637
FXUS65 KRIW 280751
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
151 AM MDT WED MAY 28 2025
KEY MESSAGES
- ANOTHER UNSETTLED DAY TODAY WITH A SCATTERING OF SHOWERS AND
THUNDERSTORMS.
- DRIER AND WARMER TOMORROW.
- THE WARMEST WEATHER OF THE YEAR IS EXPECTED THIS WEEKEND,
ESPECIALLY ON SUNDAY.
DISCUSSION
ISSUED AT 150 AM MDT WED MAY 28 2025
SOME SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE ACROSS CENTRAL
WYOMING EARLY THIS MORNING. I TOOK A BRIEF BREAK TO GO OUTSIDE
EARLIER AND SAW A COUPLE OF THE MOST BEAUTIFUL DISPLAYS OF WEATHER,
AT LEAST IN MY OPINION. THOSE ARE NIGHTTIME CLOUD TO GROUND
LIGHTNING STRIKES, TO THE NORTH OF OUR OFFICE OVER THE OWL CREEK
RANGE. THIS WILL CONTINUE TODAY AS A TROUGH AXIS ROTATING AROUND A
LARGE UPPER LEVEL LOW LOCATED OVER THE WESTERN GREAT LAKES MOVES
THROUGH THE AREA, BRINGING ANOTHER DAY OF SCATTERED SHOWERS AND
THUNDERSTORMS, MAINLY TO AREAS EAST OF THE DIVIDE. THERE IS A BIT
LESS INSTABILITY TODAY, WITH AROUND 25 PERCENT LESS CAPE THAN
YESTERDAY AND LIFTED INDICES ONLY GO DOWN TO MINUS 1, LIKELY DUE
THE COOLER TEMPERATURES AND MORE CLOUD COVER. PRECIPITABLE WATER
LEVELS REMAIN AROUND 125 PERCENT ABOVE CLIMATOLOGICAL NORMALS
THOUGH, SO THERE COULD BE SOME LOCALLY HEAVY RAIN. WITH LOWER WET
BULB ZEROS, THERE COULD ALSO BE SOME SMALL HAIL. COVERAGE SHOULD BE
SMALLER THOUGH. AS FOR AMOUNTS, THE AREAS WITH THE GREATEST CHANCE
OF A QUARTER OF AN INCH OR RAIN OR MORE SHIFT INTO CENTRAL WYOMING,
WITH THE EASTERN SLOPES OF THE WIND RIVER RANGE AND THE SOUTH SIDE
OF CASPER HAVING AROUND A 1 IN 3 CHANCE. SHOWERS SHOULD WANE THIS
EVENING AND LARGELY END BY AROUND MIDNIGHT.
THINGS LOOK QUIETER FOR THURSDAY AS RIDGING BUILDS ACROSS THE STATE.
THERE WILL STILL BE A FEW SHOWERS AND THUNDERSTORMS AROUND, BUT
THESE WOULD BE OF THE DIURNAL VARIETY AND LARGELY RESTRICTED TO THE
MOUNTAINS AND ADJACENT FOOTHILLS, MAINLY IN THE WESTERN HALF OF THE
STATE. THE CHANCE IS ONLY AROUND 1 OUT OF 4 AT ANY GIVEN SPOT.
TEMPERATURES WILL WARM AS WELL, LIKELY RETURNING TO NEAR NORMAL
LEVELS.
THERE IS A NEW WRINKLE IN THE FORECAST FOR FRIDAY AS A SHORTWAVE
MOVES BY TO THE NORTH. THE MODELS DO HAVE SOME DIFFERENCES IN THE
DETAILS WITH THIS IN REGARDS TO POSSIBLE COVERAGE OF CONVECTION.
FOR NOW WE PLAYED THE MIDDLE GROUND WITH THE BEST CHANCE OF SHOWERS
AND STORMS ACROSS EASTERN PORTIONS OF THE AREA. IN ADDITION, IT
COULD BECOME RATHER WINDY AFTER THE PASSAGE IN THE FAVORED NORTHWEST
FLOW AREAS LIKE BUFFALO, BUT THE PRESSURE GRADIENT AND MID LEVEL
WINDS DO NOT SUPPORT HIGH WIND AT THIS TIME.
DRY WEATHER THEN RETURNS FOR SATURDAY AS WE TURN UP THE HEAT ACROSS
THE AREA. MANY AREAS WILL BE WELL INTO THE 80S. THE HEAT LOOKS TO
PEAK ON SUNDAY AS SOUTHWEST FLOW INCREASES AHEAD OF AN UPPER LEVEL
LOW. THIS COULD BE THE DAY WE SEE THE FIRST 90 DEGREE HIGH
TEMPERATURES ACROSS THE AREA IN THE WARMEST LOCATIONS. A FEW
THUNDERSTORMS WILL THEN BE POSSIBLE AS MOISTURE INCREASES ACROSS THE
WEST AHEAD OF THE UPPER LEVEL LOW. WE WILL THEN ENTER INTO A COOLER
AND WETTER PATTERN AS AN UPPER LEVEL LOW APPROACHES THE AREA,
BRINGING AN INCREASED CHANCE OF SHOWERS. DETAILS ARE IMPOSSIBLE TO
GIVE THIS FAR OUT, BUT THERE IS GREATER THAN A 1 IN 2 CHANCE OF
BELOW NORMAL TEMPERATURES AND ABOVE NORMAL PRECIPITATION FOR THE
FIRST PART OF NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 951 PM MDT TUE MAY 27 2025
ONGOING SHOWERS CONTINUE TO WANE LATE THIS EVENING, THOUGH KCPR WILL
BE FAVORED TO SEE LIGHT SHOWERS AT TIMES THROUGH THE EARLY MORNING
HOURS. THE NEXT SHORTWAVE ARRIVES OVERNIGHT, WHICH IS EXPECTED TO
BRING LIGHT RAIN TO MOST TERMINALS EAST OF THE DIVIDE AFTER 10Z.
KCPR, AGAIN, WILL BE MOST FAVORED DURING THIS TIME, AND WILL LIKELY
SEE MVFR CEILINGS THROUGH MOST OF WEDNESDAY MORNING. REMAINING
TERMINALS ARE EXPECTED TO PREVAIL VFR. THE UNSETTLED CONDITIONS
CONTINUE INTO THE AFTERNOON AS CONVECTION DEVELOPS AGAIN ACROSS THE
AREA. KCOD AND KWRL ARE LEAST LIKELY TO SEE THIS ACTIVITY, FOLLOWED
BY KRIW AND KJAC. OTHER TERMINALS NOW CARRY PROB30 GROUPS TO ACCOUNT
FOR THE POTENTIAL, AND AT LEAST KRIW AND KJAC MAY EVENTUALLY
NEED THIS ADDED AS WELL. THE MAIN CONCERN IS AGAIN GUSTY AND
VARIABLE OUTFLOW WIND. SHOWERS AND THUNDERSTORMS WILL WANE AFTER
SUNSET, LEAVING INCREASING OR CLEARING CEILINGS THROUGH THE END
OF THE PERIOD.
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...MYERS
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