474
FXUS65 KRIW 190839
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
239 AM MDT FRI JUN 19 2026
KEY MESSAGES
- WARM AND DRY CONDITIONS RETURN ACROSS THE FORECAST AREA TODAY.
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS WILL BE
CONCENTRATED FOR AREAS WEST OF THE DIVIDE DUE TO THE
COMBINATION OF WIND GUSTS UP TO 25 MPH AND HUMIDITY VALUES AS
LOW AS 8%.
- VERY ISOLATED VIRGA SHOWERS WILL ALSO BE POSSIBLE ACROSS THE
AREA THIS AFTERNOON AND EARLY EVENING. GUSTS OF 50 TO 60 MPH
COULD OCCUR FROM A PASSING SHOWER.
- AN APPROACHING DISTURBANCE LOOKS TO BRING WIDESPREAD CHANCES
FOR SHOWERS AND THUNDERSTORMS OVER THE WEEKEND. THE BEST
CHANCES FOR A WETTING RAIN REMAIN OVER THE NORTHERN HALF OF
THE FORECAST AREA.
- THE FIRST WEEK OF SUMMER IS LOOKING WARM WITH DAILY CHANCES
FOR SHOWERS AND THUNDERSTORMS.
DISCUSSION
ISSUED AT 230 AM MDT FRI JUN 19 2026
A RIDGE WILL BUILD OVER THE REGION FROM THE WEST TODAY, AS PACIFIC
MOISTURE BEGINS TO ENTER THE REGION. HIGHS THIS AFTERNOON WILL BE IN
THE 70S AND 80S, WITH READINGS APPROACHING THE 90 DEGREE MARK OVER
THE WESTERN HALF OF SWEETWATER COUNTY. WINDS WILL NOT BE AS STRONG
TODAY AS THE SFC PRESSURE GRADIENT LOOSENS AND THE RIDGE AXIS SHIFTS
OVER THE COWBOY STATE. WEST WINDS, WITH GUSTS UP TO 25 MPH, WILL
DEVELOP OVER AREAS WEST OF THE DIVIDE BY MID-AFTERNOON AND DECREASE
IN THE EVENING. AT THE SAME TIME, ANOTHER SURGE OF EASTERLY WINDS
WILL OCCUR OVER NATRONA COUNTY INTO THE WIND RIVER BASIN, WITH GUSTS
OF 25 TO 35 MPH OCCURRING THROUGH 08Z. ELEVATED TO CRITICAL FIRE
WEATHER CONDITIONS WILL ALSO RETURN ACROSS SOUTHERN PORTIONS OF THE
FORECAST AREA, DUE TO THE AFOREMENTIONED WINDS AND HUMIDITY VALUES
AS LOW AS 8%. VIRGA SHOWERS WILL BE POSSIBLE ACROSS THE CWA THROUGH
THE AFTERNOON INTO THE EARLY EVENING. BRIEF GUSTS OF 50 TO 60 MPH
COULD OCCUR FROM THESE SHOWERS, DUE TO THE LARGE DEWPOINT SPREADS
THAT WILL BE PRESENT. ANOTHER AREA OF VIRGA SHOWERS WILL DEVELOP
OVER FAR WESTERN PORTIONS AFTER 06Z SATURDAY, MOVING EAST OF THE
DIVIDE BY THE PREDAWN HOURS SATURDAY MORNING. THIS WILL BE A
PRECURSOR TO THE MORE WIDESPREAD CONVECTIVE ACTIVITY EXPECTED
DURING THE DAY SATURDAY.
CHANCES FOR PRECIPITATION RETURN FOR THE WEEKEND, AS A REMNANT
PACIFIC LOW MOVES OVER THE REGION. NORTHERN PORTIONS OF THE CWA
CONTINUE TO HAVE THE BEST CHANCES TO RECEIVE ANY PRECIPITATION, WITH
FORECASTED RAINFALL AMOUNTS TRENDING DOWNWARDS AGAIN (NO SURPRISE).
AMOUNTS ARE NOW IN THE 0.20" TO 0.40" RANGE SATURDAY THROUGH MONDAY,
WITH PORTIONS OF NATRONA COUNTY TRENDING ABOVE 0.10". LOCALLY HEAVY
RAIN REMAINS POSSIBLE FROM THESE STORMS, AS PRECIPITABLE WATER
VALUES OF 0.60" TO 1" ARE STILL FORECASTED. PRECIPITATION CHANCES
LINGER INTO MONDAY, AS A CANADIAN COLD FRONT MOVES OVER AREAS EAST
OF THE DIVIDE. DRY CONDITIONS RETURN TO THE REGION TUESDAY, AS A
STRONG AREA OF HIGH PRESSURE DEVELOPS OVER THE DESERT SOUTHWEST.
MODELS REMAIN SPLIT WHETHER SHORTWAVES WILL MOVE OVER THE
PACNW/NORTHERN ROCKIES FROM WEDNESDAY TO FRIDAY, KEEPING
PRECIPITATION CHANCES UP AND THE RIDGE SUPPRESSED TO THE SOUTH.
GIVEN THE LATEST CPC OUTLOOKS OF A 33% CHANCE FOR ABOVE NORMAL
PRECIPITATION, CONFIDENCE IS LOW TO MEDIUM AT THIS TIME.
AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 1028 PM MDT THU JUN 18 2026
VFR CONDITIONS CONTINUE AT ALL SITES THROUGH THE NEXT 24 HOURS.
HIGH CLOUDS WILL CONTINUE TO SPREAD ACROSS THE STATE THROUGH THE
NIGHT, WITH SOME THINNING FRIDAY MORNING. SOME MIDLEVEL CLOUDS
WILL MOVE INTO THE VICINITY OF KBYG OVERNIGHT, BUT SHOULD BE
HOLDING ABOVE 4000 FEET. HIGH CIRRUS VARIES THROUGH THE DAY,
BUT MOST LOWER CLOUD COVER WILL REMAIN AT A MINIMUM AND NON-
IMPACTFUL. WINDS WEST OF THE DIVIDE WILL REMAIN BREEZY FROM THE
WEST FRIDAY AFTERNOON, WITH KBPI/KPNA GUSTING NEAR 20KTS. WINDS
EAST OF THE DIVIDE WILL REMAIN LIGHT FROM THE EAST, WITH A FEW
GUSTS NEAR 20KTS AT KCPR AROUND 00Z/20.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC FOR
THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE
FORECASTS.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...LAVOIE
AVIATION...STRAUB
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