463
FXUS65 KRIW 271628
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1028 AM MDT TUE MAY 27 2025
KEY MESSAGES
- AFTER NOON TODAY, SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP OVER THE MOUNTAINS, AND DRIFT SOUTHEASTWARD OVER THE
BASINS LATE THIS AFTERNOON AND EVENING.
- SEVERAL HIGH-RESOLUTION FORECAST MODELS SHOW TRAINING
THUNDERSTORMS OVER THE EASTERN FOOTHILLS OF THE BIGHORNS THIS
AFTERNOON, LEADING TO AN ISOLATED FLASH FLOODING CONCERN.
- NORTHERN AND CENTRAL WYOMING WILL SEE DRIZZLE AND RAIN SHOWERS
CONTINUE OVERNIGHT INTO WEDNESDAY MORNING. THE POWDER RIVER
BASIN LOOKS TO RECEIVE THE MOST RAIN WITH THIS QUICK-MOVING
WEATHER SYSTEM.
- WARMING TEMPERATURES CONTINUE TO LOOK LIKELY FOR THE END OF
THE WEEK, PUSHING 15 TO 20 DEGREES ABOVE AVERAGE BY THIS
WEEKEND.
DISCUSSION
ISSUED AT 251 AM MDT TUE MAY 27 2025
AFTER A BIT OF LULL IN THE CONVECTION YESTERDAY, THINGS WILL BECOME
MORE ACTIVE TODAY. THE MAIN PLAYERS IN THE WEATHER ARE AN UPPER
LEVEL LOW ROTATING ACROSS THE UPPER PLAINS STATES AND A SHORTWAVE
THAT WILL BE DROPPING SOUTHWARD INTO WYOMING TODAY. RADAR ALREADY
SHOWS A FEW SHOWERS OVER MONTANA THAT MAY DROP INTO NORTHERN WYOMING
EARLY THIS MORNING, BUT MOST OF THE ACTIVITY SHOULD HOLD OFF UNTIL
THE AFTERNOON AS THE WAVE DROPS ACROSS THE AREA. JUST ABOUT ALL
LOCATIONS WILL HAVE AT LEAST A 1 IN 5 CHANCE OF A SHOWER OR
THUNDERSTORM THIS AFTERNOON OR EVENING. THE BEST CHANCE WILL BE
FOUND ACROSS AREAS EAST OF THE DIVIDE. THIS EVENT MAY HAVE SOME
STAYING POWER, WITH THE HIGHEST CHANCES IN THE EVENING HOURS ACROSS
MANY AREAS AS THE WAVE AXIS PASSES THROUGH. THERE COULD BE A DECENT
AMOUNT OF RAIN WITH THESE, WITH SOME LOCATIONS, MAINLY EAST OF THE
DIVIDE, HAVING PRECIPITABLE WATERS 125 TO 150 PERCENT HIGHER THAN
NORMAL, FAR NORTHERN AREAS HAVE AROUND A 1 IN 3 CHANCE OF A QUARTER
INCH OF QPF OR MORE. AS FOR STRONGER STORMS, THERE COULD BE A COUPLE
BUT THE CHANCE HAS DECREASED. THE MAIN THREATS WOULD BE THE USUAL
GUSTY WIND AND SMALL HAIL. THIS EVENT WILL CONTINUE INTO THE NIGHT
AS WELL, ALTHOUGH THE CHANCE OF THUNDER WILL DECREASE.
ANOTHER TROUGH AXIS ROTATING AROUND THE UPPER LEVEL LOW WILL CROSS
THE AREA ON WEDNESDAY AND BRING ANOTHER CHANCE OF SHOWERS. THE
CHANCE OF THUNDER DECREASES ON THIS DAY, WITH COOLER TEMPERATURES
AND CLOUD COVER LIMITING INSTABILITY. THE BEST CHANCE OF THUNDER MAY
SHIFT FURTHER WEST, WHERE THERE COULD BE MORE SUNSHINE. THE CHANCES
OF OVER A QUARTER INCH OF PRECIPITATION REMAIN SIMILAR, GENERALLY
AROUND 1 IN 4 TO 1 IN 3 WITH HIGHER CHANCES IN THE MOUNTAINS.
THE PATTERN WILL BEGIN TO TRANSITION ON THURSDAY AS THE UPPER LEVEL
LOW FINALLY GETS KICKED EASTWARD AND RIDGING BUILDS OVER THE
ROCKIES. THE RESULT WILL BE AN UPWARD TREND IN TEMPERATURES AND A
DOWNWARD TREND IN PRECIPITATION CHANCES. A COUPLE OF SHORTWAVES
MOVING BY TO THE NORTH MAY BRING A CHANCE OF A FEW DIURNAL SHOWERS
AND STORMS EACH DAY ON THURSDAY AND FRIDAY, MAINLY IN THE NORTH.
HOWEVER, MOST AREAS WILL NOT SEE ONE. TEMPERATURES SHOULD PEAK ON
SUNDAY, WHEN SOME OF THE LOWER ELEVATIONS EAST OF THE DIVIDE COULD
SEE THE FIRST 90 DEGREE HIGH TEMPERATURES OF THE YEAR. AND WITH THE
TEMPERATURES INCREASING, THIS WILL ENHANCE THE HIGHER ELEVATION
SNOWMELT AND LIKELY LEAD TO RISING CREEKS AND RIVERS AND POSSIBLE
SOME FLOODING CONCERNS, ESPECIALLY OVER THE WEEKEND. TO EARLY TO
PINPOINT PROBLEM AREAS, BUT WE WILL BE WATCHING IT CAREFULLY.
AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 500 AM MDT TUE MAY 27 2025
IFR CONDITIONS ONCE AGAIN THIS TUESDAY MORNING AT CPR WITH ALL
OTHER LOCATIONS VFR THROUGHOUT THE ENTIRETY OF THE PERIOD.
WINDS HAVE BEEN NON-EXISTENT AT CPR, ALLOWING FOR LOW STRATUS
AND FOG DEVELOPMENT. HOWEVER, AS HAS BEEN THE CASE, BY 14Z, THIS
SHOULD LIFT WITH DAYTIME HEATING AND MIXING TO THE SURFACE. ALL
LOCATIONS WILL REMAIN UNDER 10-15KTS THROUGH THE AFTERNOON
OUTSIDE OF ANY STORM ACTIVITY. ALL BUT JAC ARE EXPECTED TO HAVE
A CHANCE FOR STORMS, INCLUDING A PROB30 GROUP TO INDICATE THE
SPORADIC CHANCES BETWEEN 20-05Z, EARLIEST WEST OF THE DIVIDE
AND LATEST FOR CPR. MID LEVEL CEILINGS BEHIND THE STORM
ACTIVITY THROUGH THE OVERNIGHT AND INTO WEDNESDAY MORNING.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HATTINGS
AVIATION...LOWE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page