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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 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 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
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
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
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 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
FXUS65 KRIW 010920
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
320 AM 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.../12Z ISSUANCE/

VFR CONDITIONS WILL OCCUR TODAY AND TONIGHT. ISOLATED SHOWERS OR
STORMS WILL DEVELOP IN FAR SOUTHERN WY AND ALONG THE UTAH/COLORADO
BORDERS FROM 21Z THROUGH 12Z 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...AR
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 010920
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
320 AM 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.../12Z ISSUANCE/

VFR CONDITIONS WILL OCCUR TODAY AND TONIGHT. ISOLATED SHOWERS OR
STORMS WILL DEVELOP IN FAR SOUTHERN WY AND ALONG THE UTAH/COLORADO
BORDERS FROM 21Z THROUGH 12Z 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...AR
FIRE WEATHER...BRAUN











000
FXUS65 KRIW 010440
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1040 PM MDT THU APR 30 2015

UPDATED FOR 06Z AVIATION DISCUSSION.

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 216 PM MDT)

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN
CONTINUE THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH
THE SOUTHERN THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.
TEMPERATURES WILL COOL BEHIND THE COLD FRONT WITH THE COLDEST
TEMPERATURES AROUND SUNRISE FRIDAY MORNING. MOST MOUNTAIN AREAS WILL
SEE FREEZING TEMPERATURES ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS WILL PREVAIL OVERNIGHT AND THROUGH FRIDAY NIGHT.
ISOLATED SHOWERS OR STORMS WILL OCCUR ALONG THE FAR SOUTH BORDER
WITH UTAH AND COLORADO FROM 21Z FRIDAY THROUGH 06Z SATURDAY.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN
CONTINUE THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH
THE SOUTHERN THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.
TEMPERATURES WILL COOL BEHIND THE COLD FRONT WITH THE COLDEST
TEMPERATURES AROUND SUNRISE FRIDAY MORNING. MOST MOUNTAIN AREAS WILL
SEE FREEZING TEMPERATURES ALONG WITH THE WESTERN VALLEYS.  FAVORABLE
RELATIVE HUMIDITY IS EXPECTED THROUGH THE MORNING...THEN RATHER LOW
RELATIVE HUMIDITY IS EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL
REBOUND DURING THE DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL
FRIDAY AFTERNOON.

&&

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

&&

$$

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












000
FXUS65 KRIW 010440
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1040 PM MDT THU APR 30 2015

UPDATED FOR 06Z AVIATION DISCUSSION.

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 216 PM MDT)

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN
CONTINUE THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH
THE SOUTHERN THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.
TEMPERATURES WILL COOL BEHIND THE COLD FRONT WITH THE COLDEST
TEMPERATURES AROUND SUNRISE FRIDAY MORNING. MOST MOUNTAIN AREAS WILL
SEE FREEZING TEMPERATURES ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../06Z ISSUANCE/

VFR CONDITIONS WILL PREVAIL OVERNIGHT AND THROUGH FRIDAY NIGHT.
ISOLATED SHOWERS OR STORMS WILL OCCUR ALONG THE FAR SOUTH BORDER
WITH UTAH AND COLORADO FROM 21Z FRIDAY THROUGH 06Z SATURDAY.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN
CONTINUE THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH
THE SOUTHERN THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.
TEMPERATURES WILL COOL BEHIND THE COLD FRONT WITH THE COLDEST
TEMPERATURES AROUND SUNRISE FRIDAY MORNING. MOST MOUNTAIN AREAS WILL
SEE FREEZING TEMPERATURES ALONG WITH THE WESTERN VALLEYS.  FAVORABLE
RELATIVE HUMIDITY IS EXPECTED THROUGH THE MORNING...THEN RATHER LOW
RELATIVE HUMIDITY IS EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL
REBOUND DURING THE DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL
FRIDAY AFTERNOON.

&&

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

&&

$$

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













000
FXUS65 KRIW 302016
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
216 PM MDT THU APR 30 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../00Z ISSUANCE/

A PACIFIC LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE FROM THE
NORTHWEST TO THE SOUTHEAST ACROSS THE AREA THROUGH 06Z. OVER THE
MOUNTAINS AREAS OF IFR TO MVFR CEILINGS AND VISIBILITY REDUCED
IN RAIN SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS WITH UP TO HALF
INCH DIAMETER HAIL AND WIND GUSTS TO 45 KTS. THE LOWER ELEVATIONS
WILL HAVE LOCAL MVFR CEILINGS AND VISIBILITY BRIEFLY REDUCED IN RAIN
SHOWERS ALONG WITH ISOLATED THUNDERSTORMS WITH PEA SIZED HAIL AND WIND
GUSTS TO 45KTS. CLEARING WILL BEGIN IN THE NORTHWEST AFTER 00Z AND SPREAD
SOUTHEAST THROUGH 06Z FRIDAY. AFTER O6Z PREVAILING VFR CONDITIONS ARE
EXPECTED.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.  FAVORABLE RELATIVE HUMIDITY IS EXPECTED
THROUGH THE MORNING...THEN RATHER LOW RELATIVE HUMIDITY IS
EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL REBOUND DURING THE
DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL FRIDAY
AFTERNOON.

&&

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

$$

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










000
FXUS65 KRIW 302016
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
216 PM MDT THU APR 30 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../00Z ISSUANCE/

A PACIFIC LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE FROM THE
NORTHWEST TO THE SOUTHEAST ACROSS THE AREA THROUGH 06Z. OVER THE
MOUNTAINS AREAS OF IFR TO MVFR CEILINGS AND VISIBILITY REDUCED
IN RAIN SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS WITH UP TO HALF
INCH DIAMETER HAIL AND WIND GUSTS TO 45 KTS. THE LOWER ELEVATIONS
WILL HAVE LOCAL MVFR CEILINGS AND VISIBILITY BRIEFLY REDUCED IN RAIN
SHOWERS ALONG WITH ISOLATED THUNDERSTORMS WITH PEA SIZED HAIL AND WIND
GUSTS TO 45KTS. CLEARING WILL BEGIN IN THE NORTHWEST AFTER 00Z AND SPREAD
SOUTHEAST THROUGH 06Z FRIDAY. AFTER O6Z PREVAILING VFR CONDITIONS ARE
EXPECTED.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.  FAVORABLE RELATIVE HUMIDITY IS EXPECTED
THROUGH THE MORNING...THEN RATHER LOW RELATIVE HUMIDITY IS
EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL REBOUND DURING THE
DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL FRIDAY
AFTERNOON.

&&

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

$$

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









000
FXUS65 KRIW 302016
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
216 PM MDT THU APR 30 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../00Z ISSUANCE/

A PACIFIC LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE FROM THE
NORTHWEST TO THE SOUTHEAST ACROSS THE AREA THROUGH 06Z. OVER THE
MOUNTAINS AREAS OF IFR TO MVFR CEILINGS AND VISIBILITY REDUCED
IN RAIN SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS WITH UP TO HALF
INCH DIAMETER HAIL AND WIND GUSTS TO 45 KTS. THE LOWER ELEVATIONS
WILL HAVE LOCAL MVFR CEILINGS AND VISIBILITY BRIEFLY REDUCED IN RAIN
SHOWERS ALONG WITH ISOLATED THUNDERSTORMS WITH PEA SIZED HAIL AND WIND
GUSTS TO 45KTS. CLEARING WILL BEGIN IN THE NORTHWEST AFTER 00Z AND SPREAD
SOUTHEAST THROUGH 06Z FRIDAY. AFTER O6Z PREVAILING VFR CONDITIONS ARE
EXPECTED.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.  FAVORABLE RELATIVE HUMIDITY IS EXPECTED
THROUGH THE MORNING...THEN RATHER LOW RELATIVE HUMIDITY IS
EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL REBOUND DURING THE
DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL FRIDAY
AFTERNOON.

&&

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

$$

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










000
FXUS65 KRIW 302016
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
216 PM MDT THU APR 30 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

ZONAL FLOW OVER THE AREA BEGINS THE FORECAST PERIOD..WITH GENERALLY
DRY AND WARM CONDITIONS ACROSS THE FORECAST AREA. THESE BENIGN
CONDITIONS WANE SATURDAY AFTERNOON AND EVENING AS A PUSH OF MOISTURE
MOVES ACROSS WESTERN WYOMING. THIS MOISTURE SURGE WILL GENERALLY
BRING SHOWERS ACROSS SOUTHERN AND WESTERN WYOMING...THOUGH A FEW
SHOWERS MAY MOVE EAST OF THE CONTINENTAL DIVIDE DURING THE OVERNIGHT
HOURS. TEMPERATURES WILL ALSO START A GENERAL COOLING TREND...THOUGH
WILL STILL BE SEASONALLY MILD.

THE PERIODIC PUSHES OF MOISTURE CONTINUE SUNDAY AFTERNOON AND
EVENING. COVERAGE INCREASES WITH THE PUSH...WITH SHOWERS BEGINNING
OVER MUCH OF THE FORECAST AREA. SHOWER COVERAGE INCREASES EACH
AFTERNOON WITH THE CONTINUED PUSHES OF MOISTURE...WITH SHOWERS AND
THUNDERSTORMS CONTINUING INTO THE EVENING AND OVERNIGHT HOURS.

THIS PATTERN WILL CONTINUE THROUGH THURSDAY ACROSS THE AREA. AN
APPROACHING AREA OF LOW PRESSURE MAY FURTHER INCREASE COVERAGE OF
SHOWER ACTIVITY WEDNESDAY AND INTO THURSDAY...THOUGH MODELS VARY ON
THE PLACEMENT AND STRENGTH OF THE AREA OF LOW PRESSURE. THE AREA OF
LOW PRESSURE CONTINUES TO MOVE TOWARDS WYOMING ON THURSDAY...WITH
SHOWERS CONTINUING ALONG WITH COOLING TEMPERATURES.

&&

.AVIATION.../00Z ISSUANCE/

A PACIFIC LOW PRESSURE TROUGH AND COLD FRONT WILL MOVE FROM THE
NORTHWEST TO THE SOUTHEAST ACROSS THE AREA THROUGH 06Z. OVER THE
MOUNTAINS AREAS OF IFR TO MVFR CEILINGS AND VISIBILITY REDUCED
IN RAIN SHOWERS WITH EMBEDDED ISOLATED THUNDERSTORMS WITH UP TO HALF
INCH DIAMETER HAIL AND WIND GUSTS TO 45 KTS. THE LOWER ELEVATIONS
WILL HAVE LOCAL MVFR CEILINGS AND VISIBILITY BRIEFLY REDUCED IN RAIN
SHOWERS ALONG WITH ISOLATED THUNDERSTORMS WITH PEA SIZED HAIL AND WIND
GUSTS TO 45KTS. CLEARING WILL BEGIN IN THE NORTHWEST AFTER 00Z AND SPREAD
SOUTHEAST THROUGH 06Z FRIDAY. AFTER O6Z PREVAILING VFR CONDITIONS ARE
EXPECTED.

&&

.FIRE WEATHER...

A COLD FRONT HAS MOVED SOUTH THROUGH THE NORTHERN THREE QUARTERS OF
WYOMING AND WILL PUSH ON SOUTH INTO NORTHERN COLORADO BY 06Z.
AN UPPER LEVEL LOW PRESSURE TROUGH HAS MOVED THROUGH THE NORTHWEST
CORNER OF WYOMING AND WILL SWEEP SOUTH AND EAST THROUGH THE STATE
THROUGH 06Z. AHEAD OF THE UPPER LEVEL TROUGH...ALONG AND WITHIN 60
MILES NORTH OF THE COLD FRONT...SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AND STRONG GUSTY WINDS UP TO 45KTS
WILL BE A THREAT THROUGH 06Z. AFTER 06Z A FEW SHOWERS WILL LINGER
OVER THE EAST AND SOUTH BEFORE DISSIPATING.  CLEARING WILL THEN CONTINUE
THROUGH FRIDAY. A FEW SHOWERS AND THUNDERSTORMS MAY BRUSH THE SOUTHERN
THIRD OF SWEETWATER COUNTY FRIDAY AFTERNOON.  TEMPERATURES WILL COOL
BEHIND THE COLD FRONT WITH THE COLDEST TEMPERATURES AROUND SUNRISE
FRIDAY MORNING. MOST MOUNTAIN AREAS WILL SEE FREEZING TEMPERATURES
ALONG WITH THE WESTERN VALLEYS.  FAVORABLE RELATIVE HUMIDITY IS EXPECTED
THROUGH THE MORNING...THEN RATHER LOW RELATIVE HUMIDITY IS
EXPECTED FRIDAY AFTERNOON. MIXING HEIGHTS WILL REBOUND DURING THE
DAY WITH GENERALLY GOOD OR BETTER SMOKE DISPERSAL FRIDAY
AFTERNOON.

&&

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

$$

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









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