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000
FXUS65 KRIW 242326
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
526 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

EXTENDED FLASH FLOOD WATCH UNTIL 6 AM MDT MONDAY.

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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







000
FXUS65 KRIW 242326
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
526 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

EXTENDED FLASH FLOOD WATCH UNTIL 6 AM MDT MONDAY.

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH LATE TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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








000
FXUS65 KRIW 242031
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
231 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

&&

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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









000
FXUS65 KRIW 242031
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
231 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

&&

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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









000
FXUS65 KRIW 242031
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
231 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

&&

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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










000
FXUS65 KRIW 242031
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
231 PM MDT SUN MAY 24 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO OCCLUDING WITH STRONG DEFORMATION AXIS ASSOCIATED
WITH BAND OF MODERATE TO HEAVY RAINFALL WITH RATES UP TO 1 INCH
AN HOUR OVER EASTERN FREMONT COUNTY. DRY SLOT EAST AND NORTHEAST
OF UPPER LOW CENTER BECOMING UNSTABLE WITH RAPID THUNDERSTORM
DEVELOPMENT.  THUNDERSTORMS SHOULD ADVECT NORTHWEST AND WEST INTO
DEFORMATION ZONE AND OVERRUN MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. HYDROGRAPHS SHOWING STEADY
RISES ON THE POWDER RIVER AND CLEAR CREEK ON EAST SLOPES OF
BIGHORNS.  MANY AREAS HAVE ALREADY RECEIVED 1 TO 3 INCHES OF RAIN
GOING BACK TO FRIDAY NIGHT. FLASH FLOOD THREAT REMAINS ELEVATED
AND HAVE EXTENDED FLASH FLOOD WATCH OUT THROUGH 06Z THIS EVENING
AND EXPANDED COVERAGE TO INCLUDE ALL OF FREMONT AND HOT SPRINGS
COUNTIES AS WELL AS EASTERN SWEETWATER COUNTY. MOUNTAIN AREAS
SHOULD SEE SNOW LEVEL AROUND 9000 FEET LOWER THROUGH THE NIGHT TO
AROUND 8000 FEET BY SUNRISE. UPPER LOW WILL BEGIN EJECTING EAST
NORTHEAST AND WILL SEE PRECIPITATION INTENSITY DECREASE LATER
TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING TO THE NORTHWEST.  EXPECT
SOME SHOWERS AND ISOLATED THUNDERSTORMS TO REDEVELOP IN THE
NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES WILL CONTINUE THROUGH
MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

SHOWERS TO CONTINUE MONDAY EVENING AS A WEAK RIDGE OF HIGH PRESSURE
TRIES TO BUILD OVER THE AREA. THIS RIDGE WILL WEAKEN SHOWER ACTIVITY
BRIEFLY DURING THE MONDAY NIGHT PERIOD...BUT THE RIDGE AXIS SLIDES
THROUGH THE AREA QUICKLY ALLOWING SOUTHWEST FLOW TO RETURN BY
TUESDAY EVENING. SHOWERS AND THUNDERSTORMS WILL BUILD OVER THE AREA
WITH THE RETURN OF THE SOUTHWEST FLOW...WITH SOME STORMS CONTAINING
GUSTY WIND AND SMALL HAIL.

A DIURNAL TREND FOR THE SHOWER ACTIVITY THEN BECOMES FAIRLY
ESTABLISHED. SHOWERS AND THUNDERSTORMS WILL BE PRESENT DURING THE
AFTERNOON AND EARLY EVENING HOURS...WITH ACTIVITY WANING WITH LOSS
OF DAYLIGHT. TEMPERATURES WILL WORK TO WARM THROUGH THE FORECAST
PERIOD...WITH WIDESPREAD BASIN TEMPERATURES REACHING INTO THE 70S BY
THE END OF THE FORECAST PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

WIDESPREAD MVFR TO IFR CEILINGS WITH VISIBILITY REDUCED IN RAIN
AND FOG...SNOW IN THE HIGHER MOUNTAINS...OBSCURING TERRAIN
CONTINUING ALONG AND EAST OF THE CONTINENTAL DIVIDE THROUGH 18Z
MONDAY. THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING TONIGHT AND MONDAY...AND THERE WILL LIKELY BE SOME LIFTING OF
CIGS LATE MONDAY AFTERNOON FOLLOWED BY RAPID REDEVELOPMENT OF
SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON IN NORTHWEST FLOW
ALOFT.  MOST AIRPORTS WILL BE IMPACTED BY THE MVFR AND IFR CONDITIONS
TONIGHT THEN IMPROVING TO VFR BY 18Z MONDAY. THEN BRIEF MVFR CONDITIONS
WILL BE A THREAT WITH STRONGER SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON.

&&

.FIRE WEATHER...

STRONG COLD UPPER LEVEL LOW PRESSURE SYSTEM WITH CENTER NEAR
CRAIG COLORADO ASSOCIATED WITH BAND OF MODERATE TO HEAVY
RAINFALL WITH RATES UP TO 1 INCH AN HOUR OVER EASTERN FREMONT
COUNTY. DRY SLOT EAST AND NORTHEAST OF UPPER LOW CENTER BECOMING
UNSTABLE WITH RAPID THUNDERSTORM DEVELOPMENT. THUNDERSTORMS SHOULD
ADVECT NORTHWEST AND WEST INTO MORE STRATIFORM RAIN SHIELD.
PRECIPITATION OROGRAPHICALLY ENHANCED ALONG EAST SLOPES OF THE
BIGHORN AND WIND RIVER MOUNTAINS. MANY AREAS HAVE ALREADY
RECEIVED 1 TO 3 INCHES OF RAIN GOING BACK TO FRIDAY NIGHT. FLASH
FLOOD THREAT REMAINS ELEVATED AND HAVE EXTENDED FLASH FLOOD WATCH
OUT THROUGH 06Z THIS EVENING AND EXPANDED COVERAGE TO INCLUDE ALL
OF FREMONT AND HOT SPRINGS COUNTIES AS WELL AS EASTERN SWEETWATER
COUNTY. MOUNTAIN AREAS SHOULD SEE SNOW LEVEL AROUND 9000 FEET
LOWER THROUGH THE NIGHT TO AROUND 8000 FEET BY SUNRISE. UPPER LOW
WILL BEGIN EJECTING EAST NORTHEAST AND WILL SEE PRECIPITATION
INTENSITY DECREASE LATER TONIGHT WITH FLOW ALOFT SLOWLY SHIFTING
TO THE NORTHWEST. EXPECT SOME SHOWERS AND ISOLATED THUNDERSTORMS
TO REDEVELOP IN THE NORTHWEST FLOW ON MONDAY. COOL TEMPERATURES
WILL CONTINUE THROUGH MONDAY. RELATIVE HUMIDITY WILL BE ELEVATED
ACROSS THE AREA THROUGH MONDAY WITH GENERALLY LOW MIXING HEIGHTS
AND POOR SMOKE DISPERSAL ESPECIALLY EAST OF THE CONTINENTAL
DIVIDE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL MIDNIGHT MDT TONIGHT
WYZ005>011-015>020-022-030.

&&

$$

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










000
FXUS65 KRIW 241501
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
901 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

UPDATED TO EXTEND FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT.
ALSO ADDED ALL OF FREMONT AND HOT SPRINGS COUNTIES AND EASTERN
SWEETWATER COUNTY TO THE FLASH FLOOD WATCH.  RAINFALL OF AN INCH
TO 2.5 INCHES HAS ALREADY OCCURRED OVER MUCH OF THE WATCH AREA
OVER NIGHT AND THIS MORNING.

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

.AVIATION.../18Z ISSUANCE/

WIDESPREAD MVFR TO IFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR
CONDITIONS WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE
DIVIDE THROUGH 18Z MONDAY. THESE CONDITIONS WILL NOT BE AS
WIDESPREAD WEST OF THE DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT
THROUGH THE MORNING HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY AND SUNDAY NIGHT...AND THERE WILL LIKELY BE SOME
LIFTING OF CIGS LATE IN THE AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING. WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER
03Z SUNDAY ACROSS MOST OF THE AREA.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING
WYZ005>011-015>020-022-030.

&&

$$

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







000
FXUS65 KRIW 241501
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
901 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

UPDATED TO EXTEND FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT.
ALSO ADDED ALL OF FREMONT AND HOT SPRINGS COUNTIES AND EASTERN
SWEETWATER COUNTY TO THE FLASH FLOOD WATCH.  RAINFALL OF AN INCH
TO 2.5 INCHES HAS ALREADY OCCURRED OVER MUCH OF THE WATCH AREA
OVER NIGHT AND THIS MORNING.

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

.AVIATION.../18Z ISSUANCE/

WIDESPREAD MVFR TO IFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR
CONDITIONS WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE
DIVIDE THROUGH 18Z MONDAY. THESE CONDITIONS WILL NOT BE AS
WIDESPREAD WEST OF THE DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT
THROUGH THE MORNING HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY AND SUNDAY NIGHT...AND THERE WILL LIKELY BE SOME
LIFTING OF CIGS LATE IN THE AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING. WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER
03Z SUNDAY ACROSS MOST OF THE AREA.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING
WYZ005>011-015>020-022-030.

&&

$$

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








000
FXUS65 KRIW 241501
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
901 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

UPDATED TO EXTEND FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT.
ALSO ADDED ALL OF FREMONT AND HOT SPRINGS COUNTIES AND EASTERN
SWEETWATER COUNTY TO THE FLASH FLOOD WATCH.  RAINFALL OF AN INCH
TO 2.5 INCHES HAS ALREADY OCCURRED OVER MUCH OF THE WATCH AREA
OVER NIGHT AND THIS MORNING.

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

.AVIATION.../18Z ISSUANCE/

WIDESPREAD MVFR TO IFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR
CONDITIONS WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE
DIVIDE THROUGH 18Z MONDAY. THESE CONDITIONS WILL NOT BE AS
WIDESPREAD WEST OF THE DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT
THROUGH THE MORNING HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY AND SUNDAY NIGHT...AND THERE WILL LIKELY BE SOME
LIFTING OF CIGS LATE IN THE AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING. WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER
03Z SUNDAY ACROSS MOST OF THE AREA.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING
WYZ005>011-015>020-022-030.

&&

$$

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








000
FXUS65 KRIW 241501
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
901 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

UPDATED TO EXTEND FLASH FLOOD WATCH UNTIL MIDNIGHT TONIGHT.
ALSO ADDED ALL OF FREMONT AND HOT SPRINGS COUNTIES AND EASTERN
SWEETWATER COUNTY TO THE FLASH FLOOD WATCH.  RAINFALL OF AN INCH
TO 2.5 INCHES HAS ALREADY OCCURRED OVER MUCH OF THE WATCH AREA
OVER NIGHT AND THIS MORNING.

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

.AVIATION.../18Z ISSUANCE/

WIDESPREAD MVFR TO IFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR
CONDITIONS WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE
DIVIDE THROUGH 18Z MONDAY. THESE CONDITIONS WILL NOT BE AS
WIDESPREAD WEST OF THE DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT
THROUGH THE MORNING HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY AND SUNDAY NIGHT...AND THERE WILL LIKELY BE SOME
LIFTING OF CIGS LATE IN THE AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING. WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER
03Z SUNDAY ACROSS MOST OF THE AREA.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING
WYZ005>011-015>020-022-030.

&&

$$

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







000
FXUS65 KRIW 240901
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
301 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

&&

.AVIATION.../12Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.


&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 240901
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
301 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

&&

.AVIATION.../12Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.


&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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









000
FXUS65 KRIW 240901
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
301 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

&&

.AVIATION.../12Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.


&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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









000
FXUS65 KRIW 240901
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
301 AM MDT SUN MAY 24 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF CONTINUES ACROSS THE WRN CONUS
WITH CLOSED LOW OVR WRN CO/SRN WY...WITH NICE VORT LOBE ROTATING
ANTI-CLOCKWISE AROUND CNTRL CLOSED PORTION OF THE LOW INTO SCNTRL
WY. EMBEDDED SW ALSO ROTATING AROUND THE LOW...NOW STRETCHED
DIAGONALLY ACROSS WY FROM THE SW TO NCNTRL. SFC HAS GENERAL HIGH P
NORTH OVR MT...HIGH P SOUTH OVR CO/NM...WITH A WEAK LOW P
TROF/DEVELOPING FRONT IN BETWEEN AND ACROSS CNTRL WY.

EARLY MORNING FOG WILL CONTINUE TO BE POSSIBLE OVR MUCH OF THE FA
THRU TUE MORNING...ESPECIALLY E OF THE DIVIDE.  OTHERWISE...MAINLY
HYDROLOGIC CONCERNS AS UPR TROF MIGRATES EWD WHILE THE CNTRL UPR LOW
SLOWLY PULLS FROM CO/WY BORDER AREA INTO THE HIGH PLAINS BY THIS
EVENING. WEAK SFC CYCLOGENESIS TO TAKE PLACE FROM ERN/NERN CO INTO
SERN WY AND WRN NE. LOW TO MID LVL MOISTURE RETURN AROUND THE
DEVELOPING SFC LOW...WHILE MID/UPR MOISTURE ACCOMPANYING THE UPR
WAVE/CLOSED LOW DEEPENS MOISTURE E OF THE DIVIDE...WITH PWS RANGING
FROM 0.70 TO 0.80...WILL GIVE ANOTHER DAY OF PLENTIFUL
RAINFALL...AGAIN ESPECIALLY E OF THE DIVIDE. WIDESPREAD AREAS OF NEW
PRECIPITATION THRU SUNDAY EVENING WILL RANGE FROM .75 TO 1.25
INCHES...WITH SOME PREFERRED LOCATIONS ALONG THE E SIDE OF THE
BIGHORNS...NEAR/OVR THE SRN BIGHORNS...AND THE GREEN AND ERN
WIND RIVER MOUNTAINS...WHERE PRECIP WILL BE ENHANCED DUE TO TERRAIN
LIFT OR TERRAIN INDUCED CONVERGENCE. EVEN THE FOOTHILLS OF THE
WESTERN SIDE OF THE BIGHORNS WILL BE SUSCEPTABLE TO ENHANCED PRECIP
AS DEEP FLOW MOVES AROUND FROM THE NORTH. FLASH FLOODING WILL
CONTINUE TO BE A CONCERN FOR ANOTHER DAY E OF THE DIVIDE...AND HAVE
ADDED THE WESTERN BIGHORNS  AND WASHAKIE COUNTY TO THE CURRENT FLASH
FLOOD WATCH AREA. AREAS SATURATED MOST OVR THE PAST COUPLE OF DAYS
INCLUDE FREMONT COUNTY...PARTICULARLY WRN AND SRN PORTIONS...MOST OF
NATRONA COUNTY...THE SRN AND ERN PORTIONS OF WASHAKIE COUNTY...AND
AREAS IMMEDIATELY ADJACENT TO THESE COUNT AREAS. AGAIN...THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING
MOSTLY ABOVE -1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY WELL
ABOVE ZERO FOR MOST OF THAT TIME. EXPECT...A TRACE TO AN INCH OR TWO
DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500 FEET...WITH ONLY
THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR 4 INCHES BY MONDAY
MORNING. STORM MOVEMENT IMPROVES SLIGHTLY...EVENTUALLY BECOMING NRLY
AT 15 TO 20 MPH MOST LOCATIONS BY THE END OF THE TODAY EXCEPT FOR
JOHNSON COUNTY WHICH WILL KEEP MOVEMENT OUT OF THE E OT NE. SEVERE
WX WILL REMAIN MOSTLY WELL EAST TO SOUTHEAST OF FA WITH CONTINUED
RELATIVELY LOW SHEAR CONDITIONS. THE BEST CHANCES FOR SMALL HAIL UP
TO ONE HALF INCH AND PERHAPS A BOUNDARY LOCKED FUNNEL CLOUD WILL LAY
ACROSS THE FAR ERN FA...WITH A SMALLER CHANCE FOR SMALL HAIL NEAR
THE FAR WRN BORDER AREA WHERE SOME POSSIBLE INCREASED SUNSHINE MAY
ENHANCE A COUPLE OF STORMS.

TONIGHT THRU TUESDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE FAR WRN FA MONDAY WHILE
THE REST OF THE FA WILL BE UNDER THE INFLUENCE OF A SW ROTATING INTO
THE AREA FROM THE NE AROUND THE EXITING LOW...WITH MORE
SHOWER/THUNDER ACTIVITY...ALBEIT ON A LESSER BASIS. OTHERWISE...A
BIT WARMER AND MORE UNSTABLE WITH PERHAPS AN BETTER SPRINKLING OF
STRONGER THUNDERSTORMS MIXED IN WITH SHOWERS ON TUESDAY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

GFS MODEL CONTINUES ITS TREND FROM PREVIOUS NIGHTS BY TAKING A
WEATHER SYSTEM FROM THE PACIFIC NW WEDNESDAY AND MOVING IT INTO
IDAHO THURSDAY. ON FRIDAY THE GFS TAKES A MORE SOUTHEAST TRACK
TOWARD SW WY OR NORTHERN UTAH AND THEN TO NW COLORADO BY FRIDAY
NIGHT. FROM THERE IT DRIFTS EAST THROUGH NORTHERN COLORADO SATURDAY
AND OUT OF THE AREA SATURDAY NIGHT. WITH MOISTURE PRESENT AND ANY
SUNSHINE THAT OCCURS...INSTABILITY WILL OCCUR AND THUS SHOWERS AND
THUNDERSTORMS WILL FORM IN THE AFTERNOON AND EVENING. LINGERING
SHOWERS DURING THE LATE NIGHT AND MORNING HOURS. NEXT SUNDAY LOOKS
LIKE A QUIETER DAY WITH ONLY ISOLATED SHOWERS OR STORMS IN NW WY IN
THE AFTERNOON. THE ECMWF MODEL IS SIMILAR WEDNESDAY THROUGH THURSDAY
BUT THEN THE ECMWF SPEEDS UP THE WEATHER SYSTEM MOVEMENT ON FRIDAY
AND TAKES IT OUT OF THE AREA BY SATURDAY MORNING. THEN IT HAS MOSTLY
DRY WEATHER FOR SATURDAY AND NEXT SUNDAY WITH ONLY ISOLATED SHOWERS
OR STORMS. WILL FOLLOW A MORE GFS SPEED FOR NOW AS MOST OF THESE
SYSTEMS HAVE BEEN SLOWER MOVING OUT OVER THE PAST MONTH. WILL PLAY
NEXT SATURDAY WITH A SLIGHT CHANCE OF SHOWERS AND ISOLATED STORMS
AND THEN ISOLATED MOUNTAIN ACTIVITY NEXT SUNDAY. AS FOR TEMPS...WED
HIGH TEMPS IN THE 60S TO LOWER 70S...THEN HIGHS THURSDAY ABOUT THE
SAME AS WED TO SLIGHTLY COOLER IN SOME PLACES. FRIDAY LOOKS A LITTLE
COOLER WITH MORE CLOUDS EXPECTED AS THE SYSTEM MOVES THROUGH THE
AREA. THEN A LITTLE WARMER SATURDAY AND EVEN WARMER NEXT SUNDAY TO
EXIT THE MONTH OF MAY.

&&

.AVIATION.../12Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.


&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH TUESDAY AS
RELATIVELY COOL AND WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION...WITH BETWEEN A HALF AN INCH AND AN INCH AND A
QUARTER EAST OF THE DIVIDE...AND LIGHT MOUNTAIN SNOW IS EXPECTED
TODAY AND TONIGHT...WITH EMBEDDED THUNDERSTORMS POSSIBLE EACH
AFTERNOON AND EARLY EVENING THROUGH TUESDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 240557
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1157 PM MDT SAT MAY 23 2015

.UPDATE...WESTERN BIGHORN RANGE AND WASHAKIE COUNTY ADDED TO FLASH
FLOOD WATCH THROUGH SUNDAY AFTERNOON.

&&

.AVIATION.../06Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.

&&

.PREV DISCUSSION... /ISSUED 305 PM MDT SAT MAY 23 2015/

SHORT TERM...TONIGHT THROUGH SUNDAY

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECIALLY FROM 06Z TO 15Z SUNDAY.

FIRE WEATHER...

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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






000
FXUS65 KRIW 240557
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1157 PM MDT SAT MAY 23 2015

.UPDATE...WESTERN BIGHORN RANGE AND WASHAKIE COUNTY ADDED TO FLASH
FLOOD WATCH THROUGH SUNDAY AFTERNOON.

&&

.AVIATION.../06Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.

&&

.PREV DISCUSSION... /ISSUED 305 PM MDT SAT MAY 23 2015/

SHORT TERM...TONIGHT THROUGH SUNDAY

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECIALLY FROM 06Z TO 15Z SUNDAY.

FIRE WEATHER...

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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






000
FXUS65 KRIW 240557
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1157 PM MDT SAT MAY 23 2015

.UPDATE...WESTERN BIGHORN RANGE AND WASHAKIE COUNTY ADDED TO FLASH
FLOOD WATCH THROUGH SUNDAY AFTERNOON.

&&

.AVIATION.../06Z ISSUANCE/

WIDESPREAD MVFR CONDITIONS AND MTN OBSCURATIONS...LCL IFR CONDITIONS
WITH NMRS -SHRA WILL CONTINUE ALONG AND EAST OF THE DIVIDE THROUGH
16Z SUNDAY.   THESE CONDITIONS WILL NOT BE AS WIDESPREAD WEST OF THE
DIVIDE WHICH MAY SEE MORE FOG DEVELOPMENT THROUGH THE MORNING
HOURS.

THE UPPER LOW OVER WESTERN COLORADO WILL SLOWLY LIFT NE INTO EASTERN
WYOMING ON SUNDAY...AND THERE WILL LIKELY BE SOME LIFTING OF CIGS
LATE SUNDAY MORNING INTO EARLY SUNDAY AFTERNOON FOLLOWED BY RAPID
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS THROUGH THE AFTERNOON AND
EARLY EVENING.  WIDESPREAD MVFR -RA/AREAS OF IFR RA BR...MTN
OBSCURATIONS ON THE BACKSIDE OF THE UPPER LOW WILL FOLLOW AFTER 03Z
SUNDAY ACROSS MOST OF THE AREA.

&&

.PREV DISCUSSION... /ISSUED 305 PM MDT SAT MAY 23 2015/

SHORT TERM...TONIGHT THROUGH SUNDAY

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECIALLY FROM 06Z TO 15Z SUNDAY.

FIRE WEATHER...

..FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ006-008>011-015-018>020-022.

&&

$$

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







000
FXUS65 KRIW 232105
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 PM MDT SAT MAY 23 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

.AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ009>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 232105
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 PM MDT SAT MAY 23 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

.AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ009>011-015-018>020-022.

&&

$$

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







000
FXUS65 KRIW 232105
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 PM MDT SAT MAY 23 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

.AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ009>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 232105
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 PM MDT SAT MAY 23 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

.AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

...FLASH FLOOD WATCH IN EFFECT FROM 3 PM MDT THIS AFTERNOON THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SUNDAY AFTERNOON
WYZ009>011-015-018>020-022.

&&

$$

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







000
FXUS65 KRIW 232010
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
210 PM MDT SAT MAY 23 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

...FLASH FLOOD WATCH IN EFFECT FROM 9 PM MDT THIS EVENING THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THE DEPARTING AREA OF LOW PRESSURE WILL CONTINUE TO LIFT ALONG THE
EASTERN BORDER OF THE FORECAST AREA...BRINGING PERSISTENT SHOWER
ACTIVITY ACROSS NATRONA AND JOHNSON COUNTIES. WHILE THE HEAVIEST
RAINS ARE ANTICIPATED TO FALL DURING THE AFTERNOON HOURS...SOME
SHOWERS WILL REMAIN OVER THE AREA THROUGH THE EVENING HOURS AS THE
SYSTEM BREAKS DOWN.

SHOWERS WILL WEAKEN THROUGH THE OVERNIGHT HOURS...BUT WILL RETURN ON
MONDAY FOLLOWING THE TYPICAL PATTERN OF AFTERNOON SHOWERS AND
THUNDERSTORMS. MODELS AGAIN ARE PEGGING NATRONA AND JOHNSON COUNTIES
WITH SHOWER ACTIVITY. SHOWER AND THUNDERSTORM ACTIVITY WILL WANE IN
THE AFTERNOON AS A VERY BRIEF TRANSITORY RIDGE WORKS ITS WAY THROUGH
WESTERN AND CENTRAL WYOMING.

A RETURN OF SOUTHWEST FLOW TUESDAY EVENING WILL ALLOW ADDITIONAL
SHOWER AND THUNDERSTORMS TO RETURN...THOUGH COVERAGE WILL REMAIN
LIMITED OVERNIGHT. A STRONGER SOUTHWEST FLOW WILL PERMIT
MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE STATE
FOR BOTH WEDNESDAY AND THURSDAY. MODELS DO VARY A BIT FRIDAY
AFTERNOON...THOUGH BOTH AGREE THAT ANOTHER ROUND OF SHOWER ACTIVITY
IS FAVORABLE. HOWEVER...THE LOCATION OF THE POTENTIALLY STRONGER
AREAS OF SHOWER ACTIVITY REMAINS IN QUESTION. OVERALL...TEMPERATURES
WILL WARM THROUGH THE EARLY PORTIONS OF THE FORECAST PERIOD...AND
THEN REMAIN SEASONABLE IN THE MID 60S THROUGH MUCH OF THE FORECAST
PERIOD.

&&

.AVIATION.../00Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

&&

.FIRE WEATHER...

...FLASH FLOOD WATCH IN EFFECT FROM 9 PM MDT THIS EVENING THROUGH
6 PM MDT SUNDAY AFTERNOON...

SATURATED TO NEAR SATURATED SOILS FROM RECENT RAINFALL WILL
COMBINE WITH AREAS OF POTENTIAL HEAVY RAIN ACROSS JOHNSON...
NATRONA AND FREMONT COUNTIES THIS EVENING THROUGH 6 PM MDT ON
SUNDAY. THE THREAT OF FLASH FLOODING WILL BE ALONG SMALL STREAMS
AND IRRIGATION CANALS IN AND NEAR THE FOOTHILLS OF THE BIGHORN AND
WIND RIVER MOUNTAINS... AS WELL AS CASPER MOUNTAIN AND THE GREEN
AND RATTLESNAKE MOUNTAINS. A STRONG SPRING STORM WILL PRODUCE
CONDITIONS FAVORABLE FOR PROLONGED HEAVY RAIN WITH RAINFALL RATES
OF A HALF INCH TO AN INCH AN HOUR WITH TOTAL RAINFALL OF 2 TO 4
INCHES POSSIBLE.  SNOWFALL WILL BE LIMITED TO ELEVATIONS ABOVE
8500 FEET TONIGHT INCREASING TO 9000 FEET ON SUNDAY.  COOLER
TEMPERATURES WILL RESULT WITH WIDESPREAD CLOUD COVER AND EVAPORATIVE
COOLING FROM PRECIPITATION. RELATIVE HUMIDITY WILL BE HIGH WITH LOW
MIXING HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.  AREAS OF THE
WEST AND NORTHWEST HAVE THE BEST CHANCE FOR GOOD SMOKE DISPERSAL
SUNDAY AFTERNOON.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 9 PM MDT THIS EVENING THROUGH SUNDAY
AFTERNOON WYZ009>011-015-018>020-022.

&&

$$

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







000
FXUS65 KRIW 231915
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
115 PM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

ISSUING FLASH FLOOD WATCH FOR JOHNSON...NATRONA AND PORTIONS OF
FREMONT COUNTIES FROM 9 PM MDT THIS EVENING THROUGH 6 PM MDT
SUNDAY. SATURATED TO NEAR SATURATED SOILS OVER THE AREA WITH LOCAL
HEAVY RAIN THROUGH THE PERIOD WILL COMBINE TO SIGNIFICANTLY INCREASE
THE CHANCE OF FLASH FLOODING OVER AND NEAR THE FOOTHILLS OF THE
WIND RIVER...BIGHORN AND NORTH LARAMIE MOUNTAINS INCLUDING CASPER...
BUFFALO AND LANDER.

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

.AVIATION.../18Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 9 PM MDT THIS EVENING THROUGH SUNDAY
AFTERNOON WYZ009>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 231915
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
115 PM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

ISSUING FLASH FLOOD WATCH FOR JOHNSON...NATRONA AND PORTIONS OF
FREMONT COUNTIES FROM 9 PM MDT THIS EVENING THROUGH 6 PM MDT
SUNDAY. SATURATED TO NEAR SATURATED SOILS OVER THE AREA WITH LOCAL
HEAVY RAIN THROUGH THE PERIOD WILL COMBINE TO SIGNIFICANTLY INCREASE
THE CHANCE OF FLASH FLOODING OVER AND NEAR THE FOOTHILLS OF THE
WIND RIVER...BIGHORN AND NORTH LARAMIE MOUNTAINS INCLUDING CASPER...
BUFFALO AND LANDER.

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

.AVIATION.../18Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 9 PM MDT THIS EVENING THROUGH SUNDAY
AFTERNOON WYZ009>011-015-018>020-022.

&&

$$

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









000
FXUS65 KRIW 231915
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
115 PM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

ISSUING FLASH FLOOD WATCH FOR JOHNSON...NATRONA AND PORTIONS OF
FREMONT COUNTIES FROM 9 PM MDT THIS EVENING THROUGH 6 PM MDT
SUNDAY. SATURATED TO NEAR SATURATED SOILS OVER THE AREA WITH LOCAL
HEAVY RAIN THROUGH THE PERIOD WILL COMBINE TO SIGNIFICANTLY INCREASE
THE CHANCE OF FLASH FLOODING OVER AND NEAR THE FOOTHILLS OF THE
WIND RIVER...BIGHORN AND NORTH LARAMIE MOUNTAINS INCLUDING CASPER...
BUFFALO AND LANDER.

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

.AVIATION.../18Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 9 PM MDT THIS EVENING THROUGH SUNDAY
AFTERNOON WYZ009>011-015-018>020-022.

&&

$$

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









000
FXUS65 KRIW 231915
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
115 PM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

ISSUING FLASH FLOOD WATCH FOR JOHNSON...NATRONA AND PORTIONS OF
FREMONT COUNTIES FROM 9 PM MDT THIS EVENING THROUGH 6 PM MDT
SUNDAY. SATURATED TO NEAR SATURATED SOILS OVER THE AREA WITH LOCAL
HEAVY RAIN THROUGH THE PERIOD WILL COMBINE TO SIGNIFICANTLY INCREASE
THE CHANCE OF FLASH FLOODING OVER AND NEAR THE FOOTHILLS OF THE
WIND RIVER...BIGHORN AND NORTH LARAMIE MOUNTAINS INCLUDING CASPER...
BUFFALO AND LANDER.

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

.AVIATION.../18Z ISSUANCE/

AREAS OF MVFR TO IFR CEILINGS AND VISIBILITY REDUCED IN RAIN AND
FOG WILL INCREASE ACROSS THE AREA THIS AFTERNOON AND EVENING WITH
MOUNTAIN OBSCURATIONS BECOMING MORE WIDESPREAD.  THE HEAVIEST
AND MOST WIDESPREAD SHOWERS...WITH ISOLATED EMBEDDED THUNDERSTORMS
WITH SMALL HAIL...WILL BE ALONG AND EAST OF THE CONTINENTAL DIVIDE.
ALL OF THE AIRPORTS WILL HAVE A THREAT OF MVFR TO IFR CONDITIONS...
ESPECAILLY FROM 06Z TO 15Z SUNDAY.

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 9 PM MDT THIS EVENING THROUGH SUNDAY
AFTERNOON WYZ009>011-015-018>020-022.

&&

$$

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








000
FXUS65 KRIW 230905
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 AM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

&&

.AVIATION.../12Z ISSUANCE/

CONFIDENCE IS LOW ON THE EXTENT/TIMING OF IFR/MVFR CONDITIONS FROM
LOW CEILINGS...FOG AND/OR RAIN THROUGH 00Z SUNDAY. A DRY SLOT IS
EXPECTED OVER MUCH OF SOUTHERN AND EASTERN SECTIONS THIS MORNING
LIMITING SHRA ACTIVITY...BUT FOG/LOW CEILINGS REMAIN POSSIBLE.
ANOTHER WAVE PUSHES OVER THE REGION SATURDAY AFTERNOON...WITH
SCATTERED TO NUMEROUS SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE
ENTIRE AREA IN THE AFTERNOON. A MORE WIDESPREAD AREA OF MVFR/IFR
CEILINGS WITH A MORE STEADY RAIN SHOULD DEVELOP EAST OF THE
DIVIDE...AND EASTERN SWEETWATER COUNTY TONIGHT. MOUNTAINS WILL BE
OBSCURED MUCH OF THE TIME. PLEASE SEE THE AVIATION WEATHER CENTER
FOR THE LATEST INFORMATION ON ICING FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

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





000
FXUS65 KRIW 230905
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 AM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

&&

.AVIATION.../12Z ISSUANCE/

CONFIDENCE IS LOW ON THE EXTENT/TIMING OF IFR/MVFR CONDITIONS FROM
LOW CEILINGS...FOG AND/OR RAIN THROUGH 00Z SUNDAY. A DRY SLOT IS
EXPECTED OVER MUCH OF SOUTHERN AND EASTERN SECTIONS THIS MORNING
LIMITING SHRA ACTIVITY...BUT FOG/LOW CEILINGS REMAIN POSSIBLE.
ANOTHER WAVE PUSHES OVER THE REGION SATURDAY AFTERNOON...WITH
SCATTERED TO NUMEROUS SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE
ENTIRE AREA IN THE AFTERNOON. A MORE WIDESPREAD AREA OF MVFR/IFR
CEILINGS WITH A MORE STEADY RAIN SHOULD DEVELOP EAST OF THE
DIVIDE...AND EASTERN SWEETWATER COUNTY TONIGHT. MOUNTAINS WILL BE
OBSCURED MUCH OF THE TIME. PLEASE SEE THE AVIATION WEATHER CENTER
FOR THE LATEST INFORMATION ON ICING FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

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






000
FXUS65 KRIW 230905
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
305 AM MDT SAT MAY 23 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

WV IMAGERY SHOWING LARGE UPR TROF ACROSS THE WRN CONUS WITH CLOSED
LOW OVR WRN AZ...EMBEDDED SW WITHIN CLOSED PORTION ROTATING
ANTI-CLOCKWISE THRU CNTRL WY AS WE SPEAK. SFC HAS GENERAL LOW P ACROSS
THE WEST...HIGH P TO THE EAST AND WEAK TROF/BOUNDARY STRETCHING FROM
CNTRL NE INTO NERN CO.

THE FCST FOR THE MEMORIAL DAY WEEKEND...UPR LOW MIGRATES FROM WEST
OF THE 4 CORNERS REGION SLOWLY TO THE N...CENTERING ACROSS WRN CO
BUT SPREADING OVR TOP OF WY BY DAY`S END TODAY. MID TO UPR LVL
VORTICITY WILL INCREASE WITH THE APPROACH OF THE UPR LOW. THE DAY
WILL BE MARKED BY SUFFICIENT BUOYANCY BUT LOW SHEAR THRU MUCH DEPTH.
DISORGANIZED SHOWERS WITH SOME EMBEDDED THUNDER BY AFTERNOON WILL BE
RELATIVELY SLOW MOVERS AGAIN...FROM S TO N AND 10 MPH +/- E OF THE
DIVIDE...SE TO NW/E TO W WEST OF THE DIVIDE. ML CAPE SHOULD TOP OUT
ACROSS THE CWA AT <=500 J/KG...BUT AVG 250 J/KG FOR MOST LOCATIONS.
PWS LOOK TO BE A BIT LESS THAN TODAY...BUT STILL AOA 0.60 E OF THE
DIVIDE...AOB 0.5 W OF THE DIVIDE...WITH HIGHEST VALUES SETTLING IN
OVR THE BIGHORN BASIN AND THE EXTREME ERN PORTIONS OF JOHNSON AND
NATRONA COUNTIES. EXPECTING SOME MID LVL DRYING THRU THE MORNING HRS
WITH BITS OF SUNSHINE POSSIBLE ACROSS THE SRN...CNTRL AND ERN FA.
THIS WILL INCREASE LL LAPSE RATES AND INSTABILITY OVR THESE
AREA...EMBEDDING A FEW THUNDERSTORMS AMIDST THE AMORPHOUS MASS OF
SHOWERS EXPECTED BY MID TO LATE AFTERNOON. ADDITIONALLY...WITH A
MODEST SFC LOW MOVING INTO WRN CO AND SRN WY...ERLY RETURN FLOW AND
SMALL WARM FRONT SETS UP ACROSS ERN AND CNTRL WY...ALLOWING FOR
TERRAIN INDUCED CONVERGENCE TO SET UP FROM THE ERN WIND RIVER
MOUNTAINS...EWD ALONG THE GREEN MOUNTAINS AND SOUTH ACROSS ERN
SWEETWATER COUNTY. THIS AREA WOULD LIKELY SEE A COUPLE OF THE
STRONGER STORMS OF THE DAY.

TONIGHT THROUGH SUNDAY...EARLY MORNING FOG WILL ALSO BE POSSIBLE OVR
MANY AREAS THROUGHOUT THE FCST. OTHERWISE...SFC CYCLOGENESIS TAKES
PLACE FROM ERN/NERN CO INTO SERN WY AND WRN NE. BETWEEN LOW TO MID
LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR MOISTURE FROM
ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY PLENTIFUL RAINFALL
WILL BE HAD OVER THE FAR ERN FA THRU THE DAY SUNDAY. THIS SYSTEM
CONTINUES TO LOOK COMPARATIVELY WARM...WITH H7 TEMPS REMAINING ABOVE
-1 DEG C THRU THE ENTIRE FCST PERIOD...AND REALLY ABOVE ZERO FOR
MOST OF THAT TIME.  GENERALLY...A TRACE TO AND INCH OR TWO WILL BE
POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS ABOVE 9500
FEET...WITH ONLY THE HIGHEST ELEVATIONS RECEIVING AN ISOLATED 3 OR
SO INCHES. STORM MOVEMENT IMPROVES SLIGHTLY...NOW REVERSING AND
BECOMING N TO S AT 15 TO 20 MPH. SEVERE WX WILL REMAIN MOSTLY EAST
TO SOUTHEAST OF FA THROUGH THE PERIOD WITH CONTINUED LOW SHEAR
CONDITIONS ONLY ABLE TO PROVIDE OCCASIONAL ISOLATED SMALL
HAIL...ESPECIALLY W OF THE DIVIDE.

SUNDAY NIGHT THRU MONDAY...SYSTEM PUSHES EWD INTO THE PLAINS WITH
TRANSITIONAL RIDGING TAKING PLACE ACROSS THE WRN FA WHILE THE ERN FA
IS FCST TO BE THE RECIPIENT OF A BACKSIDE UPR SW ROTATING AROUND THE
EXITING LOW...WITH BETTER SHOWER/THUNDER ACTIVITY/COVERAGE ACROSS
THE ERN CWA. OTHERWISE...A BIT WARMER AND MORE UNSTABLE WITH PERHAPS
AN BETTER SPRINKLING OF STRONGER THUNDERSTORMS MIXED IN WITH
SHOWERS. LOW SHEAR CONDITIONS ALSO PERSIST HOWEVER...KEEPING STORM
ORGANIZATION AT A MINIMUM...WHILE STORM MOTION IMPROVES EVEN
MORE...FROM THE NW TO SE AT 20 TO 25 MPH.

.LONG TERM...TUESDAY THROUGH SATURDAY

GFS MODEL CONTINUES ITS CONSISTENT FORECAST FOR TUESDAY THROUGH
FRIDAY. IT HAS A WEATHER SYSTEM SPINNING OVER THE PACIFIC NW STATES
WHICH CREATES SW FLOW ALOFT OVER WY TUE AND WED. THE SYSTEM MOVES
INTO IDAHO THURSDAY AND INTO NW WY FRIDAY...THEN ACROSS NORTHERN WY
FRIDAY NIGHT AND INTO WESTERN SOUTH DAKOTA NEXT SATURDAY AFTERNOON.
A DAILY CHANCE FOR SHOWERS AND STORMS IN THE AFTERNOON AND EVENING
HOURS WITH LINGERING SHOWERS LATE NIGHT AND MORNING HOURS TUESDAY
THROUGH FRIDAY. NEXT SATURDAY THE SHOWERS AND STORMS LOOK TO BE
MAINLY OVER THE NORTH WITH LESSER COVERAGE CENTRAL AND SOUTH. THE
ECMWF MODEL IS SIMILAR TO THE GFS MODEL WITH THE WEATHER PATTERN
THROUGH THURSDAY NIGHT. IT HAS A DIFFERENT TRACK ON FRIDAY BUT THE
TROUGH IS STILL MOVING THROUGH FRIDAY INTO FRI NIGHT. THEN THE ECMWF
MODEL IS ONLY SHOWING ISOLATED SHOWERS OR STORMS. THE FORECAST WILL
REFLECT A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON AND EVENING
WITH LESSER COVERAGE OF SHOWERS LATE NIGHT AND DURING THE MORNING.
NEXT SATURDAY WILL BE MOSTLY DRY IN THE SOUTHWEST WITH ISOLATED
COVERAGE FOR THE REST OF THE AREA. WILL HOWEVER KEEP A LITTLE CHANCE
OF PRECIP IN THE NORTHEAST ZONES NEXT SATURDAY. AS FOR HIGH TEMPS...
THERE WILL BE LITTLE CHANGE FROM DAY TO DAY WITH 60S TO LOWER 70S
FOR THE LOWER ELEVATIONS AND 40S AND 50S FOR THE MOUNTAINS. THESE
HIGHS ASSUME SOME SUNSHINE EACH DAY AND NOT A LOW OVERCAST DAY(S)
LIKE WE HAVE SEEN DURING THE PAST WEEK.

&&

.AVIATION.../12Z ISSUANCE/

CONFIDENCE IS LOW ON THE EXTENT/TIMING OF IFR/MVFR CONDITIONS FROM
LOW CEILINGS...FOG AND/OR RAIN THROUGH 00Z SUNDAY. A DRY SLOT IS
EXPECTED OVER MUCH OF SOUTHERN AND EASTERN SECTIONS THIS MORNING
LIMITING SHRA ACTIVITY...BUT FOG/LOW CEILINGS REMAIN POSSIBLE.
ANOTHER WAVE PUSHES OVER THE REGION SATURDAY AFTERNOON...WITH
SCATTERED TO NUMEROUS SHOWERS WITH ISOLATED THUNDERSTORMS OVER THE
ENTIRE AREA IN THE AFTERNOON. A MORE WIDESPREAD AREA OF MVFR/IFR
CEILINGS WITH A MORE STEADY RAIN SHOULD DEVELOP EAST OF THE
DIVIDE...AND EASTERN SWEETWATER COUNTY TONIGHT. MOUNTAINS WILL BE
OBSCURED MUCH OF THE TIME. PLEASE SEE THE AVIATION WEATHER CENTER
FOR THE LATEST INFORMATION ON ICING FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

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





000
FXUS65 KRIW 230515 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1115 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS. IN ADDITION...A WEAK 700MB
CIRCULATION WILL DRIFT FROM WESTERN WYOMING THIS EVENING TO
NORTHEAST WY LATER SATURDAY...ADDING TO THE
CONVERGENCE/LIFT...ENHANCING PRECIP AMOUNTS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../06Z ISSUANCE/

CONFIDENCE IS LOW ON THE EXTENT/TIMING OF IFR/MVFR CONDITIONS FROM
LOW CEILINGS...FOG AND/OR RAIN THROUGH 00Z SUNDAY. A DRY SLOT IS
EXPECTED PUSH NORTHWARD AND IMPACT MUCH OF SOUTHERN AND EASTERN
SECTIONS THROUGH SATURDAY MORNING LIMITING SHRA ACTIVITY...BUT
FOG/LOW CEILINGS REMAIN POSSIBLE. ANOTHER WAVE PUSHES OVER THE
REGION SATURDAY AFTERNOON...WITH SCATTERED TO NUMEROUS SHOWERS WITH
ISOLATED THUNDERSTORMS OVER THE ENTIRE AREA IN THE AFTERNOON. A MORE
WIDESPREAD AREA OF MVFR/IFR CEILINGS WITH A MORE STEADY RAIN SHOULD
DEVELOP EAST OF THE DIVIDE...AND EASTERN SWEETWATER COUNTY SATURDAY
NIGHT. MOUNTAINS WILL BE OBSCURED MUCH OF THE TIME. PLEASE SEE THE
AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON ICING
FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

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













000
FXUS65 KRIW 230515 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1115 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS. IN ADDITION...A WEAK 700MB
CIRCULATION WILL DRIFT FROM WESTERN WYOMING THIS EVENING TO
NORTHEAST WY LATER SATURDAY...ADDING TO THE
CONVERGENCE/LIFT...ENHANCING PRECIP AMOUNTS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../06Z ISSUANCE/

CONFIDENCE IS LOW ON THE EXTENT/TIMING OF IFR/MVFR CONDITIONS FROM
LOW CEILINGS...FOG AND/OR RAIN THROUGH 00Z SUNDAY. A DRY SLOT IS
EXPECTED PUSH NORTHWARD AND IMPACT MUCH OF SOUTHERN AND EASTERN
SECTIONS THROUGH SATURDAY MORNING LIMITING SHRA ACTIVITY...BUT
FOG/LOW CEILINGS REMAIN POSSIBLE. ANOTHER WAVE PUSHES OVER THE
REGION SATURDAY AFTERNOON...WITH SCATTERED TO NUMEROUS SHOWERS WITH
ISOLATED THUNDERSTORMS OVER THE ENTIRE AREA IN THE AFTERNOON. A MORE
WIDESPREAD AREA OF MVFR/IFR CEILINGS WITH A MORE STEADY RAIN SHOULD
DEVELOP EAST OF THE DIVIDE...AND EASTERN SWEETWATER COUNTY SATURDAY
NIGHT. MOUNTAINS WILL BE OBSCURED MUCH OF THE TIME. PLEASE SEE THE
AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON ICING
FORECASTS.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

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












000
FXUS65 KRIW 222105 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
259 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS. IN ADDITION...A WEAK 700MB
CIRCULATION WILL DRIFT FROM WESTERN WYOMING THIS EVENING TO
NORTHEAST WY LATER SATURDAY...ADDING TO THE
CONVERGENCE/LIFT...ENHANCING PRECIP AMOUNTS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../00Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN WHERE CLOUD BASES WILL BE BETWEEN 3
AND 4K IN SOME AREAS...NORTHERLY TO EASTERLY LOW LEVEL MOIST FLOW
WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR MUCH OF
THE EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM MOVING
INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY THIS
EVENING WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE
EXPECTED AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST
ON AND OFF THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE
ATMOSPHERE WILL BECOME MORE UNSTABLE GIVING RISE TO SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY
RAIN AND SMALL HAIL.

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

SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM COLORADO...UTAH
AND IDAHO RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN OBSCURATIONS/LOCALLY
HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS WILL CONTINUE WELL
INTO THE EVENING WITH LINGERING SHOWERS THEREAFTER. IN
ADDITION...THERE WILL BE PATCHES OF CLOUDS WITH BASES RANGING
FROM 3 TO 4K THROUGHOUT THE REGION. ANOTHER ROUND OF THUNDERSTORMS
IS EXPECTED TO MOVE IN FROM THE SOUTH SATURDAY AS THE LOW PRESSURE
CENTER NEAR LAS VEGAS TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

$$

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









000
FXUS65 KRIW 222105 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
259 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS. IN ADDITION...A WEAK 700MB
CIRCULATION WILL DRIFT FROM WESTERN WYOMING THIS EVENING TO
NORTHEAST WY LATER SATURDAY...ADDING TO THE
CONVERGENCE/LIFT...ENHANCING PRECIP AMOUNTS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../00Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN WHERE CLOUD BASES WILL BE BETWEEN 3
AND 4K IN SOME AREAS...NORTHERLY TO EASTERLY LOW LEVEL MOIST FLOW
WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR MUCH OF
THE EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM MOVING
INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY THIS
EVENING WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE
EXPECTED AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST
ON AND OFF THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE
ATMOSPHERE WILL BECOME MORE UNSTABLE GIVING RISE TO SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY
RAIN AND SMALL HAIL.

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

SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM COLORADO...UTAH
AND IDAHO RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN OBSCURATIONS/LOCALLY
HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS WILL CONTINUE WELL
INTO THE EVENING WITH LINGERING SHOWERS THEREAFTER. IN
ADDITION...THERE WILL BE PATCHES OF CLOUDS WITH BASES RANGING
FROM 3 TO 4K THROUGHOUT THE REGION. ANOTHER ROUND OF THUNDERSTORMS
IS EXPECTED TO MOVE IN FROM THE SOUTH SATURDAY AS THE LOW PRESSURE
CENTER NEAR LAS VEGAS TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

$$

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










000
FXUS65 KRIW 222059
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
259 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../00Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN WHERE CLOUD BASES WILL BE BETWEEN 3
AND 4K IN SOME AREAS...NORTHERLY TO EASTERLY LOW LEVEL MOIST FLOW
WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR MUCH OF
THE EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM MOVING
INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY THIS
EVENING WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE
EXPECTED AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST
ON AND OFF THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE
ATMOSPHERE WILL BECOME MORE UNSTABLE GIVING RISE TO SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY
RAIN AND SMALL HAIL.

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

SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM COLORADO...UTAH
AND IDAHO RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN OBSCURATIONS/LOCALLY
HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS WILL CONTINUE WELL
INTO THE EVENING WITH LINGERING SHOWERS THEREAFTER. IN
ADDITION...THERE WILL BE PATCHES OF CLOUDS WITH BASES RANGING
FROM 3 TO 4K THROUGHOUT THE REGION. ANOTHER ROUND OF THUNDERSTORMS
IS EXPECTED TO MOVE IN FROM THE SOUTH SATURDAY AS THE LOW PRESSURE
CENTER NEAR LAS VEGAS TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

$$

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







000
FXUS65 KRIW 222059
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
259 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../00Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN WHERE CLOUD BASES WILL BE BETWEEN 3
AND 4K IN SOME AREAS...NORTHERLY TO EASTERLY LOW LEVEL MOIST FLOW
WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR MUCH OF
THE EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM MOVING
INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY THIS
EVENING WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE
EXPECTED AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST
ON AND OFF THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE
ATMOSPHERE WILL BECOME MORE UNSTABLE GIVING RISE TO SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY
RAIN AND SMALL HAIL.

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

SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM COLORADO...UTAH
AND IDAHO RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN OBSCURATIONS/LOCALLY
HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS WILL CONTINUE WELL
INTO THE EVENING WITH LINGERING SHOWERS THEREAFTER. IN
ADDITION...THERE WILL BE PATCHES OF CLOUDS WITH BASES RANGING
FROM 3 TO 4K THROUGHOUT THE REGION. ANOTHER ROUND OF THUNDERSTORMS
IS EXPECTED TO MOVE IN FROM THE SOUTH SATURDAY AS THE LOW PRESSURE
CENTER NEAR LAS VEGAS TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

$$

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






000
FXUS65 KRIW 222059
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
259 PM MDT FRI MAY 22 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

...WET UNSETTLED PATTERN TO CONTINUE...

LOW CLOUDS AND COOL TEMPERATURES EAST OF THE DIVIDE ARE PREVALENT
ALONG AND SOUTH OF THE OWL CREEK MTNS AND ALONG AND EAST OF THE BIG
HORN MTNS INCLUDING AREAS ACROSS THE WIND RIVER BASIN INTO NATRONA
AND JOHNSON COUNTIES. A COOL NORTHEASTERLY FLOW IS FEEDING LOW LEVEL
MOISTURE INTO THESE AREAS AND FOR THIS REASON...DO NOT EXPECT MUCH
IN THE WAY OF THUNDERSTORMS FOR THE REMAINDER OF THIS AFTERNOON AND
EVENING IN THESE AREAS. THE AIRMASS IS MUCH MORE UNSTABLE WEST OF
THE DIVIDE. THE BIG HORN BASIN HAS RECEIVED MORE SUNSHINE THEN THE
REST OF THE AREA EAST OF THE DIVIDE SO THIS AREA COULD ALSO BE
PRIMED FOR MORE THUNDERSTORM ACTIVITY FOR THE REST OF TODAY. A
THUNDERSTORM HAS ALREADY FORMED NEAR MEETEETSE WITH OTHER T STORMS
PREVALENT WEST OF THE DIVIDE. CURRENTLY THE MAIN CIRCULATION OF OUR
NEXT CLOSED LOW APPEARS TO BE OVER THE NEVADA/CALIFORNIA/ARIZONA
TRIPLE POINT. THE SSW SOMEWHAT DIFLUENT FLOW WILL ENCOURAGE
THUNDERSTORM DEVELOPMENT FOR THE REST OF TODAY EXCEPT IN THE
AFOREMENTIONED STABLE AREAS. THE LOW WILL TRAVEL TO UTAH TONIGHT AND
THEN TOWARD WYOMING SATURDAY ALONG WITH A TROUGH TROUGH EXTENDING TO
WYOMING OUT AHEAD OF IT. SOME SNOW IS EXPECTED TO FALL ABOVE 9500
FEET OR SO LATE TONIGHT WITH UP TO AN INCH AND A HALF OF SNOW
EXPECTED AT THESE ELEVATIONS IN THE WIND RIVER RANGE AFTER MIDNIGHT
TONIGHT. MORE WIDESPREAD THUNDERSTORM ACTIVITY IS EXPECTED SATURDAY
WITH SOMEWHAT MILDER TEMPS EXPECTED THANKS TO THE SSW FLOW AHEAD OF
THE APPROACHING LOW BEFORE SHORT LIVED COOLER AIR FLOWS IN AROUND
THE BACKSIDE OF THE LOW. HOWEVER...THE STRONGEST STORMS SHOULD HOLD
OFF UNTIL AFTER 21Z SATURDAY SINCE WITH AREAS EAST OF THE DIVIDE
STILL CONTENDING WITH A COOL MOIST EASTERLY FLOW MAKING IT DIFFICULT
TO TAKE ADVANTAGE OF MUCH SOLAR INSULATION AT LEAST UNTIL THEN AS
SFC CYCLOGENESIS TAKES PLACE IN SE CO. AS HAS BEEN THE CASE THESE
LAST COUPLE OF WEEKS...ANY THUNDERSTORMS THAT DO FORM WILL LIKELY
PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL GIVEN THE LOW LEVEL LC
AND LOW ELEVATION WET BULB ZEROS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE SLOWLY
EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL WYOMING
WITH SOUTHWEST FLOW ALOFT OVER THE AREA.  THE AIRMASS WILL BE
UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN MOUNTAINS
AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE EVENING.
SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL LINGER INTO
SUNDAY MORNING.  A CANADIAN COLD FRONT WILL SLIDE SOUTH THROUGH MUCH
OF THE AREA AS THE UPPER LOW DRIFTS SLOWLY EAST OVER THE COLD
FRONT.  SHOWERS WILL BE WIDESPREAD ACROSS THE AREA WITH COOL
TEMPERATURES.  ENOUGH INSTABILITY WILL BE OVER THE AREA IN THE
EVENING TO SUPPORT ISOLATED THUNDERSTORMS WITH SMALL HAIL.  SNOW
LEVELS WILL LOWER THROUGH SATURDAY NIGHT DOWN TO AROUND 7500 FEET.
SUNDAY WILL BE COOL AND REMAINING SHOWERY WITH A FEW ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO
THE EAST AS ANOTHER INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL
DECREASE THROUGH SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING
OVER THE WESTERN MOUNTAINS.  LESS MOISTURE WILL BE OVER THE AREA ON
MONDAY BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH
ISOLATED AFTERNOON AND EVENING THUNDERSTORMS.  MONDAY NIGHT WILL SEE
A SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH WILL
SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY AND
TUESDAY NIGHT WITH MORE SHOWERS...ESPECIALLY OVER THE WESTERN AND
NORTHERN MOUNTAINS.  TEMPERATURES SHOULD BE SLIGHTLY WARMER.  THE
TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE NORTH AND
EAST ACROSS THE AREA WITH INCREASING SHOWERS AND ISOLATED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING.  THE TROUGH WILL
BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN COLD FRONT
MOVES SOUTH BRINGING GENERAL COOLING.  THE FLOW ALOFT WILL BECOME
ZONAL THURSDAY AND FRIDAY WITH DRYING AND WARMING.  THIS WILL KEEP
SOME SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND NORTHERN
MOUNTAINS. MODELS BEGIN TO DIVERGE WITH THE FASTER MOVING SHORT WAVE
TROUGHS IN THE ZONAL FLOW WHICH DECREASES THE CONFIDENCE IN THE
STRENGTH AND TIMING OF PRECIPITATION.

&&

.AVIATION.../00Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN WHERE CLOUD BASES WILL BE BETWEEN 3
AND 4K IN SOME AREAS...NORTHERLY TO EASTERLY LOW LEVEL MOIST FLOW
WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR MUCH OF
THE EVENING AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM MOVING
INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY THIS
EVENING WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE
EXPECTED AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST
ON AND OFF THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE
ATMOSPHERE WILL BECOME MORE UNSTABLE GIVING RISE TO SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY
RAIN AND SMALL HAIL.

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

SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM COLORADO...UTAH
AND IDAHO RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN OBSCURATIONS/LOCALLY
HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS WILL CONTINUE WELL
INTO THE EVENING WITH LINGERING SHOWERS THEREAFTER. IN
ADDITION...THERE WILL BE PATCHES OF CLOUDS WITH BASES RANGING
FROM 3 TO 4K THROUGHOUT THE REGION. ANOTHER ROUND OF THUNDERSTORMS
IS EXPECTED TO MOVE IN FROM THE SOUTH SATURDAY AS THE LOW PRESSURE
CENTER NEAR LAS VEGAS TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

$$

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







000
FXUS65 KRIW 221757
AFDRIW

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE RIVERTON WY
1156 AM MDT FRI MAY 22 2015

TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWING LARGE DEEP TROF WRN CONUS...CLOSED LOW OVR
CALIFORNIA...SW RIDGE CNTRL CONUS...DEEP TROF ERN CONUS. WEAK SW
MOVING NWD THRU CNTRL WY THIS EVENING...WITH STRONGER SW TO THE
SOUTH...ROTATING ANTI-CLOCKWISE AROUND THE CLOSED LOW...SPREADING
OVR COLORADO. SFC HAS HIGH P CNTRL CONUS...LOW P AND NEARLY
STATIONARY FRONT WEST OF WY...DRAPED FROM NRN ID...SWD THRU UT AND
INTO WRN NM. ISOLATED TO WIDELY SCATTERED SHOWERS SPRINKLED AROUND
THE FA TONIGHT.

THRU TODAY...SW CURRENTLY OVR COLORADO WILL CONTINUE TO
ROTATE NWD ACROSS WY THIS AFTERNOON/EVENING/OVERNIGHT...WITH SW AXIS
BISECTING WY FROM SW TO NE BY THIS TIME TOMORROW. THIS WILL AID IN
KICKING OFF ANOTHER BATCH OF SHRA/TSRA. OTHERWISE...LL ERN FLOW
ACROSS MOST OF THE AREA E OF THE DIVIDE WILL STRENGTHEN...KEEPING
GOOD AMOUNTS OF LL MOISTURE ACROSS THE FA...WHILE MORE MID/UPR LVL
MOISTURE MOVES INTO THE REGION FROM THE SOUTH. DIRECTIONAL AND SPEED
SHEAR NOT PARTICULARLY IMPRESSIVE WITH RATHER WEAK MID/UPR FLOW IN
PLACE. BUOYANCY WILL BE MODEST WITH ML CAPE RANGING FROM 300 TO 500
J/KG FOR MOST OF THE CNTRL AND WRN FA...WEAKER TO THE EAST. STRONGER
STORMS OF THE DAY CURRENTLY LOOK TO FORM ACROSS THE FAR WEST...FROM
N OF JACKSON S TO AROUND KEMMERER WHERE WHERE SOME MARGINALLY
BETTER CHANCES FOR SUNSHINE WILL OCCUR...ALONG WITH CHCS FOR MAINLY
SMALL HAIL.

THE REST OF THE FCST FOR THE MEMORIAL DAY WEEKEND...COOL AND WET.
UPR LOW MIGRATES FROM NEAR THE 4 CORNERS REGION TO THE NRN HIGH
PLAINS BY THE END OF THE FCST...WHILE SFC CYCLOGENESIS TAKES PLACE
FROM ERN/NERN CO INTO THE CNTRL PLAINS THRU THE SAME PERIOD. BETWEEN
LOW TO MID LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR
MOISTURE FROM ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY
PLENTIFUL RAINFALL AND SOME SNOWFALL WILL BE HAD OVER THE SAME
PERIOD. THIS WILL...HOWEVER...BE A COMPARATIVELY WARM SYSTEM THE WAY
IT STANDS NOW WITH H7 TEMPS NOT DROPPING AT ANY ONE TIME TO MUCH
LESS THAN -1/-2DEG C...AND EVEN THEN FOR ONLY SHORT PERIODS AS THE
UPR LOW ROTATES ACROSS THE STATE. SUNDAY MORNING WILL LIKELY SEE THE
COLD TEMPS OVR THE NW FCST QUAD...BUT WITH LITTLE ATTENDING SNOWFALL
AS THE SYSTEM PULLS AWAY. GENERALLY...A TRACE TO AND INCH OR TWO
WILL BE POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS AND ONLY
ACROSS THE HIGHEST ELEVATIONS...ISOLATED 3 INCHES. SEVERE WX SHOULD
REMAIN MOSTLY EAST TO SOUTHEAST OF FA THROUGH THE PERIOD WITH ONLY
ISOLATED SMALL HAIL A SMALL THREAT THROUGHOUT. EARLY MORNING FOG
WILL ALSO BE POSSIBLE OVR MANY AREAS THROUGHOUT THE FCST.
.SHORT TERM...

.LONG TERM...MONDAY THROUGH FRIDAY

THE LONG RANGE MODELS ARE IN MODEST AGREEMENT WITH THE WEATHER
PATTERN MONDAY THROUGH FRIDAY. MEMORIAL DAY WILL BE DRIER FOR MOST
PLACES WITH MAINLY ISOLATED AFTERNOON SHOWERS OR STORMS. ACTIVITY
COULD BE A LITTLE MORE NUMEROUS IN THE FAR WEST LATE IN THE DAY INTO
MONDAY EVENING. HIGH TEMPS ON MEMORIAL DAY WILL BE AT OR SLIGHTLY
BELOW NORMAL WITH 50S AND 60S...40S TO LOW 50S FOR THE MOUNTAINS.

FOR TUESDAY THROUGH THURSDAY...A WEATHER SYSTEM SETTLES INTO THE
PACIFIC NW PER THE GFS MODEL AND MOVES INTO IDAHO THURSDAY NIGHT.
THEN IT BRINGS THE WEATHER SYSTEM THROUGH THE REGION FRIDAY. THE
ECMWF MODEL IS A BIT DIFFERENT AND FASTER AS IT DROPS THE WEATHER
SYSTEM INTO IDAHO TUESDAY NIGHT AND ACROSS THE ROCKIES WED NIGHT
AND THURSDAY MORNING. THEN THE ECMWF MODEL HAS FAIRLY QUIET
WEATHER FOR NEXT FRIDAY. BOTH MODELS HAVE BEEN CONSISTENT IN THEIR
TIMING THE PAST FEW MODEL RUNS. WILL LEAN TOWARD THE GFS SOLUTION
TONIGHT. THIS MEANS A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON
AND EVENING FROM TUE THROUGH FRI. COVERAGE SHOULD INCREASE OVER
THE WEST AND NORTH LATER NEXT WEEK AS THE SYSTEM GETS CLOSER AND
EVENTUALLY PASSES THROUGH THE AREA. WILL SEE HOW THINGS LOOK
TONIGHT AND SEE IF ANY CHANGES ARE NEEDED. AS FOR HIGH TEMPS TUE
THROUGH FRI...LITTLE DAY TO DAY CHANGE WITH 60S TO LOW 70S AND 50S
FOR THE MOUNTAINS. OF COURSE TOO MUCH CLOUD COVER WILL PRODUCE
COOLER THAN FORECASTED HIGHS.

&&

.AVIATION.../18Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN...NORTHERLY TO EASTERLY LOW LEVEL
MOIST FLOW WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR
MUCH OF THE AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM
MOVING INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY
WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE EXPECTED
AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST ON AND OFF
THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE ATMOSPHERE WILL
BECOME MORE UNSTABLE RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY RAIN AND SMALL HAIL.

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

VFR CONDITIONS WILL START THE AFTERNOON OUT...EXCEPT FOR KRKS WHERE
OCCASIONAL MVFR CONDITIONS DUE TO LOW CIGS WILL OCCUR...BEFORE
ANOTHER ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM
COLORADO AND UTAH RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN
OBSCURATIONS/LOCALLY HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS
WILL CONTINUE WELL INTO THE EVENING WITH LINGERING SHOWERS
THEREAFTER. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO MOVE IN
FROM THE SOUTH SATURDAY AS THE LOW PRESSURE CENTER NEAR LAS VEGAS
TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...LIPSON
FIRE WEATHER...BRAUN









000
FXUS65 KRIW 221757
AFDRIW

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE RIVERTON WY
1156 AM MDT FRI MAY 22 2015

TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWING LARGE DEEP TROF WRN CONUS...CLOSED LOW OVR
CALIFORNIA...SW RIDGE CNTRL CONUS...DEEP TROF ERN CONUS. WEAK SW
MOVING NWD THRU CNTRL WY THIS EVENING...WITH STRONGER SW TO THE
SOUTH...ROTATING ANTI-CLOCKWISE AROUND THE CLOSED LOW...SPREADING
OVR COLORADO. SFC HAS HIGH P CNTRL CONUS...LOW P AND NEARLY
STATIONARY FRONT WEST OF WY...DRAPED FROM NRN ID...SWD THRU UT AND
INTO WRN NM. ISOLATED TO WIDELY SCATTERED SHOWERS SPRINKLED AROUND
THE FA TONIGHT.

THRU TODAY...SW CURRENTLY OVR COLORADO WILL CONTINUE TO
ROTATE NWD ACROSS WY THIS AFTERNOON/EVENING/OVERNIGHT...WITH SW AXIS
BISECTING WY FROM SW TO NE BY THIS TIME TOMORROW. THIS WILL AID IN
KICKING OFF ANOTHER BATCH OF SHRA/TSRA. OTHERWISE...LL ERN FLOW
ACROSS MOST OF THE AREA E OF THE DIVIDE WILL STRENGTHEN...KEEPING
GOOD AMOUNTS OF LL MOISTURE ACROSS THE FA...WHILE MORE MID/UPR LVL
MOISTURE MOVES INTO THE REGION FROM THE SOUTH. DIRECTIONAL AND SPEED
SHEAR NOT PARTICULARLY IMPRESSIVE WITH RATHER WEAK MID/UPR FLOW IN
PLACE. BUOYANCY WILL BE MODEST WITH ML CAPE RANGING FROM 300 TO 500
J/KG FOR MOST OF THE CNTRL AND WRN FA...WEAKER TO THE EAST. STRONGER
STORMS OF THE DAY CURRENTLY LOOK TO FORM ACROSS THE FAR WEST...FROM
N OF JACKSON S TO AROUND KEMMERER WHERE WHERE SOME MARGINALLY
BETTER CHANCES FOR SUNSHINE WILL OCCUR...ALONG WITH CHCS FOR MAINLY
SMALL HAIL.

THE REST OF THE FCST FOR THE MEMORIAL DAY WEEKEND...COOL AND WET.
UPR LOW MIGRATES FROM NEAR THE 4 CORNERS REGION TO THE NRN HIGH
PLAINS BY THE END OF THE FCST...WHILE SFC CYCLOGENESIS TAKES PLACE
FROM ERN/NERN CO INTO THE CNTRL PLAINS THRU THE SAME PERIOD. BETWEEN
LOW TO MID LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR
MOISTURE FROM ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY
PLENTIFUL RAINFALL AND SOME SNOWFALL WILL BE HAD OVER THE SAME
PERIOD. THIS WILL...HOWEVER...BE A COMPARATIVELY WARM SYSTEM THE WAY
IT STANDS NOW WITH H7 TEMPS NOT DROPPING AT ANY ONE TIME TO MUCH
LESS THAN -1/-2DEG C...AND EVEN THEN FOR ONLY SHORT PERIODS AS THE
UPR LOW ROTATES ACROSS THE STATE. SUNDAY MORNING WILL LIKELY SEE THE
COLD TEMPS OVR THE NW FCST QUAD...BUT WITH LITTLE ATTENDING SNOWFALL
AS THE SYSTEM PULLS AWAY. GENERALLY...A TRACE TO AND INCH OR TWO
WILL BE POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS AND ONLY
ACROSS THE HIGHEST ELEVATIONS...ISOLATED 3 INCHES. SEVERE WX SHOULD
REMAIN MOSTLY EAST TO SOUTHEAST OF FA THROUGH THE PERIOD WITH ONLY
ISOLATED SMALL HAIL A SMALL THREAT THROUGHOUT. EARLY MORNING FOG
WILL ALSO BE POSSIBLE OVR MANY AREAS THROUGHOUT THE FCST.
.SHORT TERM...

.LONG TERM...MONDAY THROUGH FRIDAY

THE LONG RANGE MODELS ARE IN MODEST AGREEMENT WITH THE WEATHER
PATTERN MONDAY THROUGH FRIDAY. MEMORIAL DAY WILL BE DRIER FOR MOST
PLACES WITH MAINLY ISOLATED AFTERNOON SHOWERS OR STORMS. ACTIVITY
COULD BE A LITTLE MORE NUMEROUS IN THE FAR WEST LATE IN THE DAY INTO
MONDAY EVENING. HIGH TEMPS ON MEMORIAL DAY WILL BE AT OR SLIGHTLY
BELOW NORMAL WITH 50S AND 60S...40S TO LOW 50S FOR THE MOUNTAINS.

FOR TUESDAY THROUGH THURSDAY...A WEATHER SYSTEM SETTLES INTO THE
PACIFIC NW PER THE GFS MODEL AND MOVES INTO IDAHO THURSDAY NIGHT.
THEN IT BRINGS THE WEATHER SYSTEM THROUGH THE REGION FRIDAY. THE
ECMWF MODEL IS A BIT DIFFERENT AND FASTER AS IT DROPS THE WEATHER
SYSTEM INTO IDAHO TUESDAY NIGHT AND ACROSS THE ROCKIES WED NIGHT
AND THURSDAY MORNING. THEN THE ECMWF MODEL HAS FAIRLY QUIET
WEATHER FOR NEXT FRIDAY. BOTH MODELS HAVE BEEN CONSISTENT IN THEIR
TIMING THE PAST FEW MODEL RUNS. WILL LEAN TOWARD THE GFS SOLUTION
TONIGHT. THIS MEANS A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON
AND EVENING FROM TUE THROUGH FRI. COVERAGE SHOULD INCREASE OVER
THE WEST AND NORTH LATER NEXT WEEK AS THE SYSTEM GETS CLOSER AND
EVENTUALLY PASSES THROUGH THE AREA. WILL SEE HOW THINGS LOOK
TONIGHT AND SEE IF ANY CHANGES ARE NEEDED. AS FOR HIGH TEMPS TUE
THROUGH FRI...LITTLE DAY TO DAY CHANGE WITH 60S TO LOW 70S AND 50S
FOR THE MOUNTAINS. OF COURSE TOO MUCH CLOUD COVER WILL PRODUCE
COOLER THAN FORECASTED HIGHS.

&&

.AVIATION.../18Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN...NORTHERLY TO EASTERLY LOW LEVEL
MOIST FLOW WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR
MUCH OF THE AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM
MOVING INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY
WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE EXPECTED
AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST ON AND OFF
THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE ATMOSPHERE WILL
BECOME MORE UNSTABLE RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY RAIN AND SMALL HAIL.

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

VFR CONDITIONS WILL START THE AFTERNOON OUT...EXCEPT FOR KRKS WHERE
OCCASIONAL MVFR CONDITIONS DUE TO LOW CIGS WILL OCCUR...BEFORE
ANOTHER ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM
COLORADO AND UTAH RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN
OBSCURATIONS/LOCALLY HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS
WILL CONTINUE WELL INTO THE EVENING WITH LINGERING SHOWERS
THEREAFTER. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO MOVE IN
FROM THE SOUTH SATURDAY AS THE LOW PRESSURE CENTER NEAR LAS VEGAS
TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...LIPSON
FIRE WEATHER...BRAUN









000
FXUS65 KRIW 221757
AFDRIW

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE RIVERTON WY
1156 AM MDT FRI MAY 22 2015

TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWING LARGE DEEP TROF WRN CONUS...CLOSED LOW OVR
CALIFORNIA...SW RIDGE CNTRL CONUS...DEEP TROF ERN CONUS. WEAK SW
MOVING NWD THRU CNTRL WY THIS EVENING...WITH STRONGER SW TO THE
SOUTH...ROTATING ANTI-CLOCKWISE AROUND THE CLOSED LOW...SPREADING
OVR COLORADO. SFC HAS HIGH P CNTRL CONUS...LOW P AND NEARLY
STATIONARY FRONT WEST OF WY...DRAPED FROM NRN ID...SWD THRU UT AND
INTO WRN NM. ISOLATED TO WIDELY SCATTERED SHOWERS SPRINKLED AROUND
THE FA TONIGHT.

THRU TODAY...SW CURRENTLY OVR COLORADO WILL CONTINUE TO
ROTATE NWD ACROSS WY THIS AFTERNOON/EVENING/OVERNIGHT...WITH SW AXIS
BISECTING WY FROM SW TO NE BY THIS TIME TOMORROW. THIS WILL AID IN
KICKING OFF ANOTHER BATCH OF SHRA/TSRA. OTHERWISE...LL ERN FLOW
ACROSS MOST OF THE AREA E OF THE DIVIDE WILL STRENGTHEN...KEEPING
GOOD AMOUNTS OF LL MOISTURE ACROSS THE FA...WHILE MORE MID/UPR LVL
MOISTURE MOVES INTO THE REGION FROM THE SOUTH. DIRECTIONAL AND SPEED
SHEAR NOT PARTICULARLY IMPRESSIVE WITH RATHER WEAK MID/UPR FLOW IN
PLACE. BUOYANCY WILL BE MODEST WITH ML CAPE RANGING FROM 300 TO 500
J/KG FOR MOST OF THE CNTRL AND WRN FA...WEAKER TO THE EAST. STRONGER
STORMS OF THE DAY CURRENTLY LOOK TO FORM ACROSS THE FAR WEST...FROM
N OF JACKSON S TO AROUND KEMMERER WHERE WHERE SOME MARGINALLY
BETTER CHANCES FOR SUNSHINE WILL OCCUR...ALONG WITH CHCS FOR MAINLY
SMALL HAIL.

THE REST OF THE FCST FOR THE MEMORIAL DAY WEEKEND...COOL AND WET.
UPR LOW MIGRATES FROM NEAR THE 4 CORNERS REGION TO THE NRN HIGH
PLAINS BY THE END OF THE FCST...WHILE SFC CYCLOGENESIS TAKES PLACE
FROM ERN/NERN CO INTO THE CNTRL PLAINS THRU THE SAME PERIOD. BETWEEN
LOW TO MID LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR
MOISTURE FROM ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY
PLENTIFUL RAINFALL AND SOME SNOWFALL WILL BE HAD OVER THE SAME
PERIOD. THIS WILL...HOWEVER...BE A COMPARATIVELY WARM SYSTEM THE WAY
IT STANDS NOW WITH H7 TEMPS NOT DROPPING AT ANY ONE TIME TO MUCH
LESS THAN -1/-2DEG C...AND EVEN THEN FOR ONLY SHORT PERIODS AS THE
UPR LOW ROTATES ACROSS THE STATE. SUNDAY MORNING WILL LIKELY SEE THE
COLD TEMPS OVR THE NW FCST QUAD...BUT WITH LITTLE ATTENDING SNOWFALL
AS THE SYSTEM PULLS AWAY. GENERALLY...A TRACE TO AND INCH OR TWO
WILL BE POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS AND ONLY
ACROSS THE HIGHEST ELEVATIONS...ISOLATED 3 INCHES. SEVERE WX SHOULD
REMAIN MOSTLY EAST TO SOUTHEAST OF FA THROUGH THE PERIOD WITH ONLY
ISOLATED SMALL HAIL A SMALL THREAT THROUGHOUT. EARLY MORNING FOG
WILL ALSO BE POSSIBLE OVR MANY AREAS THROUGHOUT THE FCST.
.SHORT TERM...

.LONG TERM...MONDAY THROUGH FRIDAY

THE LONG RANGE MODELS ARE IN MODEST AGREEMENT WITH THE WEATHER
PATTERN MONDAY THROUGH FRIDAY. MEMORIAL DAY WILL BE DRIER FOR MOST
PLACES WITH MAINLY ISOLATED AFTERNOON SHOWERS OR STORMS. ACTIVITY
COULD BE A LITTLE MORE NUMEROUS IN THE FAR WEST LATE IN THE DAY INTO
MONDAY EVENING. HIGH TEMPS ON MEMORIAL DAY WILL BE AT OR SLIGHTLY
BELOW NORMAL WITH 50S AND 60S...40S TO LOW 50S FOR THE MOUNTAINS.

FOR TUESDAY THROUGH THURSDAY...A WEATHER SYSTEM SETTLES INTO THE
PACIFIC NW PER THE GFS MODEL AND MOVES INTO IDAHO THURSDAY NIGHT.
THEN IT BRINGS THE WEATHER SYSTEM THROUGH THE REGION FRIDAY. THE
ECMWF MODEL IS A BIT DIFFERENT AND FASTER AS IT DROPS THE WEATHER
SYSTEM INTO IDAHO TUESDAY NIGHT AND ACROSS THE ROCKIES WED NIGHT
AND THURSDAY MORNING. THEN THE ECMWF MODEL HAS FAIRLY QUIET
WEATHER FOR NEXT FRIDAY. BOTH MODELS HAVE BEEN CONSISTENT IN THEIR
TIMING THE PAST FEW MODEL RUNS. WILL LEAN TOWARD THE GFS SOLUTION
TONIGHT. THIS MEANS A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON
AND EVENING FROM TUE THROUGH FRI. COVERAGE SHOULD INCREASE OVER
THE WEST AND NORTH LATER NEXT WEEK AS THE SYSTEM GETS CLOSER AND
EVENTUALLY PASSES THROUGH THE AREA. WILL SEE HOW THINGS LOOK
TONIGHT AND SEE IF ANY CHANGES ARE NEEDED. AS FOR HIGH TEMPS TUE
THROUGH FRI...LITTLE DAY TO DAY CHANGE WITH 60S TO LOW 70S AND 50S
FOR THE MOUNTAINS. OF COURSE TOO MUCH CLOUD COVER WILL PRODUCE
COOLER THAN FORECASTED HIGHS.

&&

.AVIATION.../18Z ISSUANCE/

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

EXCEPT FOR THE BIG HORN BASIN...NORTHERLY TO EASTERLY LOW LEVEL
MOIST FLOW WILL KEEP LOW CLOUDS/MVFR/IFR/MTN OBSCURATIONS AROUND FOR
MUCH OF THE AFTERNOON AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM
MOVING INTO THE AREA FROM THE SOUTHERN GREAT BASIN AREA. INSTABILITY
WILL BE RELATIVELY WEAK SO MAINLY JUST RAIN SHOWERS ARE EXPECTED
AROUND THE AREA. THESE CONDITIONS ARE EXPECTED TO PERSIST ON AND OFF
THROUGH ABOUT 21Z SATURDAY AFTER WHICH TIME THE ATMOSPHERE WILL
BECOME MORE UNSTABLE RESULTING IN SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACCOMPANIED BY LOCALLY HEAVY RAIN AND SMALL HAIL.

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

VFR CONDITIONS WILL START THE AFTERNOON OUT...EXCEPT FOR KRKS WHERE
OCCASIONAL MVFR CONDITIONS DUE TO LOW CIGS WILL OCCUR...BEFORE
ANOTHER ROUND OF SCATTERED TO NUMEROUS THUNDERSTORMS MOVE IN FROM
COLORADO AND UTAH RESULTING IN LOCAL MVFR/IFR CONDITIONS/MTN
OBSCURATIONS/LOCALLY HEAVY RAIN AND SMALL HAIL. THESE THUNDERSTORMS
WILL CONTINUE WELL INTO THE EVENING WITH LINGERING SHOWERS
THEREAFTER. ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO MOVE IN
FROM THE SOUTH SATURDAY AS THE LOW PRESSURE CENTER NEAR LAS VEGAS
TRACKS NORTHEAST TO WYOMING.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...LIPSON
FIRE WEATHER...BRAUN










000
FXUS65 KRIW 220942
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
342 AM MDT FRI MAY 22 2015

TODAY THROUGH SUNDAY NIGHT

WV IMAGERY SHOWING LARGE DEEP TROF WRN CONUS...CLOSED LOW OVR
CALIFORNIA...SW RIDGE CNTRL CONUS...DEEP TROF ERN CONUS. WEAK SW
MOVING NWD THRU CNTRL WY THIS EVENING...WITH STRONGER SW TO THE
SOUTH...ROTATING ANTI-CLOCKWISE AROUND THE CLOSED LOW...SPREADING
OVR COLORADO. SFC HAS HIGH P CNTRL CONUS...LOW P AND NEARLY
STATIONARY FRONT WEST OF WY...DRAPED FROM NRN ID...SWD THRU UT AND
INTO WRN NM. ISOLATED TO WIDELY SCATTERED SHOWERS SPRINKLED AROUND
THE FA TONIGHT.

THRU TODAY...SW CURRENTLY OVR COLORADO WILL CONTINUE TO
ROTATE NWD ACROSS WY THIS AFTERNOON/EVENING/OVERNIGHT...WITH SW AXIS
BISECTING WY FROM SW TO NE BY THIS TIME TOMORROW. THIS WILL AID IN
KICKING OFF ANOTHER BATCH OF SHRA/TSRA. OTHERWISE...LL ERN FLOW
ACROSS MOST OF THE AREA E OF THE DIVIDE WILL STRENGTHEN...KEEPING
GOOD AMOUNTS OF LL MOISTURE ACROSS THE FA...WHILE MORE MID/UPR LVL
MOISTURE MOVES INTO THE REGION FROM THE SOUTH. DIRECTIONAL AND SPEED
SHEAR NOT PARTICULARLY IMPRESSIVE WITH RATHER WEAK MID/UPR FLOW IN
PLACE. BUOYANCY WILL BE MODEST WITH ML CAPE RANGING FROM 300 TO 500
J/KG FOR MOST OF THE CNTRL AND WRN FA...WEAKER TO THE EAST. STRONGER
STORMS OF THE DAY CURRENTLY LOOK TO FORM ACROSS THE FAR WEST...FROM
N OF JACKSON S TO AROUND KEMMERER WHERE WHERE SOME MARGINALLY
BETTER CHANCES FOR SUNSHINE WILL OCCUR...ALONG WITH CHCS FOR MAINLY
SMALL HAIL.

THE REST OF THE FCST FOR THE MEMORIAL DAY WEEKEND...COOL AND WET.
UPR LOW MIGRATES FROM NEAR THE 4 CORNERS REGION TO THE NRN HIGH
PLAINS BY THE END OF THE FCST...WHILE SFC CYCLOGENESIS TAKES PLACE
FROM ERN/NERN CO INTO THE CNTRL PLAINS THRU THE SAME PERIOD. BETWEEN
LOW TO MID LVL MOISTURE RETURN AROUND THE SFC LOW...AND MID UPR
MOISTURE FROM ACCOMPANYING THE UPR WAVE/CLOSED LOW...RELATIVELY
PLENTIFUL RAINFALL AND SOME SNOWFALL WILL BE HAD OVER THE SAME
PERIOD. THIS WILL...HOWEVER...BE A COMPARATIVELY WARM SYSTEM THE WAY
IT STANDS NOW WITH H7 TEMPS NOT DROPPING AT ANY ONE TIME TO MUCH
LESS THAN -1/-2DEG C...AND EVEN THEN FOR ONLY SHORT PERIODS AS THE
UPR LOW ROTATES ACROSS THE STATE. SUNDAY MORNING WILL LIKELY SEE THE
COLD TEMPS OVR THE NW FCST QUAD...BUT WITH LITTLE ATTENDING SNOWFALL
AS THE SYSTEM PULLS AWAY. GENERALLY...A TRACE TO AND INCH OR TWO
WILL BE POSSIBLE DURING THE COLDEST PORTION OF THE NIGHTS AND ONLY
ACROSS THE HIGHEST ELEVATIONS...ISOLATED 3 INCHES. SEVERE WX SHOULD
REMAIN MOSTLY EAST TO SOUTHEAST OF FA THROUGH THE PERIOD WITH ONLY
ISOLATED SMALL HAIL A SMALL THREAT THROUGHOUT. EARLY MORNING FOG
WILL ALSO BE POSSIBLE OVR MANY AREAS THROUGHOUT THE FCST.
.SHORT TERM...

.LONG TERM...MONDAY THROUGH FRIDAY

THE LONG RANGE MODELS ARE IN MODEST AGREEMENT WITH THE WEATHER
PATTERN MONDAY THROUGH FRIDAY. MEMORIAL DAY WILL BE DRIER FOR MOST
PLACES WITH MAINLY ISOLATED AFTERNOON SHOWERS OR STORMS. ACTIVITY
COULD BE A LITTLE MORE NUMEROUS IN THE FAR WEST LATE IN THE DAY INTO
MONDAY EVENING. HIGH TEMPS ON MEMORIAL DAY WILL BE AT OR SLIGHTLY
BELOW NORMAL WITH 50S AND 60S...40S TO LOW 50S FOR THE MOUNTAINS.

FOR TUESDAY THROUGH THURSDAY...A WEATHER SYSTEM SETTLES INTO THE
PACIFIC NW PER THE GFS MODEL AND MOVES INTO IDAHO THURSDAY NIGHT.
THEN IT BRINGS THE WEATHER SYSTEM THROUGH THE REGION FRIDAY. THE
ECMWF MODEL IS A BIT DIFFERENT AND FASTER AS IT DROPS THE WEATHER
SYSTEM INTO IDAHO TUESDAY NIGHT AND ACROSS THE ROCKIES WED NIGHT
AND THURSDAY MORNING. THEN THE ECMWF MODEL HAS FAIRLY QUIET
WEATHER FOR NEXT FRIDAY. BOTH MODELS HAVE BEEN CONSISTENT IN THEIR
TIMING THE PAST FEW MODEL RUNS. WILL LEAN TOWARD THE GFS SOLUTION
TONIGHT. THIS MEANS A CHANCE OF SHOWERS AND STORMS EACH AFTERNOON
AND EVENING FROM TUE THROUGH FRI. COVERAGE SHOULD INCREASE OVER
THE WEST AND NORTH LATER NEXT WEEK AS THE SYSTEM GETS CLOSER AND
EVENTUALLY PASSES THROUGH THE AREA. WILL SEE HOW THINGS LOOK
TONIGHT AND SEE IF ANY CHANGES ARE NEEDED. AS FOR HIGH TEMPS TUE
THROUGH FRI...LITTLE DAY TO DAY CHANGE WITH 60S TO LOW 70S AND 50S
FOR THE MOUNTAINS. OF COURSE TOO MUCH CLOUD COVER WILL PRODUCE
COOLER THAN FORECASTED HIGHS.

&&

.AVIATION.../12Z ISSUANCE/

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

EXPECT CONDITIONS TO BE VFR THROUGH AT LEAST 00Z/SAT AT ALL
TERMINALS. WEST-EAST ORIENTED AREA OF CONVECTION WILL LIFT NORTH
ACROSS THE FORECAST AREAS BETWEEN 21Z/FRI AND 03Z/SAT...SIMILAR TO
WHAT WAS SEEN THURSDAY. INSTABILITY LOOKS A LITTLE MORE FAVORABLE
FOR WEAK CONVECTION AT KCPR. MAIN HAZARD WITH THE SHOWERS AND STORMS
WILL BE HEAVY RAIN. MID-LEVEL CIRCULATION ALONG THE WESTERN WYOMING
BORDER AT 00Z. CONVERGENCE AXIS WILL PINWHEEL NORTH DURING THE
EVENING AND PROVIDE PERHAPS A BETTER PERIOD OF WIDESPREAD SHOWERS
AND STORMS. PLENTY OF ENERGY AND MOISTURE TO WORK WITH THROUGH AT
LEAST 06Z/SAT. HAVE KEPT VCSH AT MANY TERMINALS BUT COULD SEE MORE
DEFINITIVE PERIOD OF PREVAILING -SHRA BETWEEN 00Z-06Z/SAT. LEFT EXIT
REGION OF 100KT+ JET MAY ALSO ASSIST LIFT FRIDAY EVENING...
ESPECIALLY ACROSS CENTRAL WYOMING. MOUNTAIN TOP OBSCURATIONS WILL BE
WIDESPREAD ABOVE ABOUT 9K-10K MSL THROUGHOUT MUCH OF THE FORECAST
PERIOD...ESPECIALLY ALONG THE WIND RIVER RANGE AND THE SOUTHERN
PORTIONS OF THE ABSAROKA AND BIGHORN RANGES.

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

STEADY STREAM OF SHORTWAVE ENERGY WILL HEAD NORTH ACROSS THE
FORECAST AREA TODAY. VFR CONDITIONS WILL LARGELY BE THE RULE THROUGH
00Z/SAT...WITH THE EXCEPTION BEING MVFR CONDITIONS WITH THE
STRONGEST STORMS LATE TODAY. SHORTWAVE IN SOUTHERN COLORADO WILL
CONTINUE TO LIFT AS THE KICKER UPPER LOW MOVES EAST. EXPECT
CONVECTION TO ORIENT IN A WEST-EAST BAND ACROSS FAR SOUTHERN WYOMING
BY 18Z TODAY. SIMILAR TO THURSDAY...THIS AREA OF CONVECTION WILL LIFT
NORTH THROUGH 00Z/SAT. THEREFORE...HAVE VCTS BY 19Z/FRI AT KRKS AND
BY 21Z/FRI AT KBPI...KPNA...AND KJAC. MAIN HAZARD WILL BE HEAVY
RAIN. AFTER 00Z/SAT...700MB CIRCULATION AND LOW-LEVEL SOUTHERLY FLOW
MAY ENHANCE PRECIPITATION ACROSS THE GREEN RIVER BASIN FROM KBPI TO
KPNA. THIS WOULD BE THE MOST LIKELY PERIOD OF MVFR CONDITIONS AT
THESE TWO TERMINALS. MOUNTAIN TOP OBSCURATIONS WILL BE COMMON
THROUGH THE FORECAST PERIOD WITH LOWERING CEILINGS AFTER 00Z/SAT.

&&

.FIRE WEATHER...

FIRE DANGER LOW AND WILL REMAIN LOW THROUGH THE HOLIDAY WEEKEND
AS COOL AND RELATIVELY WET WEATHER REMAINS IN PLACE AS YET ANOTHER
VIGOROUS UPPER LEVEL SYSTEM ROTATES ACROSS THE REGION. WIDESPREAD
PRECIPITATION WITH LIGHT MOUNTAIN SNOW IS EXPECTED EACH DAY...WITH
EMBEDDED THUNDERSTORMS POSSIBLE EACH AFTERNOON AND EARLY EVENING.

&&

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

&&

$$

SHORT TERM...BRAUN
LONG TERM...AR
AVIATION...CNJ
FIRE WEATHER...BRAUN






000
FXUS65 KRIW 220530
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1130 PM MDT THU MAY 21 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

AREAS OF LOW CLOUDS AND FOG HAVE LIFTED INTO A LOW CUMULUS CLOUD
DECK BETWEEN 3 AND 4K AS ABUNDANT GROUND MOISTURE CONTINUES TO
CONTRIBUTE TO THE LOWER AIRMASS AS TEMPS AND CORRESPONDING LCLS
RISE. THE STUBBORN HIGH IN WESTERN CANADA HAS DIVERTED ANOTHER
CLOSED LOW SOUTH TO OFF THE CALIFORNIA COAST. THE CIRCULATION
AROUND THIS LOW IS ARRIVING AS A SOUTH SOUTHWEST DIFLUENT FLOW
ACROSS WYOMING OUT AHEAD OF IT. SCATTERED THUNDERSTORMS UNDERNEATH
THIS FLOW HAVE ERUPTED ACROSS YELLOWSTONE PARK/ABSAROKAS AS WELL AS
ACROSS SOUTHWEST WY WHERE A SHORTWAVE/VORT LOBE IS TRACKING NORTH
NORTHEAST WITHIN THE SSW DIFLUENT FLOW IN SOUTHERN WY. WITH THE
RELATIVELY LOW LCL AND LOW WET BULB ZERO...MANY OF THESE CELLS
COULD PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL. AS THIS
SHORTWAVE TRACKS NNE...THE TREND WILL BE FOR MORE STORM CELLS TO
DEVELOP ACROSS THE REST OF NORTHERN AND ALSO CENTRAL AND EASTERN
PORTIONS OF THE CWA. TONIGHT THE LOW CENTER WILL TRACK EAST ACROSS
SOUTHERN CALIFORNIA ALONG WITH A WEAK TROUGH EXTENDING NORTHEAST
FROM THE LOW NORTHEAST INTO WYOMING. WITH THE TROUGHINESS OVHD
FRIDAY...EXPECT NUMEROUS SHOWERS TO DEVELOP ACROSS CENTRAL AND
SOUTHERN WY FRIDAY BY LATE MORNING. THE STORMS WILL BE LAST TO
ARRIVE IN NORTH CENTRAL AND NORTHEAST WY WHERE MORE SOLAR
INSULATION WILL TAKE PLACE THROUGH THE LATER AFTERNOON HOURS FOR
FEWER...LATER BUT STRONGER THUNDERSTORMS AS THE TROUGHINESS
CONTINUES TO EXTEND NORTHEAST. TEMPS WILL WARM UP TO MORE SEASONAL
LEVELS BY FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE
SLOWLY EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL
WYOMING WITH SOUTHWEST FLOW ALOFT OVER THE AREA. THE AIRMASS WILL
BE UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN
MOUNTAINS AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE
EVENING. SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL
LINGER INTO SATURDAY MORNING. A CANADIAN COLD FRONT WILL SLIDE
SOUTH THROUGH MUCH OF THE ARA ON SATURDAY AS THE UPPER LOW DRIFTS
SLOWLY EAST OVER THE COLD FRONT. SHOWERS WILL BE WIDESPREAD ACROSS
THE AREA WITH COOL TEMPERATURES. ENOUGH INSTABILITY WILL BE OVER
THE AREA SATURDAY AFTERNOON AND EVENING TO SUPPORT ISOLATED
THUNDERSTORMS WITH SMALL HAIL. SNOW LEVELS WILL LOWER THROUGH
SATURDAY NIGHT DOWN TO AROUND 8000 FEET. SUNDAY WILL BE COOL AND
REMAINING SHOWERY WITH A FEW ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO THE EAST AS ANOTHER
INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL DECREASE THROUGH
SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING OVER THE
WESTERN MOUNTAINS. LESS MOISTURE WILL BE OVER THE AREA ON MONDAY
BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS. MONDAY NIGHT WILL SEE A
SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH
WILL SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY
AND TUESDAY NIGHT WITH MORE SHOWERS... ESPECIALLY OVER THE WESTERN
AND NORTHERN MOUNTAINS. TEMPERATURES SHOULD BE SLIGHTLY WARMER.
THE TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE
NORTH AND EAST ACROSS THE AREA WITH INCREASING SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING. THE TROUGH
WILL BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN
COLD FRONT MOVES SOUTH BRINGING GENERAL COOLING.


&&

.AVIATION.../06Z ISSUANCE/

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

CONDITIONS THROUGH 21Z/FRI WILL BE VFR AT ALL TERMINALS. SHORTWAVE
ENERGY WILL ROTATE NORTH AHEAD OF MORE IMPRESSIVE SHORTWAVE OVER
NORTHERN NEW MEXICO. EXPECT THAT SHOWERS OVER THE BIG HORN BASIN
WILL DISSIPATE LATE TONIGHT WHILE KRIW AND KLND COULD SEE ISOLATED
WEAK CONVECTION THROUGH THE OVERNIGHT HOURS. ENERGY WITH THE MORE
VIGOROUS SHORTWAVE WILL REACH CENTRAL WYOMING IN THE 20Z-22Z/FRI
TIMEFRAME. THE EVOLUTION MAY BE VERY SIMILAR TO THURSDAY. APPEARS
THERE COULD BE A LITTLE MORE INSTABILITY TO GENERATE AT LEAST
SHOWERS AT KCPR...WHEREAS STABLE AIR LIMITED THAT THURSDAY. 700MB
LOW SHOULD BE ALONG THE WESTERN WYOMING BORDER BY 00Z/SAT. PLENTY OF
ENERGY AND MOISTURE AVAILABLE TO KEEP SHOWERS AND ISOLATED
THUNDERSTORMS GOING THROUGH 06Z/SAT. HAVE KEPT VCSH AT MANY
TERMINALS BUT COULD SEE MORE DEFINITIVE PERIOD OF PREVAILING -SHRA
BETWEEN 00Z-06Z/SAT. THERE COULD ALSO BE SOME AID FROM THE LEFT EXIT
REGION OF THE JET DURING THAT SPAN. MOUNTAIN TOP OBSCURATIONS WILL
BE WIDESPREAD ABOVE ABOUT 9K-10K MSL THROUGHOUT MUCH OF THE FORECAST
PERIOD...ESPECIALLY ALONG THE WIND RIVER RANGE AND THE SOUTHERN
PORTIONS OF THE ABSAROKA AND BIGHORN RANGES.

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

YET MORE SHORTWAVE ENERGY ROTATING NORTH TONIGHT. CLOUD TOPS ARE
ALREADY COOLING AHEAD OF VIGOROUS SHORTWAVE OVER NORTHERN NEW MEXICO
PER IR IMAGERY. CONVECTION IS LIKELY TO CONTINUE THROUGH THE
NIGHT...WITH VFR CONDITIONS LARGELY THE RULE. COULD SEE SOME
LOCALIZED MVFR WITH THE STRONGER CONVECTION AND IN THE GREEN RIVER
VALLEY AROUND KBPI AND KPNA. NEW MEXICO SHORTWAVE WILL LIFT NORTH
DURING THE DAY AS LARGER UPPER LOW TO THE WEST MOVES FARTHER INLAND.
CONVECTION MAY AGAIN ORIENT WEST-EAST ACROSS FAR SOUTHERN WYOMING BY
18Z/FRI. SIMILAR TO THURSDAY...THIS AREA OF CONVECTION WILL LIFT
NORTH THROUGH 00Z/SAT. THEREFORE...HAVE VCTS BY 19Z/FRI AT KRKS AND
BY 21Z/FRI AT KBPI...KPNA...AND KJAC. CERTAINLY COULD BE A FAIRLY
STEADY PERIOD OF RAIN...ESPECIALLY AT KBPI AND KPNA...DURING THE
LATE AFTERNOON HOURS FRIDAY. MOUNTAIN TOP OBSCURATIONS WILL BE
COMMON THROUGH THE FORECAST PERIOD WITH LOWERING CEILINGS AFTER
00Z/SAT.

&&

.FIRE WEATHER...

FIRE DANGER RELATIVELY LOW AS SEASONAL TO COOL AND RELATIVELY MOIST
CONDITIONS PERSIST. A WEAK UPPER LEVEL DISTURBANCE WILL BRING
ISOLATED CONVECTION MAINLY WEST OF THE DIVIDE FOR THE REST OF THIS
AFTERNOON AND EVENING. DEEPER MOISTURE WILL MOVE TOWARD THE AREA
FOR FRIDAY AND BRING ANOTHER CHANCE OF A WETTING RAIN FROM FRIDAY
INTO FRIDAY NIGHT. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS THAT WILL PERSIST INTO SATURDAY AS WELL. SNOW LEVELS
WILL DROP TO 8000 FEET LATE SATURDAY NIGHT AND SUNDAY MORNING.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...C.BAKER
AVIATION...CNJ
FIRE WEATHER...LIPSON












000
FXUS65 KRIW 220530
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1130 PM MDT THU MAY 21 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

AREAS OF LOW CLOUDS AND FOG HAVE LIFTED INTO A LOW CUMULUS CLOUD
DECK BETWEEN 3 AND 4K AS ABUNDANT GROUND MOISTURE CONTINUES TO
CONTRIBUTE TO THE LOWER AIRMASS AS TEMPS AND CORRESPONDING LCLS
RISE. THE STUBBORN HIGH IN WESTERN CANADA HAS DIVERTED ANOTHER
CLOSED LOW SOUTH TO OFF THE CALIFORNIA COAST. THE CIRCULATION
AROUND THIS LOW IS ARRIVING AS A SOUTH SOUTHWEST DIFLUENT FLOW
ACROSS WYOMING OUT AHEAD OF IT. SCATTERED THUNDERSTORMS UNDERNEATH
THIS FLOW HAVE ERUPTED ACROSS YELLOWSTONE PARK/ABSAROKAS AS WELL AS
ACROSS SOUTHWEST WY WHERE A SHORTWAVE/VORT LOBE IS TRACKING NORTH
NORTHEAST WITHIN THE SSW DIFLUENT FLOW IN SOUTHERN WY. WITH THE
RELATIVELY LOW LCL AND LOW WET BULB ZERO...MANY OF THESE CELLS
COULD PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL. AS THIS
SHORTWAVE TRACKS NNE...THE TREND WILL BE FOR MORE STORM CELLS TO
DEVELOP ACROSS THE REST OF NORTHERN AND ALSO CENTRAL AND EASTERN
PORTIONS OF THE CWA. TONIGHT THE LOW CENTER WILL TRACK EAST ACROSS
SOUTHERN CALIFORNIA ALONG WITH A WEAK TROUGH EXTENDING NORTHEAST
FROM THE LOW NORTHEAST INTO WYOMING. WITH THE TROUGHINESS OVHD
FRIDAY...EXPECT NUMEROUS SHOWERS TO DEVELOP ACROSS CENTRAL AND
SOUTHERN WY FRIDAY BY LATE MORNING. THE STORMS WILL BE LAST TO
ARRIVE IN NORTH CENTRAL AND NORTHEAST WY WHERE MORE SOLAR
INSULATION WILL TAKE PLACE THROUGH THE LATER AFTERNOON HOURS FOR
FEWER...LATER BUT STRONGER THUNDERSTORMS AS THE TROUGHINESS
CONTINUES TO EXTEND NORTHEAST. TEMPS WILL WARM UP TO MORE SEASONAL
LEVELS BY FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE
SLOWLY EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL
WYOMING WITH SOUTHWEST FLOW ALOFT OVER THE AREA. THE AIRMASS WILL
BE UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN
MOUNTAINS AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE
EVENING. SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL
LINGER INTO SATURDAY MORNING. A CANADIAN COLD FRONT WILL SLIDE
SOUTH THROUGH MUCH OF THE ARA ON SATURDAY AS THE UPPER LOW DRIFTS
SLOWLY EAST OVER THE COLD FRONT. SHOWERS WILL BE WIDESPREAD ACROSS
THE AREA WITH COOL TEMPERATURES. ENOUGH INSTABILITY WILL BE OVER
THE AREA SATURDAY AFTERNOON AND EVENING TO SUPPORT ISOLATED
THUNDERSTORMS WITH SMALL HAIL. SNOW LEVELS WILL LOWER THROUGH
SATURDAY NIGHT DOWN TO AROUND 8000 FEET. SUNDAY WILL BE COOL AND
REMAINING SHOWERY WITH A FEW ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO THE EAST AS ANOTHER
INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL DECREASE THROUGH
SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING OVER THE
WESTERN MOUNTAINS. LESS MOISTURE WILL BE OVER THE AREA ON MONDAY
BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS. MONDAY NIGHT WILL SEE A
SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH
WILL SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY
AND TUESDAY NIGHT WITH MORE SHOWERS... ESPECIALLY OVER THE WESTERN
AND NORTHERN MOUNTAINS. TEMPERATURES SHOULD BE SLIGHTLY WARMER.
THE TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE
NORTH AND EAST ACROSS THE AREA WITH INCREASING SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING. THE TROUGH
WILL BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN
COLD FRONT MOVES SOUTH BRINGING GENERAL COOLING.


&&

.AVIATION.../06Z ISSUANCE/

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

CONDITIONS THROUGH 21Z/FRI WILL BE VFR AT ALL TERMINALS. SHORTWAVE
ENERGY WILL ROTATE NORTH AHEAD OF MORE IMPRESSIVE SHORTWAVE OVER
NORTHERN NEW MEXICO. EXPECT THAT SHOWERS OVER THE BIG HORN BASIN
WILL DISSIPATE LATE TONIGHT WHILE KRIW AND KLND COULD SEE ISOLATED
WEAK CONVECTION THROUGH THE OVERNIGHT HOURS. ENERGY WITH THE MORE
VIGOROUS SHORTWAVE WILL REACH CENTRAL WYOMING IN THE 20Z-22Z/FRI
TIMEFRAME. THE EVOLUTION MAY BE VERY SIMILAR TO THURSDAY. APPEARS
THERE COULD BE A LITTLE MORE INSTABILITY TO GENERATE AT LEAST
SHOWERS AT KCPR...WHEREAS STABLE AIR LIMITED THAT THURSDAY. 700MB
LOW SHOULD BE ALONG THE WESTERN WYOMING BORDER BY 00Z/SAT. PLENTY OF
ENERGY AND MOISTURE AVAILABLE TO KEEP SHOWERS AND ISOLATED
THUNDERSTORMS GOING THROUGH 06Z/SAT. HAVE KEPT VCSH AT MANY
TERMINALS BUT COULD SEE MORE DEFINITIVE PERIOD OF PREVAILING -SHRA
BETWEEN 00Z-06Z/SAT. THERE COULD ALSO BE SOME AID FROM THE LEFT EXIT
REGION OF THE JET DURING THAT SPAN. MOUNTAIN TOP OBSCURATIONS WILL
BE WIDESPREAD ABOVE ABOUT 9K-10K MSL THROUGHOUT MUCH OF THE FORECAST
PERIOD...ESPECIALLY ALONG THE WIND RIVER RANGE AND THE SOUTHERN
PORTIONS OF THE ABSAROKA AND BIGHORN RANGES.

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

YET MORE SHORTWAVE ENERGY ROTATING NORTH TONIGHT. CLOUD TOPS ARE
ALREADY COOLING AHEAD OF VIGOROUS SHORTWAVE OVER NORTHERN NEW MEXICO
PER IR IMAGERY. CONVECTION IS LIKELY TO CONTINUE THROUGH THE
NIGHT...WITH VFR CONDITIONS LARGELY THE RULE. COULD SEE SOME
LOCALIZED MVFR WITH THE STRONGER CONVECTION AND IN THE GREEN RIVER
VALLEY AROUND KBPI AND KPNA. NEW MEXICO SHORTWAVE WILL LIFT NORTH
DURING THE DAY AS LARGER UPPER LOW TO THE WEST MOVES FARTHER INLAND.
CONVECTION MAY AGAIN ORIENT WEST-EAST ACROSS FAR SOUTHERN WYOMING BY
18Z/FRI. SIMILAR TO THURSDAY...THIS AREA OF CONVECTION WILL LIFT
NORTH THROUGH 00Z/SAT. THEREFORE...HAVE VCTS BY 19Z/FRI AT KRKS AND
BY 21Z/FRI AT KBPI...KPNA...AND KJAC. CERTAINLY COULD BE A FAIRLY
STEADY PERIOD OF RAIN...ESPECIALLY AT KBPI AND KPNA...DURING THE
LATE AFTERNOON HOURS FRIDAY. MOUNTAIN TOP OBSCURATIONS WILL BE
COMMON THROUGH THE FORECAST PERIOD WITH LOWERING CEILINGS AFTER
00Z/SAT.

&&

.FIRE WEATHER...

FIRE DANGER RELATIVELY LOW AS SEASONAL TO COOL AND RELATIVELY MOIST
CONDITIONS PERSIST. A WEAK UPPER LEVEL DISTURBANCE WILL BRING
ISOLATED CONVECTION MAINLY WEST OF THE DIVIDE FOR THE REST OF THIS
AFTERNOON AND EVENING. DEEPER MOISTURE WILL MOVE TOWARD THE AREA
FOR FRIDAY AND BRING ANOTHER CHANCE OF A WETTING RAIN FROM FRIDAY
INTO FRIDAY NIGHT. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS THAT WILL PERSIST INTO SATURDAY AS WELL. SNOW LEVELS
WILL DROP TO 8000 FEET LATE SATURDAY NIGHT AND SUNDAY MORNING.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...C.BAKER
AVIATION...CNJ
FIRE WEATHER...LIPSON











000
FXUS65 KRIW 220530
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1130 PM MDT THU MAY 21 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

AREAS OF LOW CLOUDS AND FOG HAVE LIFTED INTO A LOW CUMULUS CLOUD
DECK BETWEEN 3 AND 4K AS ABUNDANT GROUND MOISTURE CONTINUES TO
CONTRIBUTE TO THE LOWER AIRMASS AS TEMPS AND CORRESPONDING LCLS
RISE. THE STUBBORN HIGH IN WESTERN CANADA HAS DIVERTED ANOTHER
CLOSED LOW SOUTH TO OFF THE CALIFORNIA COAST. THE CIRCULATION
AROUND THIS LOW IS ARRIVING AS A SOUTH SOUTHWEST DIFLUENT FLOW
ACROSS WYOMING OUT AHEAD OF IT. SCATTERED THUNDERSTORMS UNDERNEATH
THIS FLOW HAVE ERUPTED ACROSS YELLOWSTONE PARK/ABSAROKAS AS WELL AS
ACROSS SOUTHWEST WY WHERE A SHORTWAVE/VORT LOBE IS TRACKING NORTH
NORTHEAST WITHIN THE SSW DIFLUENT FLOW IN SOUTHERN WY. WITH THE
RELATIVELY LOW LCL AND LOW WET BULB ZERO...MANY OF THESE CELLS
COULD PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL. AS THIS
SHORTWAVE TRACKS NNE...THE TREND WILL BE FOR MORE STORM CELLS TO
DEVELOP ACROSS THE REST OF NORTHERN AND ALSO CENTRAL AND EASTERN
PORTIONS OF THE CWA. TONIGHT THE LOW CENTER WILL TRACK EAST ACROSS
SOUTHERN CALIFORNIA ALONG WITH A WEAK TROUGH EXTENDING NORTHEAST
FROM THE LOW NORTHEAST INTO WYOMING. WITH THE TROUGHINESS OVHD
FRIDAY...EXPECT NUMEROUS SHOWERS TO DEVELOP ACROSS CENTRAL AND
SOUTHERN WY FRIDAY BY LATE MORNING. THE STORMS WILL BE LAST TO
ARRIVE IN NORTH CENTRAL AND NORTHEAST WY WHERE MORE SOLAR
INSULATION WILL TAKE PLACE THROUGH THE LATER AFTERNOON HOURS FOR
FEWER...LATER BUT STRONGER THUNDERSTORMS AS THE TROUGHINESS
CONTINUES TO EXTEND NORTHEAST. TEMPS WILL WARM UP TO MORE SEASONAL
LEVELS BY FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE
SLOWLY EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL
WYOMING WITH SOUTHWEST FLOW ALOFT OVER THE AREA. THE AIRMASS WILL
BE UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN
MOUNTAINS AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE
EVENING. SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL
LINGER INTO SATURDAY MORNING. A CANADIAN COLD FRONT WILL SLIDE
SOUTH THROUGH MUCH OF THE ARA ON SATURDAY AS THE UPPER LOW DRIFTS
SLOWLY EAST OVER THE COLD FRONT. SHOWERS WILL BE WIDESPREAD ACROSS
THE AREA WITH COOL TEMPERATURES. ENOUGH INSTABILITY WILL BE OVER
THE AREA SATURDAY AFTERNOON AND EVENING TO SUPPORT ISOLATED
THUNDERSTORMS WITH SMALL HAIL. SNOW LEVELS WILL LOWER THROUGH
SATURDAY NIGHT DOWN TO AROUND 8000 FEET. SUNDAY WILL BE COOL AND
REMAINING SHOWERY WITH A FEW ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO THE EAST AS ANOTHER
INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL DECREASE THROUGH
SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING OVER THE
WESTERN MOUNTAINS. LESS MOISTURE WILL BE OVER THE AREA ON MONDAY
BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS. MONDAY NIGHT WILL SEE A
SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH
WILL SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY
AND TUESDAY NIGHT WITH MORE SHOWERS... ESPECIALLY OVER THE WESTERN
AND NORTHERN MOUNTAINS. TEMPERATURES SHOULD BE SLIGHTLY WARMER.
THE TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE
NORTH AND EAST ACROSS THE AREA WITH INCREASING SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING. THE TROUGH
WILL BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN
COLD FRONT MOVES SOUTH BRINGING GENERAL COOLING.


&&

.AVIATION.../06Z ISSUANCE/

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

CONDITIONS THROUGH 21Z/FRI WILL BE VFR AT ALL TERMINALS. SHORTWAVE
ENERGY WILL ROTATE NORTH AHEAD OF MORE IMPRESSIVE SHORTWAVE OVER
NORTHERN NEW MEXICO. EXPECT THAT SHOWERS OVER THE BIG HORN BASIN
WILL DISSIPATE LATE TONIGHT WHILE KRIW AND KLND COULD SEE ISOLATED
WEAK CONVECTION THROUGH THE OVERNIGHT HOURS. ENERGY WITH THE MORE
VIGOROUS SHORTWAVE WILL REACH CENTRAL WYOMING IN THE 20Z-22Z/FRI
TIMEFRAME. THE EVOLUTION MAY BE VERY SIMILAR TO THURSDAY. APPEARS
THERE COULD BE A LITTLE MORE INSTABILITY TO GENERATE AT LEAST
SHOWERS AT KCPR...WHEREAS STABLE AIR LIMITED THAT THURSDAY. 700MB
LOW SHOULD BE ALONG THE WESTERN WYOMING BORDER BY 00Z/SAT. PLENTY OF
ENERGY AND MOISTURE AVAILABLE TO KEEP SHOWERS AND ISOLATED
THUNDERSTORMS GOING THROUGH 06Z/SAT. HAVE KEPT VCSH AT MANY
TERMINALS BUT COULD SEE MORE DEFINITIVE PERIOD OF PREVAILING -SHRA
BETWEEN 00Z-06Z/SAT. THERE COULD ALSO BE SOME AID FROM THE LEFT EXIT
REGION OF THE JET DURING THAT SPAN. MOUNTAIN TOP OBSCURATIONS WILL
BE WIDESPREAD ABOVE ABOUT 9K-10K MSL THROUGHOUT MUCH OF THE FORECAST
PERIOD...ESPECIALLY ALONG THE WIND RIVER RANGE AND THE SOUTHERN
PORTIONS OF THE ABSAROKA AND BIGHORN RANGES.

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

YET MORE SHORTWAVE ENERGY ROTATING NORTH TONIGHT. CLOUD TOPS ARE
ALREADY COOLING AHEAD OF VIGOROUS SHORTWAVE OVER NORTHERN NEW MEXICO
PER IR IMAGERY. CONVECTION IS LIKELY TO CONTINUE THROUGH THE
NIGHT...WITH VFR CONDITIONS LARGELY THE RULE. COULD SEE SOME
LOCALIZED MVFR WITH THE STRONGER CONVECTION AND IN THE GREEN RIVER
VALLEY AROUND KBPI AND KPNA. NEW MEXICO SHORTWAVE WILL LIFT NORTH
DURING THE DAY AS LARGER UPPER LOW TO THE WEST MOVES FARTHER INLAND.
CONVECTION MAY AGAIN ORIENT WEST-EAST ACROSS FAR SOUTHERN WYOMING BY
18Z/FRI. SIMILAR TO THURSDAY...THIS AREA OF CONVECTION WILL LIFT
NORTH THROUGH 00Z/SAT. THEREFORE...HAVE VCTS BY 19Z/FRI AT KRKS AND
BY 21Z/FRI AT KBPI...KPNA...AND KJAC. CERTAINLY COULD BE A FAIRLY
STEADY PERIOD OF RAIN...ESPECIALLY AT KBPI AND KPNA...DURING THE
LATE AFTERNOON HOURS FRIDAY. MOUNTAIN TOP OBSCURATIONS WILL BE
COMMON THROUGH THE FORECAST PERIOD WITH LOWERING CEILINGS AFTER
00Z/SAT.

&&

.FIRE WEATHER...

FIRE DANGER RELATIVELY LOW AS SEASONAL TO COOL AND RELATIVELY MOIST
CONDITIONS PERSIST. A WEAK UPPER LEVEL DISTURBANCE WILL BRING
ISOLATED CONVECTION MAINLY WEST OF THE DIVIDE FOR THE REST OF THIS
AFTERNOON AND EVENING. DEEPER MOISTURE WILL MOVE TOWARD THE AREA
FOR FRIDAY AND BRING ANOTHER CHANCE OF A WETTING RAIN FROM FRIDAY
INTO FRIDAY NIGHT. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS THAT WILL PERSIST INTO SATURDAY AS WELL. SNOW LEVELS
WILL DROP TO 8000 FEET LATE SATURDAY NIGHT AND SUNDAY MORNING.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...C.BAKER
AVIATION...CNJ
FIRE WEATHER...LIPSON












000
FXUS65 KRIW 220530
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1130 PM MDT THU MAY 21 2015

.SHORT TERM...TONIGHT THROUGH FRIDAY

AREAS OF LOW CLOUDS AND FOG HAVE LIFTED INTO A LOW CUMULUS CLOUD
DECK BETWEEN 3 AND 4K AS ABUNDANT GROUND MOISTURE CONTINUES TO
CONTRIBUTE TO THE LOWER AIRMASS AS TEMPS AND CORRESPONDING LCLS
RISE. THE STUBBORN HIGH IN WESTERN CANADA HAS DIVERTED ANOTHER
CLOSED LOW SOUTH TO OFF THE CALIFORNIA COAST. THE CIRCULATION
AROUND THIS LOW IS ARRIVING AS A SOUTH SOUTHWEST DIFLUENT FLOW
ACROSS WYOMING OUT AHEAD OF IT. SCATTERED THUNDERSTORMS UNDERNEATH
THIS FLOW HAVE ERUPTED ACROSS YELLOWSTONE PARK/ABSAROKAS AS WELL AS
ACROSS SOUTHWEST WY WHERE A SHORTWAVE/VORT LOBE IS TRACKING NORTH
NORTHEAST WITHIN THE SSW DIFLUENT FLOW IN SOUTHERN WY. WITH THE
RELATIVELY LOW LCL AND LOW WET BULB ZERO...MANY OF THESE CELLS
COULD PRODUCE LOCALLY HEAVY RAINFALL AND SMALL HAIL. AS THIS
SHORTWAVE TRACKS NNE...THE TREND WILL BE FOR MORE STORM CELLS TO
DEVELOP ACROSS THE REST OF NORTHERN AND ALSO CENTRAL AND EASTERN
PORTIONS OF THE CWA. TONIGHT THE LOW CENTER WILL TRACK EAST ACROSS
SOUTHERN CALIFORNIA ALONG WITH A WEAK TROUGH EXTENDING NORTHEAST
FROM THE LOW NORTHEAST INTO WYOMING. WITH THE TROUGHINESS OVHD
FRIDAY...EXPECT NUMEROUS SHOWERS TO DEVELOP ACROSS CENTRAL AND
SOUTHERN WY FRIDAY BY LATE MORNING. THE STORMS WILL BE LAST TO
ARRIVE IN NORTH CENTRAL AND NORTHEAST WY WHERE MORE SOLAR
INSULATION WILL TAKE PLACE THROUGH THE LATER AFTERNOON HOURS FOR
FEWER...LATER BUT STRONGER THUNDERSTORMS AS THE TROUGHINESS
CONTINUES TO EXTEND NORTHEAST. TEMPS WILL WARM UP TO MORE SEASONAL
LEVELS BY FRIDAY.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

A PACIFIC LOW PRESSURE TROUGH OVER THE GREAT BASIN WILL MOVE
SLOWLY EAST SPREADING PACIFIC MOISTURE INTO WESTERN AND CENTRAL
WYOMING WITH SOUTHWEST FLOW ALOFT OVER THE AREA. THE AIRMASS WILL
BE UNSTABLE WITH SHOWERS...RATHER WIDESPREAD OVER THE WESTERN
MOUNTAINS AND ISOLATED THUNDERSTORMS PASSING THROUGH DURING THE
EVENING. SHOWERS WITH SOME SNOW IN THE HIGHER MOUNTAINS WILL
LINGER INTO SATURDAY MORNING. A CANADIAN COLD FRONT WILL SLIDE
SOUTH THROUGH MUCH OF THE ARA ON SATURDAY AS THE UPPER LOW DRIFTS
SLOWLY EAST OVER THE COLD FRONT. SHOWERS WILL BE WIDESPREAD ACROSS
THE AREA WITH COOL TEMPERATURES. ENOUGH INSTABILITY WILL BE OVER
THE AREA SATURDAY AFTERNOON AND EVENING TO SUPPORT ISOLATED
THUNDERSTORMS WITH SMALL HAIL. SNOW LEVELS WILL LOWER THROUGH
SATURDAY NIGHT DOWN TO AROUND 8000 FEET. SUNDAY WILL BE COOL AND
REMAINING SHOWERY WITH A FEW ISOLATED AFTERNOON AND EVENING
THUNDERSTORMS AS THE UPPER LEVEL LOW EXITS TO THE EAST AS ANOTHER
INTENSIFIES OVER THE GREAT BASIN. SHOWERS WILL DECREASE THROUGH
SUNDAY NIGHT AND MONDAY MORNING WITH SOME LINGERING OVER THE
WESTERN MOUNTAINS. LESS MOISTURE WILL BE OVER THE AREA ON MONDAY
BUT SCATTERED MOUNTAIN SHOWERS CAN BE EXPECTED AGAIN WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS. MONDAY NIGHT WILL SEE A
SIGNIFICANT DECREASE IN SHOWERS BUT SOME WILL LINGER OVER THE
WESTERN MOUNTAINS INTO TUESDAY MORNING. THE GREAT BASIN TROUGH
WILL SPREAD INCREASING MOISTURE INTO THE SOUTH AND WEST TUESDAY
AND TUESDAY NIGHT WITH MORE SHOWERS... ESPECIALLY OVER THE WESTERN
AND NORTHERN MOUNTAINS. TEMPERATURES SHOULD BE SLIGHTLY WARMER.
THE TROUGH WILL REMAIN TO THE WEST SPREADING PACIFIC MOISTURE
NORTH AND EAST ACROSS THE AREA WITH INCREASING SHOWERS AND
ISOLATED THUNDERSTORMS WEDNESDAY AND WEDNESDAY EVENING. THE TROUGH
WILL BEGIN MOVING EAST OVER THE AREA AGAIN AS ANOTHER CANADIAN
COLD FRONT MOVES SOUTH BRINGING GENERAL COOLING.


&&

.AVIATION.../06Z ISSUANCE/

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

CONDITIONS THROUGH 21Z/FRI WILL BE VFR AT ALL TERMINALS. SHORTWAVE
ENERGY WILL ROTATE NORTH AHEAD OF MORE IMPRESSIVE SHORTWAVE OVER
NORTHERN NEW MEXICO. EXPECT THAT SHOWERS OVER THE BIG HORN BASIN
WILL DISSIPATE LATE TONIGHT WHILE KRIW AND KLND COULD SEE ISOLATED
WEAK CONVECTION THROUGH THE OVERNIGHT HOURS. ENERGY WITH THE MORE
VIGOROUS SHORTWAVE WILL REACH CENTRAL WYOMING IN THE 20Z-22Z/FRI
TIMEFRAME. THE EVOLUTION MAY BE VERY SIMILAR TO THURSDAY. APPEARS
THERE COULD BE A LITTLE MORE INSTABILITY TO GENERATE AT LEAST
SHOWERS AT KCPR...WHEREAS STABLE AIR LIMITED THAT THURSDAY. 700MB
LOW SHOULD BE ALONG THE WESTERN WYOMING BORDER BY 00Z/SAT. PLENTY OF
ENERGY AND MOISTURE AVAILABLE TO KEEP SHOWERS AND ISOLATED
THUNDERSTORMS GOING THROUGH 06Z/SAT. HAVE KEPT VCSH AT MANY
TERMINALS BUT COULD SEE MORE DEFINITIVE PERIOD OF PREVAILING -SHRA
BETWEEN 00Z-06Z/SAT. THERE COULD ALSO BE SOME AID FROM THE LEFT EXIT
REGION OF THE JET DURING THAT SPAN. MOUNTAIN TOP OBSCURATIONS WILL
BE WIDESPREAD ABOVE ABOUT 9K-10K MSL THROUGHOUT MUCH OF THE FORECAST
PERIOD...ESPECIALLY ALONG THE WIND RIVER RANGE AND THE SOUTHERN
PORTIONS OF THE ABSAROKA AND BIGHORN RANGES.

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

YET MORE SHORTWAVE ENERGY ROTATING NORTH TONIGHT. CLOUD TOPS ARE
ALREADY COOLING AHEAD OF VIGOROUS SHORTWAVE OVER NORTHERN NEW MEXICO
PER IR IMAGERY. CONVECTION IS LIKELY TO CONTINUE THROUGH THE
NIGHT...WITH VFR CONDITIONS LARGELY THE RULE. COULD SEE SOME
LOCALIZED MVFR WITH THE STRONGER CONVECTION AND IN THE GREEN RIVER
VALLEY AROUND KBPI AND KPNA. NEW MEXICO SHORTWAVE WILL LIFT NORTH
DURING THE DAY AS LARGER UPPER LOW TO THE WEST MOVES FARTHER INLAND.
CONVECTION MAY AGAIN ORIENT WEST-EAST ACROSS FAR SOUTHERN WYOMING BY
18Z/FRI. SIMILAR TO THURSDAY...THIS AREA OF CONVECTION WILL LIFT
NORTH THROUGH 00Z/SAT. THEREFORE...HAVE VCTS BY 19Z/FRI AT KRKS AND
BY 21Z/FRI AT KBPI...KPNA...AND KJAC. CERTAINLY COULD BE A FAIRLY
STEADY PERIOD OF RAIN...ESPECIALLY AT KBPI AND KPNA...DURING THE
LATE AFTERNOON HOURS FRIDAY. MOUNTAIN TOP OBSCURATIONS WILL BE
COMMON THROUGH THE FORECAST PERIOD WITH LOWERING CEILINGS AFTER
00Z/SAT.

&&

.FIRE WEATHER...

FIRE DANGER RELATIVELY LOW AS SEASONAL TO COOL AND RELATIVELY MOIST
CONDITIONS PERSIST. A WEAK UPPER LEVEL DISTURBANCE WILL BRING
ISOLATED CONVECTION MAINLY WEST OF THE DIVIDE FOR THE REST OF THIS
AFTERNOON AND EVENING. DEEPER MOISTURE WILL MOVE TOWARD THE AREA
FOR FRIDAY AND BRING ANOTHER CHANCE OF A WETTING RAIN FROM FRIDAY
INTO FRIDAY NIGHT. THERE WILL BE A CHANCE OF SHOWERS AND
THUNDERSTORMS THAT WILL PERSIST INTO SATURDAY AS WELL. SNOW LEVELS
WILL DROP TO 8000 FEET LATE SATURDAY NIGHT AND SUNDAY MORNING.

&&

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

$$

SHORT TERM...LIPSON
LONG TERM...C.BAKER
AVIATION...CNJ
FIRE WEATHER...LIPSON











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