943
FXUS65 KRIW 181058
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
458 AM MDT THU JUN 18 2026
KEY MESSAGES
- TEMPERATURES GRADUALLY WARM TODAY INTO FRIDAY WITH LITTLE TO
NO CHANCE OF PRECIPITATION. CONTINUED DRY AND BREEZY
CONDITIONS WILL CONTRIBUTE TO ADDITIONAL FIRE WEATHER
CONCERNS.
- A SYSTEM WILL BRING SHOWERS AND THUNDERSTORMS TO AREAS ALONG
AND EAST OF THE CONTINENTAL DIVIDE BEGINNING SATURDAY
MORNING. THE BIGHORNS AND ABSAROKAS WILL BE MOST FAVORED FOR
RAIN.
DISCUSSION
ISSUED AT 214 AM MDT THU JUN 18 2026
A PLEASANT DAY IS ON TAP TODAY, WITH SEASONAL TEMPERATURES AND
MOSTLY SUNNY SKIES. THE ONE NEGATIVE ASPECT WILL BE NORTHWEST WINDS
GUSTING UP TO 30 MPH OVER AREAS WEST OF THE DIVIDE AFTER 18Z. FIRE
WEATHER CONDITIONS WILL CONTINUE TO BE ELEVATED TO CRITICAL THIS
AFTERNOON, WITH THE HIGHEST CONCERN BEING OVER SOUTHERN PORTIONS
WHERE THE AFOREMENTIONED WINDS WILL COMBINE WITH HUMIDITY VALUES AS
LOW AS 8%.
THE REST OF THE FORECAST REMAINS ON TRACK WITH LITTLE CHANGES FROM
PREVIOUS PACKAGES. A RIDGE WILL BUILD OVER THE REGION FROM THE WEST
FRIDAY, MARKING A RETURN FOR TEMPERATURES IN THE UPPER 80S TO NEAR
90 DEGREES. FIRE WEATHER CONDITIONS WILL CONTINUE TO BE ELEVATED TO
CRITICAL, WITH CRITICAL RH VALUES (<15%) OCCURRING ACROSS AREAS WEST
OF THE DIVIDE, INCLUDING THE WESTERN VALLEYS, AND CENTRAL PORTIONS
OF THE CWA. MID TO HIGH CLOUDS WILL BEGIN TO INCREASE, IN ADVANCE TO
THE INCOMING REMNANT PACIFIC LOW. THERE IS A 10% CHANCE FOR A VIRGA
SHOWER TO OCCUR UNDER THESE CLOUDS THROUGH THE AFTERNOON.
CHANCES FOR PRECIPITATION RETURN FOR THE WEEKEND, AS THE PACIFIC LOW
MOVE OVER THE REGION. NORTHERN PORTIONS OF THE CWA LOOK TO HAVE THE
BEST CHANCES TO RECEIVE ANY PRECIPITATION, WITH FORECASTED RAINFALL
AMOUNTS TRENDING DOWNWARD SLIGHTLY BETWEEN 0.25" TO 0.50" OVER
SATURDAY, SUNDAY AND MONDAY. LOCALLY HEAVY RAIN REMAINS POSSIBLE
FROM THESE STORMS, AS PRECIPITABLE WATER VALUES OF 0.60" TO 1" ARE
STILL FORECASTED. PRECIPITATION CHANCES COULD LINGER INTO MONDAY, AS
A CANADIAN COLD FRONT MOVES OVER THE AREA. DRY CONDITIONS RETURN TO
THE REGION TUESDAY, AS A STRONG AREA OF HIGH PRESSURE DEVELOPS OVER
THE DESERT SOUTHWEST. INITIAL INDICATIONS SUGGEST THAT SHORTWAVES
WILL MOVE OVER THE PACNW/NORTHERN ROCKIES FROM WEDNESDAY TO FRIDAY,
KEEPING PRECIPITATION CHANCES UP AND THE RIDGE SUPPRESSED TO THE
SOUTH.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 453 AM MDT THU JUN 18 2026
SKC SKIES ACROSS MUCH OF THE AREA, WITH CLOUDS CONTINUING TO
DECREASE OVER THE BIGHORNS AND JOHNSON COUNTY. WINDS WILL BE
LIGHT, WITH TERMINALS WEST OF THE DIVIDE GUSTING UP TO 25KT
AFTER 18Z. SIMILAR WINDS WILL IMPACT KRIW AND KLND AROUND 23Z.
NORTHERLY/NORTHEASTERLY WINDS WILL INCREASE AT KCOD AND KCPR
RESPECTIVELY AROUND 01Z/02Z, SUBSIDING AFTER 06Z. FEW-SCT
FL150-250 CLOUDS WILL INCREASE FROM THE WEST AFTER 22Z,
SPREADING EASTWARD ACROSS THE FORECAST AREA THROUGH THE REST OF
THE TAF PERIOD.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZDV AND ZLC
FOR THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE
FORECASTS.
FIRE WEATHER
ISSUED AT 214 AM MDT THU JUN 18 2026
ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS CONTINUE TODAY,
WITH CRITICAL RH VALUES ACROSS SOUTHERN ZONES, AS WELL AS ZONES
280 AND 283. WEST-NORTHWEST WINDS, WITH GUSTS UP TO 30 MPH WILL
BE CONFINED TO AREAS WEST OF THE DIVIDE IN THE AFTERNOON.
NORTHEASTERLY WINDS INCREASE OVER ZONES 280/281 AFTER 1900, WITH
GUSTS UP TO 30 MPH. THESE WINDS WILL SLOWLY DECREASE OVERNIGHT
TONIGHT, ENDING BY SUNRISE FRIDAY MORNING.
SIMILAR CONDITIONS RETURN FRIDAY, WITH WESTERLY WINDS GUSTING UP
TO 25 MPH BEING MAINLY CONFINED OVER AREAS WEST OF THE DIVIDE.
THERE WILL BE A 10% CHANCE FOR A VIRGA SHOWER ACROSS THE AREA
THROUGH THE AFTERNOON.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...LAVOIE
AVIATION...LAVOIE
FIRE WEATHER...LAVOIE
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