED WITH DEEP MIXING WILL RESULT IN DEWPOINTS
TO DROP INTO THE 20S ACROSS NERN WY AND FAR WRN...WITH SOME TEENS
POSSIBLE OVER NERN WY AND THE BLKHLS. THIS WILL RESULT IN RELATIVE
HUMIDITIES OF 10 TO 15 PERCENT...AND POSSIBLY LOWER OVER PARTS OF
NERN WY. WINDS WILL GENERALLY BE IN THE 10 TO 20 MPH RANGE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...13
FIRE WEATHER...JOHNSON




000
FXUS63 KUNR 021726
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1126 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

WATER VAPOR SHOWS UPPER TROF WORKING THROUGH THE PAC NW INTO THE
NRN ROCKIES EARLY THIS MRNG. AT THE SFC...AN ASSOCIATED LEE TROF
IS PUSHING INTO ERN MT/ERN WY SUPPORTING SLY BL FLOW OVER THE
CWFA.

TODAY...UPPER TROF WILL CONTINUE ITS EWD PROGRESSION...WITH SFC
TROF ADVANCING THROUGH THE WRN DAKOTAS DURING THE AFTN. MOISTURE
POOLING ALONG/AHEAD OF THIS SFC TROF WILL RESULT IN A CORRIDOR OF
NEAR 1000J/KG MLCAPE EXTENDING NWD INTO CNTRL SD. OVERALL MOISTURE
WILL BE RATHER SCANT AND MID LVL WINDS RELATIVELY LIGHT...SO
PROBABLY NOT MORE THAN A FEW PULSE TYPE STRONG STORMS IN THE LATE
AFTN/EARLY EVE. TEMPS WILL BE VERY WARM TODAY GIVEN THERMAL RIDGE
PASSING OVERHEAD...AND BEHIND THE SFC TROF DEEP MIXING AND VERY
DRY AIR WILL RESULT IN MINIMUM RELATIVE HUMIDITIES OF 10 TO 15
PERCENT...AND POSSIBLY IN THE SINGLE DIGITS OVER PARTS OF NERN WY.

SUNDAY...HIGH PRESSURE WILL BUILD INTO THE WRN DAKOTAS WITH
NOTICEABLY COOLER TEMPS AND BREEZY N/NE WINDS EXPECTED. SOME LATE
DAY STORMS POSSIBLE IN NERN WY AND THE BLKHLS GIVEN STEEP LO LEVEL
LAPSE RATES AND WEAK CYCLONIC FLOW ALOFT. BETTER CHANCE FOR
SHRA/TSRA ACRS NERN WY AND FAR WRN SD LATE SUNDAY NIGHT AS AREA
COMES UNDER INFLUENCE OF RIGHT REAR QUAD OF JET STREAK OVER ND.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 218 AM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS
EXPECTED MONDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH
DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A
STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS AND ECM
ARE SHOWING AROUND AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE END
OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1126 AM MDT SAT MAY 2 2015

ISOLATED SHRA/TSRA ARE POSSIBLE THIS AFTERNOON AND
EVENING...MAINLY ACROSS CENTRAL SD. MVFR CONDITIONS WILL BE
POSSIBLE NEAR TSRA. OTHERWISE VFR CONDITIONS EXPECTED THROUGH THE
FORECAST PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 218 AM MDT SAT MAY 2 2015

VERY WARM TEMPS COMBINED WITH DEEP MIXING WILL RESULT IN DEWPOINTS
TO DROP INTO THE 20S ACROSS NERN WY AND FAR WRN...WITH SOME TEENS
POSSIBLE OVER NERN WY AND THE BLKHLS. THIS WILL RESULT IN RELATIVE
HUMIDITIES OF 10 TO 15 PERCENT...AND POSSIBLY LOWER OVER PARTS OF
NERN WY. WINDS WILL GENERALLY BE IN THE 10 TO 20 MPH RANGE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...13
FIRE WEATHER...JOHNSON



000
FXUS65 KCYS 021632
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1032 AM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 523 AM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH THE TAF PERIOD. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER AROUND 20Z ACROSS SOUTHEAST
WY. THESE STORMS WILL BE HIGH BASED WITH BRIEF GUSTY AND ERRATIC
WINDS BEING THE MAIN THREAT. THE SHOWER ACTIVITY WILL DIMINISH
AFTER SUNSET. WEST WINDS WILL GUST TO 20-25 KTS FROM LATE MORNING
THROUGH THE AFTERNOON...MAINLY ACROSS SOUTHEAST WY.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 021632
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1032 AM MDT SAT MAY 2 2015

.UPDATE...

ISSUED AT 1025 AM MDT SAT MAY 2 2015

SUNNY SKIES WILL GIVE WAY TO SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS OVER MUCH OF SOUTHEAST WYOMING THIS AFTERNOON.
ACTIVITY WILL FIRST FORM WEST OF THE LARAMIE RANGE EARLY THIS
AFTERNOON AND THEN SPILL EASTWARD INTO THE PLAINS LATER IN THE
AFTERNOON AND EARLY EVENING. EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE WILL LIKELY STAY ON THE DRY SIDE WITH
MOST SHOWER AND THUNDERSTORM ACTIVITY REMAINING TO THE SOUTH.
SEVERE THUNDERSTORM POTENTIAL IS VERY LOW TODAY. A FEW STORMS WILL
LIKELY PRODUCE GUSTY WINDS AND SMALL HAIL BUT VERY MINIMAL CHANCE
FOR LARGER HAIL.

&&

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 523 AM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH THE TAF PERIOD. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER AROUND 20Z ACROSS SOUTHEAST
WY. THESE STORMS WILL BE HIGH BASED WITH BRIEF GUSTY AND ERRATIC
WINDS BEING THE MAIN THREAT. THE SHOWER ACTIVITY WILL DIMINISH
AFTER SUNSET. WEST WINDS WILL GUST TO 20-25 KTS FROM LATE MORNING
THROUGH THE AFTERNOON...MAINLY ACROSS SOUTHEAST WY.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC




000
FXUS65 KCYS 021126
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
526 AM MDT SAT MAY 2 2015

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 523 AM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH THE TAF PERIOD. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER AROUND 20Z ACROSS SOUTHEAST
WY. THESE STORMS WILL BE HIGH BASED WITH BRIEF GUSTY AND ERRATIC
WINDS BEING THE MAIN THREAT. THE SHOWER ACTIVITY WILL DIMINISH
AFTER SUNSET. WEST WINDS WILL GUST TO 20-25 KTS FROM LATE MORNING
THROUGH THE AFTERNOON...MAINLY ACROSS SOUTHEAST WY.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 021126
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
526 AM MDT SAT MAY 2 2015

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 523 AM MDT SAT MAY 2 2015

VFR CONDITIONS THROUGH THE TAF PERIOD. ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE AFTER AROUND 20Z ACROSS SOUTHEAST
WY. THESE STORMS WILL BE HIGH BASED WITH BRIEF GUSTY AND ERRATIC
WINDS BEING THE MAIN THREAT. THE SHOWER ACTIVITY WILL DIMINISH
AFTER SUNSET. WEST WINDS WILL GUST TO 20-25 KTS FROM LATE MORNING
THROUGH THE AFTERNOON...MAINLY ACROSS SOUTHEAST WY.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC




000
FXUS65 KCYS 020918
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
318 AM MDT SAT MAY 2 2015

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC



000
FXUS65 KCYS 020918
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
318 AM MDT SAT MAY 2 2015

.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 245 AM MDT SAT MAY 2 2015

FORECAST CHALLENGES DEAL WITH PRECIP CHANCES THROUGH THE SHORT
TERM.

CURRENTLY...WATER VAPOR IMAGERY CONTINUES TO SHOW AN AREA OF LOW
PRESSURE OVER THE DESERT SOUTHWEST THIS MORNING. CONVECTION HAS
PRETTY MUCH COME TO AN END AND MOSAIC RADAR ACROSS WYOMING AND
COLORADO. AT THE SURFACE...WE ARE SEEING ANOTHER COLD FRONT
PUSHING INTO THE PACNW.

FOR TODAY...INITIALLY DRY THIS MORNING. GUIDANCE GENERALLY AGREES
THAT CONVECTION WILL BEGIN BREAKING OUT ACROSS SOUTHERN WYOMING
AFTER 18Z. BEST CHANCES APPEAR TO BE ALONG AND SOUTH OF THE I-80
CORRIDOR FROM CHEYENNE TO RAWLINS AND HAVE OUR HIGHEST POP
FORECAST FOR THIS AREA. NAM...AND TO A LESSER EXTENT THE ECMWF HAS
SOME LIGHT PRECIP CHANCES FURTHER NORTH...SO WILL KEEP SOME LOW
CHANCE POPS GOING FOR NORTH OF I-80 FOR THIS AFTERNOON.

LESS UNSTABLE TODAY OVER FRIDAY AND SEE THE STORM PREDICTION
CENTER HAS MOVED THEIR MARGINAL RISK AREA FURTHER EAST TODAY
ACROSS CENTRAL NEBRASKA...SO DO FEEL CONFIDENT THAT SEVERE
THUNDERSTORMS WILL NOT BE AN ISSUE TODAY.

CONVECTION PICKS UP AGAIN SUNDAY AFTERNOON AND BECOMES A LITTLE
MORE WIDESPREAD...ESPECIALLY WEST OF THE LARAMIE RANGE AS THE
SURFACE FRONT MOVES TO NEAR THE WYOMING/COLORADO LINE. AREAS EAST
OF THE LARAMIE RANGE WILL SEE UPSLOPING EASTERLY TO NORTHEASTERLY
WINDS THAT COULD AID IN OROGRAPHIC CONVECTION ALONG THIS SIDE OF
THE LARAMIE RANGE. DO GET A PIECE OF ENERGY OFF THE DESERT
SOUTHWEST UPPER LOW THAT TRACKS ACROSS NORTHEAST COLORADO SUNDAY
EVENING.

BETTER CHANCES FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
MONDAY AS BOUNDARY REMAINS ALONG THE LARAMIE RANGE. DIFFERENCES
SEEN BETWEEN GFS AND ECMWF ON PRECIP PLACEMENT MONDAY WITH THE
ECMWF MORE WIDESPREAD AND GFS CONFINING SHOWERS TO CARBON COUNTY.
FOR NOW...WILL GO WITH THE ECMWF SOLUTION WITH HIGH CHANCE POPS
ACROSS MUCH OF THE CWFA. BUT WE WILL NEED TO MONITOR AND
CONVECTIVE COMPLEXES THAT FORM OVER CENTRAL KANSAS. THEY COULD
REALLY CUT OFF OUR LOW LEVEL MOISTURE TRANSPORT INTO NORTHEAST
COLORADO AND EXTREME EASTERN WYOMING MONDAY AFTERNOON/EVENING.

.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 245 AM MDT SAT MAY 2 2015

PRETTY ACTIVE EXTENDED PERIOD WITH PERIODS OF PRECIP POSSIBLE.
SHORTWAVE WILL SWING NORTHEASTWARD FROM NEW MEXICO INTO NORTHEAST
COLORADO ON TUES. LLVL MOISTURE IN SOUTHEAST WINDS WILL BE
PLENTIFUL AHEAD OF THIS FEATURE WITH THE GFS SHOWING PW VALUES
APPROACHING 1 INCH ACROSS THE NEBRASKA PANHANDLE AND 0.75 INCHES
BACK TOWARD CHEYENNE. THERE IS NOT MUCH INSTABILITY PRESENT WITH
WIDESPREAD LOW CLOUDS...SO WILL LIKELY BE MORE OF A STRATIFORM
RAIN EVENT WITH EMBEDDED ISOLATED TSTMS. BOTH THE GFS AND ECMWF
ARE TARGETING AREAS TO THE EAST OF THE LARAMIE RANGE (AND
ESPECIALLY THE NE PANHANDLE) ON TUES AFTN AND EVENING...SO HAVE
THE HIGHEST POPS OUT THERE. UPPER LEVEL WAVE PUSHES INTO NEBRASKA
BY WED WITH ANOTHER GOOD CHANCE OF RAIN OVER AREAS TO THE EAST OF
THE LARAMIE RANGE. MODELS INDICATE SOME DRYING ACROSS THE PLAINS
BY THURS AS LLVL WINDS BECOME MORE WEST TO SOUTHWEST. THURS WILL
PROBABLY SEE THE LEAST COVERAGE OF STORMS...ESPECIALLY TO THE EAST
OF THE LARAMIE RANGE...SO DROPPED POPS TO 20-30 PERCENT. UPPER
LEVEL LOW IS THEN PROGGED TO CLOSE OFF OVER THE GREAT BASIN BY
FRI. SFC DEWPOINTS INCREASE ACROSS THE CWA AS WINDS TURN TO THE
SOUTHEAST AND UPPER LEVEL DIVERGENCE IS GOOD BY LATE FRI...SO HAVE
POPS BACK UP INTO THE 30-40 PERCENT RANGE. CHANCES OF STRONG TO
SVR STORMS WILL BE MINIMAL THROUGH THE LONG TERM...EXCEPT FOR
PERHAPS FRI WHEN INSTABILITY AND DEEP LAYER SHEAR ARE SUFFICIENTLY
HIGH OVER THE SOUTHERN PANHANDLE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT SAT MAY 2 2015

MINIMAL FIRE WEATHER CONCERNS FOR THE WEEKEND AND UPCOMING WEEK
AS HIGH CHANCES FOR WETTING RAINS OCCUR ON AN ALMOST DAILY BASIS.
FIRE ZONE 301 COULD SEE AFTERNOON HUMIDITIES CLOSE TO CRITICAL
TODAY...BUT WINDS SHOULD STAY BELOW CRITICAL THRESHOLDS. LOW
PRESSURE OVER THE 4 CORNERS AREA WILL CONTINUE TO SPIN PIECES OF
ENERGY NORTHEAST INTO SOUTHERN WYOMING EACH DAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...GCC
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...GCC




000
FXUS65 KRIW 020909
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
309 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.


&&

.AVIATION.../12Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...HATTINGS
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 020909
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
309 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...SANDWICHED BETWEEN
UPR LOW TO THE N...UPR HIGH TO THE S. SFC HAS WEAK SFC HIGH PRESSURE
ACROSS MUCH OF THE WRN CONUS...WITH A WEAK TROF CUTTING WY IN HALF
FROM N TO S.

TODAY...MODEST MID/UPR MOISTURE WILL INVADE THE FA FROM BOTH THE NW
AND SW ALONG WITH A COUPLE OF WEAK UPR LVL DISTURBANCES MOVING INTO
THE REGION THIS AFTERNOON/EVENING.  THIS WILL INITIATE SOME SHOWERS
AND ISOLATED THUNDER ACROSS THE SRN HALF AND NRN PORTIONS OF THE FA
AS A WEAK WARM FRONTAL BOUNDARY FORMS AND MOVES NORTH INTO CNTRL WY
FROM THE SOUTH WHILE A WEAK COLD FRONT MOVES SOUTH FROM THE NORTH. A
LITTLE STRONGER UPR LVL FORCING ACROSS THE SOUTH WILL ALLOW FOR
SOMEWHAT BETTER COVERAGE LATER THIS AFTERNOON THAN ACROSS THE NORTH
THRU THE EVENING HRS. BEST COVERAGE EXPECTED WEST OF THE DIVIDE IN
GENERAL. THIS TIME PERIOD WILL BE CHARACTERIZED BY A DRY
SFC...ELEVATED CONVECTION MOVING E AT 25 TO 35 KTS UNDER STRONG
LAPSE RATES BUT LITTLE BUOYANCY...WITH 1 TO 6 KM SHEAR RUNNING
BETWEEN 20 AND 25 KTS...ENOUGH TO KEEP STORMS SOMEWHAT
ORGANIZED...AND DCAPE RUNNING BETWEEN 500 AND 700 J/KG. DEFINITELY A
GUST FEST WITH TALLER STORMS THAT DO FORM WITH THEIR CLOUD BASES
RUNNING AROUND 8K FT OR HIGHER AND LOTS OF EVAPORATION GOING ON
BELOW. THAT SAID...MOST SHOWERS/STORMS SHOULD KEEP GUSTS BELOW
SEVERE...THE EXCEPTION BEING A COUPLE OF STORMS THAT MOVE ACROSS
MOUNTAIN RIDGE LINES WITH THE AREA IMMEDIATELY TO THE LEE OF THE
BARRIER BEING SOME WHAT SUSCEPTIBLE TO NEAR SVR GUSTS. SMALL HAIL
WILL BE POSSIBLE...BUT MAINLY ACROSS THE SRN FA WHERE THE
DYNAMICS ARE MORE FAVORABLE. VIL OF THE DAY (NON DIGITAL) FOR 1
INCH HAIL WOULD BE AROUND 45...ALTHOUGH THAT IS A LONG WAY TO
TRAVEL THROUGH RELATIVELY DRY AIR AND STILL REMAIN LARGE ENOUGH. THE
ACTION WILL SUBSIDE IN THE EVENING AS DARKNESS APPROACHES.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. ANOTHER UPR DISTURBANCE IS STILL SCHEDULED
TO ROTATE INTO THE REGION OUT OF THE SW CONUS DURING THE DAY...ALONG
W/ INCREASED MID LVL MOISTURE. BOUNDARY/FRONT TO THE S MAY STILL BE
LIFTED NWD DURING THE DAY WITH THE BEST AREA OF CONVECTIVE PRECIP
AND STRONGER FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU
MOST OF NATRONA COUNTY. THIS BOUNDARY WILL BE THE AREA TO WATCH FOR
STRONGER BRIEF STORMS OF THE DAY WITH A BETTER CHANCES FOR SMALL
HAIL...BUT LESS CHANCES FOR STRONG WIND GUSTS. FURTHER NORTH...SHEAR
WILL BE MUCH STRONGER...BUT THERMODYNAMICS WILL BE MUCH
WEAKER...WITH GENERALLY TOO MUCH SHEAR FOR THE AMOUNT OF CAPE...WITH
FAST MOVING SHOWERS COMING AND GOING. HOWEVER...WITH LCLS
SIGNIFICANTLY LOWER ACROSS THE NORTH AND ALONG THE BOUNDARY...NOT
OUT OF THE QUESTION TO GET A BRIEF SPIN-UP OF SOME KIND.

MONDAY...SOMEWHAT LESS MOISTURE THAN SUNDAY SHOULD MAKE IT AROUND
THE SRN CONUS HIGH AS INFLUENCES FROM UPSTREAM TROF BEGIN TO PUSH
MOISTURE AND THE UPR HIGH TO THE EAST A BIT. WITH STATIONARY FRONT
HANGING AROUND/THRU CNTRL WY UP AGAIN THE WIND RIVER AND ABSAROKA
MOUNTAINS AND GENERAL DEEP HIGH PRESSURE BUILDING OVR THE CNTRL
PLAINS...MOISTURE WILL GET SHUNTED WWD...WITH MOST OF THE DAY`S
ACTION WEST OF THE DIVIDE. STRONGER STORM OF THE DAY WILL RESIDE
ACROSS THE WRN MOUNTAINS...WITH GUSTY WINDS AND SMALL HAIL
POSSIBLE...BUT SHOULD BE BELOW SEVERE LIMITS.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...A PACIFIC STORM SYSTEM WILL DIG ACROSS THE NORTHWEST U.S.
INTO THE GREAT BASIN DURING THIS PERIOD BRINGING CHANCES OF SHOWERS
AND THUNDERSTORMS EACH DAY ALONG WITH AN OVERALL COOLING TREND.

DISCUSSION...MEDIUM RANGE GLOBAL MODELS HAVE COME INTO BETTER
AGREEMENT OVER THE LAST 24 HOURS WITH TWO PACIFIC SYSTEMS THAT WILL
IMPACT THE AREA DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW
NEAR 28N/137W EARLY THIS MORNING WHICH WILL BE KICKED EASTWARD BY
THE SECOND NORTHERN STREAM UPPER LOW MOVING EAST ACROSS THE GULF OF
ALASKA.   REMNANTS OF THE SUB-TROPICAL LOW ARE EXPECTED TO MOVE INTO
THE SW U.S. AND THEN LIFT NNE ACROSS THE SOUTHERN ROCKIES AND
CENTRAL HIGH PLAINS ON TUESDAY AS IT ENCOUNTERS BACKSIDE OF STRONG
RIDGE OVER THE PLAINS/SE U.S.  THIS SYSTEM WILL SPREAD SHOWERS AND
THUNDERSTORMS NORTH ACROSS THE AREA TUESDAY.  BOTH THE ECMWF AND GFS
HAVE SHIFTED SFC TROUGH AXIS A BIT FURTHER EAST TUESDAY WITH THE
HEAVIEST PRECIPITATION EXPECTED TO PUSH NORTHWARD ACROSS FAR EAST
WYOMING.  HOWEVER...MOST OF THE WEST AND CENTRAL WYOMING CAN EXPECT
AT LEAST SCATTERED SHOWER ACTIVITY THROUGH WEDNESDAY.  THERE MAY BE
A BREAK IN SHOWERS WEDNESDAY NIGHT INTO THURSDAY BETWEEN THE FIRST
SYSTEM LIFTING INTO THE NORTHERN PLAINS AND THE SECOND SYSTEM
DIGGING SOUTH ACROSS THE INTERMOUNTAIN WEST.  THIS LATTER SYSTEM IS
EXPECTED TO CUTOFF THURSDAY NIGHT OVER THE WESTERN GREAT
BASIN...GRADUALLY FILLING AND FRAGMENTING OUT AS IT WOBBLES EAST
ACROSS THE GREAT BASIN INTO THE CENTRAL ROCKIES FRIDAY AND SATURDAY.
MORE WIDESPREAD AND HEAVIER WCB PRECIPITATION IS POSSIBLE OUT AHEAD
OF THIS SYSTEM ACROSS THE AREA FRIDAY AND SATURDAY.  SNOW LEVELS ARE
EXPECTED TO REMAIN MOSTLY ABOVE 7.5KFT ON FRIDAY...POSSIBLY LOWERING
TO BETWEEN 6-7KFT ON SATURDAY.


&&

.AVIATION.../12Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

FIRE DANGER ENHANCED BUT BELOW CRITICAL TODAY AND SUNDAY AS MOISTURE
SLOWLY BEGINS TO INFILTRATE THE REGION. ELEVATED SHOWERS AND
ISOLATED THUNDERSTORMS WILL INCREASE MAINLY WEST OF THE DIVIDE BY
LATE AFTERNOON...WITH GUSTY WINDS...OCCASIONAL LIGHTNING AND SMALL
HAIL WILL BE POSSIBLE. MINIMUM RH PERCENT VALUES WILL DROP INTO
THE TEENS ACROSS THE LOWER ELEVATIONS OF CENTRAL AND NORTHERN
WYOMING...TO THE 20S TO NEAR 30 IN THE MOUNTAINS AND ACROSS THE
SOUTHERN DISPATCH ZONES. WINDS WILL INCREASE OUT OF THE WEST AT 10
TO 20 MPH FOR MANY LOCATIONS EXCEPT THE BIGHORN BASIN WHICH WILL
REMAIN ON THE LIGHTER SIDE. SUNDAY CAN BE CHARACTERIZED AS COOLER
AND MORE HUMID REGION WIDE...WITH BETTER CHANCES FOR PRECIPITATION
ACROSS THE ENTIRE FORECAST AREA. LESS WIND OVERALL THAN
TODAY...EXCEPT FOR ERRATIC WINDS UNDER/NEAR SHOWERS AND STORMS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...HATTINGS
FIRE WEATHER...BRAUN









000
FXUS63 KUNR 020831
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
231 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

WATER VAPOR SHOWS UPPER TROF WORKING THROUGH THE PAC NW INTO THE
NRN ROCKIES EARLY THIS MRNG. AT THE SFC...AN ASSOCIATED LEE TROF
IS PUSHING INTO ERN MT/ERN WY SUPPORTING SLY BL FLOW OVER THE
CWFA.

TODAY...UPPER TROF WILL CONTINUE ITS EWD PROGRESSION...WITH SFC
TROF ADVANCING THROUGH THE WRN DAKOTAS DURING THE AFTN. MOISTURE
POOLING ALONG/AHEAD OF THIS SFC TROF WILL RESULT IN A CORRIDOR OF
NEAR 1000J/KG MLCAPE EXTENDING NWD INTO CNTRL SD. OVERALL MOISTURE
WILL BE RATHER SCANT AND MID LVL WINDS RELATIVELY LIGHT...SO
PROBABLY NOT MORE THAN A FEW PULSE TYPE STRONG STORMS IN THE LATE
AFTN/EARLY EVE. TEMPS WILL BE VERY WARM TODAY GIVEN THERMAL RIDGE
PASSING OVERHEAD...AND BEHIND THE SFC TROF DEEP MIXING AND VERY
DRY AIR WILL RESULT IN MINIMUM RELATIVE HUMIDITIES OF 10 TO 15
PERCENT...AND POSSIBLY IN THE SINGLE DIGITS OVER PARTS OF NERN WY.

SUNDAY...HIGH PRESSURE WILL BUILD INTO THE WRN DAKOTAS WITH
NOTICEABLY COOLER TEMPS AND BREEZY N/NE WINDS EXPECTED. SOME LATE
DAY STORMS POSSIBLE IN NERN WY AND THE BLKHLS GIVEN STEEP LO LEVEL
LAPSE RATES AND WEAK CYCLONIC FLOW ALOFT. BETTER CHANCE FOR
SHRA/TSRA ACRS NERN WY AND FAR WRN SD LATE SUNDAY NIGHT AS AREA
COMES UNDER INFLUENCE OF RIGHT REAR QUAD OF JET STREAK OVER ND.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 218 AM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS
EXPECTED MONDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH
DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A
STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS AND ECM
ARE SHOWING AROUND AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE END
OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SATURDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EVENING...MAINLY ACROSS CENTRAL SD. COULD BE SOME
LOCAL MVFR CIGS/VSBY AND STRONG WINDS WITH THE SHOWERS/THUNDERSTORMS.

&&

.FIRE WEATHER...
ISSUED AT 218 AM MDT SAT MAY 2 2015

VERY WARM TEMPS COMBINED WITH DEEP MIXING WILL RESULT IN DEWPOINTS
TO DROP INTO THE 20S ACROSS NERN WY AND FAR WRN...WITH SOME TEENS
POSSIBLE OVER NERN WY AND THE BLKHLS. THIS WILL RESULT IN RELATIVE
HUMIDITIES OF 10 TO 15 PERCENT...AND POSSIBLY LOWER OVER PARTS OF
NERN WY. WINDS WILL GENERALLY BE IN THE 10 TO 20 MPH RANGE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...POJORLIE
FIRE WEATHER...JOHNSON




000
FXUS63 KUNR 020831
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
231 AM MDT SAT MAY 2 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

WATER VAPOR SHOWS UPPER TROF WORKING THROUGH THE PAC NW INTO THE
NRN ROCKIES EARLY THIS MRNG. AT THE SFC...AN ASSOCIATED LEE TROF
IS PUSHING INTO ERN MT/ERN WY SUPPORTING SLY BL FLOW OVER THE
CWFA.

TODAY...UPPER TROF WILL CONTINUE ITS EWD PROGRESSION...WITH SFC
TROF ADVANCING THROUGH THE WRN DAKOTAS DURING THE AFTN. MOISTURE
POOLING ALONG/AHEAD OF THIS SFC TROF WILL RESULT IN A CORRIDOR OF
NEAR 1000J/KG MLCAPE EXTENDING NWD INTO CNTRL SD. OVERALL MOISTURE
WILL BE RATHER SCANT AND MID LVL WINDS RELATIVELY LIGHT...SO
PROBABLY NOT MORE THAN A FEW PULSE TYPE STRONG STORMS IN THE LATE
AFTN/EARLY EVE. TEMPS WILL BE VERY WARM TODAY GIVEN THERMAL RIDGE
PASSING OVERHEAD...AND BEHIND THE SFC TROF DEEP MIXING AND VERY
DRY AIR WILL RESULT IN MINIMUM RELATIVE HUMIDITIES OF 10 TO 15
PERCENT...AND POSSIBLY IN THE SINGLE DIGITS OVER PARTS OF NERN WY.

SUNDAY...HIGH PRESSURE WILL BUILD INTO THE WRN DAKOTAS WITH
NOTICEABLY COOLER TEMPS AND BREEZY N/NE WINDS EXPECTED. SOME LATE
DAY STORMS POSSIBLE IN NERN WY AND THE BLKHLS GIVEN STEEP LO LEVEL
LAPSE RATES AND WEAK CYCLONIC FLOW ALOFT. BETTER CHANCE FOR
SHRA/TSRA ACRS NERN WY AND FAR WRN SD LATE SUNDAY NIGHT AS AREA
COMES UNDER INFLUENCE OF RIGHT REAR QUAD OF JET STREAK OVER ND.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 218 AM MDT SAT MAY 2 2015

NEARLY ZONAL UPPER FLOW WILL CONTINUE INTO TUESDAY WITH
NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND LOWER
70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING DAILY
CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING THE
AFTERNOON/EVENING HOURS. BREEZY SOUTHEASTERLY RETURN FLOW IS
EXPECTED MONDAY AS HIGH PRESSURE SLIDES OVER MN.

UPPER FLOW THEN BECOMES SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH
DEVELOPS OVER THE WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A
STRONG DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS AND ECM
ARE SHOWING AROUND AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE END
OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SATURDAY NIGHT
ISSUED AT 218 AM MDT SAT MAY 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY THIS
AFTERNOON. ISOLATED SHOWERS/THUNDERSTORMS ARE POSSIBLE THIS
AFTERNOON AND EVENING...MAINLY ACROSS CENTRAL SD. COULD BE SOME
LOCAL MVFR CIGS/VSBY AND STRONG WINDS WITH THE SHOWERS/THUNDERSTORMS.

&&

.FIRE WEATHER...
ISSUED AT 218 AM MDT SAT MAY 2 2015

VERY WARM TEMPS COMBINED WITH DEEP MIXING WILL RESULT IN DEWPOINTS
TO DROP INTO THE 20S ACROSS NERN WY AND FAR WRN...WITH SOME TEENS
POSSIBLE OVER NERN WY AND THE BLKHLS. THIS WILL RESULT IN RELATIVE
HUMIDITIES OF 10 TO 15 PERCENT...AND POSSIBLY LOWER OVER PARTS OF
NERN WY. WINDS WILL GENERALLY BE IN THE 10 TO 20 MPH RANGE.

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...POJORLIE
FIRE WEATHER...JOHNSON



000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020506
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1106 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1102 PM MDT FRI MAY 1 2015

PATCHY FOG WITH IFR CONDITIONS NEAR THE SOUTHERN LARAMIE RANGE
WILL PERSIST THE NEXT FEW HOURS BUT SHOULD DISSIPATE AS WEST WINDS
ERODE THE FOG. FOG WILL BE POSSIBLE AT THE KCYS TAF SITE BUT OTHER
TAF SITES WILL LIKELY NOT BE AFFECTED TONIGHT. OTHERWISE FOR
TONIGHT THROUGH TOMORROW MORNING VFR FOR MOST OF THE FORECAST
AREA. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AGAIN
DEVELOP SATURDAY AFTERNOON. GUSTY WINDS AND SMALL HAIL WILL BE
POSSIBLE WITH SOME STORMS.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 020458
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1058 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS. A
PACIFIC TROUGH WILL ENTER NORTHWEST WYOMING AFTER 18Z SATURDAY AND
HELP PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE 9500
FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN
MOUNTAINS FROM 18Z TO 05Z SUNDAY. THE HIGHER MOUNTAINS WILL BE
OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND THUNDERSTORMS. THE
COVERAGE IS NOT EXPECTED TO BE WIDESPREAD ENOUGH TO SINGLE OUT ANY
AIRPORT FOR LOWER CEILINGS AND VISIBILITY SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...HATTINGS
FIRE WEATHER...C.BAKER











000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7



000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 020444
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1044 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MDT FRI MAY 1 2015

(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH EARLY SATURDAY AFTERNOON.
ISOLATED SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING..MAINLY ACROSS CENTRAL SOUTH DAKOTA. LCL MVFR CIGS/IFR
VSBY WITH THE THUNDERSTORMS ALONG WITH STRONG WINDS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS65 KCYS 020402
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1002 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020402
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1002 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 020402
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1002 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 020402
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1002 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 959 PM MDT FRI MAY 1 2015

WE HAVE ADDED AREAS OF DENSE FOG THROUGH AROUND 1 AM FOR THE
INTERSTATE 80 SUMMIT BETWEEN LARAMIE AND CHEYENNE AS WELL AS
OVER THE WESTERN FOOTHILLS OF LARAMIE COUNTY BASED ON WEBCAMS.
WE BELIEVE THE FOG WILL QUICKLY DISSIPATE BETWEEN MIDNIGHT AND
3 AM AS THE BOUNDARY LAYER WINDS BECOME WEST.

UPDATE ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020337
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
937 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 932 PM MDT FRI MAY 1 2015

GRIDDED FORECASTS UPDATED TO REMOVE SHOWERS AND THUNDERSTORMS
FOR THE REST OF THE NIGHT AND TO ADJUST
TEMPERATURES...DEWPOINTS...WINDS AND CLOUD COVER FOR THE REST OF
THE NIGHT.

UPDATE ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 020005
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
605 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020005
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
605 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020005
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
605 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020005
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
605 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 020005
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
605 PM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 602 PM MDT FRI MAY 1 2015

OUR GRIDDED FORECASTS HAVE BEEN UPDATED PRIMARILY TO ACCOUNT
FOR SPATIAL COVERAGE OF SHOWERS AND THUNDERSTORMS...OVER
EASTERN LARAMIE COUNTY OF WYOMING...AND OVER KIMBALL AND WESTERN
CHEYENNE COUNTIES OF NEBRASKA. HAVE TOUCHED UP OTHER
METEOROLOGICAL VARIABLES FOR THE REST OF THE NIGHT BASED ON
TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.


&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...RUBIN
SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH




000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS65 KCYS 012349
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
549 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WITHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 536 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS WILL DIE OFF ACROSS FAR SOUTHEAST
WYOMING AND SOUTHERN NEBRASKA PANHANDLE OVER THE NEXT FEW HOURS.
OTHER THAN LOCAL MVFR NEAR SHOWERS AND THUNDERSTORMS MAINLY
LOOKING AT VFR THROUGH THE TAF PERIOD...ALTHOUGH PATCHY RADIATION
FOG IS POSSIBLE LATE TONIGHT WITH LIGHT WINDS. ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS SATURDAY AFTERNOON...SOME WITH GUSTY
WINDS AND SMALL HAIL.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...SML
FIRE WEATHER...CLH



000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7



000
FXUS63 KUNR 012326
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
526 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 525 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY AFTERNOON. ISOLATED
SHOWERS/THUNDERSTORMS POSSIBLE ACROSS CENTRAL SOUTH DAKOTA LATE
SATURDAY AFTERNOON.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...7




000
FXUS65 KCYS 012156
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
356 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WTIHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM MDT FRI MAY 1 2015

AVIATION CONCERNS CENTER AROUND TIMING AND PLACEMENT OF CONVECTION
THIS AFTERNOON AND EARLY EVENING...WHILE CAN ALWAYS BE A TRICKY.
ALL SITES WITH THE EXCEPTION OF KCYS WILL BEGIN THE PERIOD IN
VFR. PESKY STRATOCU DECK WILL KEEP BKN020-030 AGL IN PLACE AT KCYS
AT LEAST FOR THE NEXT HOUR OR TWO. LATEST HRRR INITIATE
-SHRA/-TSRA DEVELOPMENT ALONG THE DIFFERENTIAL HEATING AXIS (NR
THE LARAMIE RANGE W OF KCYS) BETWEEN THIS STRATOCU DECK AND THE
CLEARING TO THE WEST 20-21Z. CONFIDENCE HAS INCREASED ENOUGH TO
ADD A TEMPO -TSRA GROUP INTO KCYS. CONFIDENCE IS LOWER WEST OF
THIS AREA OF DIFFERENTIAL HEATING...SO HAVE KEPT VCTS IN KCYS.
HAVE ADDED VCTS TO THE NEBRASKA PANHANDLE SITES AS WELL LATER THIS
AFTERNOON AS WHATEVER CONVECTION DOES MANAGE TO DEVELOP TRANSLATES
EAST. IF THIS ACTIVITY DOES IMPACT AN AIRIFIELD...EXPECT MVFR
CIGS/VSBYS ALONG WITH BRIEF +RA...THE POTENTIAL FROM SMALL GS
ALONG WITH GUSTY WINDS. AM NOT CONFIDENT ENOUGH IN TIMING OR
PLACEMENT TO INCLUDE IN THE TAF...BUT WILL BE MONITORING RADAR
TRENDS CLOSELY THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...CLH



000
FXUS65 KCYS 012156
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
356 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WTIHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM MDT FRI MAY 1 2015

AVIATION CONCERNS CENTER AROUND TIMING AND PLACEMENT OF CONVECTION
THIS AFTERNOON AND EARLY EVENING...WHILE CAN ALWAYS BE A TRICKY.
ALL SITES WITH THE EXCEPTION OF KCYS WILL BEGIN THE PERIOD IN
VFR. PESKY STRATOCU DECK WILL KEEP BKN020-030 AGL IN PLACE AT KCYS
AT LEAST FOR THE NEXT HOUR OR TWO. LATEST HRRR INITIATE
-SHRA/-TSRA DEVELOPMENT ALONG THE DIFFERENTIAL HEATING AXIS (NR
THE LARAMIE RANGE W OF KCYS) BETWEEN THIS STRATOCU DECK AND THE
CLEARING TO THE WEST 20-21Z. CONFIDENCE HAS INCREASED ENOUGH TO
ADD A TEMPO -TSRA GROUP INTO KCYS. CONFIDENCE IS LOWER WEST OF
THIS AREA OF DIFFERENTIAL HEATING...SO HAVE KEPT VCTS IN KCYS.
HAVE ADDED VCTS TO THE NEBRASKA PANHANDLE SITES AS WELL LATER THIS
AFTERNOON AS WHATEVER CONVECTION DOES MANAGE TO DEVELOP TRANSLATES
EAST. IF THIS ACTIVITY DOES IMPACT AN AIRIFIELD...EXPECT MVFR
CIGS/VSBYS ALONG WITH BRIEF +RA...THE POTENTIAL FROM SMALL GS
ALONG WITH GUSTY WINDS. AM NOT CONFIDENT ENOUGH IN TIMING OR
PLACEMENT TO INCLUDE IN THE TAF...BUT WILL BE MONITORING RADAR
TRENDS CLOSELY THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...CLH



000
FXUS65 KCYS 012156
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
356 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WTIHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM MDT FRI MAY 1 2015

AVIATION CONCERNS CENTER AROUND TIMING AND PLACEMENT OF CONVECTION
THIS AFTERNOON AND EARLY EVENING...WHILE CAN ALWAYS BE A TRICKY.
ALL SITES WITH THE EXCEPTION OF KCYS WILL BEGIN THE PERIOD IN
VFR. PESKY STRATOCU DECK WILL KEEP BKN020-030 AGL IN PLACE AT KCYS
AT LEAST FOR THE NEXT HOUR OR TWO. LATEST HRRR INITIATE
-SHRA/-TSRA DEVELOPMENT ALONG THE DIFFERENTIAL HEATING AXIS (NR
THE LARAMIE RANGE W OF KCYS) BETWEEN THIS STRATOCU DECK AND THE
CLEARING TO THE WEST 20-21Z. CONFIDENCE HAS INCREASED ENOUGH TO
ADD A TEMPO -TSRA GROUP INTO KCYS. CONFIDENCE IS LOWER WEST OF
THIS AREA OF DIFFERENTIAL HEATING...SO HAVE KEPT VCTS IN KCYS.
HAVE ADDED VCTS TO THE NEBRASKA PANHANDLE SITES AS WELL LATER THIS
AFTERNOON AS WHATEVER CONVECTION DOES MANAGE TO DEVELOP TRANSLATES
EAST. IF THIS ACTIVITY DOES IMPACT AN AIRIFIELD...EXPECT MVFR
CIGS/VSBYS ALONG WITH BRIEF +RA...THE POTENTIAL FROM SMALL GS
ALONG WITH GUSTY WINDS. AM NOT CONFIDENT ENOUGH IN TIMING OR
PLACEMENT TO INCLUDE IN THE TAF...BUT WILL BE MONITORING RADAR
TRENDS CLOSELY THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...CLH



000
FXUS65 KCYS 012156
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
356 PM MDT FRI MAY 1 2015

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 354 PM MDT FRI MAY 1 2015

SHOWERS AND THUNDERSTORMS ARE ON THE UPTICK ALONG THE INTERSTATE 80
CORRIDOR IN SOUTHEAST WY THIS AFTERNOON. AS EXPECTED...THE GREATEST
COVERAGE HAS BEEN IN ALBANY IN LARAMIE COUNTIES WITH ENHANCED LOWER
LEVEL CONVERGENCE ALONG THE LARAMIE RANGE. THE KCYS RADAR LOOP ALSO
SHOWS NUMEROUS BOUNDARIES IN THE VICINITY OF CYS...LIKELY PLAYING A
ROLE IN CONVECTIVE EVOLUTION. CLOUDS CLEARED LATE THIS AM...HELPING
PUSH SFC TEMPS INTO THE 55-65 DEGREE RANGE AMID DECENT LLVL MOISTURE
WITH DEWPOINTS IN THE MID 40S F. THIS BENEATH STEEP MID LEVEL LAPSE
RATES ON THE ORDER OF 8-9 DEG C/KM IS CONTRIBUTING TO SBCAPES ON THE
ORDER OF 1500 J/KG PER THE 21Z SPC MESOANALYSIS. GFS AND NAM BUFKIT
SOUNDINGS BOTH SHOW H5 FLOW AROUND 30 KTS...WHICH COMBINED WITH GOOD
VEERING IN THE SFC-500 MILLIBAR LAYER IS CONTRIBUTING TO EFFECTIVE
BULK SHEAR VALUES FAVORABLE FOR ROTATING UPDRAFTS (35-45 KTS). COULD
SEE A HAIL THREAT EVOLVE WITH SOME CELLS...BUT DO NOT EXPECT TO SEE
MORE THAN ONE OR TWO SEVERE STORMS. OPTED TO MAINTAIN SMALL HAIL AND
GUSTY WIND WORDING IN THE OFFICIAL FORECAST. LATEST HRRR HAS CHANGED
VERY LITTLE FROM THIS MORNING...AND APPEARS TO BE ACCURATELY SHOWING
CONVECTIVE ELEMENTS BETWEEN LARAMIE AND CHEYENNE. FOR THAT REASON...
WILL MAINTAIN LIKELY POPS FOR THOSE AREAS. CONVECTIVE COVERAGE WILL
DWINDLE OVERNIGHT WITH THE LOSS OF DAYTIME HEATING/INSTABILITY.

QUASI-ZONAL FLOW ALOFT PERSISTS INTO SATURDAY. A SERIES OF MID LEVEL
DISTURBANCES WILL TRAVERSE THE FLOW OVER THE CENTRAL ROCKIES...ONCE
AGAIN PROMOTING AFTERNOON CONVECTION CHANCES. THE DAY 2 SPC OUTLOOK
HAS SHIFTED THE MARGINAL RISK EAST OF OUR CWA...WHICH MAKES SENSE AS
THE LATEST IN-HOUSE WRF PLACES THE BEST INSTABILITY AXIS EAST OF AN
ALLIANCE TO SIDNEY LINE BETWEEN 18-20Z SAT. POTENTIAL FOR WIDESPREAD
THUNDERSTORMS WILL DEPEND ON THE TIMING OF THE DRYLINE. GFS AND NAM
BOTH PUSH THIS FEATURE EAST OF THE CWA BY EARLY TO MID AFTERNOON...
BUT MODELS TEND TO MIX DRYLINES A BIT QUICKLY. LATER SHIFTS MAY NEED
TO ADJUST POPS ACCORDINGLY IF IT APPEARS THE LOW-LEVEL CONVERGENCE
ZONE WILL HANG ANY FURTHER WEST. A MUCH WARMER DAY APPEARS TO BE ON
TAP TOMORROW FOR THE PLAINS WITH WESTERLY DOWNSLOPE FLOW...AND 700
MILLIBAR TEMPS AROUND 8-10 DEG C.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 354 PM MDT FRI MAY 1 2015

THIS PERIOD WILL BE DOMINATED BY GENERALLY CONSISTENT SOUTHWEST
FLOW ACROSS THE INTERMOUNTAIN WEST AS YET ANOTHER LARGE SCALE
TROUGH IS CARVED INTO THE WRN CONUS. MOISTURE ADVECTION ALONG WITH
DIFFICULT TO TIME SHORTWAVES EMBEDDED WTIHIN THIS FLOW WILL SET
THE STAGE FOR A RELATIVELY UNSETTLED PERIOD. THIS BEGINS ON
SUNDAY/MONDAY AS WEAK SFC BOUNDARY SETTLES SOUTH ACROSS THE PLAINS
HANGING UP AROUND THE FRONT RANGE. MEANWHILE...RELATIVELY WEAK
SHORTWAVE ENERGY WILL LIFT ACROSS THIS BOUNDARY AND WHEN COMBINED
WITH WEAK INSTABILITY PROGS (SBCAPE 300- 500 J/KG) WILL PRODUCE
AFTERNOON/EVENING CONVECTION BOTH DAYS. A STRONGER EJECTING TROUGH
WILL MOVE THROUGH THE CWFA TUE/WED. BUT WITH MORE MOISTURE AND
THICKER CLOUD CANOPY...INSTABILITIES ARE PROGD TO BE LESS.
SOUTHWEST FLOW PERSISTS INTO THURSDAY WITH THE NEXT TROUGH
SWINGING OUT OF THE DEEPENING WEST COAST TROUGH FOR FRIDAY OR
FRIDAY NIGHT...DEPENDING ON THE MEDIUM RANGE GUIDANCE OF CHOICE.
ISOLATED TO SCATTERED LATE DAY SHOWERS AND THUNDERSTORMS ARE HARD
TO ARGUE WITH REALLY ANY DAY NEXT WEEK. SO HAVE KEPT PRECIP
CHANCES FAIRLY BROAD BRUSH BUT NOT WIDESPREAD NEXT WEEK. SUNDAY
WILL BE THE WARMEST DAY OF THE WEEK WITH HIGHS REACHING THE
60S/70S. HIGHS WILL FALL BACK INTO THE 60S GENERALLY MON-FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM MDT FRI MAY 1 2015

AVIATION CONCERNS CENTER AROUND TIMING AND PLACEMENT OF CONVECTION
THIS AFTERNOON AND EARLY EVENING...WHILE CAN ALWAYS BE A TRICKY.
ALL SITES WITH THE EXCEPTION OF KCYS WILL BEGIN THE PERIOD IN
VFR. PESKY STRATOCU DECK WILL KEEP BKN020-030 AGL IN PLACE AT KCYS
AT LEAST FOR THE NEXT HOUR OR TWO. LATEST HRRR INITIATE
-SHRA/-TSRA DEVELOPMENT ALONG THE DIFFERENTIAL HEATING AXIS (NR
THE LARAMIE RANGE W OF KCYS) BETWEEN THIS STRATOCU DECK AND THE
CLEARING TO THE WEST 20-21Z. CONFIDENCE HAS INCREASED ENOUGH TO
ADD A TEMPO -TSRA GROUP INTO KCYS. CONFIDENCE IS LOWER WEST OF
THIS AREA OF DIFFERENTIAL HEATING...SO HAVE KEPT VCTS IN KCYS.
HAVE ADDED VCTS TO THE NEBRASKA PANHANDLE SITES AS WELL LATER THIS
AFTERNOON AS WHATEVER CONVECTION DOES MANAGE TO DEVELOP TRANSLATES
EAST. IF THIS ACTIVITY DOES IMPACT AN AIRIFIELD...EXPECT MVFR
CIGS/VSBYS ALONG WITH BRIEF +RA...THE POTENTIAL FROM SMALL GS
ALONG WITH GUSTY WINDS. AM NOT CONFIDENT ENOUGH IN TIMING OR
PLACEMENT TO INCLUDE IN THE TAF...BUT WILL BE MONITORING RADAR
TRENDS CLOSELY THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 354 PM MDT FRI MAY 1 2015

FIRE WEATHER CONCERNS WILL BE ON THE LOW SIDE WITH DAILY CHANCES FOR
SHOWERS AND THUNDERSTORMS. WHILE ANY GIVEN STORM MAY PRODUCE GUSTY
AND ERRATIC WINDS...NO DRY LIGHTNING IS EXPECTED. AFTERNOON RELATIVE
HUMIDITY VALUES SHOULD REMAIN ABOVE 15 PERCENT.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CLH
LONG TERM...CAH
AVIATION...CAH
FIRE WEATHER...CLH



000
FXUS63 KUNR 012033
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
233 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...13



000
FXUS63 KUNR 012033
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
233 PM MDT FRI MAY 1 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 232 PM MDT FRI MAY 1 2015

UPPER LEVEL SHORTWAVE TROUGH NOW ENTERING WESTERN
MT...SUPPORTING A SFC LOW OVER THE NORTHERN PLAINS. THIS SYSTEM
WILL QUICKLY PROGRESS EAST ACROSS THE NORTHERN PLAINS IN THE
PERIOD. POS THETA-E ADV WILL REV UP TONIGHT ACROSS THE
FA...ALTHOUGH LIMITED MOISTURE WILL LIKELY KEEP ANY ELEVATED
CONVECTION AT BAY...SUPPORTING MAINLY ACCAS/VIRGA ACROSS THE
NORTHERN THIRD. SFC TROUGH/DRYLINE WILL SHIFT EAST ACROSS THE AREA
SAT MORNING...TIMING WITH PEAK HEATING OVER THE EASTERN FA. LL
MOISTURE ADVECTION...COUPLED WITH WEAK LSA/PEAK HEATING WILL
SUPPORT AN ISOLD SHRA/TS THREAT OVER THE EASTERN THIRD OF THE FA
LATE SAT AFTERNOON AND EVENING. DECENT CAPE IN EXCESS OF 1000 J/KG
WILL BE IN PLACE IN SCENTRAL SD...POSSIBLY SUPPORTING A
PULSE/STRONG STORM OR TWO. HOWEVER..DEEP LAYER SHEAR REMAINS QUITE
LOW...LESS THAN 25 KNOTS WHERE CONVECTION IS EXPECTED. WARM DAY
EXPECTED SAT...WITH HIGHS IN THE MID TO UPPER 80S ON THE SD
PLAINS...SLIGHTLY COOLER OVER NE WY AND THE BLACK HILLS.

A FEW LINGERING SHRA/TS ARE POSSIBLE OVER FAR EASTERN SCENTRAL
SD...GIVEN A DEVELOPING NOCTURNAL LLJ AHEAD OF THE LL TROUGH.
OTHERWISE...THERE IS SOME WEAK INDICATION IN FORECAST MODELS FOR
MAYBE A SHRA OVER FAR NW AREAS OVERNIGHT SAT AS AN UPPER LEVEL JET
STREAK GRAZES THE AREA. HOWEVER...LEFT THINGS DRY ATTM GIVEN
CONCERNS ON MOISTURE.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE
WESTERN CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG
DISTURBANCE EJECTING INTO THE CENTRAL/NORTHERN PLAINS WED/THU
WHICH WOULD BRING INCREASING CHANCES FOR PRECIPITATION. GFS IS
SHOWING WELL OVER AN INCH OF QPF FOR MANY LOCATIONS ACROSS WRN SD.
CYCLONIC FLOW IS EXPECTED TO CONTINUE ACROSS THE REGION FOR THE
END OF NEXT WEEK...WITH CHANCES OF PRECIP PERSISTING.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 232 PM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...13
AVIATION...13




000
FXUS65 KRIW 012032
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO
THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN
THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND 18Z SATURDAY. THE TROUGH WILL COMBINE WITH THE SUBTROPICAL
MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE
9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND
WESTERN MOUNTAINS FROM 18Z TO 00Z SUNDAY. SMALL HAIL AND STRONG
WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 012032
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO
THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN
THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND 18Z SATURDAY. THE TROUGH WILL COMBINE WITH THE SUBTROPICAL
MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE
9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND
WESTERN MOUNTAINS FROM 18Z TO 00Z SUNDAY. SMALL HAIL AND STRONG
WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS65 KRIW 012032
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO
THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN
THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND 18Z SATURDAY. THE TROUGH WILL COMBINE WITH THE SUBTROPICAL
MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE
9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND
WESTERN MOUNTAINS FROM 18Z TO 00Z SUNDAY. SMALL HAIL AND STRONG
WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 012032
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
232 PM MDT FRI MAY 1 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT WITH WARMER
TEMPERATURES. SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE
GREAT BASIN INTO THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW
PRESSURE TROUGH IN THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST
CORNER OF WYOMING AROUND NOON SATURDAY. THE NORTHERN TROUGH WILL
COMBINE WITH THE SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN
SHOWERS...POSSIBLE SNOW ABOVE 9500 FEET... AND ISOLATED
THUNDERSTORMS OVER THE SOUTHWEST AND WESTERN MOUNTAINS FROM NOON
TO 6 PM MDT. SMALL HAIL AND STRONG WIND GUSTS ARE EXPECTED WITH
THE THUNDERSTORMS. EAST OF THE CONTINENTAL DIVIDE ACROSS THE NORTH
AND EAST WILL HAVE INCREASING CLOUDS BUT THE SHOWERS AND
THUNDERSTORMS ARE NOT EXPECTED IN THESE AREAS UNTIL THE EVENING
HOURS. TEMPERATURES WILL WARM ACROSS THE AREA WITH LOCAL COOLING
WITH HEAVIER PRECIPITATION.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A SLIGHT TURN TO A SOUTHWEST FLOW PATTERN WILL LEAVE A LIGHT AMOUNT
OF MOISTURE ACROSS THE AREA SATURDAY EVENING...WITH A FEW SHOWERS
AND THUNDERSTORMS POSSIBLE. THIS FLOW PATTERN WILL CONTINUE INTO
SUNDAY...WITH SHOWERS MORE FAVORABLE ACROSS SOUTHERN WYOMING DUE TO
THE CONTINUED ZONAL FLOW PATTERN ACROSS THE NORTHER HALF OF THE
STATE. A FEW SHOWERS IS CERTAINLY NOT OUT OF THE QUESTION ACROSS THE
ENTIRETY OF THE FORECAST AREA...AS IS INDICATED IN THE CURRENT
FORECAST. THIS PATTERN CONTINUES ON MONDAY...WITH AN APPROACHING
WAVE OF LOW PRESSURE MOVING OFF THE PACIFIC COAST.

THIS WAVE WILL MOVE INTO THE INTERMOUNTAIN WEST TUESDAY...WITH A
CLOSED AREA OF LOW PRESSURE MOVING OVER THE PACIFIC NORTHWEST. THIS
AREA OF LOW PRESSURE IS EXPECTED TO MOVE SOUTH ACROSS WASHINGTON AND
INTO THE INTERMOUNTAIN WEST BY WEDNESDAY AFTERNOON...WITH SOME
MODELS INDICATING THE SYSTEM DIVING STRAIGHT SOUTH INTO THE DESERT
SOUTHWEST BY THURSDAY AFTERNOON. THIS WILL BRING IN SOME COOLER
TEMPERATURES ACROSS THE FORECAST AREA.

DEPENDING ON MODEL PREFERENCE...THE END OF THE FORECAST PERIOD CAN
VARY SIGNIFICANTLY. THE GFS PUSHES THE AREA OF LOW PRESSURE THROUGH
THE AREA WITH SHOWER COVERAGE INCREASING OVER THE AREA THROUGH THE
EARLY PART OF THE WEEKEND. HOWEVER...THE ECMWF KEEPS THE AREA OF LOW
PRESSURE OVER WESTERN HALF OF THE FORECAST AREA....THOUGH
PRECIPITATION MAY STILL SPREAD ACROSS MUCH OF THE FORECAST AREA
THROUGH FRIDAY NIGHT. TEMPERATURES WILL GENERALLY CONTINUE TO COOL
IN RESPONSE TO THIS SYSTEM THOUGH WILL REMAIN SEASONALLY MILD.

&&

.AVIATION.../00Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AT THE AIRPORTS.
ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
SUBTROPICAL MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO
THE SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN
THE PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND 18Z SATURDAY. THE TROUGH WILL COMBINE WITH THE SUBTROPICAL
MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE SNOW ABOVE
9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE SOUTHWEST AND
WESTERN MOUNTAINS FROM 18Z TO 00Z SUNDAY. SMALL HAIL AND STRONG
WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. THE HIGHER
MOUNTAINS WILL BE OBSCURED LOCALLY WITH THE HEAVIER SHOWERS AND
THUNDERSTORMS. THE COVERAGE IS NOT EXPECTED TO BE WIDESPREAD
ENOUGH TO SINGLE OUT ANY AIRPORT FOR LOWER CEILINGS AND VISIBILITY
SATURDAY AFTERNOON.

&&

.FIRE WEATHER...

ISOLATED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS SOUTHERN
SWEETWATER COUNTY WITH WIND GUSTS TO 45KTS POSSIBLE THIS EVENING.
THE REST OF THE AREA WILL BE MOSTLY CLEAR OVERNIGHT.  SUBTROPICAL
MOISTURE WILL MOVE NORTHEAST FROM THE GREAT BASIN INTO THE
SOUTHWEST BY EARLY MORNING. A PACIFIC LOW PRESSURE TROUGH IN THE
PACIFIC NORTHWEST WILL ENTER THE NORTHWEST CORNER OF WYOMING
AROUND NOON SATURDAY. THE TROUGH WILL COMBINE WITH THE
SUBTROPICAL MOISTURE TO PRODUCE SCATTERED RAIN SHOWERS...POSSIBLE
SNOW ABOVE 9500 FEET... AND ISOLATED THUNDERSTORMS OVER THE
SOUTHWEST AND WESTERN MOUNTAINS FROM NOON TO 6 PM MDT. SMALL HAIL AND
STRONG WIND GUSTS ARE EXPECTED WITH THE THUNDERSTORMS. EAST OF THE
CONTINENTAL DIVIDE ACROSS THE NORTH AND EAST WILL HAVE INCREASING
CLOUDS BUT THE SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED IN THESE
AREAS UNTIL THE EVENING HOURS. TEMPERATURES WILL WARM ACROSS THE
AREA WITH LOCAL COOLING WITH HEAVIER PRECIPITATION. TRANSPORT
WINDS AND MIXING HEIGHTS WILL COMBINE FOR GOOD TO BETTER SMOKE
DISPERSAL SATURDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...C.BAKER
LONG TERM...BRANHAM
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS65 KRIW 011816
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1216 PM MDT FRI MAY 1 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...WITH EXITING WEAK SW
TROF TO THE E AND ACROSS THE NRN AND CNTRL PLAINS...HIGH PRESSURE
RIDGE OVR THE SW CONUS. SFC HAS WEAK SFC HIGH PRESSURE ACROSS MUCH
OF THE WRN CONUS...LOWER PRESSURE UNDER THE HIGH IN THE DESERT
SW.

TODAY...DRYING AND WARMING WILL RULE BEHIND THURSDAY`S
SYSTEM...WITH MOST OF THE FA REMAINING DRY AND MOSTLY SUNNY UNDER
INCREASINGLY ZONAL FLOW ALOFT. VERY SLIGHT CHC THAT A WEAK STALLED
FRONT DRIFTING AROUND THE BORDER AREA WITH COLORADO THIS AFTERNOON
COULD TRIGGER A SHOWER OR TWO OVR THE SRN PORTION OF THE CWA.
SAT...A MODEST AREA OF MOISTURE ALONG WITH AN UPR LVL DISTURBANCE
ROTATING INTO THE REGION AROUND AN UPR LVL HIGH OVR THE SRN
CONUS...WILL INITIATE SOME SHOWERS AND ISOLATED THUNDER ACROSS
MAINLY THE SRN HALF OF THE FA LATER IN THE AFTERNOON. A SECONDARY
AREA OF SHOWERS WILL ALSO FORM OVR THE NRN FA SAT NIGHT AS A
MODEST CLIPPER TYPE FRONT MOVES THRU THE NRN AND NERN ZONES.
AGAIN...LITTLE MOISTURE AND LOW INSTABILITY WITH PRECLUDE MUCH IN
THE WAY OF SIGNIFICANT PRECIP.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. AN UPR DISTURBANCE WILL ROTATE INTO THE
REGION OUT OF THE SW CONUS FROM THE S DURING THE DAY...ALONG W/
INCREASED MID LVL MOISTURE. FRONT MAY BE LIFTED NWD DURING THE DAY
WITH SOME LOW P DEVELOPMENT OVR THE SW WITH BEST AREA OF PRECIP
FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU MOST OF
NATRONA COUNTY. THIS WILL ALSO BE THE REGION WHERE BETTER...ALBEIT
WEAK...SHEAR WILL OCCUR. SO...CLOUDY SKIES WITH RAIN SHOWERS AND
ISOLATED THUNDER WILL RULE THE DAY ACROSS THE SW HALF OF THE
FA...WHERE HIGH LAPSE RATES BUT LOW BUOYANCY WILL BE FOUND. MORE
CLOUDY THAN SHOWERY TO THE NE...WHERE BOTH DECENT LAPSE RATES OR
BUOYANCY WILL BE HARDER TO FIND...AND MORE TERRAIN FORCED
PRECIP/CONVECTION IS EXPECTED.

.LONG TERM...MONDAY THROUGH FRIDAY

SYNOPSIS...A TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE AREA
TUESDAY AND WEDNESDAY BRINGING INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS ALONG WITH COOLER TEMPERATURES. THIS COOL AND
UNSETTLED PATTERN MAY PERSIST THROUGH FRIDAY.

DISCUSSION...TWO PACIFIC SYSTEMS WILL BE THE MAIN WEATHER MAKERS
DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW NEAR 30N/135W
EARLY THIS MORNING AND THE SECOND IS A NORTHERN STREAM LOW MOVING
ALONG 50N...JUST SOUTH OF THE ALEUTIAN CHAIN.  BY MONDAY
MORNING...THE NORTHERN STREAM SYSTEM WILL PROGRESS TO NEAR VANCOUVER
ISLAND...KICKING THE SOUTHERN SYSTEM INTO SOUTHERN CALIFORNIA.
THIS LATTER SOUTHERN STREAM SYSTEM IS THEN FORECAST TO TRACK ENE
ACROSS THE SOUTHERN ROCKIES TUESDAY...LIFTING INTO THE CENTRAL HIGH
PLAINS ON WEDNESDAY.  THERE IS GOOD OVERALL AGREEMENT AMONG
MEDIUM-RANGE GUIDANCE WITH THIS DEPICTION.  THE MAIN PROBLEM
CONTINUES TO BE WHERE THE NORTHERN STREAM KICKER WILL GO.  30/12Z
ECMWF AND GFS WERE IN BETTER AGREEMENT DIGGING AT LEAST A GOOD CHUNK
OF THIS ENERGY SOUTH ACROSS THE WESTERN U.S. AS IT MAKES LANDFALL
TUESDAY.  ECMWF...AFTER HINTING AT THIS IDEA 12 HOURS AGO...HAS
REVERTED BACK TO A MORE PROGRESSIVE TROUGH PUSHING ACROSS THE
CANADIAN ROCKIES WEDNESDAY.  LATEST GFS/GEFS MEAN SHOW A CLOSED LOW
NEAR RENO BY 00Z THURSDAY...THE CANADIAN HAS THE CLOSED LOW A BIT
FURTHER NORTH.  FORECAST SIDES WITH THE GFS/CANADIAN RUNS THAT SHOW
BETTER RUN-TO-RUN CONSISTENCY.

SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO SPREAD UP FROM THE SOUTH
ON MONDAY WITH SOME HINT OF SOME ENERGY FRAGMENTING FROM BAJA LOW
INTO THE AREA...COMBINING WITH LOW LEVEL ESE FLOW EAST OF THE
DIVIDE.  THE BEST CHANCE OF STORMS WILL BE ACROSS THE SOUTH AND EAST
WITH A FEW STRONG STORMS POSSIBLE MAINLY OVER NATRONA COUNTY.

MORE ABUNDANT MOISTURE WILL ADVECT INTO THE AREA TUESDAY AND
WEDNESDAY AS MAIN BAJA LOW LIFTS SOUTH AND EAST OF THE AREA.  MORE
CLOUD COVER...SHOWER AND THUNDERSTORM ACTIVITY WILL RESULT IN COOLER
TEMPERATURES BY WEDNESDAY.

IN THE THURSDAY TIMEFRAME...SOMEWHAT OF A BREAK IN PRECIPITATION IS
SHOWN BETWEEN THE BAJA LOW LIFTING OUT OF THE AREA AND THE UPPER LOW
DIGGING INTO THE INTERMOUNTAIN WEST...BUT CONFIDENCE IS LOW IN THESE
DETAILS.  THE BIGGER PICTURE OF A CLOSED LOW WOBBLING ACROSS THE
GREAT BASIN LATE IN THE WEEK WARRANTS KEEPING CHANCES OF
PRECIPITATION IN THROUGH THE END OF THE WEEK AND CONTINUING AN
OVERALL COOLING TREND.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL OCCUR THROUGH 18Z SATURDAY. ISOLATED SHOWERS OR STORMS
WILL DEVELOP IN FAR SOUTHERN WY AND ALONG THE UTAH/COLORADO
BORDERS FROM 21Z THROUGH 18Z SATURDAY. THIS ACTIVITY IS EXPECTED
TO STAY SOUTH OF THE KRKS AIRPORT.

.FIRE WEATHER...

FIRE DANGER BELOW CRITICAL TODAY AND FRIDAY WITH
WARM AND DRY CONDITIONS AND MOSTLY SUNNY SKIES. MINIMUM RH PERCENT
VALUES WILL DROP INTO THE TEENS ACROSS THE LOWER ELEVATIONS TO 20S
IN THE MOUNTAINS. TODAY...HOWEVER...WINDS WILL BE LIGHT AT LESS THAN
15 MPH FOR MOST LOCATIONS. SATURDAY WILL SEE SOME INCREASE IN WINDS
ACROSS THE SOUTHERN AND WESTERN DISPATCH ZONES...BUT ALSO MORE
CLOUD...HUMIDITY...AND PRECIPITATION CHANCES ACROSS THESE SAME
AREAS. SUNDAY CAN BE CHARACTERIZED AS COOLER AND MORE HUMID AREA
WIDE...WITH SOME CHANCE FOR PRECIPITATION ACROSS THE ENTIRE FORECAST
AREA.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN






000
FXUS65 KRIW 011816
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1216 PM MDT FRI MAY 1 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...WITH EXITING WEAK SW
TROF TO THE E AND ACROSS THE NRN AND CNTRL PLAINS...HIGH PRESSURE
RIDGE OVR THE SW CONUS. SFC HAS WEAK SFC HIGH PRESSURE ACROSS MUCH
OF THE WRN CONUS...LOWER PRESSURE UNDER THE HIGH IN THE DESERT
SW.

TODAY...DRYING AND WARMING WILL RULE BEHIND THURSDAY`S
SYSTEM...WITH MOST OF THE FA REMAINING DRY AND MOSTLY SUNNY UNDER
INCREASINGLY ZONAL FLOW ALOFT. VERY SLIGHT CHC THAT A WEAK STALLED
FRONT DRIFTING AROUND THE BORDER AREA WITH COLORADO THIS AFTERNOON
COULD TRIGGER A SHOWER OR TWO OVR THE SRN PORTION OF THE CWA.
SAT...A MODEST AREA OF MOISTURE ALONG WITH AN UPR LVL DISTURBANCE
ROTATING INTO THE REGION AROUND AN UPR LVL HIGH OVR THE SRN
CONUS...WILL INITIATE SOME SHOWERS AND ISOLATED THUNDER ACROSS
MAINLY THE SRN HALF OF THE FA LATER IN THE AFTERNOON. A SECONDARY
AREA OF SHOWERS WILL ALSO FORM OVR THE NRN FA SAT NIGHT AS A
MODEST CLIPPER TYPE FRONT MOVES THRU THE NRN AND NERN ZONES.
AGAIN...LITTLE MOISTURE AND LOW INSTABILITY WITH PRECLUDE MUCH IN
THE WAY OF SIGNIFICANT PRECIP.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. AN UPR DISTURBANCE WILL ROTATE INTO THE
REGION OUT OF THE SW CONUS FROM THE S DURING THE DAY...ALONG W/
INCREASED MID LVL MOISTURE. FRONT MAY BE LIFTED NWD DURING THE DAY
WITH SOME LOW P DEVELOPMENT OVR THE SW WITH BEST AREA OF PRECIP
FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU MOST OF
NATRONA COUNTY. THIS WILL ALSO BE THE REGION WHERE BETTER...ALBEIT
WEAK...SHEAR WILL OCCUR. SO...CLOUDY SKIES WITH RAIN SHOWERS AND
ISOLATED THUNDER WILL RULE THE DAY ACROSS THE SW HALF OF THE
FA...WHERE HIGH LAPSE RATES BUT LOW BUOYANCY WILL BE FOUND. MORE
CLOUDY THAN SHOWERY TO THE NE...WHERE BOTH DECENT LAPSE RATES OR
BUOYANCY WILL BE HARDER TO FIND...AND MORE TERRAIN FORCED
PRECIP/CONVECTION IS EXPECTED.

.LONG TERM...MONDAY THROUGH FRIDAY

SYNOPSIS...A TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE AREA
TUESDAY AND WEDNESDAY BRINGING INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS ALONG WITH COOLER TEMPERATURES. THIS COOL AND
UNSETTLED PATTERN MAY PERSIST THROUGH FRIDAY.

DISCUSSION...TWO PACIFIC SYSTEMS WILL BE THE MAIN WEATHER MAKERS
DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW NEAR 30N/135W
EARLY THIS MORNING AND THE SECOND IS A NORTHERN STREAM LOW MOVING
ALONG 50N...JUST SOUTH OF THE ALEUTIAN CHAIN.  BY MONDAY
MORNING...THE NORTHERN STREAM SYSTEM WILL PROGRESS TO NEAR VANCOUVER
ISLAND...KICKING THE SOUTHERN SYSTEM INTO SOUTHERN CALIFORNIA.
THIS LATTER SOUTHERN STREAM SYSTEM IS THEN FORECAST TO TRACK ENE
ACROSS THE SOUTHERN ROCKIES TUESDAY...LIFTING INTO THE CENTRAL HIGH
PLAINS ON WEDNESDAY.  THERE IS GOOD OVERALL AGREEMENT AMONG
MEDIUM-RANGE GUIDANCE WITH THIS DEPICTION.  THE MAIN PROBLEM
CONTINUES TO BE WHERE THE NORTHERN STREAM KICKER WILL GO.  30/12Z
ECMWF AND GFS WERE IN BETTER AGREEMENT DIGGING AT LEAST A GOOD CHUNK
OF THIS ENERGY SOUTH ACROSS THE WESTERN U.S. AS IT MAKES LANDFALL
TUESDAY.  ECMWF...AFTER HINTING AT THIS IDEA 12 HOURS AGO...HAS
REVERTED BACK TO A MORE PROGRESSIVE TROUGH PUSHING ACROSS THE
CANADIAN ROCKIES WEDNESDAY.  LATEST GFS/GEFS MEAN SHOW A CLOSED LOW
NEAR RENO BY 00Z THURSDAY...THE CANADIAN HAS THE CLOSED LOW A BIT
FURTHER NORTH.  FORECAST SIDES WITH THE GFS/CANADIAN RUNS THAT SHOW
BETTER RUN-TO-RUN CONSISTENCY.

SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO SPREAD UP FROM THE SOUTH
ON MONDAY WITH SOME HINT OF SOME ENERGY FRAGMENTING FROM BAJA LOW
INTO THE AREA...COMBINING WITH LOW LEVEL ESE FLOW EAST OF THE
DIVIDE.  THE BEST CHANCE OF STORMS WILL BE ACROSS THE SOUTH AND EAST
WITH A FEW STRONG STORMS POSSIBLE MAINLY OVER NATRONA COUNTY.

MORE ABUNDANT MOISTURE WILL ADVECT INTO THE AREA TUESDAY AND
WEDNESDAY AS MAIN BAJA LOW LIFTS SOUTH AND EAST OF THE AREA.  MORE
CLOUD COVER...SHOWER AND THUNDERSTORM ACTIVITY WILL RESULT IN COOLER
TEMPERATURES BY WEDNESDAY.

IN THE THURSDAY TIMEFRAME...SOMEWHAT OF A BREAK IN PRECIPITATION IS
SHOWN BETWEEN THE BAJA LOW LIFTING OUT OF THE AREA AND THE UPPER LOW
DIGGING INTO THE INTERMOUNTAIN WEST...BUT CONFIDENCE IS LOW IN THESE
DETAILS.  THE BIGGER PICTURE OF A CLOSED LOW WOBBLING ACROSS THE
GREAT BASIN LATE IN THE WEEK WARRANTS KEEPING CHANCES OF
PRECIPITATION IN THROUGH THE END OF THE WEEK AND CONTINUING AN
OVERALL COOLING TREND.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL OCCUR THROUGH 18Z SATURDAY. ISOLATED SHOWERS OR STORMS
WILL DEVELOP IN FAR SOUTHERN WY AND ALONG THE UTAH/COLORADO
BORDERS FROM 21Z THROUGH 18Z SATURDAY. THIS ACTIVITY IS EXPECTED
TO STAY SOUTH OF THE KRKS AIRPORT.

.FIRE WEATHER...

FIRE DANGER BELOW CRITICAL TODAY AND FRIDAY WITH
WARM AND DRY CONDITIONS AND MOSTLY SUNNY SKIES. MINIMUM RH PERCENT
VALUES WILL DROP INTO THE TEENS ACROSS THE LOWER ELEVATIONS TO 20S
IN THE MOUNTAINS. TODAY...HOWEVER...WINDS WILL BE LIGHT AT LESS THAN
15 MPH FOR MOST LOCATIONS. SATURDAY WILL SEE SOME INCREASE IN WINDS
ACROSS THE SOUTHERN AND WESTERN DISPATCH ZONES...BUT ALSO MORE
CLOUD...HUMIDITY...AND PRECIPITATION CHANCES ACROSS THESE SAME
AREAS. SUNDAY CAN BE CHARACTERIZED AS COOLER AND MORE HUMID AREA
WIDE...WITH SOME CHANCE FOR PRECIPITATION ACROSS THE ENTIRE FORECAST
AREA.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN






000
FXUS65 KRIW 011816
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1216 PM MDT FRI MAY 1 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT

IMAGERY SHOWING NEAR ZONAL FLOW ALOFT OVR WY...WITH EXITING WEAK SW
TROF TO THE E AND ACROSS THE NRN AND CNTRL PLAINS...HIGH PRESSURE
RIDGE OVR THE SW CONUS. SFC HAS WEAK SFC HIGH PRESSURE ACROSS MUCH
OF THE WRN CONUS...LOWER PRESSURE UNDER THE HIGH IN THE DESERT
SW.

TODAY...DRYING AND WARMING WILL RULE BEHIND THURSDAY`S
SYSTEM...WITH MOST OF THE FA REMAINING DRY AND MOSTLY SUNNY UNDER
INCREASINGLY ZONAL FLOW ALOFT. VERY SLIGHT CHC THAT A WEAK STALLED
FRONT DRIFTING AROUND THE BORDER AREA WITH COLORADO THIS AFTERNOON
COULD TRIGGER A SHOWER OR TWO OVR THE SRN PORTION OF THE CWA.
SAT...A MODEST AREA OF MOISTURE ALONG WITH AN UPR LVL DISTURBANCE
ROTATING INTO THE REGION AROUND AN UPR LVL HIGH OVR THE SRN
CONUS...WILL INITIATE SOME SHOWERS AND ISOLATED THUNDER ACROSS
MAINLY THE SRN HALF OF THE FA LATER IN THE AFTERNOON. A SECONDARY
AREA OF SHOWERS WILL ALSO FORM OVR THE NRN FA SAT NIGHT AS A
MODEST CLIPPER TYPE FRONT MOVES THRU THE NRN AND NERN ZONES.
AGAIN...LITTLE MOISTURE AND LOW INSTABILITY WITH PRECLUDE MUCH IN
THE WAY OF SIGNIFICANT PRECIP.

SUNDAY...FRONT THRU THE FA E OF THE DIVIDE WITH SHALLOW UPSLOPE
UNDER WESTERLIES ALOFT. AN UPR DISTURBANCE WILL ROTATE INTO THE
REGION OUT OF THE SW CONUS FROM THE S DURING THE DAY...ALONG W/
INCREASED MID LVL MOISTURE. FRONT MAY BE LIFTED NWD DURING THE DAY
WITH SOME LOW P DEVELOPMENT OVR THE SW WITH BEST AREA OF PRECIP
FORCING OCCURRING BETWEEN ROCK SPRINGS...TO THE NE THRU MOST OF
NATRONA COUNTY. THIS WILL ALSO BE THE REGION WHERE BETTER...ALBEIT
WEAK...SHEAR WILL OCCUR. SO...CLOUDY SKIES WITH RAIN SHOWERS AND
ISOLATED THUNDER WILL RULE THE DAY ACROSS THE SW HALF OF THE
FA...WHERE HIGH LAPSE RATES BUT LOW BUOYANCY WILL BE FOUND. MORE
CLOUDY THAN SHOWERY TO THE NE...WHERE BOTH DECENT LAPSE RATES OR
BUOYANCY WILL BE HARDER TO FIND...AND MORE TERRAIN FORCED
PRECIP/CONVECTION IS EXPECTED.

.LONG TERM...MONDAY THROUGH FRIDAY

SYNOPSIS...A TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE AREA
TUESDAY AND WEDNESDAY BRINGING INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS ALONG WITH COOLER TEMPERATURES. THIS COOL AND
UNSETTLED PATTERN MAY PERSIST THROUGH FRIDAY.

DISCUSSION...TWO PACIFIC SYSTEMS WILL BE THE MAIN WEATHER MAKERS
DURING THIS PERIOD.  THE FIRST IS A SUB-TROPICAL LOW NEAR 30N/135W
EARLY THIS MORNING AND THE SECOND IS A NORTHERN STREAM LOW MOVING
ALONG 50N...JUST SOUTH OF THE ALEUTIAN CHAIN.  BY MONDAY
MORNING...THE NORTHERN STREAM SYSTEM WILL PROGRESS TO NEAR VANCOUVER
ISLAND...KICKING THE SOUTHERN SYSTEM INTO SOUTHERN CALIFORNIA.
THIS LATTER SOUTHERN STREAM SYSTEM IS THEN FORECAST TO TRACK ENE
ACROSS THE SOUTHERN ROCKIES TUESDAY...LIFTING INTO THE CENTRAL HIGH
PLAINS ON WEDNESDAY.  THERE IS GOOD OVERALL AGREEMENT AMONG
MEDIUM-RANGE GUIDANCE WITH THIS DEPICTION.  THE MAIN PROBLEM
CONTINUES TO BE WHERE THE NORTHERN STREAM KICKER WILL GO.  30/12Z
ECMWF AND GFS WERE IN BETTER AGREEMENT DIGGING AT LEAST A GOOD CHUNK
OF THIS ENERGY SOUTH ACROSS THE WESTERN U.S. AS IT MAKES LANDFALL
TUESDAY.  ECMWF...AFTER HINTING AT THIS IDEA 12 HOURS AGO...HAS
REVERTED BACK TO A MORE PROGRESSIVE TROUGH PUSHING ACROSS THE
CANADIAN ROCKIES WEDNESDAY.  LATEST GFS/GEFS MEAN SHOW A CLOSED LOW
NEAR RENO BY 00Z THURSDAY...THE CANADIAN HAS THE CLOSED LOW A BIT
FURTHER NORTH.  FORECAST SIDES WITH THE GFS/CANADIAN RUNS THAT SHOW
BETTER RUN-TO-RUN CONSISTENCY.

SHOWERS AND THUNDERSTORMS SHOULD BEGIN TO SPREAD UP FROM THE SOUTH
ON MONDAY WITH SOME HINT OF SOME ENERGY FRAGMENTING FROM BAJA LOW
INTO THE AREA...COMBINING WITH LOW LEVEL ESE FLOW EAST OF THE
DIVIDE.  THE BEST CHANCE OF STORMS WILL BE ACROSS THE SOUTH AND EAST
WITH A FEW STRONG STORMS POSSIBLE MAINLY OVER NATRONA COUNTY.

MORE ABUNDANT MOISTURE WILL ADVECT INTO THE AREA TUESDAY AND
WEDNESDAY AS MAIN BAJA LOW LIFTS SOUTH AND EAST OF THE AREA.  MORE
CLOUD COVER...SHOWER AND THUNDERSTORM ACTIVITY WILL RESULT IN COOLER
TEMPERATURES BY WEDNESDAY.

IN THE THURSDAY TIMEFRAME...SOMEWHAT OF A BREAK IN PRECIPITATION IS
SHOWN BETWEEN THE BAJA LOW LIFTING OUT OF THE AREA AND THE UPPER LOW
DIGGING INTO THE INTERMOUNTAIN WEST...BUT CONFIDENCE IS LOW IN THESE
DETAILS.  THE BIGGER PICTURE OF A CLOSED LOW WOBBLING ACROSS THE
GREAT BASIN LATE IN THE WEEK WARRANTS KEEPING CHANCES OF
PRECIPITATION IN THROUGH THE END OF THE WEEK AND CONTINUING AN
OVERALL COOLING TREND.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS WILL OCCUR THROUGH 18Z SATURDAY. ISOLATED SHOWERS OR STORMS
WILL DEVELOP IN FAR SOUTHERN WY AND ALONG THE UTAH/COLORADO
BORDERS FROM 21Z THROUGH 18Z SATURDAY. THIS ACTIVITY IS EXPECTED
TO STAY SOUTH OF THE KRKS AIRPORT.

.FIRE WEATHER...

FIRE DANGER BELOW CRITICAL TODAY AND FRIDAY WITH
WARM AND DRY CONDITIONS AND MOSTLY SUNNY SKIES. MINIMUM RH PERCENT
VALUES WILL DROP INTO THE TEENS ACROSS THE LOWER ELEVATIONS TO 20S
IN THE MOUNTAINS. TODAY...HOWEVER...WINDS WILL BE LIGHT AT LESS THAN
15 MPH FOR MOST LOCATIONS. SATURDAY WILL SEE SOME INCREASE IN WINDS
ACROSS THE SOUTHERN AND WESTERN DISPATCH ZONES...BUT ALSO MORE
CLOUD...HUMIDITY...AND PRECIPITATION CHANCES ACROSS THESE SAME
AREAS. SUNDAY CAN BE CHARACTERIZED AS COOLER AND MORE HUMID AREA
WIDE...WITH SOME CHANCE FOR PRECIPITATION ACROSS THE ENTIRE FORECAST
AREA.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...BRAUN
LONG TERM...AEM
AVIATION...C.BAKER
FIRE WEATHER...BRAUN







000
FXUS63 KUNR 011736
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1136 AM MDT FRI MAY 1 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 152 AM MDT FRI MAY 1 2015

AREA OF CONVECTION HAS PUSHED EAST OF SCNTRL SD EARLY THIS MRNG
WITH SFC HIGH BUILDING INTO WRN SD. THIS IS BRINGING CLEARING
SKIES TO THE CWFA. NEXT UPPER TROF IS PUSHING THROUGH THE PAC NW.

TODAY...MOSTLY CLEAR SKIES WITH HIGHS WARMING WELL INTO THE 70S ON
THE PLAINS. RETURN FLOW WILL DEVELOP AS SFC HIGH SHIFTS INTO CNTRL/ERN
SD.

SATURDAY...UPPER TROF AXIS WORKS THROUGH THE NRN ROCKIES WITH SFC
TROF PUSHING THROUGH THE WRN DAKOTAS. THERMAL RIDGE ALONG WITH
DRY W/SW LO LEVEL FLOW WILL HELP PUSH TEMPS INTO THE
80S...ESPECIALLY EAST OF THE BLKHLS. COULD SEE SOME AFTN TSTMS
ALONG/AHEAD OF THE SFC TROF ACROSS CNTRL SD WHERE MLCAPE UP TO
1000J/KG WILL EXIST. MID LEVEL FLOW LOOKS TOO WEAK TO SUPPORT MORE
THAN A FEW STRONG TO MARGINALLY SVR STORMS.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 152 AM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE WESTERN
CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG DISTURBANCE EJECTING
INTO THE CENTRAL/NORTHERN PLAINS WED/THU WHICH WOULD BRING
INCREASING CHANCES FOR PRECIPITATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1136 AM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...13



000
FXUS63 KUNR 011736
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1136 AM MDT FRI MAY 1 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 152 AM MDT FRI MAY 1 2015

AREA OF CONVECTION HAS PUSHED EAST OF SCNTRL SD EARLY THIS MRNG
WITH SFC HIGH BUILDING INTO WRN SD. THIS IS BRINGING CLEARING
SKIES TO THE CWFA. NEXT UPPER TROF IS PUSHING THROUGH THE PAC NW.

TODAY...MOSTLY CLEAR SKIES WITH HIGHS WARMING WELL INTO THE 70S ON
THE PLAINS. RETURN FLOW WILL DEVELOP AS SFC HIGH SHIFTS INTO CNTRL/ERN
SD.

SATURDAY...UPPER TROF AXIS WORKS THROUGH THE NRN ROCKIES WITH SFC
TROF PUSHING THROUGH THE WRN DAKOTAS. THERMAL RIDGE ALONG WITH
DRY W/SW LO LEVEL FLOW WILL HELP PUSH TEMPS INTO THE
80S...ESPECIALLY EAST OF THE BLKHLS. COULD SEE SOME AFTN TSTMS
ALONG/AHEAD OF THE SFC TROF ACROSS CNTRL SD WHERE MLCAPE UP TO
1000J/KG WILL EXIST. MID LEVEL FLOW LOOKS TOO WEAK TO SUPPORT MORE
THAN A FEW STRONG TO MARGINALLY SVR STORMS.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 152 AM MDT FRI MAY 1 2015

FLOW ALOFT WILL BE NEARLY ZONAL SUNDAY THROUGH TUESDAY
WITH NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES IN THE 60S AND
LOWER 70S. SEVERAL DISTURBANCES EMBEDDED IN THE FLOW WILL BRING
NEARLY DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS...ESPECIALLY
DURING THE AFTERNOON/EVENING HOURS. UPPER FLOW THEN BECOMES
SOUTHWESTERLY BY MID WEEK AS A DEEP TROUGH DEVELOPS OVER THE WESTERN
CONUS. BOTH GFS/ECMWF CONTINUE TO SHOW A STRONG DISTURBANCE EJECTING
INTO THE CENTRAL/NORTHERN PLAINS WED/THU WHICH WOULD BRING
INCREASING CHANCES FOR PRECIPITATION.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1136 AM MDT FRI MAY 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...POJORLIE
AVIATION...13




000
FXUS65 KCYS 011734
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1134 AM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 1048 AM MDT FRI MAY 1 2015

AREA WEBCAMS AND VISIBLE SATELLITE IMAGERY SHOW FOG AND/OR LOW
STRATUS RAPIDLY DIMINISHING ACROSS PORTIONS OF CARBON AND ALBANY
COUNTIES THIS AM. CLOUD COVER HAS BEEN SLOW TO ERODE OVER THE CO
FRONT RANGE WITH WEAK LLVL UPSLOPE...BUT CLOUDS ARE THINNING AND
LLVL MIXING SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES AS WE
HEAD INTO THE AFTERNOON. OUR ATTENTION THEN SHIFTS TO CONVECTIVE
POTENTIAL LATER TODAY. FORCING IS NOT AS PRONOUNCED AS PREVIOUS
DAYS...BUT INSTABILITY SHOULD BE THERE WITH STEEP MIDLEVEL LAPSE
RATES AND GOOD LLVL MOISTURE WITH SURFACE DEWPOINTS IN THE MID
40S. IF WE CAN BREAK OUT OF THE CLOUDS...OUR LOCAL WRF SUGGESTS
SBCAPE NEAR 750-1000 J/KG. 0-6KM SHEAR VECTORS ARE WESTERLY AT
AROUND 40 KTS...SUPPORTING POTENTIAL FOR ROTATING UPDRAFTS AND
HAIL PRODUCTION. THE HRRR INITIATES CONVECTION AROUND 20Z OVER
ALBANY AND LARAMIE COUNTIES...SO WENT AHEAD AND INCREASED POPS
INTO THE LIKELY CATEGORY. ALSO ADDED SMALL HAIL AND GUSTY WINDS
GIVEN THE THERMODYNAMIC/KINEMATIC ENVIRONMENT. WE COULD HAVE A
SEVERE STORM OR TWO...BUT OPTED NOT TO MENTION IN THE GRIDS AS
UNCERTAINTIES REMAIN WITH HOW CLOUDS WILL IMPACT COVERAGE OF
STRONGER STORMS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)

ISSUED AT 300 AM MDT FRI MAY 1 2015

PATTERN WILL BE CHARACTERIZED BY A ZONAL FLOW ALOFT WITH SEVERAL
WEAK IMPULSES PASSING ACROSS THE CWA IN THIS FLOW PATTERN. A SFC
BOUNDARY WILL REMAIN BANKED UP ALONG THE HIGHER TERRAIN OF SE
WYOMING TODAY BEFORE ERODING EASTWARD OVERNIGHT INTO SATURDAY.
THIS BOUNDARY SHOULD INTERACT WITH THESE WEAK DISTURBANCES AND
SOME INSTABILITY TO PRODUCE SCTD SHOWERS AND A FEW STORMS MAINLY
OVER SE WYOMING TODAY. CAPE VALUES RANGE FROM ABOUT 500-1000J/KG
AGAINST THE LARAMIE RANGE THIS AFTERNOON BUT SHEAR VALUES RATHER
LOW SO A FEW STRONGER STORMS POSSIBLE. ACTIVITY SHOULD MOVE
OUT/DISSIPATE THIS EVENING LEAVING A QUIET NIGHT TONIGHT. MORE OF
THE SAME EXPECTED FOR SATURDAY AND SUNDAY EXCEPT AFTERNOON AND
EVENING CONVECTION SHOULD MAKE MORE PROGRESS EASTWARD AS THE SFC
BOUNDARY SHIFTS EAST. CAPE VALUES MUCH LESS OVERALL EXCEPT OVER
PARTS OF THE PANHANDLE WHERE THEY EXCEED 1500 J/KG LATE IN THE
MORNING BEFORE SHIFTING EAST OF THE CWA. WARMER TEMPS FOR SATURDAY
THEN THE NEXT COOL FRONT WILL PASS ACROSS EARLY SUNDAY RESULTING
IN ABOUT 5-15 DEGREES OF COOLING...GREATEST OVER THE PANHANDLE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI MAY 1 2015

MUCH OF THE LONG TERM REMAINS UNSETTLED AS GUIDANCE CONTINUES TO
SHOW ALMOST DAILY PRECIP CHANCES OVER THE CWFA.

AREA REMAINS UNDER EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW SUNDAY
NIGHT INTO MONDAY AS A SURFACE HIGH OVER WESTERN SOUTH DAKOTA
REMAINS NEARLY STATIONARY.

EACH DAY THERE LOOKS TO BE PIECES OF ENERGY BEING DRAWN NORTH INTO
THE AREA FROM THE DESERT SOUTHWEST THAT INTERACTS WITH A BOUNDARY
THAT IS STALLED ALONG THE LARAMIE RANGE. MONDAY
AFTERNOON...CONVECTION IS CONCENTRATED MAINLY ACROSS OUR WESTERN
ZONES...BUT AS THE LOW PRESSURE SYSTEM MOVES INTO COLORADO
TUESDAY...OUR EASTERN ZONES GET SOME PRETTY GOOD RAINFALL. BEST
PRECIP CHANCES APPEAR TO BE ALONG THE WYOMING/COLORADO BORDER
ALONG INTERSTATE 80.

UPPER LOW SLOW TO MOVE OUT OF COLORADO AND WE SHOULD SEE
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY ACROSS
THE ENTIRE CWFA. FINALLY BY THURSDAY...UPPER LOW MOVES NORTHEAST
INTO THE DAKOTAS. NOT MUCH OF A BREAK IN PRECIP THOUGH AS A SECOND
SHORTWAVE MOVES IN BEHIND THIS ONE FOR FRIDAY. AREA WILL CONTINUE
TO SEE ABOVE NORMAL CHANCES FOR MUCH NEEDED RAINFALL INTO THE END
OF THE WEEK.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1134 AM MDT FRI MAY 1 2015

AVIATION CONCERNS CENTER AROUND TIMING AND PLACEMENT OF CONVECTION
THIS AFTERNOON AND EARLY EVENING...WHILE CAN ALWAYS BE A TRICKY.
ALL SITES WITH THE EXCEPTION OF KCYS WILL BEGIN THE PERIOD IN
VFR. PESKY STRATOCU DECK WILL KEEP BKN020-030 AGL IN PLACE AT KCYS
AT LEAST FOR THE NEXT HOUR OR TWO. LATEST HRRR INITIATE
-SHRA/-TSRA DEVELOPMENT ALONG THE DIFFERENTIAL HEATING AXIS (NR
THE LARAMIE RANGE W OF KCYS) BETWEEN THIS STRATOCU DECK AND THE
CLEARING TO THE WEST 20-21Z. CONFIDENCE HAS INCREASED ENOUGH TO
ADD A TEMPO -TSRA GROUP INTO KCYS. CONFIDENCE IS LOWER WEST OF
THIS AREA OF DIFFERENTIAL HEATING...SO HAVE KEPT VCTS IN KCYS.
HAVE ADDED VCTS TO THE NEBRASKA PANHANDLE SITES AS WELL LATER THIS
AFTERNOON AS WHATEVER CONVECTION DOES MANAGE TO DEVELOP TRANSLATES
EAST. IF THIS ACTIVITY DOES IMPACT AN AIRIFIELD...EXPECT MVFR
CIGS/VSBYS ALONG WITH BRIEF +RA...THE POTENTIAL FROM SMALL GS
ALONG WITH GUSTY WINDS. AM NOT CONFIDENT ENOUGH IN TIMING OR
PLACEMENT TO INCLUDE IN THE TAF...BUT WILL BE MONITORING RADAR
TRENDS CLOSELY THIS AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT FRI MAY 1 2015

CONCERNS TO REMAIN LOW THROUGH THE WEEKEND INTO EARLY NEXT WEEK
WITH NEARLY DAILY CHANCES FOR SHOWERS AND A FEW STORMS...BUT NO
DRY LIGHTNING.  WEATHER FACTORS REMAINING NON-CRITICAL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...CLH
SHORT TERM...RE
LONG TERM...GCC
AVIATION...CAH
FIRE WEATHER...RE




000
FXUS65 KCYS 011717
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1117 AM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 1048 AM MDT FRI MAY 1 2015

AREA WEBCAMS AND VISIBLE SATELLITE IMAGERY SHOW FOG AND/OR LOW
STRATUS RAPIDLY DIMINISHING ACROSS PORTIONS OF CARBON AND ALBANY
COUNTIES THIS AM. CLOUD COVER HAS BEEN SLOW TO ERODE OVER THE CO
FRONT RANGE WITH WEAK LLVL UPSLOPE...BUT CLOUDS ARE THINNING AND
LLVL MIXING SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES AS WE
HEAD INTO THE AFTERNOON. OUR ATTENTION THEN SHIFTS TO CONVECTIVE
POTENTIAL LATER TODAY. FORCING IS NOT AS PRONOUNCED AS PREVIOUS
DAYS...BUT INSTABILITY SHOULD BE THERE WITH STEEP MIDLEVEL LAPSE
RATES AND GOOD LLVL MOISTURE WITH SURFACE DEWPOINTS IN THE MID
40S. IF WE CAN BREAK OUT OF THE CLOUDS...OUR LOCAL WRF SUGGESTS
SBCAPE NEAR 750-1000 J/KG. 0-6KM SHEAR VECTORS ARE WESTERLY AT
AROUND 40 KTS...SUPPORTING POTENTIAL FOR ROTATING UPDRAFTS AND
HAIL PRODUCTION. THE HRRR INITIATES CONVECTION AROUND 20Z OVER
ALBANY AND LARAMIE COUNTIES...SO WENT AHEAD AND INCREASED POPS
INTO THE LIKELY CATEGORY. ALSO ADDED SMALL HAIL AND GUSTY WINDS
GIVEN THE THERMODYNAMIC/KINEMATIC ENVIRONMENT. WE COULD HAVE A
SEVERE STORM OR TWO...BUT OPTED NOT TO MENTION IN THE GRIDS AS
UNCERTAINTIES REMAIN WITH HOW CLOUDS WILL IMPACT COVERAGE OF
STRONGER STORMS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)

ISSUED AT 300 AM MDT FRI MAY 1 2015

PATTERN WILL BE CHARACTERIZED BY A ZONAL FLOW ALOFT WITH SEVERAL
WEAK IMPULSES PASSING ACROSS THE CWA IN THIS FLOW PATTERN. A SFC
BOUNDARY WILL REMAIN BANKED UP ALONG THE HIGHER TERRAIN OF SE
WYOMING TODAY BEFORE ERODING EASTWARD OVERNIGHT INTO SATURDAY.
THIS BOUNDARY SHOULD INTERACT WITH THESE WEAK DISTURBANCES AND
SOME INSTABILITY TO PRODUCE SCTD SHOWERS AND A FEW STORMS MAINLY
OVER SE WYOMING TODAY. CAPE VALUES RANGE FROM ABOUT 500-1000J/KG
AGAINST THE LARAMIE RANGE THIS AFTERNOON BUT SHEAR VALUES RATHER
LOW SO A FEW STRONGER STORMS POSSIBLE. ACTIVITY SHOULD MOVE
OUT/DISSIPATE THIS EVENING LEAVING A QUIET NIGHT TONIGHT. MORE OF
THE SAME EXPECTED FOR SATURDAY AND SUNDAY EXCEPT AFTERNOON AND
EVENING CONVECTION SHOULD MAKE MORE PROGRESS EASTWARD AS THE SFC
BOUNDARY SHIFTS EAST. CAPE VALUES MUCH LESS OVERALL EXCEPT OVER
PARTS OF THE PANHANDLE WHERE THEY EXCEED 1500 J/KG LATE IN THE
MORNING BEFORE SHIFTING EAST OF THE CWA. WARMER TEMPS FOR SATURDAY
THEN THE NEXT COOL FRONT WILL PASS ACROSS EARLY SUNDAY RESULTING
IN ABOUT 5-15 DEGREES OF COOLING...GREATEST OVER THE PANHANDLE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI MAY 1 2015

MUCH OF THE LONG TERM REMAINS UNSETTLED AS GUIDANCE CONTINUES TO
SHOW ALMOST DAILY PRECIP CHANCES OVER THE CWFA.

AREA REMAINS UNDER EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW SUNDAY
NIGHT INTO MONDAY AS A SURFACE HIGH OVER WESTERN SOUTH DAKOTA
REMAINS NEARLY STATIONARY.

EACH DAY THERE LOOKS TO BE PIECES OF ENERGY BEING DRAWN NORTH INTO
THE AREA FROM THE DESERT SOUTHWEST THAT INTERACTS WITH A BOUNDARY
THAT IS STALLED ALONG THE LARAMIE RANGE. MONDAY
AFTERNOON...CONVECTION IS CONCENTRATED MAINLY ACROSS OUR WESTERN
ZONES...BUT AS THE LOW PRESSURE SYSTEM MOVES INTO COLORADO
TUESDAY...OUR EASTERN ZONES GET SOME PRETTY GOOD RAINFALL. BEST
PRECIP CHANCES APPEAR TO BE ALONG THE WYOMING/COLORADO BORDER
ALONG INTERSTATE 80.

UPPER LOW SLOW TO MOVE OUT OF COLORADO AND WE SHOULD SEE
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY ACROSS
THE ENTIRE CWFA. FINALLY BY THURSDAY...UPPER LOW MOVES NORTHEAST
INTO THE DAKOTAS. NOT MUCH OF A BREAK IN PRECIP THOUGH AS A SECOND
SHORTWAVE MOVES IN BEHIND THIS ONE FOR FRIDAY. AREA WILL CONTINUE
TO SEE ABOVE NORMAL CHANCES FOR MUCH NEEDED RAINFALL INTO THE END
OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 647 AM MDT FRI MAY 1 2015

PATCHY FOG AND LOW CLOUDS RESIDE WEST OF THE LARAMIE RANGE THIS
MORNING. KRWL DOWN NOW IN STRATUS THAT IS EXPECTED TO CONTINUE
UNTIL 15Z OR SO. MVFR CONDITIONS HERE AT KCYS SHOULD IMPROVE BY
MID MORNING WITH HEATING. AFTERNOON CONVECTION FOR KCYS...KLAR AND
POSSIBLY THE SOUTHERN PANHANDLE AIRPORTS.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT FRI MAY 1 2015

CONCERNS TO REMAIN LOW THROUGH THE WEEKEND INTO EARLY NEXT WEEK
WITH NEARLY DAILY CHANCES FOR SHOWERS AND A FEW STORMS...BUT NO
DRY LIGHTNING.  WEATHER FACTORS REMAINING NON-CRITICAL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...CLH
SHORT TERM...RE
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RE



000
FXUS65 KCYS 011717
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1117 AM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 1048 AM MDT FRI MAY 1 2015

AREA WEBCAMS AND VISIBLE SATELLITE IMAGERY SHOW FOG AND/OR LOW
STRATUS RAPIDLY DIMINISHING ACROSS PORTIONS OF CARBON AND ALBANY
COUNTIES THIS AM. CLOUD COVER HAS BEEN SLOW TO ERODE OVER THE CO
FRONT RANGE WITH WEAK LLVL UPSLOPE...BUT CLOUDS ARE THINNING AND
LLVL MIXING SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES AS WE
HEAD INTO THE AFTERNOON. OUR ATTENTION THEN SHIFTS TO CONVECTIVE
POTENTIAL LATER TODAY. FORCING IS NOT AS PRONOUNCED AS PREVIOUS
DAYS...BUT INSTABILITY SHOULD BE THERE WITH STEEP MIDLEVEL LAPSE
RATES AND GOOD LLVL MOISTURE WITH SURFACE DEWPOINTS IN THE MID
40S. IF WE CAN BREAK OUT OF THE CLOUDS...OUR LOCAL WRF SUGGESTS
SBCAPE NEAR 750-1000 J/KG. 0-6KM SHEAR VECTORS ARE WESTERLY AT
AROUND 40 KTS...SUPPORTING POTENTIAL FOR ROTATING UPDRAFTS AND
HAIL PRODUCTION. THE HRRR INITIATES CONVECTION AROUND 20Z OVER
ALBANY AND LARAMIE COUNTIES...SO WENT AHEAD AND INCREASED POPS
INTO THE LIKELY CATEGORY. ALSO ADDED SMALL HAIL AND GUSTY WINDS
GIVEN THE THERMODYNAMIC/KINEMATIC ENVIRONMENT. WE COULD HAVE A
SEVERE STORM OR TWO...BUT OPTED NOT TO MENTION IN THE GRIDS AS
UNCERTAINTIES REMAIN WITH HOW CLOUDS WILL IMPACT COVERAGE OF
STRONGER STORMS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)

ISSUED AT 300 AM MDT FRI MAY 1 2015

PATTERN WILL BE CHARACTERIZED BY A ZONAL FLOW ALOFT WITH SEVERAL
WEAK IMPULSES PASSING ACROSS THE CWA IN THIS FLOW PATTERN. A SFC
BOUNDARY WILL REMAIN BANKED UP ALONG THE HIGHER TERRAIN OF SE
WYOMING TODAY BEFORE ERODING EASTWARD OVERNIGHT INTO SATURDAY.
THIS BOUNDARY SHOULD INTERACT WITH THESE WEAK DISTURBANCES AND
SOME INSTABILITY TO PRODUCE SCTD SHOWERS AND A FEW STORMS MAINLY
OVER SE WYOMING TODAY. CAPE VALUES RANGE FROM ABOUT 500-1000J/KG
AGAINST THE LARAMIE RANGE THIS AFTERNOON BUT SHEAR VALUES RATHER
LOW SO A FEW STRONGER STORMS POSSIBLE. ACTIVITY SHOULD MOVE
OUT/DISSIPATE THIS EVENING LEAVING A QUIET NIGHT TONIGHT. MORE OF
THE SAME EXPECTED FOR SATURDAY AND SUNDAY EXCEPT AFTERNOON AND
EVENING CONVECTION SHOULD MAKE MORE PROGRESS EASTWARD AS THE SFC
BOUNDARY SHIFTS EAST. CAPE VALUES MUCH LESS OVERALL EXCEPT OVER
PARTS OF THE PANHANDLE WHERE THEY EXCEED 1500 J/KG LATE IN THE
MORNING BEFORE SHIFTING EAST OF THE CWA. WARMER TEMPS FOR SATURDAY
THEN THE NEXT COOL FRONT WILL PASS ACROSS EARLY SUNDAY RESULTING
IN ABOUT 5-15 DEGREES OF COOLING...GREATEST OVER THE PANHANDLE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI MAY 1 2015

MUCH OF THE LONG TERM REMAINS UNSETTLED AS GUIDANCE CONTINUES TO
SHOW ALMOST DAILY PRECIP CHANCES OVER THE CWFA.

AREA REMAINS UNDER EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW SUNDAY
NIGHT INTO MONDAY AS A SURFACE HIGH OVER WESTERN SOUTH DAKOTA
REMAINS NEARLY STATIONARY.

EACH DAY THERE LOOKS TO BE PIECES OF ENERGY BEING DRAWN NORTH INTO
THE AREA FROM THE DESERT SOUTHWEST THAT INTERACTS WITH A BOUNDARY
THAT IS STALLED ALONG THE LARAMIE RANGE. MONDAY
AFTERNOON...CONVECTION IS CONCENTRATED MAINLY ACROSS OUR WESTERN
ZONES...BUT AS THE LOW PRESSURE SYSTEM MOVES INTO COLORADO
TUESDAY...OUR EASTERN ZONES GET SOME PRETTY GOOD RAINFALL. BEST
PRECIP CHANCES APPEAR TO BE ALONG THE WYOMING/COLORADO BORDER
ALONG INTERSTATE 80.

UPPER LOW SLOW TO MOVE OUT OF COLORADO AND WE SHOULD SEE
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY ACROSS
THE ENTIRE CWFA. FINALLY BY THURSDAY...UPPER LOW MOVES NORTHEAST
INTO THE DAKOTAS. NOT MUCH OF A BREAK IN PRECIP THOUGH AS A SECOND
SHORTWAVE MOVES IN BEHIND THIS ONE FOR FRIDAY. AREA WILL CONTINUE
TO SEE ABOVE NORMAL CHANCES FOR MUCH NEEDED RAINFALL INTO THE END
OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 647 AM MDT FRI MAY 1 2015

PATCHY FOG AND LOW CLOUDS RESIDE WEST OF THE LARAMIE RANGE THIS
MORNING. KRWL DOWN NOW IN STRATUS THAT IS EXPECTED TO CONTINUE
UNTIL 15Z OR SO. MVFR CONDITIONS HERE AT KCYS SHOULD IMPROVE BY
MID MORNING WITH HEATING. AFTERNOON CONVECTION FOR KCYS...KLAR AND
POSSIBLY THE SOUTHERN PANHANDLE AIRPORTS.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT FRI MAY 1 2015

CONCERNS TO REMAIN LOW THROUGH THE WEEKEND INTO EARLY NEXT WEEK
WITH NEARLY DAILY CHANCES FOR SHOWERS AND A FEW STORMS...BUT NO
DRY LIGHTNING.  WEATHER FACTORS REMAINING NON-CRITICAL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...CLH
SHORT TERM...RE
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RE




000
FXUS65 KCYS 011717
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1117 AM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 1048 AM MDT FRI MAY 1 2015

AREA WEBCAMS AND VISIBLE SATELLITE IMAGERY SHOW FOG AND/OR LOW
STRATUS RAPIDLY DIMINISHING ACROSS PORTIONS OF CARBON AND ALBANY
COUNTIES THIS AM. CLOUD COVER HAS BEEN SLOW TO ERODE OVER THE CO
FRONT RANGE WITH WEAK LLVL UPSLOPE...BUT CLOUDS ARE THINNING AND
LLVL MIXING SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES AS WE
HEAD INTO THE AFTERNOON. OUR ATTENTION THEN SHIFTS TO CONVECTIVE
POTENTIAL LATER TODAY. FORCING IS NOT AS PRONOUNCED AS PREVIOUS
DAYS...BUT INSTABILITY SHOULD BE THERE WITH STEEP MIDLEVEL LAPSE
RATES AND GOOD LLVL MOISTURE WITH SURFACE DEWPOINTS IN THE MID
40S. IF WE CAN BREAK OUT OF THE CLOUDS...OUR LOCAL WRF SUGGESTS
SBCAPE NEAR 750-1000 J/KG. 0-6KM SHEAR VECTORS ARE WESTERLY AT
AROUND 40 KTS...SUPPORTING POTENTIAL FOR ROTATING UPDRAFTS AND
HAIL PRODUCTION. THE HRRR INITIATES CONVECTION AROUND 20Z OVER
ALBANY AND LARAMIE COUNTIES...SO WENT AHEAD AND INCREASED POPS
INTO THE LIKELY CATEGORY. ALSO ADDED SMALL HAIL AND GUSTY WINDS
GIVEN THE THERMODYNAMIC/KINEMATIC ENVIRONMENT. WE COULD HAVE A
SEVERE STORM OR TWO...BUT OPTED NOT TO MENTION IN THE GRIDS AS
UNCERTAINTIES REMAIN WITH HOW CLOUDS WILL IMPACT COVERAGE OF
STRONGER STORMS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)

ISSUED AT 300 AM MDT FRI MAY 1 2015

PATTERN WILL BE CHARACTERIZED BY A ZONAL FLOW ALOFT WITH SEVERAL
WEAK IMPULSES PASSING ACROSS THE CWA IN THIS FLOW PATTERN. A SFC
BOUNDARY WILL REMAIN BANKED UP ALONG THE HIGHER TERRAIN OF SE
WYOMING TODAY BEFORE ERODING EASTWARD OVERNIGHT INTO SATURDAY.
THIS BOUNDARY SHOULD INTERACT WITH THESE WEAK DISTURBANCES AND
SOME INSTABILITY TO PRODUCE SCTD SHOWERS AND A FEW STORMS MAINLY
OVER SE WYOMING TODAY. CAPE VALUES RANGE FROM ABOUT 500-1000J/KG
AGAINST THE LARAMIE RANGE THIS AFTERNOON BUT SHEAR VALUES RATHER
LOW SO A FEW STRONGER STORMS POSSIBLE. ACTIVITY SHOULD MOVE
OUT/DISSIPATE THIS EVENING LEAVING A QUIET NIGHT TONIGHT. MORE OF
THE SAME EXPECTED FOR SATURDAY AND SUNDAY EXCEPT AFTERNOON AND
EVENING CONVECTION SHOULD MAKE MORE PROGRESS EASTWARD AS THE SFC
BOUNDARY SHIFTS EAST. CAPE VALUES MUCH LESS OVERALL EXCEPT OVER
PARTS OF THE PANHANDLE WHERE THEY EXCEED 1500 J/KG LATE IN THE
MORNING BEFORE SHIFTING EAST OF THE CWA. WARMER TEMPS FOR SATURDAY
THEN THE NEXT COOL FRONT WILL PASS ACROSS EARLY SUNDAY RESULTING
IN ABOUT 5-15 DEGREES OF COOLING...GREATEST OVER THE PANHANDLE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI MAY 1 2015

MUCH OF THE LONG TERM REMAINS UNSETTLED AS GUIDANCE CONTINUES TO
SHOW ALMOST DAILY PRECIP CHANCES OVER THE CWFA.

AREA REMAINS UNDER EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW SUNDAY
NIGHT INTO MONDAY AS A SURFACE HIGH OVER WESTERN SOUTH DAKOTA
REMAINS NEARLY STATIONARY.

EACH DAY THERE LOOKS TO BE PIECES OF ENERGY BEING DRAWN NORTH INTO
THE AREA FROM THE DESERT SOUTHWEST THAT INTERACTS WITH A BOUNDARY
THAT IS STALLED ALONG THE LARAMIE RANGE. MONDAY
AFTERNOON...CONVECTION IS CONCENTRATED MAINLY ACROSS OUR WESTERN
ZONES...BUT AS THE LOW PRESSURE SYSTEM MOVES INTO COLORADO
TUESDAY...OUR EASTERN ZONES GET SOME PRETTY GOOD RAINFALL. BEST
PRECIP CHANCES APPEAR TO BE ALONG THE WYOMING/COLORADO BORDER
ALONG INTERSTATE 80.

UPPER LOW SLOW TO MOVE OUT OF COLORADO AND WE SHOULD SEE
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY ACROSS
THE ENTIRE CWFA. FINALLY BY THURSDAY...UPPER LOW MOVES NORTHEAST
INTO THE DAKOTAS. NOT MUCH OF A BREAK IN PRECIP THOUGH AS A SECOND
SHORTWAVE MOVES IN BEHIND THIS ONE FOR FRIDAY. AREA WILL CONTINUE
TO SEE ABOVE NORMAL CHANCES FOR MUCH NEEDED RAINFALL INTO THE END
OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 647 AM MDT FRI MAY 1 2015

PATCHY FOG AND LOW CLOUDS RESIDE WEST OF THE LARAMIE RANGE THIS
MORNING. KRWL DOWN NOW IN STRATUS THAT IS EXPECTED TO CONTINUE
UNTIL 15Z OR SO. MVFR CONDITIONS HERE AT KCYS SHOULD IMPROVE BY
MID MORNING WITH HEATING. AFTERNOON CONVECTION FOR KCYS...KLAR AND
POSSIBLY THE SOUTHERN PANHANDLE AIRPORTS.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT FRI MAY 1 2015

CONCERNS TO REMAIN LOW THROUGH THE WEEKEND INTO EARLY NEXT WEEK
WITH NEARLY DAILY CHANCES FOR SHOWERS AND A FEW STORMS...BUT NO
DRY LIGHTNING.  WEATHER FACTORS REMAINING NON-CRITICAL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...CLH
SHORT TERM...RE
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RE



000
FXUS65 KCYS 011717
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1117 AM MDT FRI MAY 1 2015

.UPDATE...
ISSUED AT 1048 AM MDT FRI MAY 1 2015

AREA WEBCAMS AND VISIBLE SATELLITE IMAGERY SHOW FOG AND/OR LOW
STRATUS RAPIDLY DIMINISHING ACROSS PORTIONS OF CARBON AND ALBANY
COUNTIES THIS AM. CLOUD COVER HAS BEEN SLOW TO ERODE OVER THE CO
FRONT RANGE WITH WEAK LLVL UPSLOPE...BUT CLOUDS ARE THINNING AND
LLVL MIXING SHOULD GIVE WAY TO AT LEAST PARTLY SUNNY SKIES AS WE
HEAD INTO THE AFTERNOON. OUR ATTENTION THEN SHIFTS TO CONVECTIVE
POTENTIAL LATER TODAY. FORCING IS NOT AS PRONOUNCED AS PREVIOUS
DAYS...BUT INSTABILITY SHOULD BE THERE WITH STEEP MIDLEVEL LAPSE
RATES AND GOOD LLVL MOISTURE WITH SURFACE DEWPOINTS IN THE MID
40S. IF WE CAN BREAK OUT OF THE CLOUDS...OUR LOCAL WRF SUGGESTS
SBCAPE NEAR 750-1000 J/KG. 0-6KM SHEAR VECTORS ARE WESTERLY AT
AROUND 40 KTS...SUPPORTING POTENTIAL FOR ROTATING UPDRAFTS AND
HAIL PRODUCTION. THE HRRR INITIATES CONVECTION AROUND 20Z OVER
ALBANY AND LARAMIE COUNTIES...SO WENT AHEAD AND INCREASED POPS
INTO THE LIKELY CATEGORY. ALSO ADDED SMALL HAIL AND GUSTY WINDS
GIVEN THE THERMODYNAMIC/KINEMATIC ENVIRONMENT. WE COULD HAVE A
SEVERE STORM OR TWO...BUT OPTED NOT TO MENTION IN THE GRIDS AS
UNCERTAINTIES REMAIN WITH HOW CLOUDS WILL IMPACT COVERAGE OF
STRONGER STORMS.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)

ISSUED AT 300 AM MDT FRI MAY 1 2015

PATTERN WILL BE CHARACTERIZED BY A ZONAL FLOW ALOFT WITH SEVERAL
WEAK IMPULSES PASSING ACROSS THE CWA IN THIS FLOW PATTERN. A SFC
BOUNDARY WILL REMAIN BANKED UP ALONG THE HIGHER TERRAIN OF SE
WYOMING TODAY BEFORE ERODING EASTWARD OVERNIGHT INTO SATURDAY.
THIS BOUNDARY SHOULD INTERACT WITH THESE WEAK DISTURBANCES AND
SOME INSTABILITY TO PRODUCE SCTD SHOWERS AND A FEW STORMS MAINLY
OVER SE WYOMING TODAY. CAPE VALUES RANGE FROM ABOUT 500-1000J/KG
AGAINST THE LARAMIE RANGE THIS AFTERNOON BUT SHEAR VALUES RATHER
LOW SO A FEW STRONGER STORMS POSSIBLE. ACTIVITY SHOULD MOVE
OUT/DISSIPATE THIS EVENING LEAVING A QUIET NIGHT TONIGHT. MORE OF
THE SAME EXPECTED FOR SATURDAY AND SUNDAY EXCEPT AFTERNOON AND
EVENING CONVECTION SHOULD MAKE MORE PROGRESS EASTWARD AS THE SFC
BOUNDARY SHIFTS EAST. CAPE VALUES MUCH LESS OVERALL EXCEPT OVER
PARTS OF THE PANHANDLE WHERE THEY EXCEED 1500 J/KG LATE IN THE
MORNING BEFORE SHIFTING EAST OF THE CWA. WARMER TEMPS FOR SATURDAY
THEN THE NEXT COOL FRONT WILL PASS ACROSS EARLY SUNDAY RESULTING
IN ABOUT 5-15 DEGREES OF COOLING...GREATEST OVER THE PANHANDLE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 300 AM MDT FRI MAY 1 2015

MUCH OF THE LONG TERM REMAINS UNSETTLED AS GUIDANCE CONTINUES TO
SHOW ALMOST DAILY PRECIP CHANCES OVER THE CWFA.

AREA REMAINS UNDER EASTERLY TO SOUTHEASTERLY UPSLOPE FLOW SUNDAY
NIGHT INTO MONDAY AS A SURFACE HIGH OVER WESTERN SOUTH DAKOTA
REMAINS NEARLY STATIONARY.

EACH DAY THERE LOOKS TO BE PIECES OF ENERGY BEING DRAWN NORTH INTO
THE AREA FROM THE DESERT SOUTHWEST THAT INTERACTS WITH A BOUNDARY
THAT IS STALLED ALONG THE LARAMIE RANGE. MONDAY
AFTERNOON...CONVECTION IS CONCENTRATED MAINLY ACROSS OUR WESTERN
ZONES...BUT AS THE LOW PRESSURE SYSTEM MOVES INTO COLORADO
TUESDAY...OUR EASTERN ZONES GET SOME PRETTY GOOD RAINFALL. BEST
PRECIP CHANCES APPEAR TO BE ALONG THE WYOMING/COLORADO BORDER
ALONG INTERSTATE 80.

UPPER LOW SLOW TO MOVE OUT OF COLORADO AND WE SHOULD SEE
WIDESPREAD CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY ACROSS
THE ENTIRE CWFA. FINALLY BY THURSDAY...UPPER LOW MOVES NORTHEAST
INTO THE DAKOTAS. NOT MUCH OF A BREAK IN PRECIP THOUGH AS A SECOND
SHORTWAVE MOVES IN BEHIND THIS ONE FOR FRIDAY. AREA WILL CONTINUE
TO SEE ABOVE NORMAL CHANCES FOR MUCH NEEDED RAINFALL INTO THE END
OF THE WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 647 AM MDT FRI MAY 1 2015

PATCHY FOG AND LOW CLOUDS RESIDE WEST OF THE LARAMIE RANGE THIS
MORNING. KRWL DOWN NOW IN STRATUS THAT IS EXPECTED TO CONTINUE
UNTIL 15Z OR SO. MVFR CONDITIONS HERE AT KCYS SHOULD IMPROVE BY
MID MORNING WITH HEATING. AFTERNOON CONVECTION FOR KCYS...KLAR AND
POSSIBLY THE SOUTHERN PANHANDLE AIRPORTS.


&&

.FIRE WEATHER...
ISSUED AT 300 AM MDT FRI MAY 1 2015

CONCERNS TO REMAIN LOW THROUGH THE WEEKEND INTO EARLY NEXT WEEK
WITH NEARLY DAILY CHANCES FOR SHOWERS AND A FEW STORMS...BUT NO
DRY LIGHTNING.  WEATHER FACTORS REMAINING NON-CRITICAL.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...CLH
SHORT TERM...RE
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...RE




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