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000
FXUS65 KRIW 010840
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
240 AM MDT SUN MAY 1 2016

.SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT

FINALLY SOME IMPROVING CONDITIONS ACROSS THE AREA AND A RETURN OF
SOME SUNSHINE FOR SOME MUCH NEEDED DRYING OUT. THERE ARE STILL A FEW
SHOWERS ON THE RADAR THIS MORNING BUT THESE SHOULD DIMINISH BY EARLY
AFTERNOON AND THEN FEATURE...SHOCKING...INCREASING AMOUNTS OF
SUNSHINE THROUGH THE DAY AS DRIER AIR MOVES IN FROM THE NORTH AS
HIGH PRESSURE DROPS IN FROM MONTANA. TEMPERATURES WILL
STILL BE BELOW NORMAL...BUT WARMER THAN RECENT DAYS AND WITH THE
SUNSHINE IT WILL FEEL MUCH BETTER THAN RECENT DAYS. THE MAIN CONCERN
THIS MORNING WILL BE SOME PATCHY FOG WHERE CLEARING MAY TAKE PLACE.
CONTINUITY HAD THAT COVERED FAIRLY WELL SO WE LEFT IT. IN
ADDITION...THERE WILL STILL BE GUSTY WINDS ACROSS SOUTHERN
WYOMING. HOWEVER...NOT HIGH ENOUGH TO WARRANT ANY HIGH WIND
HIGHLIGHTS. TONIGHT LOOKS MAINLY DRY AND COOL. THERE COULD BE SOME
FOG IN PLACES...SO WE ADDED PATCHY FOG FOR LATE TONIGHT IN AREAS THAT
HAD SUBSTANTIAL RAIN OVER THE PAST FEW DAYS WITH NARROW TEMPERATURE-
DEW POINT SPREADS EXPECTED.

THERE IS A BIT OF UNCERTAINTY FOR MONDAY HOWEVER AS A FLY HAS
ENTERED THE SOUP FOR MONDAY AFTERNOON. THAT FLY IS SHORTWAVE THAT
WILL MOVE RAPIDLY DOWN FROM CANADA AND INTO THE STATE MONDAY
AFTERNOON AND EVENING. THE NAM RETROGRADES THE WAVE INTO WYOMING AND
BRINGS SOME CONVECTION TO PORTIONS OF THE STATE. THE GFS IS WELL
EAST OF THE AREA WITH THE WAVE. THE EUROPEAN IS IN THE MIDDLE BUT
STILL KEEPS IT EAST OF THE AREA. FOR NOW...AS A COMPROMISE WE
INTRODUCED SOME ISOLATED TO THE HIGHER ELEVATIONS EAST OF THE
DIVIDE. TEMPERATURES WILL CONTINUE TO BE ON THE UPWARD
SWING...FINALLY APPROACHING SEASONAL NORMALS.

THERE IS THE SAME DILEMMA FOR TUESDAY. THE NAM HAS CONVECTION OVER
SOUTHERN WYOMING WITH THE LOW STALLED OVER THE AREA. MEANWHILE...THE
GFS AND EUROPEAN ARE DRY WITH A RIDGE FIRMLY IN CONTROL. AGAIN...WE
ADDED SOME SLIGHT POPS ACROSS THE SOUTH BUT MOST AREAS WILL BE DRY
MOST OF THE TIME. THERE WILL FINALLY BE SOME SPRING LIKE
TEMPERATURES FOR THE FIRST TIME IN OVER A WEEK. MANY LOWER
ELEVATIONS SHOULD SEE HIGH TEMPERATURES RISE INTO THE 70S.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

SYNOPSIS...UPPER RIDGE WILL BRING DRY AND MILD WEATHER ACROSS THE
AREA ON WEDNESDAY.  ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL PUSH INTO THE WEST THURSDAY AHEAD OF THE NEXT PACIFIC STORM
SYSTEM...WHILE CENTRAL WYOMING WILL SEE UNSEASONABLY MILD AND MAINLY
DRY WEATHER.  THE PACIFIC STORM SYSTEM WILL MOVE INTO THE GREAT
BASIN FRIDAY AND LINGER THROUGH THE WEEKEND...BRINGING CHANCES OF
SHOWERS AND THUNDERSTORMS ACROSS THE AREA ALONG WITH A COOLING
TREND.

DISCUSSION...GFS SHOWS BETTER RUN-TO-RUN CONTINUITY THAN ECMWF WITH
THE GFS DEVELOPING A REX BLOCK OVER THE ROCKIES/GREAT BASIN NEXT
WEEKEND.  THE ECMWF HAS SHOWN WIDELY VARYING INTERACTIONS WITH SW
LOW AND NORTHERN STREAM OVER THE LAST FEW RUNS.  GFS/GEFS MEAN WAS
USED FOR THIS FORECAST PERIOD.

OMEGA BLOCK BEGINS THIS PERIOD WITH UPPER RIDGE ACROSS THE ROCKIES
FLANKED BY LOWS OFF THE WEST COAST AND ACROSS THE EASTERN U.S. UPPER
RIDGE SHIFTS EAST INTO THE PLAINS ON THURSDAY/THURSDAY NIGHT AS
WESTERN UPPER LOW SLOWLY MOVES INTO THE LAS VEGAS AREA BY 0Z
SATURDAY.  GFS HAS TRENDED SLIGHTLY WARMER OVER LAST FEW RUNS WITH
H7 TEMPS NEAR 10C ACROSS CENTRAL WYOMING ON THURSDAY...SO FORECAST
CONTINUES TO TEND TEMPERATURES WARMER WITH SOME HIGHS IN THE LOWER
80S ACROSS THE LOWER CENTRAL BASINS ON THURSDAY.  MOISTURE AND
SLIGHT INSTABILITY IN SOUTHERLY DIFLUENT FLOW WILL BEGIN TO SPREAD
SOME SHOWERS AND THUNDERSTORMS NEAR AND WEST OF THE DIVIDE THURSDAY.
EASTERLY LOW LEVEL FLOW WILL BRING BETTER MOISTURE...INSTABILITY AND
SHEAR INTO CENTRAL AREAS ON FRIDAY WITH THE POTENTIAL FOR SOME
STRONG TO SEVERE THUNDERSTORMS.  A MORE WIDESPREAD PRECIPITATION
EVENT IS SETTING UP FOR NEXT WEEKEND WITH CUTOFF UPPER LOW OVER THE
GREAT BASIN WITH LOW LEVEL UPSLOPE FLOW EAST OF THE DIVIDE.  AT THIS
POINT...SNOW LEVELS ARE PROGGED TO REMAIN >=9KFT SO IMPACTS ON
TRAVEL SHOULD BE MINIMAL.  HOWEVER...SIGNIFICANT RAINFALL ON
MOUNTAIN SNOWPACK MAY ELEVATE FLOODING CONCERNS.


&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

SOME LOW CLOUDS OR FOG WILL FORM IN PLACES WITH MVFR/IFR CONDITIONS
UNTIL 17Z. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

LINGERING RAIN AND SNOW SHOWERS IN CENTRAL WY WILL END BY 15Z. SOME
LOW CLOUDS OR FOG WILL FORM IN PLACES WITH MVFR/IFR CONDITIONS UNTIL
17Z. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW TODAY. ANY SHOWERS SHOULD END THIS
MORNING WITH INCREASING AMOUNTS OF SUNSHINE THROUGH THE DAY. A GUSTY
EASTERLY WIND WILL BLOW FROM THE RATTLESNAKE RANGE ACROSS SOUTHERN
WYOMING. HOWEVER...RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE
CRITICAL LEVELS. EXPECT WARMING AND DRIER CONDITIONS THROUGH AROUND
WEDNESDAY WITH THE EXCEPTION OF THE MOUNTAINS WHERE AN ISOLATED
AFTERNOON THUNDERSTORM MAY FIRE. EXPECT MAINLY LIGHT WINDS FROM
MONDAY INTO THE MIDDLE OF THE WEEK.
&&

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

$$

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





000
FXUS65 KRIW 010840
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
240 AM MDT SUN MAY 1 2016

.SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT

FINALLY SOME IMPROVING CONDITIONS ACROSS THE AREA AND A RETURN OF
SOME SUNSHINE FOR SOME MUCH NEEDED DRYING OUT. THERE ARE STILL A FEW
SHOWERS ON THE RADAR THIS MORNING BUT THESE SHOULD DIMINISH BY EARLY
AFTERNOON AND THEN FEATURE...SHOCKING...INCREASING AMOUNTS OF
SUNSHINE THROUGH THE DAY AS DRIER AIR MOVES IN FROM THE NORTH AS
HIGH PRESSURE DROPS IN FROM MONTANA. TEMPERATURES WILL
STILL BE BELOW NORMAL...BUT WARMER THAN RECENT DAYS AND WITH THE
SUNSHINE IT WILL FEEL MUCH BETTER THAN RECENT DAYS. THE MAIN CONCERN
THIS MORNING WILL BE SOME PATCHY FOG WHERE CLEARING MAY TAKE PLACE.
CONTINUITY HAD THAT COVERED FAIRLY WELL SO WE LEFT IT. IN
ADDITION...THERE WILL STILL BE GUSTY WINDS ACROSS SOUTHERN
WYOMING. HOWEVER...NOT HIGH ENOUGH TO WARRANT ANY HIGH WIND
HIGHLIGHTS. TONIGHT LOOKS MAINLY DRY AND COOL. THERE COULD BE SOME
FOG IN PLACES...SO WE ADDED PATCHY FOG FOR LATE TONIGHT IN AREAS THAT
HAD SUBSTANTIAL RAIN OVER THE PAST FEW DAYS WITH NARROW TEMPERATURE-
DEW POINT SPREADS EXPECTED.

THERE IS A BIT OF UNCERTAINTY FOR MONDAY HOWEVER AS A FLY HAS
ENTERED THE SOUP FOR MONDAY AFTERNOON. THAT FLY IS SHORTWAVE THAT
WILL MOVE RAPIDLY DOWN FROM CANADA AND INTO THE STATE MONDAY
AFTERNOON AND EVENING. THE NAM RETROGRADES THE WAVE INTO WYOMING AND
BRINGS SOME CONVECTION TO PORTIONS OF THE STATE. THE GFS IS WELL
EAST OF THE AREA WITH THE WAVE. THE EUROPEAN IS IN THE MIDDLE BUT
STILL KEEPS IT EAST OF THE AREA. FOR NOW...AS A COMPROMISE WE
INTRODUCED SOME ISOLATED TO THE HIGHER ELEVATIONS EAST OF THE
DIVIDE. TEMPERATURES WILL CONTINUE TO BE ON THE UPWARD
SWING...FINALLY APPROACHING SEASONAL NORMALS.

THERE IS THE SAME DILEMMA FOR TUESDAY. THE NAM HAS CONVECTION OVER
SOUTHERN WYOMING WITH THE LOW STALLED OVER THE AREA. MEANWHILE...THE
GFS AND EUROPEAN ARE DRY WITH A RIDGE FIRMLY IN CONTROL. AGAIN...WE
ADDED SOME SLIGHT POPS ACROSS THE SOUTH BUT MOST AREAS WILL BE DRY
MOST OF THE TIME. THERE WILL FINALLY BE SOME SPRING LIKE
TEMPERATURES FOR THE FIRST TIME IN OVER A WEEK. MANY LOWER
ELEVATIONS SHOULD SEE HIGH TEMPERATURES RISE INTO THE 70S.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

SYNOPSIS...UPPER RIDGE WILL BRING DRY AND MILD WEATHER ACROSS THE
AREA ON WEDNESDAY.  ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL PUSH INTO THE WEST THURSDAY AHEAD OF THE NEXT PACIFIC STORM
SYSTEM...WHILE CENTRAL WYOMING WILL SEE UNSEASONABLY MILD AND MAINLY
DRY WEATHER.  THE PACIFIC STORM SYSTEM WILL MOVE INTO THE GREAT
BASIN FRIDAY AND LINGER THROUGH THE WEEKEND...BRINGING CHANCES OF
SHOWERS AND THUNDERSTORMS ACROSS THE AREA ALONG WITH A COOLING
TREND.

DISCUSSION...GFS SHOWS BETTER RUN-TO-RUN CONTINUITY THAN ECMWF WITH
THE GFS DEVELOPING A REX BLOCK OVER THE ROCKIES/GREAT BASIN NEXT
WEEKEND.  THE ECMWF HAS SHOWN WIDELY VARYING INTERACTIONS WITH SW
LOW AND NORTHERN STREAM OVER THE LAST FEW RUNS.  GFS/GEFS MEAN WAS
USED FOR THIS FORECAST PERIOD.

OMEGA BLOCK BEGINS THIS PERIOD WITH UPPER RIDGE ACROSS THE ROCKIES
FLANKED BY LOWS OFF THE WEST COAST AND ACROSS THE EASTERN U.S. UPPER
RIDGE SHIFTS EAST INTO THE PLAINS ON THURSDAY/THURSDAY NIGHT AS
WESTERN UPPER LOW SLOWLY MOVES INTO THE LAS VEGAS AREA BY 0Z
SATURDAY.  GFS HAS TRENDED SLIGHTLY WARMER OVER LAST FEW RUNS WITH
H7 TEMPS NEAR 10C ACROSS CENTRAL WYOMING ON THURSDAY...SO FORECAST
CONTINUES TO TEND TEMPERATURES WARMER WITH SOME HIGHS IN THE LOWER
80S ACROSS THE LOWER CENTRAL BASINS ON THURSDAY.  MOISTURE AND
SLIGHT INSTABILITY IN SOUTHERLY DIFLUENT FLOW WILL BEGIN TO SPREAD
SOME SHOWERS AND THUNDERSTORMS NEAR AND WEST OF THE DIVIDE THURSDAY.
EASTERLY LOW LEVEL FLOW WILL BRING BETTER MOISTURE...INSTABILITY AND
SHEAR INTO CENTRAL AREAS ON FRIDAY WITH THE POTENTIAL FOR SOME
STRONG TO SEVERE THUNDERSTORMS.  A MORE WIDESPREAD PRECIPITATION
EVENT IS SETTING UP FOR NEXT WEEKEND WITH CUTOFF UPPER LOW OVER THE
GREAT BASIN WITH LOW LEVEL UPSLOPE FLOW EAST OF THE DIVIDE.  AT THIS
POINT...SNOW LEVELS ARE PROGGED TO REMAIN >=9KFT SO IMPACTS ON
TRAVEL SHOULD BE MINIMAL.  HOWEVER...SIGNIFICANT RAINFALL ON
MOUNTAIN SNOWPACK MAY ELEVATE FLOODING CONCERNS.


&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

SOME LOW CLOUDS OR FOG WILL FORM IN PLACES WITH MVFR/IFR CONDITIONS
UNTIL 17Z. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

LINGERING RAIN AND SNOW SHOWERS IN CENTRAL WY WILL END BY 15Z. SOME
LOW CLOUDS OR FOG WILL FORM IN PLACES WITH MVFR/IFR CONDITIONS UNTIL
17Z. OTHERWISE VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW TODAY. ANY SHOWERS SHOULD END THIS
MORNING WITH INCREASING AMOUNTS OF SUNSHINE THROUGH THE DAY. A GUSTY
EASTERLY WIND WILL BLOW FROM THE RATTLESNAKE RANGE ACROSS SOUTHERN
WYOMING. HOWEVER...RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE
CRITICAL LEVELS. EXPECT WARMING AND DRIER CONDITIONS THROUGH AROUND
WEDNESDAY WITH THE EXCEPTION OF THE MOUNTAINS WHERE AN ISOLATED
AFTERNOON THUNDERSTORM MAY FIRE. EXPECT MAINLY LIGHT WINDS FROM
MONDAY INTO THE MIDDLE OF THE WEEK.
&&

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

$$

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





000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1102 PM MDT SAT APR 30 2016

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 151 PM MDT)

BROAD LOW WITH A COUPLE OF EMBEDDED CLOSED LOWS ACROSS THE WRN
2/3RDS OF THE CONUS. DEEPER CLOSED SYSTEM NOW CENTERED ACROSS THE
CNTRL PLAINS WITH THE SFC PORTION OF THE LOW NOW OVR MO. LONG
TRAJECTORY FEED OF MOISTURE FEEDS UP ACROSS THE MS VALLEY...THEN WWD
ACROSS SD/NE...TAILING OFF INTO ERN AND SRN WY/NRN CO. MOST PRECIP
WITHIN THE FA IS CURRENTLY LOCATED OVR CNTRL/SRN WY...FALLING OFF
QUICKLY TO THE NORTH.

TODAY THRU THIS EVENING...THE UPR LOW STALLS OUT...ONLY MAKING IT
AS FAR E AS THE MO VALLEY BY AROUND MIDNIGHT...WITH THE SFC PORTION
OF THE SYSTEM TRACKING TO IL. GENERALLY...THIS SLOW PROGRESSION EWD
WILL ALSO SLOWLY TAKE THE MOISTURE WITH IT...WITH THE MORE
STRATIFORM PRECIP E OF THE DIVIDE FALLING OFF IN PARALLEL. COLD AIR
ALOFT W OF THE DIVIDE...HOWEVER...WILL ALLOW FOR SOME -SHRA/ISO -
TSRA THIS AFTERNOON/EARLY EVENING...WITH THE WRN/SRN MOUNTAINS
REAPING THE BENEFITS FROM THIS ISOLATED TO SCATTERED PRECIP.

HAVE DECIDED TO CANCEL THE ADVISORIES FOR ALL ZONES EXCEPT ZONE 15
(ERN WIND RIVER MOUNTAINS)...AS THE BETTER PRECIP/SNOW CAME THROUGH
MID MORNING...BEFORE MIXING WITH OR TURNING TO ALL RAIN BELOW 5500
FEET BY LATE MORNING. ADDITIONALLY...QPF TRENDS ARE FAVORING THE THE
TERRAIN FORCED AREAS WITH A NE ASPECT. ALSO ACCUMULATING SNOW SEEMS
TO BE MOSTLY RELEGATED TO ELEVATIONS ABOVE 6000 TO 6200 FEET THIS
AFTERNOON. SO...EVEN AS SNOW ELEVATIONS FALL THROUGH THE AFTERNOON
AND INTO THE EVENING...SO WILL THE PRECIP WITH MUCH LESS CHANCE TO
ACCUMULATE. OTHERWISE...SIGNIFICANT SNOWFALL TOTALS WILL GENERALLY
LIE BETWEEN 3 AND 9 INCHES ACROSS THE ERN WIND RIVER MOUNTAINS...2
TO 7 INCHES OVER/CLOSE TO CASPER MOUNTAIN...2 TO 6 INCHES IN THE SRN
ABSAROKAS...AND PERHAPS AN INCH TO 2 INCHES OVR PORTIONS OF NATRONA
AND FREMONT COUNTIES.

SUNDAY WILL BE HIGHLIGHTED BY A FOLDING RIDGE AND DRYING ACROSS THE
FA FROM N TO S THROUGH THE DAY...WITH ONLY A FEW LINGERING MORNING
SHOWERS GIVING WAY TO A SPURIOUS SHOWER OR TWO...MAINLY IN THE
BIGHORN...LARAMIE...OR MEDICINE BOW MOUNTAINS. WARM UP
BEGINS...WITH HIGHS REACHING INTO THE 40S TO MID 50S ACROSS THE
LOWER ELEVATIONS...WITH 30S AND 40S IN THE MOUNTAINS.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

MOISTURE AND NORTHEASTERLY UPSLOPE FLOW WILL TAPER OFF ON SUNDAY
NIGHT AS THE UPPER LOW PRESSURE AREA SPLITS WITH THE NORTHEASTERN
PART OF THE LOW EXITING TO THE EAST WHILE A LARGE CLOSED LOW
CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN AND DESERT
SOUTHWEST WEST OF THE FOUR CORNERS AREA. DRYING OCCURS FROM NORTH TO
SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH FROM ALBERTA
ON MONDAY AND MONDAY NIGHT. THE WEAKENING OF THE SOUTHWEST LOW MAY
BE TOO FAST AND THE MODELS START TO DIFFER WITH THE DEMISE OF THE
LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS INTO THE WEST. THIS
LEADS TO SIGNIFICANT DRYING AND WARMING TUESDAY THROUGH THURSDAY.
WHEN THE RIDGE AXIS MOVES INTO EASTERN WYOMING...SOUTH SOUTHWEST
FLOW MOVES INTO WESTERN WYOMING WITH SOME SHOWERS DEVELOPING
WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN MOUNTAINS. THE SPREAD
BETWEEN THE MODEL SOLUTIONS BECOMES QUITE LARGE...BUT WITH A GENERAL
LONG WAVE HIGH PRESSURE RIDGE...THE MAIN DIFFERENCES ARE TO THE WEST
AND EAST OF THE AREA WHERE LONG WAVE TROUGHS BRACKET THE RIDGE.
WEDNESDAY AND THURSDAY HIGHS WARM NICELY INTO THE UPPER 60S AND 70S
WITH THE WARMEST TEMPERATURES IN THE BIGHORN BASIN.  SHOWERS
EXPECTED TO BECOME SCATTERED OVER THE WESTERN MOUNTAINS WITH
ISOLATED THUNDERSTORMS DUE TO HEATING.  SHOULD HAVE ENOUGH RESIDUAL
MOISTURE ON THE GROUND TO EVAPORATE AND PROVIDE NEEDED MOISTURE FOR
CONVECTION. AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN ON
FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO NORTHEAST
FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND INCREASED
MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND RAIN
MOVING INTO NEXT WEEKEND.  TEMPERATURES EXPECTED TO COOL
SIGNIFICANTLY ON SATURDAY AS SHOWERS BECOME MORE WIDESPREAD AND
EAST TO NORTHEAST UPSLOPE FLOW DEEPENS AND MOISTENS.  SNOW LEVEL
SHOULD START OUT AROUND 9000 FEET WITH A RAIN SNOW MIX DOWN TO 7500
FEET.

&&

.AVIATION.../06Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. ISOLATED RAIN OR
SNOW SHOWERS WILL END BY 12Z. PATCHY LOW CLOUDS OR FOG WILL FORM IN
PLACES OVERNIGHT WITH MVFR/IFR CONDITIONS UNTIL 17Z.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. SOME LOW CLOUDS OR
FOG WILL FORM IN PLACES OVERNIGHT INTO SUNDAY MORNING WITH MVFR/IFR
CONDITIONS UNTIL 17Z.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER FOR ALL LOCATIONS CONTINUES WITH HIGH
MINIMUM RH VALUES ONLY BOTTOMING OUT IN THE MID 40S TO MID 80S
(PERCENT) ACROSS THE ENTIRE REGION. THERE WILL BE CHANCES FOR
ISOLATED TO SCATTERED SHOWERS OR AN ISOLATED THUNDERSTORM OR TWO
ACROSS THE SOUTH AND SOUTHWEST WY THIS AFTERNOON. MUCH BETTER
CHANCES FOR RAIN AND OR SNOW WILL OCCUR EAST OF THE DIVIDE...
ESPECIALLY ACROSS CENTRAL WYOMING TODAY  THROUGH THIS EVENING.
PRECIPITATION ENDS ACROSS WYOMING SUNDAY...HOWEVER FIRE DANGER WILL
REMAIN LOW FOR THE MOST PART AS LOTS OF RESIDUAL MOISTURE REMAINS
ACROSS MUCH OF THE STATE AND GREEN UP BEGINS. WINDS...HOWEVER...WILL
BE QUITE GUSTY ACROSS THE SOUTHERN PORTION OF WYOMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR WYZ015.

&&

$$

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





000
FXUS65 KRIW 301951
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
151 PM MDT SAT APR 30 2016

.SHORT TERM...TONIGHT THROUGH SUNDAY

BROAD LOW WITH A COUPLE OF EMBEDDED CLOSED LOWS ACROSS THE WRN
2/3RDS OF THE CONUS. DEEPER CLOSED SYSTEM NOW CENTERED ACROSS THE
CNTRL PLAINS WITH THE SFC PORTION OF THE LOW NOW OVR MO. LONG
TRAJECTORY FEED OF MOISTURE FEEDS UP ACROSS THE MS VALLEY...THEN WWD
ACROSS SD/NE...TAILING OFF INTO ERN AND SRN WY/NRN CO. MOST PRECIP
WITHIN THE FA IS CURRENTLY LOCATED OVR CNTRL/SRN WY...FALLING OFF
QUICKLY TO THE NORTH.

TODAY THRU THIS EVENING...THE UPR LOW STALLS OUT...ONLY MAKING IT
AS FAR E AS THE MO VALLEY BY AROUND MIDNIGHT...WITH THE SFC PORTION
OF THE SYSTEM TRACKING TO IL. GENERALLY...THIS SLOW PROGRESSION EWD
WILL ALSO SLOWLY TAKE THE MOISTURE WITH IT...WITH THE MORE
STRATIFORM PRECIP E OF THE DIVIDE FALLING OFF IN PARALLEL. COLD AIR
ALOFT W OF THE DIVIDE...HOWEVER...WILL ALLOW FOR SOME -SHRA/ISO -
TSRA THIS AFTERNOON/EARLY EVENING...WITH THE WRN/SRN MOUNTAINS
REAPING THE BENEFITS FROM THIS ISOLATED TO SCATTERED PRECIP.

HAVE DECIDED TO CANCEL THE ADVISORIES FOR ALL ZONES EXCEPT ZONE 15
(ERN WIND RIVER MOUNTAINS)...AS THE BETTER PRECIP/SNOW CAME THROUGH
MID MORNING...BEFORE MIXING WITH OR TURNING TO ALL RAIN BELOW 5500
FEET BY LATE MORNING. ADDITIONALLY...QPF TRENDS ARE FAVORING THE THE
TERRAIN FORCED AREAS WITH A NE ASPECT. ALSO ACCUMULATING SNOW SEEMS
TO BE MOSTLY RELEGATED TO ELEVATIONS ABOVE 6000 TO 6200 FEET THIS
AFTERNOON. SO...EVEN AS SNOW ELEVATIONS FALL THROUGH THE AFTERNOON
AND INTO THE EVENING...SO WILL THE PRECIP WITH MUCH LESS CHANCE TO
ACCUMULATE. OTHERWISE...SIGNIFICANT SNOWFALL TOTALS WILL GENERALLY
LIE BETWEEN 3 AND 9 INCHES ACROSS THE ERN WIND RIVER MOUNTAINS...2
TO 7 INCHES OVER/CLOSE TO CASPER MOUNTAIN...2 TO 6 INCHES IN THE SRN
ABSAROKAS...AND PERHAPS AN INCH TO 2 INCHES OVR PORTIONS OF NATRONA
AND FREMONT COUNTIES.

SUNDAY WILL BE HIGHLIGHTED BY A FOLDING RIDGE AND DRYING ACROSS THE
FA FROM N TO S THROUGH THE DAY...WITH ONLY A FEW LINGERING MORNING
SHOWERS GIVING WAY TO A SPURIOUS SHOWER OR TWO...MAINLY IN THE
BIGHORN...LARAMIE...OR MEDICINE BOW MOUNTAINS. WARM UP
BEGINS...WITH HIGHS REACHING INTO THE 40S TO MID 50S ACROSS THE
LOWER ELEVATIONS...WITH 30S AND 40S IN THE MOUNTAINS.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

MOISTURE AND NORTHEASTERLY UPSLOPE FLOW WILL TAPER OFF ON SUNDAY
NIGHT AS THE UPPER LOW PRESSURE AREA SPLITS WITH THE NORTHEASTERN
PART OF THE LOW EXITING TO THE EAST WHILE A LARGE CLOSED LOW
CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN AND DESERT
SOUTHWEST WEST OF THE FOUR CORNERS AREA. DRYING OCCURS FROM NORTH TO
SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH FROM ALBERTA
ON MONDAY AND MONDAY NIGHT. THE WEAKENING OF THE SOUTHWEST LOW MAY
BE TOO FAST AND THE MODELS START TO DIFFER WITH THE DEMISE OF THE
LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS INTO THE WEST. THIS
LEADS TO SIGNIFICANT DRYING AND WARMING TUESDAY THROUGH THURSDAY.
WHEN THE RIDGE AXIS MOVES INTO EASTERN WYOMING...SOUTH SOUTHWEST
FLOW MOVES INTO WESTERN WYOMING WITH SOME SHOWERS DEVELOPING
WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN MOUNTAINS. THE SPREAD
BETWEEN THE MODEL SOLUTIONS BECOMES QUITE LARGE...BUT WITH A GENERAL
LONG WAVE HIGH PRESSURE RIDGE...THE MAIN DIFFERENCES ARE TO THE WEST
AND EAST OF THE AREA WHERE LONG WAVE TROUGHS BRACKET THE RIDGE.
WEDNESDAY AND THURSDAY HIGHS WARM NICELY INTO THE UPPER 60S AND 70S
WITH THE WARMEST TEMPERATURES IN THE BIGHORN BASIN.  SHOWERS
EXPECTED TO BECOME SCATTERED OVER THE WESTERN MOUNTAINS WITH
ISOLATED THUNDERSTORMS DUE TO HEATING.  SHOULD HAVE ENOUGH RESIDUAL
MOISTURE ON THE GROUND TO EVAPORATE AND PROVIDE NEEDED MOISTURE FOR
CONVECTION. AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN ON
FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO NORTHEAST
FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND INCREASED
MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND RAIN
MOVING INTO NEXT WEEKEND.  TEMPERATURES EXPECTED TO COOL
SIGNIFICANTLY ON SATURDAY AS SHOWERS BECOME MORE WIDESPREAD AND
EAST TO NORTHEAST UPSLOPE FLOW DEEPENS AND MOISTENS.  SNOW LEVEL
SHOULD START OUT AROUND 9000 FEET WITH A RAIN SNOW MIX DOWN TO 7500
FEET.


&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/OCCASIONAL MVFR CONDITIONS OVER MUCH OF WESTERN WY THROUGH THE
EVENING. KRKS WILL PERSIST MVFR OVER THE SAME PERIOD. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORM CONTINUE TO BE POSSIBLE INTO THE
EVENING PERIOD WITH OCCASIONAL MVFR CONDITIONS
ACCOMPANYING...DECREASING OR ENDING BY AROUND 06Z. AREAS OF MVFR
CIGS AND OR VCFG THEN RETURN AND BE AROUND THROUGH 15Z SUNDAY.
MOUNTAIN OBSCURATION WILL ALSO BE PERSISTENT THROUGH SUNDAY
MORNING...WITH SKIES FINALLY BREAKING ACROSS THE FAR WEST BY
AFTERNOON.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND OR SNOW THROUGH EARLY THIS EVENING. FAR NORTHERN
PORTIONS OF WY WILL SEE MUCH LESS IN THE WAY OF PRECIPITATION...WITH
SKIES EVEN VFR...AT/NEAR KCOD FOR EXAMPLE. GENERALLY...THE RAIN AND
SNOW WILL DECREASE AFTER 03Z. OTHERWISE...EXPECT MVFR TO IFR
CONDITIONS IN LOW CIGS TO PERSIST OVER MOST OF CENTRAL WYOMING
THROUGH THE OVERNIGHT PERIOD...ENDING AROUND 15Z. MOUNTAINS WILL BE
FREQUENTLY OBSCURED THROUGH SUNDAY MORNING.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER FOR ALL LOCATIONS CONTINUES WITH HIGH
MINIMUM RH VALUES ONLY BOTTOMING OUT IN THE MID 40S TO MID 80S
(PERCENT) ACROSS THE ENTIRE REGION. THERE WILL BE CHANCES FOR
ISOLATED TO SCATTERED SHOWERS OR AN ISOLATED THUNDERSTORM OR TWO
ACROSS THE SOUTH AND SOUTHWEST WY THIS AFTERNOON. MUCH BETTER
CHANCES FOR RAIN AND OR SNOW WILL OCCUR EAST OF THE DIVIDE...
ESPECIALLY ACROSS CENTRAL WYOMING TODAY  THROUGH THIS EVENING.
PRECIPITATION ENDS ACROSS WYOMING SUNDAY...HOWEVER FIRE DANGER WILL
REMAIN LOW FOR THE MOST PART AS LOTS OF RESIDUAL MOISTURE REMAINS
ACROSS MUCH OF THE STATE AND GREEN UP BEGINS. WINDS...HOWEVER...WILL
BE QUITE GUSTY ACROSS THE SOUTHERN PORTION OF WYOMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR WYZ015.

&&

$$

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





000
FXUS65 KRIW 301655
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1055 AM MDT SAT APR 30 2016

.SHORT TERM...SATURDAY THROUGH MONDAY NIGHT

FINALLY SOME HOPE FOR SOME DRIER AND MORE SPRINGLIKE WEATHER IS ON
THE WAY. HOWEVER...WE HAVE TO GET THROUGH ONE TO ONE AND A HALF MORE
DAYS OF SOUP BEFORE WE GET THERE.

AN UPPER LEVEL LOW NOW SPINNING OVER EASTERN COLORADO WILL CONTINUE
TO WRAP MOISTURE BACK INTO CENTRAL WYOMING. AS A RESULT...EXPECT
MORE OF THE SAME WITH PERIODS OF RAIN AND SNOW THROUGH MUCH OF THE
DAY. WITH THE SOUTHEAST FLOW...THE HEAVIEST PRECIPITATION WILL FALL
ALONG THE EAST TO NORTHEAST FACING SLOPES OF THE MOUNTAINS AND
PLACES LIKE THE UPPER WIND RIVER BASIN. AS FOR THE ADVISORIES...WE
WILL LEAVE THEM UP. ALTHOUGH AMOUNTS WOULD REACH ADVISORY
CRITERIA...IMPACTS MAY BE MINIMAL FOR THE FOLLOWING REASONS. THE AIR
WITH THIS SYSTEM IS NOT TERRIBLY COLD WITH MOST OF THE LOWER
ELEVATIONS EXPECTED TO REMAIN NEAR TO ABOVE FREEZING. THIS COMBINED
WITH THE STRONG LATE APRIL SUN WILL MAKE IT DIFFICULT FOR SNOW TO
ACCUMULATE AT TIMES UNLESS THE RATE IS HEAVY...ESPECIALLY ON ROADS
AND OTHER PAVED SURFACES. THIS COULD BE A SITUATION WHERE THERE
COULD BE 3 TO 5 INCHES ON THE GRASS AND CAR TOPS WHILE THE ROADS ARE
ONLY WET TO SLUSHY IN SPOTS. IN ADDITION...WITH TEMPERATURES ABOVE
FREEZING FOR MUCH OF THE TIME IN THE LOWER ELEVATIONS...THE SNOW
WILL LIKELY MIX WITH RAIN AND SNOW AT TIMES. THE BIGGEST TIMES OF
CONCERN WOULD BE UNTIL AROUND 9 AM THIS MORNING AND AFTER 8 PM
TONIGHT AFTER THE SUN GOES DOWN. THE MODELS HAVE COME IN BETTER
AGREEMENT IN ENDING THE STEADY PRECIPITATION BY LATER SATURDAY NIGHT.

SUNDAY AT THIS POINT LOOKS TO BE A MAINLY DRY DAY WITH ONLY A SMALL
CHANCE OF SOME LEFTOVER SHOWERS...MAINLY DURING THE MORNING HOURS IN
CENTRAL AND SOUTHERN AREAS. AS DRIER AIR MOVES IN FROM THE
NORTH...EXPECT THE CHANCE FOR A RETURN APPEARANCE OF THAT YELLOW ORB
IN THE SKY...WHAT IS THAT THING CALLED?  OH...THE SUN. MANY AREAS
HAVE NOT SEEN IT IN SO LONG I FORGOT WHAT IT WAS CALLED. SINCE IT
HAS TAKEN LONGER TO CLEAR THAT THE MODELS HAVE INDICATED...WE KEPT
THINGS CLOUDIER WITH THE REASONING THAT IF IT GETS SUNNIER AND
WARMER...MOST PEOPLE WILL BE HAPPY. TEMPERATURES WILL BE WARMER THAN
THE PREVIOUS FEW DAYS HOWEVER.

MONDAY AT THIS POINT LOOKS TO BE ONE OF THE NICER DAYS THAT WE HAVE
HAD IN A WHILE. AT THIS POINT...THE ONLY PLACE WITH THE CHANCE OF A
FEW SHOWERS OR THUNDERSTORMS WOULD BE OVER THE FAR SOUTH WITH SOME
MOISTURE GETTING THROWN NORTHWARD FROM AN UPPER LEVEL LOW OVER THE
FOUR CORNERS REGION. BUT EVEN HERE...THEY LOOK FEW AND FAR BETWEEN.
TEMPERATURES WILL CONTINUE TO MODERATE AS WELL WITH MORE SUNSHINE.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...AN UPPER RIDGE OF HIGH PRESSURE WILL BRING WARMER AND
MAINLY DRY CONDITIONS ACROSS THE AREA TUESDAY AND WEDNESDAY.  AN
UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY MOVE ACROSS THE
SOUTHWEST U.S. INTO THE FOUR CORNERS REGION FRIDAY AND SATURDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE WEST
THURSDAY AND INTO CENTRAL WYOMING FRIDAY.  CLOUDY AND COOLER WEATHER
WITH CHANCES OF SHOWERS ARE EXPECTED ACROSS THE AREA ON SATURDAY.

DISCUSSION...BLOCKY PATTERN WITH HIGH AMPLITUDE RIDGE CENTERED OVER
THE ROCKIES...PACIFIC TROUGH ALONG THE WEST COAST BEGIN THIS PERIOD
ON TUESDAY AND WEDNESDAY.  SOME MOISTURE AND SLIGHT INSTABILITY OVER
THE WESTERN MOUNTAINS MAY RESULT IN ISOLATED SHOWERS...OTHERWISE
PLENTIFUL SUNSHINE WITH HIGH TEMPERATURES ACROSS THE VALLEYS AND
BASINS IN THE 60S AND 70S WILL BE THE RULE.

UPPER RIDGE WILL SHIFT EAST INTO THE PLAINS ON THURSDAY WITH
INCREASING SOUTHERLY FLOW ACROSS THE REGION.  WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND WEST OF A KEMMERER-
DUBOIS-POWELL LINE THURSDAY AFTERNOON/EVENING.  WARM SOUTH WIND WILL
BRING MUCH ABOVE NORMAL TEMPERATURES EAST OF THE DIVIDE WITH A FEW
NEAR 80F READINGS POSSIBLE ACROSS THE LOWER BASINS.

ECMWF IS INITIALLY SLOWER THAN GFS BRINGING SW LOW INTO THE FOUR
CORNERS REGION FRIDAY AND SATURDAY...BUT ECMWF THEN ACCELERATES
UPPER LOW INTO THE CENTRAL HIGH PLAINS BY 00Z SUNDAY WHILE GFS SHOWS
MORE OF A REX BLOCK SETTING UP OVER THE ROCKIES WITH UPPER LOW
REMAINING IN THE FOUR CORNERS AREA.  THE SLOWER SOLUTION...GFS IN
THIS CASE...USUALLY WINS OUT WITH A SW LOW AND STRONG DOWNSTREAM
RIDGING.


&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/OCCASIONAL MVFR CONDITIONS OVER MUCH OF WESTERN WY THROUGH THE
AFTERNOON. KRKS WILL PERSIST MVFR OVER THE SAME PERIOD. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE WEST THIS
AFTERNOON INTO THE EVENING WITH OCCASIONAL MVFR CONDITIONS
ACCOMPANYING. MOUNTAIN OBSCURATION WILL ALSO BE PERSISTENT THROUGH
THE EVENING PERIOD. SHOWERS WILL DECREASE TO ISOLATED ACTIVITY
BEFORE 06Z SUNDAY. HOWEVER AREAS OF MVFR CIGS AND OR VCFG WILL
BE AROUND THROUGH 15Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY THIS EVENING. FAR NORTHERN WY
WILL SEE LESS PRECIPITATION TODAY. EXPECT MVFR TO IFR CONDITIONS
OVER MOST OF THE REGION...WITH MVFR TO VFR UP NORTH. MOUNTAINS WILL
BE FREQUENTLY OBSCURED THROUGH SUNDAY MORNING. THE RAIN AND SNOW
WILL DECREASE AFTER 03Z. AREAS OF MVFR/IFR CIGS AND OR VCFG WILL
BE AROUND OVER MUCH OF THE REGION THROUGH 15Z SUNDAY.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. MANY AREAS ACROSS CENTRAL AND EASTERN WYOMING WILL HAVE A
GOOD CHANCE OF A WETTING RAIN TODAY WITH PERIODS OF MIXED RAIN AND
SNOW. HIGH PRESSURE BUILDING IN FROM THE NORTH WILL BEGIN A DRYING
TREND SUNDAY AND INTO THE FIRST PART OF NEXT WEEK.
&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO MIDNIGHT MDT
TONIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 301655
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1055 AM MDT SAT APR 30 2016

.SHORT TERM...SATURDAY THROUGH MONDAY NIGHT

FINALLY SOME HOPE FOR SOME DRIER AND MORE SPRINGLIKE WEATHER IS ON
THE WAY. HOWEVER...WE HAVE TO GET THROUGH ONE TO ONE AND A HALF MORE
DAYS OF SOUP BEFORE WE GET THERE.

AN UPPER LEVEL LOW NOW SPINNING OVER EASTERN COLORADO WILL CONTINUE
TO WRAP MOISTURE BACK INTO CENTRAL WYOMING. AS A RESULT...EXPECT
MORE OF THE SAME WITH PERIODS OF RAIN AND SNOW THROUGH MUCH OF THE
DAY. WITH THE SOUTHEAST FLOW...THE HEAVIEST PRECIPITATION WILL FALL
ALONG THE EAST TO NORTHEAST FACING SLOPES OF THE MOUNTAINS AND
PLACES LIKE THE UPPER WIND RIVER BASIN. AS FOR THE ADVISORIES...WE
WILL LEAVE THEM UP. ALTHOUGH AMOUNTS WOULD REACH ADVISORY
CRITERIA...IMPACTS MAY BE MINIMAL FOR THE FOLLOWING REASONS. THE AIR
WITH THIS SYSTEM IS NOT TERRIBLY COLD WITH MOST OF THE LOWER
ELEVATIONS EXPECTED TO REMAIN NEAR TO ABOVE FREEZING. THIS COMBINED
WITH THE STRONG LATE APRIL SUN WILL MAKE IT DIFFICULT FOR SNOW TO
ACCUMULATE AT TIMES UNLESS THE RATE IS HEAVY...ESPECIALLY ON ROADS
AND OTHER PAVED SURFACES. THIS COULD BE A SITUATION WHERE THERE
COULD BE 3 TO 5 INCHES ON THE GRASS AND CAR TOPS WHILE THE ROADS ARE
ONLY WET TO SLUSHY IN SPOTS. IN ADDITION...WITH TEMPERATURES ABOVE
FREEZING FOR MUCH OF THE TIME IN THE LOWER ELEVATIONS...THE SNOW
WILL LIKELY MIX WITH RAIN AND SNOW AT TIMES. THE BIGGEST TIMES OF
CONCERN WOULD BE UNTIL AROUND 9 AM THIS MORNING AND AFTER 8 PM
TONIGHT AFTER THE SUN GOES DOWN. THE MODELS HAVE COME IN BETTER
AGREEMENT IN ENDING THE STEADY PRECIPITATION BY LATER SATURDAY NIGHT.

SUNDAY AT THIS POINT LOOKS TO BE A MAINLY DRY DAY WITH ONLY A SMALL
CHANCE OF SOME LEFTOVER SHOWERS...MAINLY DURING THE MORNING HOURS IN
CENTRAL AND SOUTHERN AREAS. AS DRIER AIR MOVES IN FROM THE
NORTH...EXPECT THE CHANCE FOR A RETURN APPEARANCE OF THAT YELLOW ORB
IN THE SKY...WHAT IS THAT THING CALLED?  OH...THE SUN. MANY AREAS
HAVE NOT SEEN IT IN SO LONG I FORGOT WHAT IT WAS CALLED. SINCE IT
HAS TAKEN LONGER TO CLEAR THAT THE MODELS HAVE INDICATED...WE KEPT
THINGS CLOUDIER WITH THE REASONING THAT IF IT GETS SUNNIER AND
WARMER...MOST PEOPLE WILL BE HAPPY. TEMPERATURES WILL BE WARMER THAN
THE PREVIOUS FEW DAYS HOWEVER.

MONDAY AT THIS POINT LOOKS TO BE ONE OF THE NICER DAYS THAT WE HAVE
HAD IN A WHILE. AT THIS POINT...THE ONLY PLACE WITH THE CHANCE OF A
FEW SHOWERS OR THUNDERSTORMS WOULD BE OVER THE FAR SOUTH WITH SOME
MOISTURE GETTING THROWN NORTHWARD FROM AN UPPER LEVEL LOW OVER THE
FOUR CORNERS REGION. BUT EVEN HERE...THEY LOOK FEW AND FAR BETWEEN.
TEMPERATURES WILL CONTINUE TO MODERATE AS WELL WITH MORE SUNSHINE.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...AN UPPER RIDGE OF HIGH PRESSURE WILL BRING WARMER AND
MAINLY DRY CONDITIONS ACROSS THE AREA TUESDAY AND WEDNESDAY.  AN
UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY MOVE ACROSS THE
SOUTHWEST U.S. INTO THE FOUR CORNERS REGION FRIDAY AND SATURDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE WEST
THURSDAY AND INTO CENTRAL WYOMING FRIDAY.  CLOUDY AND COOLER WEATHER
WITH CHANCES OF SHOWERS ARE EXPECTED ACROSS THE AREA ON SATURDAY.

DISCUSSION...BLOCKY PATTERN WITH HIGH AMPLITUDE RIDGE CENTERED OVER
THE ROCKIES...PACIFIC TROUGH ALONG THE WEST COAST BEGIN THIS PERIOD
ON TUESDAY AND WEDNESDAY.  SOME MOISTURE AND SLIGHT INSTABILITY OVER
THE WESTERN MOUNTAINS MAY RESULT IN ISOLATED SHOWERS...OTHERWISE
PLENTIFUL SUNSHINE WITH HIGH TEMPERATURES ACROSS THE VALLEYS AND
BASINS IN THE 60S AND 70S WILL BE THE RULE.

UPPER RIDGE WILL SHIFT EAST INTO THE PLAINS ON THURSDAY WITH
INCREASING SOUTHERLY FLOW ACROSS THE REGION.  WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND WEST OF A KEMMERER-
DUBOIS-POWELL LINE THURSDAY AFTERNOON/EVENING.  WARM SOUTH WIND WILL
BRING MUCH ABOVE NORMAL TEMPERATURES EAST OF THE DIVIDE WITH A FEW
NEAR 80F READINGS POSSIBLE ACROSS THE LOWER BASINS.

ECMWF IS INITIALLY SLOWER THAN GFS BRINGING SW LOW INTO THE FOUR
CORNERS REGION FRIDAY AND SATURDAY...BUT ECMWF THEN ACCELERATES
UPPER LOW INTO THE CENTRAL HIGH PLAINS BY 00Z SUNDAY WHILE GFS SHOWS
MORE OF A REX BLOCK SETTING UP OVER THE ROCKIES WITH UPPER LOW
REMAINING IN THE FOUR CORNERS AREA.  THE SLOWER SOLUTION...GFS IN
THIS CASE...USUALLY WINS OUT WITH A SW LOW AND STRONG DOWNSTREAM
RIDGING.


&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/OCCASIONAL MVFR CONDITIONS OVER MUCH OF WESTERN WY THROUGH THE
AFTERNOON. KRKS WILL PERSIST MVFR OVER THE SAME PERIOD. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP OVER THE WEST THIS
AFTERNOON INTO THE EVENING WITH OCCASIONAL MVFR CONDITIONS
ACCOMPANYING. MOUNTAIN OBSCURATION WILL ALSO BE PERSISTENT THROUGH
THE EVENING PERIOD. SHOWERS WILL DECREASE TO ISOLATED ACTIVITY
BEFORE 06Z SUNDAY. HOWEVER AREAS OF MVFR CIGS AND OR VCFG WILL
BE AROUND THROUGH 15Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY THIS EVENING. FAR NORTHERN WY
WILL SEE LESS PRECIPITATION TODAY. EXPECT MVFR TO IFR CONDITIONS
OVER MOST OF THE REGION...WITH MVFR TO VFR UP NORTH. MOUNTAINS WILL
BE FREQUENTLY OBSCURED THROUGH SUNDAY MORNING. THE RAIN AND SNOW
WILL DECREASE AFTER 03Z. AREAS OF MVFR/IFR CIGS AND OR VCFG WILL
BE AROUND OVER MUCH OF THE REGION THROUGH 15Z SUNDAY.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. MANY AREAS ACROSS CENTRAL AND EASTERN WYOMING WILL HAVE A
GOOD CHANCE OF A WETTING RAIN TODAY WITH PERIODS OF MIXED RAIN AND
SNOW. HIGH PRESSURE BUILDING IN FROM THE NORTH WILL BEGIN A DRYING
TREND SUNDAY AND INTO THE FIRST PART OF NEXT WEEK.
&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO MIDNIGHT MDT
TONIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 300909
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
309 AM MDT SAT APR 30 2016

.SHORT TERM...SATURDAY THROUGH MONDAY NIGHT

FINALLY SOME HOPE FOR SOME DRIER AND MORE SPRINGLIKE WEATHER IS ON
THE WAY. HOWEVER...WE HAVE TO GET THROUGH ONE TO ONE AND A HALF MORE
DAYS OF SOUP BEFORE WE GET THERE.

AN UPPER LEVEL LOW NOW SPINNING OVER EASTERN COLORADO WILL CONTINUE
TO WRAP MOISTURE BACK INTO CENTRAL WYOMING. AS A RESULT...EXPECT
MORE OF THE SAME WITH PERIODS OF RAIN AND SNOW THROUGH MUCH OF THE
DAY. WITH THE SOUTHEAST FLOW...THE HEAVIEST PRECIPITATION WILL FALL
ALONG THE EAST TO NORTHEAST FACING SLOPES OF THE MOUNTAINS AND
PLACES LIKE THE UPPER WIND RIVER BASIN. AS FOR THE ADVISORIES...WE
WILL LEAVE THEM UP. ALTHOUGH AMOUNTS WOULD REACH ADVISORY
CRITERIA...IMPACTS MAY BE MINIMAL FOR THE FOLLOWING REASONS. THE AIR
WITH THIS SYSTEM IS NOT TERRIBLY COLD WITH MOST OF THE LOWER
ELEVATIONS EXPECTED TO REMAIN NEAR TO ABOVE FREEZING. THIS COMBINED
WITH THE STRONG LATE APRIL SUN WILL MAKE IT DIFFICULT FOR SNOW TO
ACCUMULATE AT TIMES UNLESS THE RATE IS HEAVY...ESPECIALLY ON ROADS
AND OTHER PAVED SURFACES. THIS COULD BE A SITUATION WHERE THERE
COULD BE 3 TO 5 INCHES ON THE GRASS AND CAR TOPS WHILE THE ROADS ARE
ONLY WET TO SLUSHY IN SPOTS. IN ADDITION...WITH TEMPERATURES ABOVE
FREEZING FOR MUCH OF THE TIME IN THE LOWER ELEVATIONS...THE SNOW
WILL LIKELY MIX WITH RAIN AND SNOW AT TIMES. THE BIGGEST TIMES OF
CONCERN WOULD BE UNTIL AROUND 9 AM THIS MORNING AND AFTER 8 PM
TONIGHT AFTER THE SUN GOES DOWN. THE MODELS HAVE COME IN BETTER
AGREEMENT IN ENDING THE STEADY PRECIPITATION BY LATER SATURDAY NIGHT.

SUNDAY AT THIS POINT LOOKS TO BE A MAINLY DRY DAY WITH ONLY A SMALL
CHANCE OF SOME LEFTOVER SHOWERS...MAINLY DURING THE MORNING HOURS IN
CENTRAL AND SOUTHERN AREAS. AS DRIER AIR MOVES IN FROM THE
NORTH...EXPECT THE CHANCE FOR A RETURN APPEARANCE OF THAT YELLOW ORB
IN THE SKY...WHAT IS THAT THING CALLED?  OH...THE SUN. MANY AREAS
HAVE NOT SEEN IT IN SO LONG I FORGOT WHAT IT WAS CALLED. SINCE IT
HAS TAKEN LONGER TO CLEAR THAT THE MODELS HAVE INDICATED...WE KEPT
THINGS CLOUDIER WITH THE REASONING THAT IF IT GETS SUNNIER AND
WARMER...MOST PEOPLE WILL BE HAPPY. TEMPERATURES WILL BE WARMER THAN
THE PREVIOUS FEW DAYS HOWEVER.

MONDAY AT THIS POINT LOOKS TO BE ONE OF THE NICER DAYS THAT WE HAVE
HAD IN A WHILE. AT THIS POINT...THE ONLY PLACE WITH THE CHANCE OF A
FEW SHOWERS OR THUNDERSTORMS WOULD BE OVER THE FAR SOUTH WITH SOME
MOISTURE GETTING THROWN NORTHWARD FROM AN UPPER LEVEL LOW OVER THE
FOUR CORNERS REGION. BUT EVEN HERE...THEY LOOK FEW AND FAR BETWEEN.
TEMPERATURES WILL CONTINUE TO MODERATE AS WELL WITH MORE SUNSHINE.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...AN UPPER RIDGE OF HIGH PRESSURE WILL BRING WARMER AND
MAINLY DRY CONDITIONS ACROSS THE AREA TUESDAY AND WEDNESDAY.  AN
UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY MOVE ACROSS THE
SOUTHWEST U.S. INTO THE FOUR CORNERS REGION FRIDAY AND SATURDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE WEST
THURSDAY AND INTO CENTRAL WYOMING FRIDAY.  CLOUDY AND COOLER WEATHER
WITH CHANCES OF SHOWERS ARE EXPECTED ACROSS THE AREA ON SATURDAY.

DISCUSSION...BLOCKY PATTERN WITH HIGH AMPLITUDE RIDGE CENTERED OVER
THE ROCKIES...PACIFIC TROUGH ALONG THE WEST COAST BEGIN THIS PERIOD
ON TUESDAY AND WEDNESDAY.  SOME MOISTURE AND SLIGHT INSTABILITY OVER
THE WESTERN MOUNTAINS MAY RESULT IN ISOLATED SHOWERS...OTHERWISE
PLENTIFUL SUNSHINE WITH HIGH TEMPERATURES ACROSS THE VALLEYS AND
BASINS IN THE 60S AND 70S WILL BE THE RULE.

UPPER RIDGE WILL SHIFT EAST INTO THE PLAINS ON THURSDAY WITH
INCREASING SOUTHERLY FLOW ACROSS THE REGION.  WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND WEST OF A KEMMERER-
DUBOIS-POWELL LINE THURSDAY AFTERNOON/EVENING.  WARM SOUTH WIND WILL
BRING MUCH ABOVE NORMAL TEMPERATURES EAST OF THE DIVIDE WITH A FEW
NEAR 80F READINGS POSSIBLE ACROSS THE LOWER BASINS.

ECMWF IS INITIALLY SLOWER THAN GFS BRINGING SW LOW INTO THE FOUR
CORNERS REGION FRIDAY AND SATURDAY...BUT ECMWF THEN ACCELERATES
UPPER LOW INTO THE CENTRAL HIGH PLAINS BY 00Z SUNDAY WHILE GFS SHOWS
MORE OF A REX BLOCK SETTING UP OVER THE ROCKIES WITH UPPER LOW
REMAINING IN THE FOUR CORNERS AREA.  THE SLOWER SOLUTION...GFS IN
THIS CASE...USUALLY WINS OUT WITH A SW LOW AND STRONG DOWNSTREAM
RIDGING.


&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

ISOLATED RAIN OR SNOW SHOWERS OVER THE WEST UNTIL 15Z WITH SOME
MVFR CIGS. OTHERWISE VFR CONDITIONS OVER WESTERN WY THROUGH THE
MORNING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER THE WEST THIS AFTERNOON INTO THE EVENING. AREAS OF MVFR
CONDITIONS WILL OCCUR ALONG WITH PARTIAL MOUNTAIN OBSCURATION.
SHOWERS WILL DECREASE TO ISOLATED ACTIVITY BY 06Z SUNDAY. HOWEVER
AREAS OF MVFR CIGS WILL LINGER THROUGH 12Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY THIS EVENING. FAR NORTHERN
WY WILL SEE LESS RAIN COVERAGE TODAY. EXPECT MVFR TO IFR CONDITIONS
OVER MOST OF THE REGION. MOUNTAINS WILL BE FREQUENTLY OBSCURED.
THE RAIN AND SNOW WILL DECREASE AFTER 00Z. AREAS OF MVFR/IFR CIGS
WILL REMAIN OVER MUCH OF THE REGION THROUGH 12Z SUNDAY.
&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. MANY AREAS ACROSS CENTRAL AND EASTERN WYOMING WILL HAVE A
GOOD CHANCE OF A WETTING RAIN TODAY WITH PERIODS OF MIXED RAIN AND
SNOW. HIGH PRESSURE BUILDING IN FROM THE NORTH WILL BEGIN A DRYING
TREND SUNDAY AND INTO THE FIRST PART OF NEXT WEEK.
&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO MIDNIGHT MDT
TONIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 300909
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
309 AM MDT SAT APR 30 2016

.SHORT TERM...SATURDAY THROUGH MONDAY NIGHT

FINALLY SOME HOPE FOR SOME DRIER AND MORE SPRINGLIKE WEATHER IS ON
THE WAY. HOWEVER...WE HAVE TO GET THROUGH ONE TO ONE AND A HALF MORE
DAYS OF SOUP BEFORE WE GET THERE.

AN UPPER LEVEL LOW NOW SPINNING OVER EASTERN COLORADO WILL CONTINUE
TO WRAP MOISTURE BACK INTO CENTRAL WYOMING. AS A RESULT...EXPECT
MORE OF THE SAME WITH PERIODS OF RAIN AND SNOW THROUGH MUCH OF THE
DAY. WITH THE SOUTHEAST FLOW...THE HEAVIEST PRECIPITATION WILL FALL
ALONG THE EAST TO NORTHEAST FACING SLOPES OF THE MOUNTAINS AND
PLACES LIKE THE UPPER WIND RIVER BASIN. AS FOR THE ADVISORIES...WE
WILL LEAVE THEM UP. ALTHOUGH AMOUNTS WOULD REACH ADVISORY
CRITERIA...IMPACTS MAY BE MINIMAL FOR THE FOLLOWING REASONS. THE AIR
WITH THIS SYSTEM IS NOT TERRIBLY COLD WITH MOST OF THE LOWER
ELEVATIONS EXPECTED TO REMAIN NEAR TO ABOVE FREEZING. THIS COMBINED
WITH THE STRONG LATE APRIL SUN WILL MAKE IT DIFFICULT FOR SNOW TO
ACCUMULATE AT TIMES UNLESS THE RATE IS HEAVY...ESPECIALLY ON ROADS
AND OTHER PAVED SURFACES. THIS COULD BE A SITUATION WHERE THERE
COULD BE 3 TO 5 INCHES ON THE GRASS AND CAR TOPS WHILE THE ROADS ARE
ONLY WET TO SLUSHY IN SPOTS. IN ADDITION...WITH TEMPERATURES ABOVE
FREEZING FOR MUCH OF THE TIME IN THE LOWER ELEVATIONS...THE SNOW
WILL LIKELY MIX WITH RAIN AND SNOW AT TIMES. THE BIGGEST TIMES OF
CONCERN WOULD BE UNTIL AROUND 9 AM THIS MORNING AND AFTER 8 PM
TONIGHT AFTER THE SUN GOES DOWN. THE MODELS HAVE COME IN BETTER
AGREEMENT IN ENDING THE STEADY PRECIPITATION BY LATER SATURDAY NIGHT.

SUNDAY AT THIS POINT LOOKS TO BE A MAINLY DRY DAY WITH ONLY A SMALL
CHANCE OF SOME LEFTOVER SHOWERS...MAINLY DURING THE MORNING HOURS IN
CENTRAL AND SOUTHERN AREAS. AS DRIER AIR MOVES IN FROM THE
NORTH...EXPECT THE CHANCE FOR A RETURN APPEARANCE OF THAT YELLOW ORB
IN THE SKY...WHAT IS THAT THING CALLED?  OH...THE SUN. MANY AREAS
HAVE NOT SEEN IT IN SO LONG I FORGOT WHAT IT WAS CALLED. SINCE IT
HAS TAKEN LONGER TO CLEAR THAT THE MODELS HAVE INDICATED...WE KEPT
THINGS CLOUDIER WITH THE REASONING THAT IF IT GETS SUNNIER AND
WARMER...MOST PEOPLE WILL BE HAPPY. TEMPERATURES WILL BE WARMER THAN
THE PREVIOUS FEW DAYS HOWEVER.

MONDAY AT THIS POINT LOOKS TO BE ONE OF THE NICER DAYS THAT WE HAVE
HAD IN A WHILE. AT THIS POINT...THE ONLY PLACE WITH THE CHANCE OF A
FEW SHOWERS OR THUNDERSTORMS WOULD BE OVER THE FAR SOUTH WITH SOME
MOISTURE GETTING THROWN NORTHWARD FROM AN UPPER LEVEL LOW OVER THE
FOUR CORNERS REGION. BUT EVEN HERE...THEY LOOK FEW AND FAR BETWEEN.
TEMPERATURES WILL CONTINUE TO MODERATE AS WELL WITH MORE SUNSHINE.

.LONG TERM...TUESDAY THROUGH SATURDAY

SYNOPSIS...AN UPPER RIDGE OF HIGH PRESSURE WILL BRING WARMER AND
MAINLY DRY CONDITIONS ACROSS THE AREA TUESDAY AND WEDNESDAY.  AN
UPPER LEVEL LOW PRESSURE SYSTEM WILL SLOWLY MOVE ACROSS THE
SOUTHWEST U.S. INTO THE FOUR CORNERS REGION FRIDAY AND SATURDAY.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO SPREAD INTO THE WEST
THURSDAY AND INTO CENTRAL WYOMING FRIDAY.  CLOUDY AND COOLER WEATHER
WITH CHANCES OF SHOWERS ARE EXPECTED ACROSS THE AREA ON SATURDAY.

DISCUSSION...BLOCKY PATTERN WITH HIGH AMPLITUDE RIDGE CENTERED OVER
THE ROCKIES...PACIFIC TROUGH ALONG THE WEST COAST BEGIN THIS PERIOD
ON TUESDAY AND WEDNESDAY.  SOME MOISTURE AND SLIGHT INSTABILITY OVER
THE WESTERN MOUNTAINS MAY RESULT IN ISOLATED SHOWERS...OTHERWISE
PLENTIFUL SUNSHINE WITH HIGH TEMPERATURES ACROSS THE VALLEYS AND
BASINS IN THE 60S AND 70S WILL BE THE RULE.

UPPER RIDGE WILL SHIFT EAST INTO THE PLAINS ON THURSDAY WITH
INCREASING SOUTHERLY FLOW ACROSS THE REGION.  WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG AND WEST OF A KEMMERER-
DUBOIS-POWELL LINE THURSDAY AFTERNOON/EVENING.  WARM SOUTH WIND WILL
BRING MUCH ABOVE NORMAL TEMPERATURES EAST OF THE DIVIDE WITH A FEW
NEAR 80F READINGS POSSIBLE ACROSS THE LOWER BASINS.

ECMWF IS INITIALLY SLOWER THAN GFS BRINGING SW LOW INTO THE FOUR
CORNERS REGION FRIDAY AND SATURDAY...BUT ECMWF THEN ACCELERATES
UPPER LOW INTO THE CENTRAL HIGH PLAINS BY 00Z SUNDAY WHILE GFS SHOWS
MORE OF A REX BLOCK SETTING UP OVER THE ROCKIES WITH UPPER LOW
REMAINING IN THE FOUR CORNERS AREA.  THE SLOWER SOLUTION...GFS IN
THIS CASE...USUALLY WINS OUT WITH A SW LOW AND STRONG DOWNSTREAM
RIDGING.


&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

ISOLATED RAIN OR SNOW SHOWERS OVER THE WEST UNTIL 15Z WITH SOME
MVFR CIGS. OTHERWISE VFR CONDITIONS OVER WESTERN WY THROUGH THE
MORNING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL DEVELOP
OVER THE WEST THIS AFTERNOON INTO THE EVENING. AREAS OF MVFR
CONDITIONS WILL OCCUR ALONG WITH PARTIAL MOUNTAIN OBSCURATION.
SHOWERS WILL DECREASE TO ISOLATED ACTIVITY BY 06Z SUNDAY. HOWEVER
AREAS OF MVFR CIGS WILL LINGER THROUGH 12Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY THIS EVENING. FAR NORTHERN
WY WILL SEE LESS RAIN COVERAGE TODAY. EXPECT MVFR TO IFR CONDITIONS
OVER MOST OF THE REGION. MOUNTAINS WILL BE FREQUENTLY OBSCURED.
THE RAIN AND SNOW WILL DECREASE AFTER 00Z. AREAS OF MVFR/IFR CIGS
WILL REMAIN OVER MUCH OF THE REGION THROUGH 12Z SUNDAY.
&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. MANY AREAS ACROSS CENTRAL AND EASTERN WYOMING WILL HAVE A
GOOD CHANCE OF A WETTING RAIN TODAY WITH PERIODS OF MIXED RAIN AND
SNOW. HIGH PRESSURE BUILDING IN FROM THE NORTH WILL BEGIN A DRYING
TREND SUNDAY AND INTO THE FIRST PART OF NEXT WEEK.
&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO MIDNIGHT MDT
TONIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 300445
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1045 PM MDT FRI APR 29 2016

.SHORT TERM...TONIGHT THROUGH SATURDAY (ISSUED AT 211 PM MDT)

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW(S) OVER THE WEST WITH THE CENTER OF
CIRC STILL NEAR THE FOUR CORNERS AREA. TWO EMBEDDED SEVERAL EMBEDDED
DISTURBANCES...KEEP ROTATING UP FROM ERN CO...PROVIDING MUCH OF THE
IMPETUS FOR LIGHT -SHRASN TODAY...MAINLY FROM THE CNTRL BASINS SOUTH
AND SOUTHEAST INTO NRN COLORADO. SFC HAS MAIN SFC LOW WELL TO THE
SOUTH ACROSS CNTRL CO...WITH ONLY A WEAK INVERTED TROF UP INTO ERN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH AND EAST.

SEASONALLY COOL/COLD CONDITIONS CONTINUE AND WILL CONTINUE THROUGH
THE FCST PERIOD...WITH RELATIVELY HIGH PWS READY TO HEAD BACK INTO
EASTERN AND CENTRAL WYOMING ON SATURDAY. OTHERWISE...A RATHER
PERSISTENT STRAT CU CLOUD DECK REMAINS OVR MUCH OF WY WITH ONLY A
FEW BREAKS IN THE CLOUDS. AS NIGHTTIME ROLLS AROUND...THE BROKEN
STRATUS DECK WILL TIGHTEN UP ONCE AGAIN AS TEMPS FALL AND MOISTURE
INCREASES FROM THE EAST TO NORTHEAST OVERNIGHT AND SATURDAY MORNING
AROUND THE DEVELOPING CYCLONE OVR THE CNTRL PLAINS. LIGHT SNOW OR
RAIN MIXED WITH SNOW WILL SLOWLY INCREASE INTO THE ERN AND CNTRL
ZONES OVERNIGHT SO THAT BY SATURDAY MORNING...RAIN/MIX/SNOWFALL
RATES WILL INCREASE TO MODERATE FROM SRN JOHNSON AND ALL OF NATRONA
COUNTIES...WWD INTO FREMONT COUNTY...PUSHING INTO THE ERN WIND RIVER
MOUNTAINS AND SRN ABSAROKAS UNDER GOOD UPSLOPE CONDITIONS.

A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR PORTIONS OF CENTRAL
WYOMING AND THE ABSAROKA MOUNTAINS...INCLUDING ZONES 2 11 16 17 18
19 20 AND 22...BEGINNING AT 12Z SAT...LASTING THRU 06Z SUN. ACROSS
THE ADVISORY AREA...THRU THOSE 18 HRS OF THE FCST PERIOD...SNOW
ACCUMULATION SHOULD GENERALLY RANGE FROM 2 TO 5 INCHES ACROSS THE
LOWER ELEVATIONS...AND FROM 3 TO 10 INCHES IN THE MOUNTAINS.
PRECIPITATION SHOULD TAPER OFF BY MIDNIGHT SATURDAY.
LIGHTER AMOUNTS OF A HALF TO A COUPLE OF INCHES IS EXPECTED
ELSEWHERE...WITH PERHAPS UP TO 4 INCHES IN THE TETONS OR
WYOMING/SALT MOUNTAIN RANGES THROUGH THE SAME PERIOD. BRISK NORTH TO
EAST WINDS WILL ALSO ACCOMPANY THIS SYSTEM...HELPING IN REDUCING
VISIBILITIES TO ONE MILE OR LESS FOR EXTENDED PERIODS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A COLD LOW PRESSURE TROUGH WILL BE OVER THE AREA SATURDAY NIGHT WITH
MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF SNOW OR A RAIN AND
SNOW MIX.  THIS WILL TAPER OFF ON SUNDAY AS THE UPPER LOW PRESSURE
AREA SPLITS WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE
EAST WHILE A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN
GREAT BASIN AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.
DRYING OCCURS FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE
AREA MOVES SOUTH FROM ALBERTA ON MONDAY AND MONDAY NIGHT. THE
WEAKENING OF THE SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START
TO DIFFER WITH THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND
WARMING TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO
EASTERN WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING
WITH SOME SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE
WESTERN MOUNTAINS. THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES
QUITE LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES IN
THE BIGHORN BASIN.  AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN
ON FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO
NORTHEAST FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND
INCREASED MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND
RAIN MOVING INTO NEXT WEEKEND.

&&

.AVIATION.../06Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

ISOLATED RAIN OR SNOW SHOWERS OVER NORTHWEST WY OVERNIGHT WITH SOME
MVFR CIGS EXPECTED. OTHERWISE VFR CONDITIONS OVER WESTERN WY THROUGH
SATURDAY MORNING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
DEVELOP OVER THE WEST SATURDAY AFTERNOON INTO THE EVENING. AREAS OF
MVFR CONDITIONS WILL OCCUR ALONG WITH PARTIAL MOUNTAIN OBSCURATION.
SHOWERS WILL DECREASE TO ISOLATED ACTIVITY BY 06Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY EVENING SATURDAY OVER MOST OF
THE REGION. FAR NORTHERN WY WILL SEE LESS RAIN COVERAGE. EXPECT MVFR
TO IFR CONDITIONS OVER MOST OF THE REGION. MOUNTAINS WILL BE
FREQUENTLY OBSCURED. THE RAIN AND SNOW WILL DECREASE AFTER 00Z
SUNDAY. AREAS OF MVFR/IFR CIGS WILL REMAIN OVER MUCH OF THE REGION
THROUGH 06Z SUNDAY.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 40S TO MID 70S
(PERCENT). SMALL CHANCES FOR ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON.
SHOWERS...BOTH RAIN AND SNOW...WILL BE ON THE INCREASE EAST OF THE
DIVIDE AND ACROSS THE WESTERN MOUNTAINS SATURDAY...KEEPING FIRE
DANGER LOW ACROSS ALL OF WYOMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...

WINTER WEATHER ADVISORY FROM 6 AM SATURDAY TO MIDNIGHT MDT
SATURDAY NIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 300445
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1045 PM MDT FRI APR 29 2016

.SHORT TERM...TONIGHT THROUGH SATURDAY (ISSUED AT 211 PM MDT)

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW(S) OVER THE WEST WITH THE CENTER OF
CIRC STILL NEAR THE FOUR CORNERS AREA. TWO EMBEDDED SEVERAL EMBEDDED
DISTURBANCES...KEEP ROTATING UP FROM ERN CO...PROVIDING MUCH OF THE
IMPETUS FOR LIGHT -SHRASN TODAY...MAINLY FROM THE CNTRL BASINS SOUTH
AND SOUTHEAST INTO NRN COLORADO. SFC HAS MAIN SFC LOW WELL TO THE
SOUTH ACROSS CNTRL CO...WITH ONLY A WEAK INVERTED TROF UP INTO ERN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH AND EAST.

SEASONALLY COOL/COLD CONDITIONS CONTINUE AND WILL CONTINUE THROUGH
THE FCST PERIOD...WITH RELATIVELY HIGH PWS READY TO HEAD BACK INTO
EASTERN AND CENTRAL WYOMING ON SATURDAY. OTHERWISE...A RATHER
PERSISTENT STRAT CU CLOUD DECK REMAINS OVR MUCH OF WY WITH ONLY A
FEW BREAKS IN THE CLOUDS. AS NIGHTTIME ROLLS AROUND...THE BROKEN
STRATUS DECK WILL TIGHTEN UP ONCE AGAIN AS TEMPS FALL AND MOISTURE
INCREASES FROM THE EAST TO NORTHEAST OVERNIGHT AND SATURDAY MORNING
AROUND THE DEVELOPING CYCLONE OVR THE CNTRL PLAINS. LIGHT SNOW OR
RAIN MIXED WITH SNOW WILL SLOWLY INCREASE INTO THE ERN AND CNTRL
ZONES OVERNIGHT SO THAT BY SATURDAY MORNING...RAIN/MIX/SNOWFALL
RATES WILL INCREASE TO MODERATE FROM SRN JOHNSON AND ALL OF NATRONA
COUNTIES...WWD INTO FREMONT COUNTY...PUSHING INTO THE ERN WIND RIVER
MOUNTAINS AND SRN ABSAROKAS UNDER GOOD UPSLOPE CONDITIONS.

A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR PORTIONS OF CENTRAL
WYOMING AND THE ABSAROKA MOUNTAINS...INCLUDING ZONES 2 11 16 17 18
19 20 AND 22...BEGINNING AT 12Z SAT...LASTING THRU 06Z SUN. ACROSS
THE ADVISORY AREA...THRU THOSE 18 HRS OF THE FCST PERIOD...SNOW
ACCUMULATION SHOULD GENERALLY RANGE FROM 2 TO 5 INCHES ACROSS THE
LOWER ELEVATIONS...AND FROM 3 TO 10 INCHES IN THE MOUNTAINS.
PRECIPITATION SHOULD TAPER OFF BY MIDNIGHT SATURDAY.
LIGHTER AMOUNTS OF A HALF TO A COUPLE OF INCHES IS EXPECTED
ELSEWHERE...WITH PERHAPS UP TO 4 INCHES IN THE TETONS OR
WYOMING/SALT MOUNTAIN RANGES THROUGH THE SAME PERIOD. BRISK NORTH TO
EAST WINDS WILL ALSO ACCOMPANY THIS SYSTEM...HELPING IN REDUCING
VISIBILITIES TO ONE MILE OR LESS FOR EXTENDED PERIODS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A COLD LOW PRESSURE TROUGH WILL BE OVER THE AREA SATURDAY NIGHT WITH
MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF SNOW OR A RAIN AND
SNOW MIX.  THIS WILL TAPER OFF ON SUNDAY AS THE UPPER LOW PRESSURE
AREA SPLITS WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE
EAST WHILE A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN
GREAT BASIN AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.
DRYING OCCURS FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE
AREA MOVES SOUTH FROM ALBERTA ON MONDAY AND MONDAY NIGHT. THE
WEAKENING OF THE SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START
TO DIFFER WITH THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND
WARMING TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO
EASTERN WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING
WITH SOME SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE
WESTERN MOUNTAINS. THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES
QUITE LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES IN
THE BIGHORN BASIN.  AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN
ON FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO
NORTHEAST FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND
INCREASED MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND
RAIN MOVING INTO NEXT WEEKEND.

&&

.AVIATION.../06Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

ISOLATED RAIN OR SNOW SHOWERS OVER NORTHWEST WY OVERNIGHT WITH SOME
MVFR CIGS EXPECTED. OTHERWISE VFR CONDITIONS OVER WESTERN WY THROUGH
SATURDAY MORNING. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
DEVELOP OVER THE WEST SATURDAY AFTERNOON INTO THE EVENING. AREAS OF
MVFR CONDITIONS WILL OCCUR ALONG WITH PARTIAL MOUNTAIN OBSCURATION.
SHOWERS WILL DECREASE TO ISOLATED ACTIVITY BY 06Z SUNDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

PERIODS OF RAIN AND SNOW THROUGH EARLY EVENING SATURDAY OVER MOST OF
THE REGION. FAR NORTHERN WY WILL SEE LESS RAIN COVERAGE. EXPECT MVFR
TO IFR CONDITIONS OVER MOST OF THE REGION. MOUNTAINS WILL BE
FREQUENTLY OBSCURED. THE RAIN AND SNOW WILL DECREASE AFTER 00Z
SUNDAY. AREAS OF MVFR/IFR CIGS WILL REMAIN OVER MUCH OF THE REGION
THROUGH 06Z SUNDAY.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 40S TO MID 70S
(PERCENT). SMALL CHANCES FOR ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON.
SHOWERS...BOTH RAIN AND SNOW...WILL BE ON THE INCREASE EAST OF THE
DIVIDE AND ACROSS THE WESTERN MOUNTAINS SATURDAY...KEEPING FIRE
DANGER LOW ACROSS ALL OF WYOMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...

WINTER WEATHER ADVISORY FROM 6 AM SATURDAY TO MIDNIGHT MDT
SATURDAY NIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 292011
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 PM MDT FRI APR 29 2016

.SHORT TERM...TONIGHT THROUGH SATURDAY

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW(S) OVER THE WEST WITH THE CENTER OF
CIRC STILL NEAR THE FOUR CORNERS AREA. TWO EMBEDDED SEVERAL EMBEDDED
DISTURBANCES...KEEP ROTATING UP FROM ERN CO...PROVIDING MUCH OF THE
IMPETUS FOR LIGHT -SHRASN TODAY...MAINLY FROM THE CNTRL BASINS SOUTH
AND SOUTHEAST INTO NRN COLORADO. SFC HAS MAIN SFC LOW WELL TO THE
SOUTH ACROSS CNTRL CO...WITH ONLY A WEAK INVERTED TROF UP INTO ERN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH AND EAST.

SEASONALLY COOL/COLD CONDITIONS CONTINUE AND WILL CONTINUE THROUGH
THE FCST PERIOD...WITH RELATIVELY HIGH PWS READY TO HEAD BACK INTO
EASTERN AND CENTRAL WYOMING ON SATURDAY. OTHERWISE...A RATHER
PERSISTENT STRAT CU CLOUD DECK REMAINS OVR MUCH OF WY WITH ONLY A
FEW BREAKS IN THE CLOUDS. AS NIGHTTIME ROLLS AROUND...THE BROKEN
STRATUS DECK WILL TIGHTEN UP ONCE AGAIN AS TEMPS FALL AND MOISTURE
INCREASES FROM THE EAST TO NORTHEAST OVERNIGHT AND SATURDAY MORNING
AROUND THE DEVELOPING CYCLONE OVR THE CNTRL PLAINS. LIGHT SNOW OR
RAIN MIXED WITH SNOW WILL SLOWLY INCREASE INTO THE ERN AND CNTRL
ZONES OVERNIGHT SO THAT BY SATURDAY MORNING...RAIN/MIX/SNOWFALL
RATES WILL INCREASE TO MODERATE FROM SRN JOHNSON AND ALL OF NATRONA
COUNTIES...WWD INTO FREMONT COUNTY...PUSHING INTO THE ERN WIND RIVER
MOUNTAINS AND SRN ABSAROKAS UNDER GOOD UPSLOPE CONDITIONS.

A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR PORTIONS OF CENTRAL
WYOMING AND THE ABSAROKA MOUNTAINS...INCLUDING ZONES 2 11 16 17 18
19 20 AND 22...BEGINNING AT 12Z SAT...LASTING THRU 06Z SUN. ACROSS
THE ADVISORY AREA...THRU THOSE 18 HRS OF THE FCST PERIOD...SNOW
ACCUMULATION SHOULD GENERALLY RANGE FROM 2 TO 5 INCHES ACROSS THE
LOWER ELEVATIONS...AND FROM 3 TO 10 INCHES IN THE MOUNTAINS.
PRECIPITATION SHOULD TAPER OFF BY MIDNIGHT SATURDAY.
LIGHTER AMOUNTS OF A HALF TO A COUPLE OF INCHES IS EXPECTED
ELSEWHERE...WITH PERHAPS UP TO 4 INCHES IN THE TETONS OR
WYOMING/SALT MOUNTAIN RANGES THROUGH THE SAME PERIOD. BRISK NORTH TO
EAST WINDS WILL ALSO ACCOMPANY THIS SYSTEM...HELPING IN REDUCING
VISIBILITIES TO ONE MILE OR LESS FOR EXTENDED PERIODS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A COLD LOW PRESSURE TROUGH WILL BE OVER THE AREA SATURDAY NIGHT WITH
MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF SNOW OR A RAIN AND
SNOW MIX.  THIS WILL TAPER OFF ON SUNDAY AS THE UPPER LOW PRESSURE
AREA SPLITS WITH THSATURDAY NIGHT THROUGH FRIDAY

A COLD LOW PRESSURE TROUGH WILL BE OVER THE AREA SATURDAY NIGHT WITH
MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF SNOW OR A RAIN AND
SNOW MIX.  THIS WILL TAPER OFF ON SUNDAY AS THE UPPER LOW PRESSURE
AREA SPLITS WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE
EAST WHILE A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN
GREAT BASIN AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.
DRYING OCCURS FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE
AREA MOVES SOUTH FROM ALBERTA ON MONDAY AND MONDAY NIGHT. THE
WEAKENING OF THE SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START
TO DIFFER WITH THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND
WARMING TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO
EASTERN WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING
WITH SOME SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE
WESTERN MOUNTAINS. THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES
QUITE LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES IN
THE BIGHORN BASIN.  AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN
ON FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO
NORTHEAST FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND
INCREASED MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND
RAIN MOVING INTO NEXT WEEKEND.
E NORTHEASTERN PART OF THE LOW EXITING TO THE
EAST WHILE A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN
GREAT BASIN AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.
DRYING OCCURS FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE
AREA MOVES SOUTH FROM ALBERTA ON MONDAY AND MONDAY NIGHT. THE
WEAKENING OF THE SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START
TO DIFFER WITH THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE
RIDGE BUILDS INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND
WARMING TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO
EASTERN WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING
WITH SOME SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE
WESTERN MOUNTAINS. THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES
QUITE LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES IN
THE BIGHORN BASIN.  AS THE PACIFIC TROUGH DIGS INTO THE GREAT BASIN
ON FRIDAY AND FORMS YET ANOTHER CUT OFF LOW...UPLSOPE EAST TO
NORTHEAST FLOW WILL RETURN TO THE AREA WITH COOLING TEMPERATURES AND
INCREASED MOISTURE AND LIFT SUPPORTING A RETURN TO AREAS OF SNOW AND
RAIN MOVING INTO NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR TO MVFR CIGS MOST AREAS THROUGH TONIGHT...WITH ISOLATED RAIN AND
SNOW SHOWERS OCCURRING NEAR KRKS AND KJAC THROUGH MUCH OF THE
FORECAST PERIOD. ADDITIONALLY... ISOLATED SHOWERS WILL DEVELOP AND
CONTINUE THROUGH LATE TONIGHT. HEAVIEST PRECIPITATION EXPECTED THIS
EVENING FOR MOST LOCATIONS...THEN AGAIN ACROSS THE FAR WEST SATURDAY
AFTERNOON. EXPECT LOCAL IFR CONDITIONS IN LOWER VSBYS AND CIGS WITH
PERSISTENT MOUNTAIN OBSCURATION THROUGH THE FORECAST PERIOD. A GUSTY
EAST TO NORTHEAST WIND TO CONTINUE AT KRKS THROUGH SATURDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR TO MVFR CIGS ACROSS THE REGION THROUGH TONIGHT...WITH ISOLATED
TO WIDELY SCATTERED LIGHT RAIN/SNOW SHOWERS CONTINUING THIS EVENING.
THEN OVERNIGHT TONIGHT...EXPECT AREAS OF MVFR TO IFR CIGS AND
PERSISTENT MOUNTAIN OBSCURATION WITH OCCASIONALLY MODERATE SNOW
MOVING INTO CENTRAL AND NORTHERN WYOMING BETWEEN 09 AND 14Z...WITH
IFR CIGS AND VSBY REDUCTIONS BECOMING MORE COMMON. A GUSTY NORTH TO
EAST WIND TO DEVELOP FOR MOST LOCATIONS ON SATURDAY.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 40S TO MID 70S
(PERCENT). SMALL CHANCES FOR ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON.
SHOWERS...BOTH RAIN AND SNOW...WILL BE ON THE INCREASE EAST OF THE
DIVIDE AND ACROSS THE WESTERN MOUNTAINS SATURDAY...KEEPING FIRE
DANGER LOW ACROSS ALL OF WYOMING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 AM SATURDAY TO MIDNIGHT MDT
SATURDAY NIGHT FOR WYZ002-011-015>020-022.

&&

$$

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





000
FXUS65 KRIW 291717
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1117 AM MDT FRI APR 29 2016

.SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT

IT LOOKS LIKE WE WILL STAY IN THE COOL AND UNSETTLED PATTERN FOR THE
NEXT FEW DAYS. HOWEVER...THERE IS A BIT OF LIGHT AT THE END OF THE
TUNNEL WE CALL THE SHORT TERM PORTION OF THE FORECAST. THE RADAR IS
FAIRLY QUIET RIGHT NOW WITH ONLY A FEW SHOWERS AROUND. THIS SHOULD
HOLD FOR MOST OF THE MORNING WITH ONLY A FEW SHOWERS AROUND.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE IN THE AFTERNOON
HOWEVER AS AN UPPER LEVEL LOW OVER SOUTHERN COLORADO BEGINS TO TURN
NORTHEASTWARD AND SOME LEE CYCLOGENESIS BEGINS TO OCCUR AND WRAPS A
BIT MORE MOISTURE BACK INTO THE AREA. THERE ARE SOME DIFFERENCES IN
QPF BUT IT DOES NOT LOOK ALL THAT HEAVY THROUGH THE DAYLIGHT HOURS.
WEST OF THE DIVIDE...JUST ENOUGH INSTABILITY WILL BE AROUND FORM A
COUPLE OF THUNDERSTORMS. TEMPERATURES WILL BE A COUPLE OF DEGREES
WARMER THAN YESTERDAY BUT STILL WELL BELOW NORMAL FOR LATE APRIL. AS
FOR SKY COVER...WE KEPT THINGS PESSIMISTIC FOR NOW. IF THERE IS MORE
SUN THAN EXPECTED...MOST PEOPLE WILL BE HAPPY.

STEADIER PRECIPITATION SHOULD THEN BEGIN WRAPPING BACK INTO EASTERN
PORTIONS OF THE AREA...MAINLY AFTER MIDNIGHT. AGAIN THE MODELS ARE
DIFFERING IN TIMING WITH THE NAM ABOUT 6 HOURS SLOWER THAN THE GFS.
FOR NOW WE SPLIT THE MIDDLE. HOWEVER...BOTH MODELS ARE SHOWING THE
STEADIEST AND HEAVIEST PRECIPITATION DURING THE DAY ON SATURDAY. THE
NEXT QUESTION IS HOW MUCH AND WHAT TYPE. IT WILL BE THE LAST DAY OF
APRIL...AND CONDITIONS FOR SNOW ARE BORDERLINE. A LOT WILL DEPEND ON
DYNAMIC COOLING AND PRECIPITATION RATE. THIS COULD BE A SITUATION
WHERE IT COULD SNOW IN SOME AREAS MUCH OF THE DAY BUT DUE TO A
COMBINATION OF ABOVE FREEZING TEMPERATURES AND A HIGH SUN ANGLE THE
SNOW WOULD HAVE A HARD TIME ACCUMULATING...ESPECIALLY ON PAVED
SURFACES. THE GRIDS DO HAVE SOME LOW END ADVISORY AMOUNTS IN
SPOTS...BUT STILL THE QUESTION IF ANY HIGHLIGHTS ARE NEEDED DUE TO
MINIMAL IMPACTS. FOR THIS...WE WILL PUNT BACK TO THE DAY SHIFT. THE
HIGHEST AMOUNTS WOULD BE ACROSS NATRONA COUNTY WHERE THE BEST
MOISTURE WOULD BE. HOWEVER...WINDS ARE NOT IDEAL FOR UPSLOPE THERE.
THINGS WILL TAPER OFF GRADUALLY SATURDAY NIGHT BUT COULD LINGER
LONGER WITH EASTERLY FLOW IN PLACES LIKE THE EAST SLOPES OF THE
ABSAROKAS INTO THE NIGHT.

SUNDAY LOOKS TO HAVE GRADUALLY IMPROVING CONDITIONS AS HIGH PRESSURE
AND DRIER AIR SLOWLY BUILDS IN FROM THE NORTH. THE NAM IS
PARTICULARLY AGGRESSIVE IN MOVING DRIER WHILE THE GFS LINGERS MORE
MOISTURE. WE KEPT THINGS DAMP FOR NOW GIVEN THE RECENT PATTERN. DRY
AIR THEN MOVES IN FOR LATER SUNDAY NIGHT. I THINK THAT LATE SUNDAY
NIGHT IS THE FIRST PERIOD THERE HAS BEEN NO QPF IN THE GRIDS FOR OVER
A WEEK.

.LONG TERM...MONDAY THROUGH FRIDAY

THE BROAD UPPER LOW OVER THE WESTERN U.S. IS EXPECTED TO FILL...AND
SHEAR OUT OVER MONDAY AND TUESDAY...WITH UPPER RIDGING TAKING ITS
PLACE BY LATE TUESDAY OR WEDNESDAY. THE ONLY FLY IN THE
OINTMENT...IS THE 00Z ECMWF SHOWS A SHORTWAVE TROUGH DIVING SOUTH
OUT OF SASKATCHEWAN LATE SUNDAY INTO THE NORTHERN PLAINS SUNDAY
NIGHT. THE ECMWF SHOWS THIS SYSTEM CLOSING OFF AND PUSHING
SOUTHWEST INTO THE COWBOY STATE MONDAY...AND LINGERING ACROSS THE
REGION TUESDAY. THE 00Z GEM ALSO SHOWS THIS FEATURE...BUT HAS
CIRCULATION OVER CENTRAL NEBRASKA AT 00Z TUESDAY. ON THE OTHER
HAND THE GFS AND PREVIOUS MODEL RUNS HAD THE FEATURE IMPACTING THE
UPPER MIDWEST AND GREAT LAKES. HAVE GONE WITH THE LATTER SOLUTION
WITH ANY CONVECTION MONDAY/TUESDAY OVER THE WEST/SOUTHWEST.
WEDNESDAY LOOKS DRY REGARDLESS. THURSDAY AND FRIDAY...MODELS SHOW
A STRONG UPPER LOW GRADUALLY PUSHING INTO CALIFORNIA. SOME ENERGY
AHEAD OF THE FEATURE COULD RESULT IN SOME CONVECTION OVER THE
WEST...WITH A BETTER SHOT ON FRIDAY.

WILL SEE A WARMING TREND NEXT WEEK WITH ABOVE AVERAGE
TEMPERATURES EXPECTED BY WEDNESDAY...AND LASTING THROUGH FRIDAY.

FOR THOSE LOOKING AHEAD TO NEXT WEEKEND...THE POTENTIAL EXISTS FOR
A STORMY WEEKEND WITH SIGNIFICANT PRECIPITATION.

&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR TO MVFR CIGS MOST AREAS THROUGH TONIGHT...WITH ISOLATED RAIN AND
SNOW SHOWERS OCCURRING NEAR KRKS AND KJAC THROUGH MUCH OF THE
FORECAST PERIOD. ADDITIONALLY... ISOLATED SHOWERS WILL DEVELOP AND
CONTINUE THROUGH LATE TONIGHT. HEAVIEST PRECIPITATION EXPECTED THIS
EVENING FOR MOST LOCATIONS. EXPECT LOCAL IFR CONDITIONS IN LOWER
VSBYS AND CIGS WITH PERSISTENT MOUNTAIN OBSCURATION THROUGH THE
PERIOD. A GUSTY WIND TO CONTINUE AT KRKS THROUGH THIS EVENING.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR TO MVFR CIGS ACROSS THE REGION THROUGH TONIGHT...WITH ISOLATED
TO WIDELY SCATTERED RAIN/SNOW SHOWERS THIS AFTERNOON AND EVENING.
TONIGHT...EXPECT AREAS OF MVFR TO IFR CIGS AND PERSISTENT MOUNTAIN
OBSCURATION. THEN LIGHT TO MODERATE SNOW WILL MOVE INTO CENTRAL AND
NORTHERN WYOMING BETWEEN 09 AND 14Z SATURDAY...WITH IFR CIGS AND
VSBY REDUCTIONS BECOMING MORE COMMON.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. THERE COULD BE SOME LOCALLY GUSTY WINDS AT TIMES ON
SATURDAY BUT RELATIVE HUMIDITY SHOULD REMAIN WELL ABOVE CRITICAL
LEVELS. PORTIONS OF CENTRAL WYOMING WILL HAVE ANOTHER CHANCE FOR A
WETTING RAIN EVENT ON SATURDAY.

&&

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

$$

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





000
FXUS65 KRIW 290822
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
222 AM MDT FRI APR 29 2016

.SHORT TERM...FRIDAY THROUGH SUNDAY NIGHT

IT LOOKS LIKE WE WILL STAY IN THE COOL AND UNSETTLED PATTERN FOR THE
NEXT FEW DAYS. HOWEVER...THERE IS A BIT OF LIGHT AT THE END OF THE
TUNNEL WE CALL THE SHORT TERM PORTION OF THE FORECAST. THE RADAR IS
FAIRLY QUIET RIGHT NOW WITH ONLY A FEW SHOWERS AROUND. THIS SHOULD
HOLD FOR MOST OF THE MORNING WITH ONLY A FEW SHOWERS AROUND.
PRECIPITATION CHANCES WILL BEGIN TO INCREASE IN THE AFTERNOON
HOWEVER AS AN UPPER LEVEL LOW OVER SOUTHERN COLORADO BEGINS TO TURN
NORTHEASTWARD AND SOME LEE CYCLOGENESIS BEGINS TO OCCUR AND WRAPS A
BIT MORE MOISTURE BACK INTO THE AREA. THERE ARE SOME DIFFERENCES IN
QPF BUT IT DOES NOT LOOK ALL THAT HEAVY THROUGH THE DAYLIGHT HOURS.
WEST OF THE DIVIDE...JUST ENOUGH INSTABILITY WILL BE AROUND FORM A
COUPLE OF THUNDERSTORMS. TEMPERATURES WILL BE A COUPLE OF DEGREES
WARMER THAN YESTERDAY BUT STILL WELL BELOW NORMAL FOR LATE APRIL. AS
FOR SKY COVER...WE KEPT THINGS PESSIMISTIC FOR NOW. IF THERE IS MORE
SUN THAN EXPECTED...MOST PEOPLE WILL BE HAPPY.

STEADIER PRECIPITATION SHOULD THEN BEGIN WRAPPING BACK INTO EASTERN
PORTIONS OF THE AREA...MAINLY AFTER MIDNIGHT. AGAIN THE MODELS ARE
DIFFERING IN TIMING WITH THE NAM ABOUT 6 HOURS SLOWER THAN THE GFS.
FOR NOW WE SPLIT THE MIDDLE. HOWEVER...BOTH MODELS ARE SHOWING THE
STEADIEST AND HEAVIEST PRECIPITATION DURING THE DAY ON SATURDAY. THE
NEXT QUESTION IS HOW MUCH AND WHAT TYPE. IT WILL BE THE LAST DAY OF
APRIL...AND CONDITIONS FOR SNOW ARE BORDERLINE. A LOT WILL DEPEND ON
DYNAMIC COOLING AND PRECIPITATION RATE. THIS COULD BE A SITUATION
WHERE IT COULD SNOW IN SOME AREAS MUCH OF THE DAY BUT DUE TO A
COMBINATION OF ABOVE FREEZING TEMPERATURES AND A HIGH SUN ANGLE THE
SNOW WOULD HAVE A HARD TIME ACCUMULATING...ESPECIALLY ON PAVED
SURFACES. THE GRIDS DO HAVE SOME LOW END ADVISORY AMOUNTS IN
SPOTS...BUT STILL THE QUESTION IF ANY HIGHLIGHTS ARE NEEDED DUE TO
MINIMAL IMPACTS. FOR THIS...WE WILL PUNT BACK TO THE DAY SHIFT. THE
HIGHEST AMOUNTS WOULD BE ACROSS NATRONA COUNTY WHERE THE BEST
MOISTURE WOULD BE. HOWEVER...WINDS ARE NOT IDEAL FOR UPSLOPE THERE.
THINGS WILL TAPER OFF GRADUALLY SATURDAY NIGHT BUT COULD LINGER
LONGER WITH EASTERLY FLOW IN PLACES LIKE THE EAST SLOPES OF THE
ABSAROKAS INTO THE NIGHT.

SUNDAY LOOKS TO HAVE GRADUALLY IMPROVING CONDITIONS AS HIGH PRESSURE
AND DRIER AIR SLOWLY BUILDS IN FROM THE NORTH. THE NAM IS
PARTICULARLY AGGRESSIVE IN MOVING DRIER WHILE THE GFS LINGERS MORE
MOISTURE. WE KEPT THINGS DAMP FOR NOW GIVEN THE RECENT PATTERN. DRY
AIR THEN MOVES IN FOR LATER SUNDAY NIGHT. I THINK THAT LATE SUNDAY
NIGHT IS THE FIRST PERIOD THERE HAS BEEN NO QPF IN THE GRIDS FOR OVER
A WEEK.

.LONG TERM...MONDAY THROUGH FRIDAY

THE BROAD UPPER LOW OVER THE WESTERN U.S. IS EXPECTED TO FILL...AND
SHEAR OUT OVER MONDAY AND TUESDAY...WITH UPPER RIDGING TAKING ITS
PLACE BY LATE TUESDAY OR WEDNESDAY. THE ONLY FLY IN THE
OINTMENT...IS THE 00Z ECMWF SHOWS A SHORTWAVE TROUGH DIVING SOUTH
OUT OF SASKATCHEWAN LATE SUNDAY INTO THE NORTHERN PLAINS SUNDAY
NIGHT. THE ECMWF SHOWS THIS SYSTEM CLOSING OFF AND PUSHING
SOUTHWEST INTO THE COWBOY STATE MONDAY...AND LINGERING ACROSS THE
REGION TUESDAY. THE 00Z GEM ALSO SHOWS THIS FEATURE...BUT HAS
CIRCULATION OVER CENTRAL NEBRASKA AT 00Z TUESDAY. ON THE OTHER
HAND THE GFS AND PREVIOUS MODEL RUNS HAD THE FEATURE IMPACTING THE
UPPER MIDWEST AND GREAT LAKES. HAVE GONE WITH THE LATTER SOLUTION
WITH ANY CONVECTION MONDAY/TUESDAY OVER THE WEST/SOUTHWEST.
WEDNESDAY LOOKS DRY REGARDLESS. THURSDAY AND FRIDAY...MODELS SHOW
A STRONG UPPER LOW GRADUALLY PUSHING INTO CALIFORNIA. SOME ENERGY
AHEAD OF THE FEATURE COULD RESULT IN SOME CONVECTION OVER THE
WEST...WITH A BETTER SHOT ON FRIDAY.

WILL SEE A WARMING TREND NEXT WEEK WITH ABOVE AVERAGE
TEMPERATURES EXPECTED BY WEDNESDAY...AND LASTING THROUGH FRIDAY.

FOR THOSE LOOKING AHEAD TO NEXT WEEKEND...THE POTENTIAL EXISTS FOR
A STORMY WEEKEND WITH SIGNIFICANT PRECIPITATION.

&&

.AVIATION.../12Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR TO MVFR CIGS THROUGH TONIGHT. ISOLATED RAIN AND SNOW SHOWERS
WILL OCCUR THROUGH 15Z WITH LOCAL IFR VSBYS/CIGS. THIS AFTERNOON
ADDITIONAL SHOWERS WILL DEVELOP AND CONTINUE THROUGH LATE TONIGHT.
EXPECT AREAS OF MVFR CIGS AND SOME MOUNTAIN OBSCURATION. A GUSTY
WIND TO CONTINUE AT KRKS THROUGH THIS AFTERNOON.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR TO MVFR CIGS ACROSS THE REGION THROUGH TONIGHT. ISOLATED
SNOW SHOWERS IN CENTRAL WY UNTIL 15Z. THEN SCATTERED RAIN
OR SNOW SHOWERS AFTER 21Z THROUGH 06Z TONIGHT WITH AREAS OF MVFR
CIGS AND SOME MOUNTAIN OBSCURATION. LIGHT SNOW MAY MOVE INTO
THE KCPR AIRPORT BY 12Z FRIDAY.

&&

.FIRE WEATHER...

FIRE DANGER SHOULD REMAIN LOW INTO THE WEEKEND AS EASTERLY FLOW
KEEPS TEMPERATURES ON THE COOL SIDE AND RELATIVE HUMIDITY ON THE
HIGH SIDE. THERE COULD BE SOME LOCALLY GUSTY WINDS AT TIMES ON
SATURDAY BUT RELATIVE HUMIDITY SHOULD REMAIN WELL ABOVE CRITICAL
LEVELS. PORTIONS OF CENTRAL WYOMING WILL HAVE ANOTHER CHANCE FOR A
WETTING RAIN EVENT ON SATURDAY.

&&

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

$$

SHORT TERM...HATTINGS
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...HATTINGS





000
FXUS65 KRIW 290445
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1045 PM MDT THU APR 28 2016

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 145 PM MDT)

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW OVER THE WEST WITH THE CENTER OF CIRC
NEAR/WEST OF THE FOUR CORNERS AREA. TWO EMBEDDED DISTURBANCES...ONE
ACROSS NRN/NERN WY WITH ANOTHER ROTATING UP FROM ERN UT/WRN CO WILL
PROVIDE MUCH OF THE IMPETUS FOR LIGHT SHRASN TODAY...MAINLY FROM THE
CNTRL BASINS SOUTH...AND ACROSS THE FAR NORTHERN PORTION OF WY
TODAY. SFC HAS MAIN SFC LOW WELL TO THE SOUTH FROM CNTRL CO TO NEAR
THE FOUR CORNERS REGION...WITH ONLY A WEAK INVERTED TROF UP INTO WRN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH TO EAST.

SEASONALLY COOL/COLD CONDITIONS...FOR THE MOST PART...CONTINUE THRU
THE FCST PERIOD...WITH A RATHER PERSISTENT STRAT CU CLOUD DECK
REMAIN OVR MUCH OF WY. A FEW BREAKS IN THE CLOUDS MAY ARRIVE THIS
AFTERNOON OVER THE BASINS FOR A SHORT PERIOD BEFORE RETURN TO
OVERCAST AGAIN TONIGHT. A FEW MORE BREAKS WITH SLIGHTLY BETTER
SUNSHINE POTENTIAL WILL BE POSSIBLE FRIDAY AFTERNOON...BEFORE
CLOSING ONCE AGAIN FRIDAY NIGHT FOR MOST LOCATIONS EXCEPT PERHAPS
THE NRN BIG HORN BASIN WHICH COULD REMAIN SCATTERED OVERNIGHT.
PRECIP POTENTIAL BEST ACROSS THE SOUTH AND WEST
TODAY/TONIGHT...EITHER ASSOCIATED WITH MOIST ADVECTION AND MODEST
UPR FORCING ROTATING INTO REGION FROM UPR LOW TO THE SOUTH...OR
ALONG/NEAR THE TROF OUT WEST. FRIDAY...OTHER THAN ISOLATED VERY
LIGHT SHOWERS POSSIBLE ACROSS MOST OF THE FA HERE AND THERE...BETTER
LOCATIONS FOR MEASURABLE PRECIP WILL BE LOCATION EITHER OVR THE WRN
MOUNTAINS FRI AFTERNOON DURING THE AFTERNOON WITH THE BEST
INSTABILITY...OR ACROSS FAR ERN SWEETWATER...ERN FREMONT...AND SRN
NATRONA COUNTIES AS THE MAIN UPR LOW HEADS TOWARDS/OVR ERN
CO...SPINNING UP A LEE CYCLONE INTO THE SRN PLAINS. HOWEVER...NONE
OF THE ACTIVITY APPEARS TO BE TOO SIGNIFICANT ATTM...WITH MOST ALL
OF THE BEST DYNAMICALLY FORCED PRECIP POTENTIAL ACROSS SERN
WY...AND POINTS FURTHER SOUTH AND EAST. THRU THE 24 HRS OF THE FCST
PERIOD...SNOW ACCUMULATION SHOULD GENERALLY RANGE FROM A TRACE TO AN
INCH ACROSS THE LOWER ELEVATIONS...TO 1 TO 3 INCHES ACROSS THE
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A COLD LOW PRESSURE TROUGH WILL REMAIN OVER THE AREA FRIDAY NIGHT
WITH MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF RAIN AND SNOW
SHOWERS OR A RAIN AND SNOW MIX.  THIS WILL CONTINUE ON SATURDAY...
SATURDAY NIGHT AND SUNDAY AS THE UPPER LOW PRESSURE AREA SPLITS
WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE EAST WHILE
A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN
AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.  DRYING OCCURS
FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH
FROM ALBERTA ON MONDAY AND MONDAY NIGHT.  THE WEAKENING OF THE
SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START TO DIFFER WITH
THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS
INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND WARMING
TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO EASTERN
WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING WITH SOME
SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN
MOUNTAINS.  THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES QUITE
LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES
IN THE BIGHORN BASIN.

&&

.AVIATION.../06Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR TO MVFR CIGS THROUGH FRIDAY NIGHT. ISOLATED RAIN AND SNOW
SHOWERS WILL OCCUR THROUGH 15Z WITH LOCAL IFR VSBYS/CIGS. FRIDAY
AFTERNOON ADDITIONAL SHOWERS WILL DEVELOP AND CONTINUE THROUGH
FRIDAY NIGHT. EXPECT AREAS OF MVFR CIGS AND SOME MOUNTAIN
OBSCURATION. A GUSTY WIND TO CONTINUE AT KRKS THROUGH FRIDAY
AFTERNOON.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR TO MVFR CIGS ACROSS THE REGION THROUGH FRIDAY NIGHT. ISOLATED
SNOW SHOWERS OVERNIGHT IN CENTRAL WY UNTIL 15Z. THEN SCATTERED RAIN
OR SNOW SHOWERS FRIDAY AFTERNOON AND NIGHT WITH AREAS OF MVFR CIGS
AND SOME MOUNTAIN OBSCURATION.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 50S TO MID 80S
(PERCENT). SMALL CHANCES FOR AN ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON
THROUGH 4 AM. FRIDAY...FIRE DANGER CONTINUES LOW ACROSS ALL OF
WYOMING.

&&

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

&&

$$

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





000
FXUS65 KRIW 290445
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1045 PM MDT THU APR 28 2016

.SHORT TERM...TONIGHT THROUGH FRIDAY (ISSUED AT 145 PM MDT)

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW OVER THE WEST WITH THE CENTER OF CIRC
NEAR/WEST OF THE FOUR CORNERS AREA. TWO EMBEDDED DISTURBANCES...ONE
ACROSS NRN/NERN WY WITH ANOTHER ROTATING UP FROM ERN UT/WRN CO WILL
PROVIDE MUCH OF THE IMPETUS FOR LIGHT SHRASN TODAY...MAINLY FROM THE
CNTRL BASINS SOUTH...AND ACROSS THE FAR NORTHERN PORTION OF WY
TODAY. SFC HAS MAIN SFC LOW WELL TO THE SOUTH FROM CNTRL CO TO NEAR
THE FOUR CORNERS REGION...WITH ONLY A WEAK INVERTED TROF UP INTO WRN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH TO EAST.

SEASONALLY COOL/COLD CONDITIONS...FOR THE MOST PART...CONTINUE THRU
THE FCST PERIOD...WITH A RATHER PERSISTENT STRAT CU CLOUD DECK
REMAIN OVR MUCH OF WY. A FEW BREAKS IN THE CLOUDS MAY ARRIVE THIS
AFTERNOON OVER THE BASINS FOR A SHORT PERIOD BEFORE RETURN TO
OVERCAST AGAIN TONIGHT. A FEW MORE BREAKS WITH SLIGHTLY BETTER
SUNSHINE POTENTIAL WILL BE POSSIBLE FRIDAY AFTERNOON...BEFORE
CLOSING ONCE AGAIN FRIDAY NIGHT FOR MOST LOCATIONS EXCEPT PERHAPS
THE NRN BIG HORN BASIN WHICH COULD REMAIN SCATTERED OVERNIGHT.
PRECIP POTENTIAL BEST ACROSS THE SOUTH AND WEST
TODAY/TONIGHT...EITHER ASSOCIATED WITH MOIST ADVECTION AND MODEST
UPR FORCING ROTATING INTO REGION FROM UPR LOW TO THE SOUTH...OR
ALONG/NEAR THE TROF OUT WEST. FRIDAY...OTHER THAN ISOLATED VERY
LIGHT SHOWERS POSSIBLE ACROSS MOST OF THE FA HERE AND THERE...BETTER
LOCATIONS FOR MEASURABLE PRECIP WILL BE LOCATION EITHER OVR THE WRN
MOUNTAINS FRI AFTERNOON DURING THE AFTERNOON WITH THE BEST
INSTABILITY...OR ACROSS FAR ERN SWEETWATER...ERN FREMONT...AND SRN
NATRONA COUNTIES AS THE MAIN UPR LOW HEADS TOWARDS/OVR ERN
CO...SPINNING UP A LEE CYCLONE INTO THE SRN PLAINS. HOWEVER...NONE
OF THE ACTIVITY APPEARS TO BE TOO SIGNIFICANT ATTM...WITH MOST ALL
OF THE BEST DYNAMICALLY FORCED PRECIP POTENTIAL ACROSS SERN
WY...AND POINTS FURTHER SOUTH AND EAST. THRU THE 24 HRS OF THE FCST
PERIOD...SNOW ACCUMULATION SHOULD GENERALLY RANGE FROM A TRACE TO AN
INCH ACROSS THE LOWER ELEVATIONS...TO 1 TO 3 INCHES ACROSS THE
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A COLD LOW PRESSURE TROUGH WILL REMAIN OVER THE AREA FRIDAY NIGHT
WITH MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF RAIN AND SNOW
SHOWERS OR A RAIN AND SNOW MIX.  THIS WILL CONTINUE ON SATURDAY...
SATURDAY NIGHT AND SUNDAY AS THE UPPER LOW PRESSURE AREA SPLITS
WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE EAST WHILE
A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN
AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.  DRYING OCCURS
FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH
FROM ALBERTA ON MONDAY AND MONDAY NIGHT.  THE WEAKENING OF THE
SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START TO DIFFER WITH
THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS
INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND WARMING
TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO EASTERN
WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING WITH SOME
SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN
MOUNTAINS.  THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES QUITE
LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES
IN THE BIGHORN BASIN.

&&

.AVIATION.../06Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR TO MVFR CIGS THROUGH FRIDAY NIGHT. ISOLATED RAIN AND SNOW
SHOWERS WILL OCCUR THROUGH 15Z WITH LOCAL IFR VSBYS/CIGS. FRIDAY
AFTERNOON ADDITIONAL SHOWERS WILL DEVELOP AND CONTINUE THROUGH
FRIDAY NIGHT. EXPECT AREAS OF MVFR CIGS AND SOME MOUNTAIN
OBSCURATION. A GUSTY WIND TO CONTINUE AT KRKS THROUGH FRIDAY
AFTERNOON.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

VFR TO MVFR CIGS ACROSS THE REGION THROUGH FRIDAY NIGHT. ISOLATED
SNOW SHOWERS OVERNIGHT IN CENTRAL WY UNTIL 15Z. THEN SCATTERED RAIN
OR SNOW SHOWERS FRIDAY AFTERNOON AND NIGHT WITH AREAS OF MVFR CIGS
AND SOME MOUNTAIN OBSCURATION.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 50S TO MID 80S
(PERCENT). SMALL CHANCES FOR AN ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON
THROUGH 4 AM. FRIDAY...FIRE DANGER CONTINUES LOW ACROSS ALL OF
WYOMING.

&&

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

&&

$$

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





000
FXUS65 KRIW 281945
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
145 PM MDT THU APR 28 2016

.SHORT TERM...TONIGHT THROUGH FRIDAY

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW OVER THE WEST WITH THE CENTER OF CIRC
NEAR/WEST OF THE FOUR CORNERS AREA. TWO EMBEDDED DISTURBANCES...ONE
ACROSS NRN/NERN WY WITH ANOTHER ROTATING UP FROM ERN UT/WRN CO WILL
PROVIDE MUCH OF THE IMPETUS FOR LIGHT SHRASN TODAY...MAINLY FROM THE
CNTRL BASINS SOUTH...AND ACROSS THE FAR NORTHERN PORTION OF WY
TODAY. SFC HAS MAIN SFC LOW WELL TO THE SOUTH FROM CNTRL CO TO NEAR
THE FOUR CORNERS REGION...WITH ONLY A WEAK INVERTED TROF UP INTO WRN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH TO EAST.

SEASONALLY COOL/COLD CONDITIONS...FOR THE MOST PART...CONTINUE THRU
THE FCST PERIOD...WITH A RATHER PERSISTENT STRAT CU CLOUD DECK
REMAIN OVR MUCH OF WY. A FEW BREAKS IN THE CLOUDS MAY ARRIVE THIS
AFTERNOON OVER THE BASINS FOR A SHORT PERIOD BEFORE RETURN TO
OVERCAST AGAIN TONIGHT. A FEW MORE BREAKS WITH SLIGHTLY BETTER
SUNSHINE POTENTIAL WILL BE POSSIBLE FRIDAY AFTERNOON...BEFORE
CLOSING ONCE AGAIN FRIDAY NIGHT FOR MOST LOCATIONS EXCEPT PERHAPS
THE NRN BIG HORN BASIN WHICH COULD REMAIN SCATTERED OVERNIGHT.
PRECIP POTENTIAL BEST ACROSS THE SOUTH AND WEST
TODAY/TONIGHT...EITHER ASSOCIATED WITH MOIST ADVECTION AND MODEST
UPR FORCING ROTATING INTO REGION FROM UPR LOW TO THE SOUTH...OR
ALONG/NEAR THE TROF OUT WEST. FRIDAY...OTHER THAN ISOLATED VERY
LIGHT SHOWERS POSSIBLE ACROSS MOST OF THE FA HERE AND THERE...BETTER
LOCATIONS FOR MEASURABLE PRECIP WILL BE LOCATION EITHER OVR THE WRN
MOUNTAINS FRI AFTERNOON DURING THE AFTERNOON WITH THE BEST
INSTABILITY...OR ACROSS FAR ERN SWEETWATER...ERN FREMONT...AND SRN
NATRONA COUNTIES AS THE MAIN UPR LOW HEADS TOWARDS/OVR ERN
CO...SPINNING UP A LEE CYCLONE INTO THE SRN PLAINS. HOWEVER...NONE
OF THE ACTIVITY APPEARS TO BE TOO SIGNIFICANT ATTM...WITH MOST ALL
OF THE BEST DYNAMICALLY FORCED PRECIP POTENTIAL ACROSS SERN
WY...AND POINTS FURTHER SOUTH AND EAST. THRU THE 24 HRS OF THE FCST
PERIOD...SNOW ACCUMULATION SHOULD GENERALLY RANGE FROM A TRACE TO AN
INCH ACROSS THE LOWER ELEVATIONS...TO 1 TO 3 INCHES ACROSS THE
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A COLD LOW PRESSURE TROUGH WILL REMAIN OVER THE AREA FRIDAY NIGHT
WITH MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF RAIN AND SNOW
SHOWERS OR A RAIN AND SNOW MIX.  THIS WILL CONTINUE ON SATURDAY...
SATURDAY NIGHT AND SUNDAY AS THE UPPER LOW PRESSURE AREA SPLITS
WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE EAST WHILE
A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN
AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.  DRYING OCCURS
FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH
FROM ALBERTA ON MONDAY AND MONDAY NIGHT.  THE WEAKENING OF THE
SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START TO DIFFER WITH
THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS
INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND WARMING
TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO EASTERN
WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING WITH SOME
SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN
MOUNTAINS.  THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES QUITE
LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES
IN THE BIGHORN BASIN.


&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/MVFR CONDITIONS WILL PREVAIL OVER MOST OF THE REGION THROUGH
THIS EVENING. SHOWERS WILL CONTINUE OVER WEST AND SOUTH WY THIS
EVENING. MAINLY MVFR TO LOCAL IFR CONDITIONS WILL RETURN TO
SOUTHWEST WY THIS EVENING...CONTINUING THROUGH 15Z. VIS REDUCTIONS
DUE TO -SN OR BR WILL BE MOST PROBABLE NEAR KJAC THROUGH 09Z. A
GUSTY NORTHEAST WIND WILL CONTINUE AT/NEAR THE KRKS AIRPORT THROUGH
THIS EVENING. IMPROVING CONDITIONS EXPECTED AFTER 15Z FOR MOST
TERMINAL LOCATIONS.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

MVFR TO OCCASIONAL VFR CIGS OVER MOST OF THE REGION EARLY THIS
EVENING...WITH SOME LIGHT RAIN AND/OR SNOW SNOW SHOWERS THROWN IN
FOR GOOD MEASURE. THEN MVFR TO OCCASIONAL IFR CIGS WILL RETURN
BEFORE MIDNIGHT FOR MOST TERMINAL LOCATIONS...LASTING THROUGH 15Z.
IMPROVING CONDITIONS EXPECTED AFTER 15Z FOR MOST TERMINAL LOCATIONS.
KCPR WILL BE MOST LIKELY TO SUCCUMB TO POSSIBLE MVFR CONDITIONS
NEAR THE END OF THE FORECAST PERIOD.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 50S TO MID 80S
(PERCENT). SMALL CHANCES FOR AN ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON
THROUGH 4 AM. FRIDAY...FIRE DANGER CONTINUES LOW ACROSS ALL OF
WYOMING.

&&

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

$$

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





000
FXUS65 KRIW 281945
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
145 PM MDT THU APR 28 2016

.SHORT TERM...TONIGHT THROUGH FRIDAY

VERY SLOW PROGRESSING 2/3 UPR WAVE PATTERN ACROSS THE NRN HEMISPHERE
IN PLACE WITH KLUDGEY LW TROF ACROSS THE CONUS WITH EMBEDDED DEEP
TROF AND ASSOCIATED CLOSED LOW OVER THE WEST WITH THE CENTER OF CIRC
NEAR/WEST OF THE FOUR CORNERS AREA. TWO EMBEDDED DISTURBANCES...ONE
ACROSS NRN/NERN WY WITH ANOTHER ROTATING UP FROM ERN UT/WRN CO WILL
PROVIDE MUCH OF THE IMPETUS FOR LIGHT SHRASN TODAY...MAINLY FROM THE
CNTRL BASINS SOUTH...AND ACROSS THE FAR NORTHERN PORTION OF WY
TODAY. SFC HAS MAIN SFC LOW WELL TO THE SOUTH FROM CNTRL CO TO NEAR
THE FOUR CORNERS REGION...WITH ONLY A WEAK INVERTED TROF UP INTO WRN
WY. LOW PRESSURE RESIDES OVR THE GB...WITH GENERAL HIGH P TO THE
E/NE INTO THE PLAINS....KEEPING MUCH OF THE LOW LVL FLOW ACROSS THE
FA FROM THE NORTH TO EAST.

SEASONALLY COOL/COLD CONDITIONS...FOR THE MOST PART...CONTINUE THRU
THE FCST PERIOD...WITH A RATHER PERSISTENT STRAT CU CLOUD DECK
REMAIN OVR MUCH OF WY. A FEW BREAKS IN THE CLOUDS MAY ARRIVE THIS
AFTERNOON OVER THE BASINS FOR A SHORT PERIOD BEFORE RETURN TO
OVERCAST AGAIN TONIGHT. A FEW MORE BREAKS WITH SLIGHTLY BETTER
SUNSHINE POTENTIAL WILL BE POSSIBLE FRIDAY AFTERNOON...BEFORE
CLOSING ONCE AGAIN FRIDAY NIGHT FOR MOST LOCATIONS EXCEPT PERHAPS
THE NRN BIG HORN BASIN WHICH COULD REMAIN SCATTERED OVERNIGHT.
PRECIP POTENTIAL BEST ACROSS THE SOUTH AND WEST
TODAY/TONIGHT...EITHER ASSOCIATED WITH MOIST ADVECTION AND MODEST
UPR FORCING ROTATING INTO REGION FROM UPR LOW TO THE SOUTH...OR
ALONG/NEAR THE TROF OUT WEST. FRIDAY...OTHER THAN ISOLATED VERY
LIGHT SHOWERS POSSIBLE ACROSS MOST OF THE FA HERE AND THERE...BETTER
LOCATIONS FOR MEASURABLE PRECIP WILL BE LOCATION EITHER OVR THE WRN
MOUNTAINS FRI AFTERNOON DURING THE AFTERNOON WITH THE BEST
INSTABILITY...OR ACROSS FAR ERN SWEETWATER...ERN FREMONT...AND SRN
NATRONA COUNTIES AS THE MAIN UPR LOW HEADS TOWARDS/OVR ERN
CO...SPINNING UP A LEE CYCLONE INTO THE SRN PLAINS. HOWEVER...NONE
OF THE ACTIVITY APPEARS TO BE TOO SIGNIFICANT ATTM...WITH MOST ALL
OF THE BEST DYNAMICALLY FORCED PRECIP POTENTIAL ACROSS SERN
WY...AND POINTS FURTHER SOUTH AND EAST. THRU THE 24 HRS OF THE FCST
PERIOD...SNOW ACCUMULATION SHOULD GENERALLY RANGE FROM A TRACE TO AN
INCH ACROSS THE LOWER ELEVATIONS...TO 1 TO 3 INCHES ACROSS THE
MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A COLD LOW PRESSURE TROUGH WILL REMAIN OVER THE AREA FRIDAY NIGHT
WITH MOIST LOW LEVEL EASTERLY FLOW PRODUCING AREAS OF RAIN AND SNOW
SHOWERS OR A RAIN AND SNOW MIX.  THIS WILL CONTINUE ON SATURDAY...
SATURDAY NIGHT AND SUNDAY AS THE UPPER LOW PRESSURE AREA SPLITS
WITH THE NORTHEASTERN PART OF THE LOW EXITING TO THE EAST WHILE
A LARGE CLOSED LOW CIRCULATION REFORMS OVER THE SOUTHERN GREAT BASIN
AND DESERT SOUTHWEST WEST OF THE FOUR CORNERS AREA.  DRYING OCCURS
FROM NORTH TO SOUTH AS A DRY SURFACE HIGH PRESSURE AREA MOVES SOUTH
FROM ALBERTA ON MONDAY AND MONDAY NIGHT.  THE WEAKENING OF THE
SOUTHWEST LOW MAY BE TOO FAST AND THE MODELS START TO DIFFER WITH
THE DEMISE OF THE LOW AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS
INTO THE WEST.  THIS LEADS TO SIGNIFICANT DRYING AND WARMING
TUESDAY THROUGH WEDNESDAY.  WHEN THE RIDGE AXIS MOVES INTO EASTERN
WYOMING...SOUTH SOUTHWEST FLOW MOVES INTO WESTERN WYOMING WITH SOME
SHOWERS DEVELOPING WEDNESDAY NIGHT AND THURSDAY OVER THE WESTERN
MOUNTAINS.  THE SPREAD BETWEEN THE MODEL SOLUTIONS BECOMES QUITE
LARGE...BUT WITH A GENERAL LONG WAVE HIGH PRESSURE RIDGE...THE
MAIN DIFFERENCES ARE TO THE WEST AND EAST OF THE AREA WHERE LONG
WAVE TROUGHS BRACKET THE RIDGE. WEDNESDAY AND THURSDAY HIGHS WARM
NICELY INTO THE UPPER 60S AND 70S WITH THE WARMEST TEMPERATURES
IN THE BIGHORN BASIN.


&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/MVFR CONDITIONS WILL PREVAIL OVER MOST OF THE REGION THROUGH
THIS EVENING. SHOWERS WILL CONTINUE OVER WEST AND SOUTH WY THIS
EVENING. MAINLY MVFR TO LOCAL IFR CONDITIONS WILL RETURN TO
SOUTHWEST WY THIS EVENING...CONTINUING THROUGH 15Z. VIS REDUCTIONS
DUE TO -SN OR BR WILL BE MOST PROBABLE NEAR KJAC THROUGH 09Z. A
GUSTY NORTHEAST WIND WILL CONTINUE AT/NEAR THE KRKS AIRPORT THROUGH
THIS EVENING. IMPROVING CONDITIONS EXPECTED AFTER 15Z FOR MOST
TERMINAL LOCATIONS.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

MVFR TO OCCASIONAL VFR CIGS OVER MOST OF THE REGION EARLY THIS
EVENING...WITH SOME LIGHT RAIN AND/OR SNOW SNOW SHOWERS THROWN IN
FOR GOOD MEASURE. THEN MVFR TO OCCASIONAL IFR CIGS WILL RETURN
BEFORE MIDNIGHT FOR MOST TERMINAL LOCATIONS...LASTING THROUGH 15Z.
IMPROVING CONDITIONS EXPECTED AFTER 15Z FOR MOST TERMINAL LOCATIONS.
KCPR WILL BE MOST LIKELY TO SUCCUMB TO POSSIBLE MVFR CONDITIONS
NEAR THE END OF THE FORECAST PERIOD.

&&

.FIRE WEATHER...

TODAY...LOW FIRE DANGER ALL LOCATIONS WITH RELATIVELY LIGHT WIND
HIGH RH VALUES...ONLY BOTTOMING OUT IN THE MID 50S TO MID 80S
(PERCENT). SMALL CHANCES FOR AN ISOLATED TO SCATTERED SHOWERS OR AN
ISOLATED THUNDERSTORM ACROSS SOUTH AND SOUTHWEST WY THIS AFTERNOON
THROUGH 4 AM. FRIDAY...FIRE DANGER CONTINUES LOW ACROSS ALL OF
WYOMING.

&&

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

$$

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





000
FXUS65 KRIW 281710
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 AM MDT THU APR 28 2016

.SHORT TERM...THURSDAY THROUGH SATURDAY NIGHT

UNSETTLED AND COOL WEATHER LOOKS TO CONTINUE INTO THE WEEKEND.
CURRENTLY A FEW LIGHT SHOWERS CONTINUE ACROSS THE AREA BUT NOTHING
HEAVY AT THIS TIME. HOWEVER...IN THIS PATTERN THERE IS ALWAYS A
CHANCE ON OF THOSE ANNOYING SNOW BANDS MAY POP UP. AND THIS LOOKS TO
BE THE RULE OF THUMB FOR MOST AREAS TODAY. MAINLY LIGHT SHOWERS
POSSIBLE AT ANY TIME BUT ESPECIALLY DURING THE AFTERNOON AND EVENING
ALONG WITH WELL BELOW NORMAL TEMPERATURES CONTINUING.  ONE AREA THAT
COULD HAVE MORE ORGANIZED PRECIPITATION WOULD BE SOUTHERN SWEETWATER
COUNTY WHERE SOME MOISTURE MAY CREEP NORTHWARD AS AN UPPER LEVEL LOW
PASSES BY TO THE SOUTH. AT THIS TIME...AMOUNTS ARE EXPECTED TO BE
MAINLY LIGHT AND MAINLY A MIX OF RAIN AND SNOW AND WITH THE LATE
APRIL SUN ANY SNOW WOULD HAVE A HARD TIME STICKING...ESPECIALLY ON
PAVED SURFACES.
THIS SHOULD END LATER TONIGHT AS THE LOW MOVES AWAY TO THE EAST.

FRIDAY SHOULD START OUT MAINLY DRY BUT COVERING OF SHOWERS WILL
INCREASE IN THE AFTERNOON AS EASTERLY FLOW DEEPENS AS THE
AFOREMENTIONED UPPER LEVEL LOW SLOWS DOWN AND TRIES TO TURN MORE
NORTH. THE MODELS HAVE DIFFERENCES ON HOW MUCH MOISTURE MAKES IT IN
WITH THE GFS AND EUROPEAN WETTER THAN THE NAM. FOR NOW...WE SPLIT
THE DIFFERENCE LEANING A BIT MORE TOWARD THE WETTER SOLUTION. THE
BEST CHANCE WOULD BE ACROSS EASTERN WYOMING WITH LESSENING CHANCES
THE FURTHER WEST YOU GO. ACROSS THE WEST...A WEAK SURFACE LOW
PASSING THROUGH IDAHO WILL BRING AN INCREASE IN SHOWERS AS WELL AS
MAYBE ENOUGH INSTABILITY FOR A FEW THUNDERSTORMS. TEMPERATURES
SHOULD BE A FEW DEGREES WARMER...BUT STILL WELL BELOW NORMAL.

THE MOST ACTIVE PERIOD MAY FRIDAY NIGHT INTO SATURDAY AS THE
UPPER LEVEL LOW MOVES INTO THE PLAINS AND A PERIOD OF ABOUT 12 TO
18 HOURS OF NORTHEASTERLY UPSLOPE TRIES TO DEVELOP. AGAIN THE
MODELS ARE SPLIT WITH THE NAM DRIER AND SLOWER...THE EUROPEAN THE
WETTEST AND FASTEST AND THE GFS TAKING THE MIDDLE GROUND.
AGAIN...FOR NOW WE COMPROMISED AND SPLIT THE MIDDLE. HOWEVER...ALL
THE MODELS KEEP THE HEAVIEST PRECIPITATION TO THE EAST OF THE
COUNTY WARNING AREA. THIS PRECIPITATION AREA SHOULD TAPER OFF
LATER AT NIGHT AS LOW MOVES AWAY TO THE EAST AND FLOW TURNS MORE
EASTERLY TO SOUTHEASTERLY. THE EXCEPTION WOULD BE A PLACE LIKE
DUBOIS OR THE LEE OF THE ABSAROKAS WHERE SOME UPSLOPE COULD
DEVELOP. 700 MILLIBAR TEMPERATURES ARE BORDERLINE FOR RAIN OR
SNOW...AROUND MINUS 5 TO MINUS 6 SO PRECIPITATION TYPE MAY DEPEND
A LOT ON DYNAMIC COOLING AND RATE OF THE PRECIPITATION.

.LONG TERM...SUNDAY THROUGH THURSDAY

AT 12Z SUNDAY...MODELS ARE IN DECENT AGREEMENT WITH THE MAIN UPPER
LOW OVER CENTRAL/NORTHERN ARIZONA. THERE WILL BE WEAK DISTURBANCES
ROTATING AROUND THIS UPPER LOW THAT WILL CONTINUE TO GIVE MUCH OF
THE AREA A CHANCE OF PRECIPITATION. THIS COULD BE ENHANCED BY SOME
WEAK UPSLOPE EAST/NORTHEAST FLOW FOR AREAS EAST OF THE DIVIDE.
HOWEVER THE MAIN MODEL TRENDS FOR SUNDAY HAS BEEN FOR LIGHTER
PRECIPITATION AND NOT AS WIDESPREAD AS WHAT IT LOOKED LIKE A FEW
DAYS AGO. STILL TEMPERATURES WILL BE WELL BELOW AVERAGE FOR LATE
APRIL.

THE UPPER LOW BEGINS TO FILL AND SHEAR OUT SUNDAY NIGHT AND
MONDAY WITH UPPER RIDGING BUILDING INTO THE AREA TUESDAY AND
WEDNESDAY. CONVECTION CHANCES WILL BE CONFINED MAINLY TO THE
MOUNTAINS OR ACROSS THE SOUTHWEST PART OF THE FORECAST AREA. A
MAJOR WARMING TREND IS EXPECTED MONDAY THROUGH WEDNESDAY WITH
TEMPERATURES RETURNING TO SEASONAL TO EVEN SLIGHTLY ABOVE AVERAGE.

BY LATE THURSDAY...A STRONG UPPER LOW IS EXPECTED TO BEGIN PUSHING INTO
CENTRAL/SOUTHERN CALIFORNIA. THE DIFLUENT FLOW AHEAD OF THIS
SYSTEM COULD RESULT IN SOME THUNDERSTORM ACTIVITY OVER THE
WEST...BUT THE EAST SHOULD REMAIN DRY...BUT BEGIN TO GET BREEZY TO
WINDY. ABOVE AVERAGE TEMPERATURES ARE EXPECTED THURSDAY WITH 70S
TO NEAR 80 EAST...WITH MID 60S TO LOWER 70S WEST IN THE LOWER
ELEVATIONS.

&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/MVFR CONDITIONS WILL PREVAIL OVER MOST OF THE REGION THROUGH
THIS EVENING. SHOWERS WILL DEVELOP OVER WEST AND SOUTH WY THIS
AFTERNOON AND EVENING. MAINLY MVFR CONDITIONS WILL RETURN ACROSS
SOUTHWEST WY THIS EVENING...CONTINUING THROUGH 15Z FRIDAY. A GUSTY
NORTHEAST WIND WILL CONTINUE AT/NEAR THE KRKS AIRPORT MOST OF THE
REST OF THE DAY AND EVENING. IMPROVING CONDITIONS EXPECTED AFTER 15Z
FRIDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

MVFR TO OCCASIONAL VFR CIGS OVER MOST OF THE REGION TODAY AND THIS
EVENING...WITH SOME LIGHT RAIN AND/OR SNOW SNOW SHOWERS THROWN IN
FOR GOOD MEASURE. MVFR TO OCCASIONAL IFR CIGS WILL RETURN LATER THIS
EVENING...LASTING THROUGH 15Z FRI. IMPROVING CONDITIONS EXPECTED
AFTER 15Z FRIDAY.

&&

.FIRE WEATHER...

FEW CONCERNS FOR MOST OF THE WEEK WITH UPPER LEVEL LOW PRESSURE
KEEPING THE WEATHER UNSETTLED. TEMPERATURES WILL AVERAGE BELOW
NORMAL WITH RELATIVE HUMIDITY REMAINING ABOVE CRITICAL LEVELS...SOME
AREAS WELL ABOVE CRITICAL LEVELS. THERE WILL BE A DAILY CHANCE FOR
SHOWERS FROM TODAY LIKELY INTO THE WEEKEND FOR MANY AREAS.

&&

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

&&

$$

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





000
FXUS65 KRIW 281710
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 AM MDT THU APR 28 2016

.SHORT TERM...THURSDAY THROUGH SATURDAY NIGHT

UNSETTLED AND COOL WEATHER LOOKS TO CONTINUE INTO THE WEEKEND.
CURRENTLY A FEW LIGHT SHOWERS CONTINUE ACROSS THE AREA BUT NOTHING
HEAVY AT THIS TIME. HOWEVER...IN THIS PATTERN THERE IS ALWAYS A
CHANCE ON OF THOSE ANNOYING SNOW BANDS MAY POP UP. AND THIS LOOKS TO
BE THE RULE OF THUMB FOR MOST AREAS TODAY. MAINLY LIGHT SHOWERS
POSSIBLE AT ANY TIME BUT ESPECIALLY DURING THE AFTERNOON AND EVENING
ALONG WITH WELL BELOW NORMAL TEMPERATURES CONTINUING.  ONE AREA THAT
COULD HAVE MORE ORGANIZED PRECIPITATION WOULD BE SOUTHERN SWEETWATER
COUNTY WHERE SOME MOISTURE MAY CREEP NORTHWARD AS AN UPPER LEVEL LOW
PASSES BY TO THE SOUTH. AT THIS TIME...AMOUNTS ARE EXPECTED TO BE
MAINLY LIGHT AND MAINLY A MIX OF RAIN AND SNOW AND WITH THE LATE
APRIL SUN ANY SNOW WOULD HAVE A HARD TIME STICKING...ESPECIALLY ON
PAVED SURFACES.
THIS SHOULD END LATER TONIGHT AS THE LOW MOVES AWAY TO THE EAST.

FRIDAY SHOULD START OUT MAINLY DRY BUT COVERING OF SHOWERS WILL
INCREASE IN THE AFTERNOON AS EASTERLY FLOW DEEPENS AS THE
AFOREMENTIONED UPPER LEVEL LOW SLOWS DOWN AND TRIES TO TURN MORE
NORTH. THE MODELS HAVE DIFFERENCES ON HOW MUCH MOISTURE MAKES IT IN
WITH THE GFS AND EUROPEAN WETTER THAN THE NAM. FOR NOW...WE SPLIT
THE DIFFERENCE LEANING A BIT MORE TOWARD THE WETTER SOLUTION. THE
BEST CHANCE WOULD BE ACROSS EASTERN WYOMING WITH LESSENING CHANCES
THE FURTHER WEST YOU GO. ACROSS THE WEST...A WEAK SURFACE LOW
PASSING THROUGH IDAHO WILL BRING AN INCREASE IN SHOWERS AS WELL AS
MAYBE ENOUGH INSTABILITY FOR A FEW THUNDERSTORMS. TEMPERATURES
SHOULD BE A FEW DEGREES WARMER...BUT STILL WELL BELOW NORMAL.

THE MOST ACTIVE PERIOD MAY FRIDAY NIGHT INTO SATURDAY AS THE
UPPER LEVEL LOW MOVES INTO THE PLAINS AND A PERIOD OF ABOUT 12 TO
18 HOURS OF NORTHEASTERLY UPSLOPE TRIES TO DEVELOP. AGAIN THE
MODELS ARE SPLIT WITH THE NAM DRIER AND SLOWER...THE EUROPEAN THE
WETTEST AND FASTEST AND THE GFS TAKING THE MIDDLE GROUND.
AGAIN...FOR NOW WE COMPROMISED AND SPLIT THE MIDDLE. HOWEVER...ALL
THE MODELS KEEP THE HEAVIEST PRECIPITATION TO THE EAST OF THE
COUNTY WARNING AREA. THIS PRECIPITATION AREA SHOULD TAPER OFF
LATER AT NIGHT AS LOW MOVES AWAY TO THE EAST AND FLOW TURNS MORE
EASTERLY TO SOUTHEASTERLY. THE EXCEPTION WOULD BE A PLACE LIKE
DUBOIS OR THE LEE OF THE ABSAROKAS WHERE SOME UPSLOPE COULD
DEVELOP. 700 MILLIBAR TEMPERATURES ARE BORDERLINE FOR RAIN OR
SNOW...AROUND MINUS 5 TO MINUS 6 SO PRECIPITATION TYPE MAY DEPEND
A LOT ON DYNAMIC COOLING AND RATE OF THE PRECIPITATION.

.LONG TERM...SUNDAY THROUGH THURSDAY

AT 12Z SUNDAY...MODELS ARE IN DECENT AGREEMENT WITH THE MAIN UPPER
LOW OVER CENTRAL/NORTHERN ARIZONA. THERE WILL BE WEAK DISTURBANCES
ROTATING AROUND THIS UPPER LOW THAT WILL CONTINUE TO GIVE MUCH OF
THE AREA A CHANCE OF PRECIPITATION. THIS COULD BE ENHANCED BY SOME
WEAK UPSLOPE EAST/NORTHEAST FLOW FOR AREAS EAST OF THE DIVIDE.
HOWEVER THE MAIN MODEL TRENDS FOR SUNDAY HAS BEEN FOR LIGHTER
PRECIPITATION AND NOT AS WIDESPREAD AS WHAT IT LOOKED LIKE A FEW
DAYS AGO. STILL TEMPERATURES WILL BE WELL BELOW AVERAGE FOR LATE
APRIL.

THE UPPER LOW BEGINS TO FILL AND SHEAR OUT SUNDAY NIGHT AND
MONDAY WITH UPPER RIDGING BUILDING INTO THE AREA TUESDAY AND
WEDNESDAY. CONVECTION CHANCES WILL BE CONFINED MAINLY TO THE
MOUNTAINS OR ACROSS THE SOUTHWEST PART OF THE FORECAST AREA. A
MAJOR WARMING TREND IS EXPECTED MONDAY THROUGH WEDNESDAY WITH
TEMPERATURES RETURNING TO SEASONAL TO EVEN SLIGHTLY ABOVE AVERAGE.

BY LATE THURSDAY...A STRONG UPPER LOW IS EXPECTED TO BEGIN PUSHING INTO
CENTRAL/SOUTHERN CALIFORNIA. THE DIFLUENT FLOW AHEAD OF THIS
SYSTEM COULD RESULT IN SOME THUNDERSTORM ACTIVITY OVER THE
WEST...BUT THE EAST SHOULD REMAIN DRY...BUT BEGIN TO GET BREEZY TO
WINDY. ABOVE AVERAGE TEMPERATURES ARE EXPECTED THURSDAY WITH 70S
TO NEAR 80 EAST...WITH MID 60S TO LOWER 70S WEST IN THE LOWER
ELEVATIONS.

&&

.AVIATION.../18Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI AIRPORTS

VFR/MVFR CONDITIONS WILL PREVAIL OVER MOST OF THE REGION THROUGH
THIS EVENING. SHOWERS WILL DEVELOP OVER WEST AND SOUTH WY THIS
AFTERNOON AND EVENING. MAINLY MVFR CONDITIONS WILL RETURN ACROSS
SOUTHWEST WY THIS EVENING...CONTINUING THROUGH 15Z FRIDAY. A GUSTY
NORTHEAST WIND WILL CONTINUE AT/NEAR THE KRKS AIRPORT MOST OF THE
REST OF THE DAY AND EVENING. IMPROVING CONDITIONS EXPECTED AFTER 15Z
FRIDAY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND AIRPORTS

MVFR TO OCCASIONAL VFR CIGS OVER MOST OF THE REGION TODAY AND THIS
EVENING...WITH SOME LIGHT RAIN AND/OR SNOW SNOW SHOWERS THROWN IN
FOR GOOD MEASURE. MVFR TO OCCASIONAL IFR CIGS WILL RETURN LATER THIS
EVENING...LASTING THROUGH 15Z FRI. IMPROVING CONDITIONS EXPECTED
AFTER 15Z FRIDAY.

&&

.FIRE WEATHER...

FEW CONCERNS FOR MOST OF THE WEEK WITH UPPER LEVEL LOW PRESSURE
KEEPING THE WEATHER UNSETTLED. TEMPERATURES WILL AVERAGE BELOW
NORMAL WITH RELATIVE HUMIDITY REMAINING ABOVE CRITICAL LEVELS...SOME
AREAS WELL ABOVE CRITICAL LEVELS. THERE WILL BE A DAILY CHANCE FOR
SHOWERS FROM TODAY LIKELY INTO THE WEEKEND FOR MANY AREAS.

&&

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

&&

$$

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





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