315
FXUS65 KRIW 281012
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
412 AM MDT SAT MAR 28 2026
KEY MESSAGES
- CRITICAL FIRE WEATHER CONDITIONS TODAY THROUGH MONDAY AS
TEMPERATURES RISE WELL ABOVE NORMAL ONCE AGAIN.
- RED FLAG WARNINGS AND FIRE WEATHER WATCHES ARE IN EFFECT FOR
THIS WEEKEND INTO MONDAY. THERE IS A CHANCE THE TIMING FOR THE
CURRENT WATCHES FOR MONDAY WILL BE SHIFTED TO START ON SUNDAY.
- WINDS WILL BE STRONGER MONDAY AHEAD OF A COLD FRONT. THERE IS
A 70-90% CHANCE FOR GUSTS OVER 50 MPH EAST OF THE DIVIDE AND A
40-60% CHANCE FOR GUSTS OVER 60 MPH.
- A COLD FRONT WILL MOVE OVER THE AREA MONDAY NIGHT INTO TUESDAY
MORNING. CHANCES FOR LIGHT SNOW OVER THE WESTERN AND NORTHERN
MOUNTAINS, AND ACCUMULATIONS LESS THAN 0.5 INCHES IN THE LOWER
ELEVATIONS EAST OF THE DIVIDE.
- A WEATHER PATTERN CHANGE IS FINALLY EXPECTED TO OCCUR TOWARD
THE LATTER HALF OF NEXT WEEK, WITH CHANCES FOR PRECIPITATION
AND COOLER TEMPERATURES FAVORED.
DISCUSSION
ISSUED AT 140 AM MDT SAT MAR 28 2026
A BROAD FLAT RIDGE IS BEGINNING TO BUILD OVER THE REGION THIS
MORNING, INDICATIVE OF THE HIGH CLOUDS OVER THE NORTHERN ROCKIES AND
GREAT BASIN. THIS WILL RESULT IN A PERSISTENT WESTERLY FLOW ALOFT,
WHICH WILL ALSO LEAD TO A LEESIDE TROUGH OVER EASTERN PORTIONS OF
THE STATE. THIS WILL TIGHTEN THE SFC PRESSURE GRADIENT AND CAUSE
WESTERLY WINDS OF 25 TO 35 MPH OVER MUCH OF THE CWA TODAY AND
SUNDAY. MOST OF JOHNSON COUNTY AND EASTERN PORTIONS OF THE BIGHORN
BASIN WILL NOT BE AFFECTED BY THESE WINDS. HOWEVER, MODEL TRENDS
HAVE INCREASED THE WINDS IN THESE AREAS WITH GUSTS UP TO 30 MPH ON
SUNDAY. WILL HOLD OFF ON CHANGING THE TIMING OF THE FIRE WEATHER
WATCHES IN THESE AREAS FOR NOW AND LET THE DAY SHIFT TAKE ANOTHER
LOOK. ADDITIONALLY, RH VALUES WILL BE CRITICALLY LOW FOR MOST LOWER
ELEVATION ZONES SATURDAY AND SUNDAY. ABOVE NORMAL TO RECORD
TEMPERATURES WILL ALSO RETURN ACROSS THE AREA. CONDITIONS WILL BE
DRY TODAY, WITH A 30% CHANCE FOR VIRGA SHOWERS OVER SOUTHERN
PORTIONS OF SWEETWATER COUNTY FROM FLAMING GORGE TO WAMSUTTER AS A
WEAK SHORTWAVE OVER WESTERN UT MOVES OVER THE UT/WY/CO BORDER.
THESE DRY CONDITIONS RETURN FOR MONDAY AS WELL, WITH WINDS
INCREASING AND BECOMING MORE WIDESPREAD ACROSS THE CWA AS A TROUGH
AND ASSOCIATED COLD FRONT APPROACH FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION WILL INCREASE OVER NORTHWESTERN PORTIONS THROUGH THE
DAY MONDAY, WITH SNOW LEVELS BETWEEN 7000FT AND 8000FT. WINDS WILL
BE MUCH STRONGER ACROSS THE AREA AS WELL, WITH AREAS EAST OF THE
DIVIDE HAVING A 70-90% CHANCE OF GUSTS OVER 50 MPH; THERE IS A 40-
60% CHANCE OF GUSTS OVER 60 MPH, WITH CODY HAVING A LOCALLY HIGH
CHANCE OF 90%. IF GUSTS OF 60 MPH WERE TO OCCUR, THEY WOULD LIKELY
OCCUR LATE IN THE AFTERNOON BETWEEN 22Z (4PM) AND 00Z (6PM) WITH
PEAK HEATING AND THE PROXIMITY OF THE FRONT BEING THE MAJOR
CONTRIBUTORS.
CHANCES FOR PRECIPITATION MONDAY NIGHT WILL INITIALLY BE MAINLY
CONFINED TO WESTERN AND NORTHERN PORTIONS, SPREADING ACROSS AREAS
EAST OF THE DIVIDE THROUGH THE OVERNIGHT HOURS. THE TIMING OF THE
FRONT HAS SPED UP AND IS NOW PROGGED TO PASS THROUGH BUFFALO AND
KEMMERER BY 03Z TUESDAY. THE ASSOCIATED AIRMASS IS RATHER COLD,
WITH 700MB TEMPERATURES RANGING FROM MINUS 6C TO MINUS 11C ACROSS
THE NORTHERN HALF OF THE CWA BY 12Z TUESDAY. SNOWFALL ACCUMULATIONS
IN THE LOWER ELEVATIONS ARE NOT EXPECTED TO BE NOTEWORTHY AT THIS
TIME, WITH ACCUMULATIONS STAYING LESS THAN 0.5". THIS WILL BE DUE TO
THE UNSEASONABLY WARM CONDITIONS FOR THE NEXT 3 DAYS AHEAD OF THE
FRONT. HOWEVER, ANY SLIPPERY CONDITIONS WILL MELT AWAY AFTER 18Z
TUESDAY AS TEMPERATURES WARM AND CLOUDS CLEAR IN THE WAKE OF THE
SYSTEM. OTHERWISE, SNOWFALL AMOUNTS IN THE NORTHERN AND WESTERN
MOUNTAINS OF 2 TO 4 INCHES ARE STILL EXPECTED.
THERE IS A CHANCE FOR PRECIPITATION OVER THE SOUTHERN HALF OF THE
CWA WEDNESDAY, AS ANOTHER WEAK EMBEDDED SHORTWAVE MOVES OVER THE
GREAT BASIN. MODELS ARE STARTING TO COME INTO BETTER AGREEMENT WITH
THE NEXT STORM SYSTEM FROM THURSDAY INTO NEXT SATURDAY.
PRECIPITATION CHANCES OVER WESTERN PORTIONS BEGIN TO INCREASE BY
THURSDAY MORNING WITH A DIFLUENT FLOW PATTERN AS THE STORM BEGINS TO
DIG OVER THE GREAT BASIN THROUGH THURSDAY NIGHT. CONFIDENCE
CONTINUES TO FAVOR THE ECMWF SOLUTION, WHICH IS THE SLOWER SOLUTION
AND KEEPS SOUTHWEST FLOW ALOFT OVER THE COWBOY STATE FRIDAY AS A
RESULT OF BOTTOMING THE TROUGH OVER THE GREAT BASIN. THIS WOULD ALSO
SPREAD PRECIPITATION CHANCES ACROSS THE REST OF THE CWA. WILL
CONTINUE TO KEEP AN EYE ON THIS SYSTEM AS RUN-TO-RUN CONSISTENCY
REMAINS IN FAVOR FOR A COOLER AND WETTER PATTERN THURSDAY THROUGH
SATURDAY.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 408 AM MDT SAT MAR 28 2026
VFR CONDITIONS WILL CONTINUE THROUGH 12Z SUNDAY WITH ONLY AREAS
OF HIGH LEVELS CLOUDS PASSING THROUGH. WIND WILL BE STRONGER
THAN YESTERDAY, WITH WIND GUSTS TO 25 KNOTS POSSIBLE IN VICINITY
OF KCPR, KRKS, KPNA AND POSSIBLY KRIW AFTER 20Z. WIND SHOULD
DECREASE TONIGHT AT MOST TAF SITES AFTER SUNSET AROUND 02Z BUT
COULD REMAIN ELEVATED IN VICINITY OF KRIW WITH THE NORTHWEST
DRAINAGE WIND DEVELOPING.
FIRE WEATHER
ISSUED AT 140 AM MDT SAT MAR 28 2026
CRITICAL FIRE WEATHER CONDITIONS RETURN TODAY AND LAST THROUGH
MONDAY. WEST WINDS WITH GUSTS OF 30 TO 35 MPH WILL OCCUR FOR
MUCH OF THE FORECAST AREA SATURDAY AND SUNDAY, WITH CHANCES
INCREASING FOR GUSTS OVER 25 MPH TO OCCUR IN ZONES 275, 281 AND
282 STARTING SUNDAY. WILL HOLD OFF FROM CHANGING THE CURRENT
TIMING OF THE FIRE WEATHER WATCHES IN THESE ZONES FOR NOW. RH
RECOVERY WILL BE FAIR TO POOR TONIGHT AND SUNDAY NIGHT.
PRECIPITATION CHANCES WILL BE CONFINED TO FAR NORTHWESTERN
PORTIONS OF THE STATE DURING THE DAY MONDAY, WITH SNOW LEVELS
AROUND 7000FT TO 8000FT. THE FRONT WILL MOVE THROUGH THE AREA
MONDAY NIGHT INTO TUESDAY MORNING WITH SNOWFALL AMOUNTS LESS
THAN 0.5 INCHES POSSIBLE OVER LOWER ELEVATIONS AREAS EAST OF THE
DIVIDE.
RIW WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING FROM NOON TODAY TO 9 PM MDT MONDAY FOR
WYZ276>280-283-285-287-289-300.
FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH MONDAY
EVENING FOR WYZ275-281-282.
DISCUSSION...LAVOIE
AVIATION...HATTINGS
FIRE WEATHER...LAVOIE
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