491
FXUS65 KRIW 212254
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
454 PM MDT SAT MAR 21 2026
KEY MESSAGES
- A COMBINATION OF VERY LOW HUMIDITY, GUSTY WINDS, AND RECORD
HIGH TEMPERATURES WILL BRING ELEVATED TO CRITICAL FIRE WEATHER
TO MUCH OF THE AREA TODAY.
- A COLD FRONT WILL BRING A 30 TO 50 PERCENT CHANCE OF LIGHT
RAIN AND SNOW TO NORTHERN WYOMING THIS EVENING AND OVERNIGHT,
MAINLY ACROSS THE MOUNTAINS. DRY BUT COOLER CONDITIONS WILL
BE SEEN ELSEWHERE ON SUNDAY.
- TEMPERATURES TREND BACK UP EARLY NEXT WEEK, WITH LITTLE CHANCE
OF PRECIPITATION THROUGH AT LEAST MIDWEEK.
UPDATE
ISSUED AT 1225 PM MDT SAT MAR 21 2026
THE FORECAST REMAINS ON TRACK TODAY. WIND IS EXPECTED TO RAMP UP
OVER THE NEXT COUPLE OF HOURS AS THE UPPER JET DIPS INTO THE AREA
AND A SURFACE LOW DEVELOPS OVER EASTERN WYOMING. THIS WILL
EXACERBATE FIRE WEATHER CONDITIONS TODAY COMPARED TO THE PAST FEW
DAYS GIVEN THE STRONGER WIND AND STILL VERY DRY MIXED LAYER. THE
COLD FRONT MENTIONED BELOW WILL PUSH INTO FAR NORTHERN WYOMING
BETWEEN 4 PM AND 6 PM BRINGING A TRANSITION TO NORTHERLY WIND AS IT
PUSHES INTO CENTRAL WYOMING THIS EVENING. WIND WILL GENERALLY
DECREASE AFTER SUNSET, THOUGH THE INITIAL ARRIVAL OF THE FRONT
IS EXPECTED TO BRING BRIEF NORTHERLY GUSTS OF 25 TO 35 MPH TO
THE BIGHORN BASIN, JOHNSON COUNTY, AND NATRONA COUNTY. BRIEF
MOUNTAIN RAIN OR SNOW MAY ACCOMPANY THE FRONT THIS EVENING
ACROSS NORTHERN WYOMING, WITH THE BEST CHANCE FOR ANY LOWER
ELEVATION RAIN ACROSS NORTHERN JOHNSON COUNTY (20 TO 40 PERCENT
CHANCE OF AT LEAST A TRACE).
DISCUSSION
ISSUED AT 1252 AM MDT SAT MAR 21 2026
IT HAS CERTAINLY BEEN AN USUALLY WARM STRETCH OF WEATHER WE HAVE HAD
OVER THE PAST FEW DAYS, WITH NUMEROUS ALL TIME MARCH RECORD HIGH
TEMPERATURES BEING BROKEN. AND IT WILL BE MORE OF THE SAME TODAY
BEFORE SOMEWHAT COOLER AIR MOVES IN FOR SUNDAY. HOWEVER, THIS
PATTERN OF ABOVE NORMAL TEMPERATURES AND BELOW NORMAL PRECIPITATION
LOOKS TO CONTINUE THROUGH MUCH OF NEXT WEEK AS WELL, MUCH TO THE
CHAGRIN OF MANY, AS WE NEED RAIN BADLY.
TODAY WILL BE ANOTHER WARM DAY, WITH TEMPERATURES CLOSE TO OR EVEN A
BIT WARMER THAN YESTERDAY. THIS SHOULD BE THE LAST DAY OF WIDESPREAD
RECORD HIGH TEMPERATURES THOUGH AS A COLD FRONT WILL BE MOVING
THROUGH TONIGHT TO BRING SOME COOLER WEATHER. HOWEVER, IT WILL ALSO
BRING SOMETHING ELSE, WIND. AND THIS WIND SHOULD BE RATHER STRONG.
THE NBM ENSEMBLE GIVES AROUND A 2 OUT OF 5 CHANCE FOR WIND GUSTS
PAST 60 MPH IN THE CODY FOOTHILLS FOR EXAMPLE. AS FOR HIGH WIND,
THINGS LOOK BORDERLINE AT THIS TIME. WE DO HAVE A FEW 50 KNOT WIND
BARBS AT 700 MILLIBARS, BUT THESE ARE LARGELY NEAR THE ABSAROKAS IN
PLACES WHERE IMPACTS ARE SMALL. CLARK COULD HAVE SOME WIND GUSTS
OVER 60 MPH, BUT WARNING CRITERIA IS HIGHER HERE AS ARE A FEW
MESONET SITES NEAR THE ABSAROKAS. SO, WE WILL HOLD OFF ON ANY HIGH
WIND HIGHLIGHTS. ELSEWHERE, THE CHANCE IS GENERALLY LESS THAN 1 OUT
OF 3. ALMOST ALL AREAS HAVE AT LEAST A 4 OUT OF 5 CHANCE OF WIND
GUSTS PAST 40 MPH THROUGH, SO IT WILL A TOUPEE AND TRASH CAN ALERT
DAY FOR ALL AREAS. HOWEVER, THERE IS A GREATER CONCERN TODAY.
THAT IS FIRE WEATHER. WE HAVE HAD A RED FLAG WARNING FOR THE PAST
THREE DAYS AND THAT WILL CONTINUE TODAY. HOWEVER, TODAY LOOKS
ESPECIALLY CONCERNING. GUIDANCE HAS BEEN A BIT TOO HIGH WITH
RELATIVE HUMIDITY THE PAST FEW DAYS, SO WE HAVE HAD TO LOWER VALUES
AGAIN TODAY. SOME AREAS WILL SEE SINGLE DIGIT HUMIDITY THIS
AFTERNOON. THIS, COMBINED WITH THE VERY DAY FUELS, HIGH TEMPERATURES
30 DEGREES ABOVE NORMAL AND WIND GUSTING PAST 40 MPH, WILL BRING
AN ESPECIALLY IMPACTFUL FIRE WEATHER DAY. WITH THIS, WE HAVE
ADDED BIG HORN COUNTY TO THE RED FLAG WARNING. ALTHOUGH HUMIDITY
MAY BE BORDERLINE, THE INCREASING WIND AND HOT TEMPERATURES
MORE THAN WARRANT IT. PLEASE DO NOT DO ANY BURNING TODAY,
ESPECIALLY IN THE AFTERNOON.
THE AFOREMENTIONED COLD FRONT WILL MOVE TOWARD NORTHERN WYOMING
LATER THIS AFTERNOON, DROPPING SOUTHWARD ACROSS THE AREA THROUGH THE
NIGHT. IT WILL BE ACCOMPANIED BY WIND, ESPECIALLY IN THE NORTHWEST
FLOW AREAS LIKE THE BIGHORN BASIN AND JOHNSON COUNTY. UNFORTUNATELY,
IT WILL NOT BE ACCOMPANIED BY SOMETHING WE NEED VERY BADLY, A DECENT
AMOUNT OF PRECIPITATION. ANY PRECIPITATION WOULD LIKELY BE
RESTRICTED TO NORTHERN WYOMING, THERE THERE MAY BE JUST ENOUGH JET
FORCING TO SQUEEZE SOME RAIN AND MOUNTAIN SNOW OUT OF THE MEAGER
MOISTURE WITH THE FRONT. THE ONLY ARE WITH A 1 OUT OF 2 CHANCE OF A
TENTH OF AN INCH OF QPF IS THE WESTERN BIGHORN RANGE. AT MOST, THE
LOWER ELEVATIONS WOULD RECEIVE 0.05 INCHES WITH MOST LOCATIONS
SEEING NOTHING. THE CHANCE OF ANY RAIN SHOULD END BY AROUND NOON
ON SUNDAY.
TEMPERATURES WILL BE COOLER ON SUNDAY BEHIND THE FRONT, BUT STILL
ABOVE NORMAL FOR MOST LOCATIONS. THE LARGEST CONTRAST WILL BE ACROSS
NORTHERN WYOMING WHERE TEMPERATURES WILL BE 20 TO 25 DEGREES COOLER
THAN ON SATURDAY. THE DIFFERENCE THEN TAPERS OFF FURTHER SOUTH, WITH
ABOUT A 10 DEGREES DIFFERENCE IN SOUTHERN WYOMING. THERE COULD STILL
BE SOME FIRE WEATHER CONCERNS THOUGH. RELATIVE HUMIDITY WILL
REMAIN VERY LOW ACROSS SOUTHERN WYOMING, POSSIBLY FALLING INTO
THE SINGLE DIGITS AGAIN. WIND LOOKS BORDERLINE AT THIS TIME
THOUGH. SO, FOR NOW WE WILL NOT ISSUE ANY EXTENSION OF THE RED
FLAG WARNING AND WILL LET FUTURE SHIFTS TAKE A CLOSER LOOK.
TEMPERATURES WILL THEN BEGIN TO RISE AGAIN AS FLOW TURNS BACK TO
WEST TO SOUTHWEST WITH FLAT RIDGING OVER THE AREA. MONDAY WILL BE
WARMER, BUT THE REAL WARMER TEMPERATURES MOVE BACK IN FOR TUESDAY
AND WEDNESDAY, WITH SOME OF THE WARMER LOCATIONS TAKING A RUN AT 80
DEGREES ONCE AGAIN. THE GREATER CONCERN WILL BE FIRE WEATHER THOUGH.
A SUBTLE SHORT WAVE WILL APPROACH ON TUESDAY. IT COULD BRING A FEW
SHOWERS TO NORTHWESTERN WYOMING BUT THE BIGGER IMPACT WILL BE
INCREASING WIND. RELATIVE HUMIDITY LOOKS BORDERLINE ON THIS DAY
THOUGH. OF MUCH MORE CONCERN IS WEDNESDAY, WHEN A STRONGER COLD
FRONT MAY APPROACH, TIGHTENING THE PRESSURE GRADIENT EVEN MORE.
THE DEW POINTS ALSO LOOK TO BE AROUND 5 TO 10 DEGREES LESS,
BRINGING A FAIRLY LARGE AREA OF RELATIVE HUMIDITY UNDER 15
PERCENT. THIS IS ANOTHER DAY TO WATCH FOR CRITICAL FIRE WEATHER.
TEMPERATURES MAY COOL AGAIN BEHIND THE FRONT FOR THE END OF
NEXT WEEK, BUT STILL SOME UNCERTAINTY. SO, THE THEME OF THE NEXT
SEVEN DAYS CONTINUES TO BE ABOVE NORMAL TEMPERATURES, BELOW
NORMAL PRECIPITATION AND PERIODS OF ELEVATED TO CRITICAL FIRE
WEATHER.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 453 PM MDT SAT MAR 21 2026
THE GUSTY WINDS DECREASE THIS EVENING. A COLD FRONT THEN MOVES IN
FROM THE NORTH, SHIFTING WINDS TO BE FROM THE NORTH TO NORTHWEST
BEHIND IT. GREATEST WINDS SHIFTS OCCUR FOR LOCATIONS EAST OF THE
DIVIDE, LIKE KCOD, KCPR, AND KWRL, WITH LESSER IMPACTS TO KLND AND
KRIW. THIS FRONT LACKS MOISTURE, SO PRECIPITATION CHANCES ARE VERY
LIMITED. KCOD HAS THE BEST CHANCE (25%) TO SEE A LIGHT SHOWER FOR A
FEW HOURS AFTER THE FRONT. KJAC WOULD BE THE NEXT MOST LIKELY (15%)
BUT ANY SHOWERS LOOK TO REMAIN OVER THE MOUNTAINS. LOW TO MID-LEVEL
CLOUDS (1500 TO 5000 FEET AGL) COULD FILTER IN BEHIND THE FRONT AT
KCOD, KCPR, AND KWRL. CONFIDENCE IS SHAKY ON HOW EXPANSIVE THESE
CLOUDS MAY BE, SO HAVE KEPT CLOUD GROUPS VFR FOR NOW, BUT IT COULD
END UP BEING MVFR.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON ICING AND TURBULENCE FORECASTS.
FIRE WEATHER
ISSUED AT 1252 AM MDT SAT MAR 21 2026
A COMBINATION OF HUMIDITY FALLING TO AROUND 10 PERCENT, RECORD
WARM TEMPERATURES AND A STRONG WIND WITH GUSTS TO AROUND 50 MPH
WILL BRING ELEVATED TO CRITICAL FIRE WEATHER TO MUCH OF WESTERN
AND CENTRAL WYOMING. AT THIS TIME, THIS LOOKS LIKE THE MOST
CONCERNING DAY OF THE LAST FOUR. CONDITIONS SHOULD IMPROVE
SOMEWHAT ON SUNDAY AS THE PASSAGE OF A COLD FRONT BRINGS COOLER
TEMPERATURES AND SOMEWHAT LESS WIND BEHIND THE FRONT.
CLIMATE
ISSUED AT 1252 AM MDT SAT MAR 21 2026
ONCE AGAIN, WE WERE 9 OF 9 IN OUR OFFICIAL CLIMATE SITES FOR
DAILY RECORD HIGH TEMPERATURES, MAKING 26 OF 27 OVER THE LAST
THREE DAYS. A FEW OTHER NOTES, WORLAND MADE IT TO 85 DEGREES
YESTERDAY. THIS IS THE SECOND CONSECUTIVE DAY OF A MONTHLY
RECORD HIGH TEMPERATURE, AND EARLIEST OCCURRENCE OF 85 DEGREES
BY OVER 3 WEEKS (THE PREVIOUS WAS APRIL 15, 1962). GREYBULL ALSO
SET AN SECOND CONSECUTIVE DAY OF A MONTHLY RECORD HIGH
TEMPERATURE (84). AND FINALLY, BUFFALO SET AN ALL TIME MARCH
RECORD HIGH OF 80. THIS IS THE FIRST RECORDED MARCH HIGH OF 80
IN BUFFALO IN STATION HISTORY (SINCE 1998) AND EARLIEST BY 24
DAYS (APRIL 14, 2015 WAS THE PREVIOUS EARLIEST).
RIW WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR WYZ275>283-
287-289.
UPDATE...MYERS
DISCUSSION...HATTINGS
AVIATION...WITTMANN
FIRE WEATHER...HATTINGS
CLIMATE...HATTINGS
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