849
FXUS65 KRIW 281737
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1137 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 /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1136 AM MDT WED MAY 28 2025
WITH A SHORTWAVE TROUGH PASSAGE, A FEW WEAK RAIN SHOWERS CONTINUE
ACROSS PORTIONS OF CENTRAL WY. LITTLE TO NO IMPACTS ARE EXPECTED,
WITH PERHAPS ONLY FEW TO SCT DECKS AROUND FL015 TO FL035. THUS, VFR
CONDITIONS WILL PREVAIL THROUGH THE PERIOD FOR ALL TERMINALS. BEHIND
THESE LIGHT SHOWERS, SATELLITE INDICATES SOME CLEARING, WHICH WILL
KICK OFF SOME SHOWERS AND THUNDERSTORMS THAT WILL BE MORE CONVECTIVE
IN NATURE. THERE IS LITTLE CHANCES FOR DIRECT IMPACTS AT TERMINALS,
HOWEVER, ENOUGH CONFIDENCE TO INCLUDE A PROB30 FOR SEVERAL TERMINALS
DURING THE LATE AFTERNOON/EARLY EVENING. HI-RES MODELS HAVE BEEN
HAVING DIFFICULTY RESOLVING TIMING/LOCATIONS OF THESE SHOWERS AND
STORMS, SO CURRENT PROB30 GROUPS REFLECT THE 16Z MODEL GUIDANCE, AND
COULD CHANGE THROUGH THE AFTERNOON AS CAMS BECOME MORE IN LINE.
WINDS WILL GENERALLY BE LIGHT THROUGH THE PERIOD, EXCEPT IN
THUNDERSTORMS AND RESULTING OUTFLOWS. GUSTS 20 TO 30KTS ARE POSSIBLE
WITH ANY STORMS AND OUTFLOWS. WITH LIGHT WINDS AND AMPLE LOW-LEVEL
MOISTURE, FOG WILL BE A POSSIBILITY. MOST LIKELY CHANCES (30 TO 40%)
ARE AT KCPR, WITH LOW-LEVEL EASTERLY WINDS FILTERING MOISTURE AND
LOW CLOUDS IN FROM EASTERN WY AND INTO THE CASPER AREA. MODEL
GUIDANCE INDICATES THAT ANY FOG/LOW CLOUD IMPACTS SHOULD ONLY LAST A
FEW HOURS AROUND SUNRISE THURSDAY MORNING. HAVE INCLUDED A FEW005
GROUP TO HINT AT FOG/LOW CLOUD DEVELOPMENT FOR KCPR.
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...HENSLEY
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