790
FXUS65 KRIW 280642
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1242 AM MDT THU MAY 28 2026
KEY MESSAGES
- A WARM, BREEZY AND MAINLY DRY DAY TODAY WITH ANY SHOWERS AND
STORMS CONFINED TO IN AND AROUND THE NORTHERN MOUNTAINS.
- A WEATHER SYSTEM APPROACHES LATE FRIDAY INTO THE WEEKEND WITH
A GOOD CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS. THE
HEAVIEST LOOKS TO FALL IN WESTERN WYOMING, BUT EXACT AMOUNTS
ARE STILL UNCERTAIN.
- ELEVATIONS ABOVE 9000 FEET MAY SEE ACCUMULATING SNOW OVER THE
WEEKEND.
DISCUSSION
ISSUED AT 1238 AM MDT THU MAY 28 2026
WE CONTINUE TO HAVE THE TWO MAIN PLAYERS IN OUR WEATHER THIS
MORNING. IN THE RIGHT (EAST) WE HAVE A RIDGE OVER THE PLAINS STATES.
AND IN THE LEFT (WEST) CORNER WE HAVE A BOWLING BALL, AKA A CLOSED
LOW THAT HAS BEEN CUT OFF FOR A FEW DAYS OVER CALIFORNIA AND NEVADA,
JUST MEANDERING A BIT FROM TIME TO TIME. THE TREND FOR DAILY
CONVECTION HAS BEEN DOWNWARD. THE WITH HEIGHTS CONTINUING TO BUILD,
IT WILL LIKELY REACH A MINIMUM TODAY. MUCH DRIER AIR WILL CONTINUE
TO MOVE EASTWARD, WITH BELOW A HALF AN INCH OR PRECIPITABLE WATER
COVERING MOST OF WESTERN AND CENTRAL WYOMING BY LATER THIS
AFTERNOON. ANY THUNDERSTORMS WOULD BE LIMITED TO FAR NORTHERN AND
NORTHEASTERN AREAS. THERE COULD BE A COUPLE NEAR THE ABSAROKAS AND
BIG HORNS WHERE SOME WEAK UPSLOPE OR HIGH LEVEL HEAT SOURCE MAY
BRING SOMETHING BUT EVEN HERE THE CHANCE IS LESS THAN 1 OUT OF 5.
THE MAIN STORY TODAY WILL BE THE WARM TEMPERATURES, WITH SOME OF THE
WARMER AREAS, LIKE THE BIGHORN BASIN, HAVING SOME AREAS THAT ECLIPSE
THE 90 DEGREE MARK THIS AFTERNOON. THERE WILL ALSO STILL BE A BIT OF
A BREEZE TODAY, BUT SOMEWHAT LIGHTER THAN YESTERDAY. AREAS IN
NORTHERN JOHNSON COUNTY STILL HAVE AROUND A 1 IN 2 CHANCE OF GUSTS
OVER 35 MPH AT TIMES THIS AFTERNOON THOUGH. ANY CONVECTION SHOULD
END FAIRLY QUICKLY THIS EVENING, WITH DRY WEATHER AFTER MIDNIGHT.
THINGS SHOULD FINALLY START MOVING ON FRIDAY AS THE RIDGE WEAKENS
AND SHIFTS A BIT EAST AND THE LOW BEGINS TO MOVE. FLOW WILL TURN
MORE TO THE SOUTHEAST THROUGH THE DAY AND INCREASE MOISTURE INTO THE
AREA. IT WILL TAKE A WHILE FOR THE ATMOSPHERE TO MOISTEN THOUGH. AS
A RESULT, MOST OF THE DAY SHOULD BE WARM AND DRY WITH ANY CONVECTION
HOLDING OFF UNTIL MID TO LATE AFTERNOON. TEMPERATURES SHOULD RUN
FAIRLY SIMILAR TO TODAY'S HIGHS.
IT IS LOOKING MORE AND MORE LIKELY THAT AT LEAST PORTIONS OF THE
AREA WILL SEE A DECENT AMOUNT OF PRECIPITATION OVER THE WEEKEND.
WHERE IT FALLS DEPENDS UPON WHERE THE LOW EVENTUALLY TRACKS AND BOTH
THE ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO HAVE DIFFERENT
SOLUTIONS. A FURTHER WEST TRACK, LIKE SOME ENSEMBLE MEMBERS AS WELL
AS THE GFS HAVE, WOULD KEEP THE HEAVIER PRECIPITATION OVER WESTERN
WYOMING. AREAS FURTHER EAST WOULD HAVE A DOWNSLOPING FLOW AND
THEREFORE LESS PRECIPITATION. IF THE LOW IS FURTHER EAST, DECENT
PRECIPITATION WOULD BE SPREAD MORE THROUGHOUT THE AREA. THE WEATHER
PREDICTION CENTER DOES HAVE NORTHERN PORTIONS OF THE AREA IN A
MARGINAL RISK OF EXCESSIVE RAINFALL AS WELL FOR BOTH SATURDAY AND
POSSIBLY SUNDAY AS THE LOW MAY SLOW DOWN AND LINGER CLOSE TO THE
AREA, BUT AGAIN THERE ARE SOLUTIONS ON BOTH SIDES OF THIS EQUATION.
AS FOR PRECIPITATION AMOUNTS, WE WILL TURN TO THE REALM OF THE
ENSEMBLES TO TRY TO ANSWER THIS QUESTION. THE NATIONAL BLEND OF
MODELS GIVES A GREATER THAN 1 IN 2 CHANCE OF A QUARTER OF AN INCH OF
QPF THROUGH MONDAY MORNING ROUGHLY NORTH AND WEST OF A ROCK SPRINGS
TO RIVERTON AND BUFFALO LINE. MUCH NORTHWESTERN WYOMING, INCLUDING
YELLOWSTONE PARK, THE ABSAROKAS AND TETONS HAVE A GREATER THAN 1 IN
2 CHANCE OF AN INCH O QPF OR MORE. STILL SOME UNCERTAINTY FOR EXACT
PLACEMENT, BUT THE CHANCE IS DEFINITELY THERE.
AND THEN WE HAVE TO TAKE A LOOK AT THE POSSIBILITY OF THE "S" WORD,
SNOW. YES, THERE COULD BE SOME SNOW WITH THIS SYSTEM. IT WILL NOT
OCCUR IN THE VALLEYS. HOWEVER, WE ARE GETTING INTO THE TIME OF YEAR
WHEN MOUNTAIN RECREATION INCREASES SUBSTANTIALLY WE HAVE TO LOOK AT
IT. THE GFS GIVES 700 MILLIBAR TEMPERATURES FALLING AS LOW AS MINUS
1, WHICH WOULD PUT SNOW LEVELS AROUND 8000 FEET. THIS MAY BE A BIT
LOW, IT LIKELY CLOSER TO 8500 OR 9000 FEET. HOWEVER, THERE COULD BE
SOME ACCUMULATION. THE NATIONAL BLEND OF MODELS GIVES A GREATER THAN
1 IN 2 CHANCE OF 3 INCHES OF SNOW ABOVE 10000 FEET THROUGH MONDAY
MORNING. SOME OF HIGHEST PEAKS IN THE WIND RIVER RANGE AND TETONS
COULD SEE 6 INCHES OR MORE OF SNOW FROM THIS. IT DOESN'T LOOK TO
IMPACT TRAVEL TO SUBSTANTIALLY SINCE ROADS ARE VERY WARM RIGHT NOW.
HOWEVER, IF YOU ARE TRAVELING OVER MOUNTAIN PASSES, DON'T BE
SURPRISED IF YOU SEE SOME SNOW THIS WEEKEND, ESPECIALLY OVER THE
HIGHER ONES LIKE TOGWOTEE PASS WHICH IS CLOSE TO 10000 FEET IN
ELEVATION.
FOLLOWING THIS, DRIER WEATHER LOOKS TO RETURN TO THE AREA AND FLOW
BECOMES MORE ZONAL WITH FLAT RIDGING BRING DRIER WEATHER AND
TEMPERATURES RETURNING TO MUCH OF THE AREA FOR THE START OF NEXT
WEEK.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1010 PM MDT WED MAY 27 2026
VFR CONDITIONS EXPECTED THROUGHOUT THE TAF PERIOD. SCT-BKN
FL150-250 CLOUDS WILL CONTINUE TO STREAM NORTHWARD FROM THE
SOUTH-SOUTHEAST DURING THIS TIME AS WELL. CONVECTION WILL BE
VERY ISOLATED THURSDAY AFTERNOON, WITH KCPR AND KCOD HAVING THE
HIGHEST CHANCES FOR ANYTHING IN THE VICINITY. PROB30 GROUPS
REMAIN IN THE FORECAST FOR THE AFTERNOON AND ENDING AROUND
00Z/01Z. WIND GUSTS BETWEEN 20 AND 30KT WILL OCCUR AS RESULT
EITHER AS WINDS MIXING TO THE SFC OR OUTFLOW BOUNDARIES. THE
LATTER WILL IMPACT TERMINALS EAST OF THE DIVIDE AFTER 02Z, LIKE
KRIW AND KWRL.
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...LAVOIE/LOWE
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