584
FXUS65 KRIW 070032
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
632 PM MDT SAT JUN 6 2026
KEY MESSAGES
- WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH THE
WEEKEND GIVEN LOW HUMIDITY, GUSTY WIND, AND HOT TEMPERATURES.
- CHANCES (10-15%) FOR VERY ISOLATED SHOWERS AND THUNDERSTORMS TONIGHT
MAINLY ACROSS NORTHERN AND WESTERN WYOMING.
- THUNDERSTORM CHANCES BECOME MORE WIDESPREAD SUNDAY (15-40%),
WITH A COUPLE OF STRONGER STORMS POSSIBLE ACROSS THE EASTERN
BIGHORN BASIN AND JOHNSON COUNTY.
UPDATE
ISSUED AT 105 PM MDT SAT JUN 6 2026
TODAY'S FORECAST OF HOT AND DRY CONDITIONS IS ON TRACK, THOUGH
SCATTERED HIGH CLOUDS HAVE DELAYED HEATING SLIGHTLY. STILL, PEAK
TEMPERATURES SHOULD REACH NEAR 100 DEGREES IN PORTIONS OF THE
BIGHORN BASIN, AS WELL AS NORTHEASTERN JOHNSON COUNTY. THERE ARE
CURRENTLY SOME WEAK, ISOLATED SHOWERS ACROSS NORTHWESTERN
WYOMING, AND THERE ARE STILL INDICATIONS THAT THERE MAY BE
ADDITIONAL DEVELOPMENT LATER TODAY AS CYCLONIC FLOW INCREASES.
CRITICAL FIRE WEATHER CONDITIONS ARE THE MORE WIDESPREAD IMPACT
GIVEN THE ELEVATED SOUTHWEST WIND. SIMILAR CONCERNS WILL BE
NOTED FOR SUNDAY, WITH THE ADDITIONAL THREAT OF MORE WIDESPREAD
AND ROBUST CONVECTION AS THE TROUGH BEGINS SWINGING IN.
DISCUSSION
ISSUED AT 206 AM MDT SAT JUN 6 2026
THE LONG-AWAITED BUCKLING OF THE MIDLEVEL FLOW HAS BEGUN TO
STRENGTHEN ACROSS THE WESTERN US, AND WILL BRING THE WARMEST DAY
OF 2026 TO MOST OF THE STATE. H7 TEMPERATURES ARE ALREADY
RUNNING 12-14C, AND WILL BE PEAKING THIS AFTERNOON BETWEEN 16
AND 18C, WHICH TRANSLATES TO THE SFC AS HIGHS IN THE UPPER 80S
TO THE UPPER 90S. ISOLATED READINGS AT 100 DEGREES MAY BE NOTED
ALONG THE LOWEST ELEVATIONS OF THE BIGHORN BASIN FOR A FEW HOURS
THIS AFTERNOON. TEMPERATURES ALOFT WILL BE COOLER FOR NW WY,
WHICH IS CLOSER TO THE INCOMING TROUGH, WHICH WILL KEEP TEMPS
MORE MODEST IN THE 70S THIS AFTERNOON.
THE SOUTHWEST FLOW AROUND THE APPROACHING TROUGH WILL BE VERY
DRY, AND WITH DRY AIR ALREADY AT THE SFC, WILL MIX WELL DOWN TO
THE SFC THIS AFTERNOON. WIND GUSTS WILL REACH 35 TO 50 MPH
THROUGH THE AFTERNOON, PICKING UP AROUND NOON AND CONTINUING
INTO THE EARLY EVENING. HUMIDITY LEVELS WILL ALSO CRASH DOWN
THIS AFTERNOON, STAYING BELOW 10 PERCENT THROUGH THE AFTERNOON.
THIS LEADS TO CRITICAL FIRE WEATHER CONCERNS ALL DAY.
TONIGHT, THE ADVANCING TROUGH MOVES OFF THE PACNW COAST INTO
THE NORTHERN ROCKIES, PUSHING THE HEAT RIDGE EASTWARD AND
OPENING UP MOST OF THE STATE FOR INCREASED MOISTURE. THERE IS A
HINT IN SOME OF THE CONVECTIVE MODELS THAT TODAY'S HEATING MAY
BE ENOUGH TO TAP THE LEADING EDGE OF THE TROUGH TO SPARK A FEW
SHOWERS EVEN INTO CENTRAL WY THIS AFTERNOON, BUT THIS WILL BE
BATTLING AGAINST THE SUBSIDENCE WITH THE RIDGE, SO THIS AREA MAY
BE LIMITED TO SOME INCREASED CU. THE BETTER CHANCES FOR SHOWERS
FIRST BUILDS INTO THE NW PARKS THIS EVENING AND OVERNIGHT AS
THE FIRST LOBE OF THE TROUGH PASSES THROUGH. THE NEXT BAND THEN
SETS UP SOMEWHERE IN CENTRAL WY DURING SUNDAY AFTERNOON,
INFLUENCED BY AN INSTABILITY AXIS ALOFT. AS THE TROUGH MOVES
EAST, AN ENHANCED AREA OF SHEAR BUILDS INTO NORTHERN WY, WHICH
WILL ALSO BE INFLUENCED BY TERRAIN SHEAR OFF THE BIGHORN RANGE.
STRONGLY SHEARED ENVIRONMENT AND INSTABILITY COULD LEAD TO
THUNDERSTORMS QUICKLY STRENGTHENING ACROSS JOHNSON COUNTY DURING
THE AFTERNOON, WITH A QUICKLY INCREASING THREAT FOR HAIL AND
VERY STRONG WINDS. SPC HAS THIS AREA IN A SLIGHT RISK ON SUNDAY,
AND WILL NEED TO MONITOR FOR FINAL TIMING.
INTO EARLY NEXT WEEK, THE MAIN TROUGH SHIFTS EAST, PUTTING THE
AXIS ALONG THE ROCKIES FOR THE FIRST HALF OF THE WEEK. RIGHT
NOW, THIS PUTS THE NORTHERN HALF OF THE STATE IN A MORE SHOWERY
PATTERN THROUGH MOST OF THE UPCOMING WEEK.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 407 PM MDT SAT JUN 6 2026
GUSTY 25KT TO 35KT SOUTHWEST WINDS WILL BE ONGOING AT THE START OF
THE TAF PERIOD, WITH OCCASIONAL GUSTS UP TO 40KT POSSIBLE.
THESE GUSTY WINDS ARE FORECAST TO DIMINISH BY 02Z/03Z SUNDAY.
OVERNIGHT WINDS ARE EXPECTED TO BE UNDER 11KT AT ALL TERMINALS.
WINDS QUICKLY INCREASE BETWEEN 14Z AND 19Z AT ALL TERMINALS,
WITH FREQUENT GUSTS OF 25KT TO 35KT.
THERE IS A 10% CHANCE OF A SHOWER OR VIRGA AT KRKS AND KCPR
THROUGH 03Z SUNDAY. LOW LIGHT RAIN CHANCES EXIST ACROSS WESTERN
WYOMING BETWEEN 05Z AND 09Z SUNDAY AND BRINGS A 30 PERCENT
CHANCE OF LIGHT RAIN TO KJAC. ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM CHANCES ARE FORECAST ON SUNDAY, WITH A 30 PERCENT
CHANCE AT KJAC, KRKS, AND KWRL. A HEAVIER SHOWER OR THUNDERSTORM
COULD RESULT IN BRIEF PERIODS OF MVFR VISIBILITIES, BUT
CONFIDENCE IN OCCURRENCE AND DURATION IS LOW AT THIS TIME.
SHOWERS ARE FORECAST TO DEVELOP IN THE AREAS OF KCOD, KBPI, AND
KPNA FOR A FEW HOURS ON SUNDAY. HOWEVER, CONFIDENCE IS AROUND 20
PERCENT IN ANYTHING ACTUALLY IMPACTING THE AFOREMENTIONED THREE
TERMINALS.
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 105 PM MDT SAT JUN 6 2026
CRITICAL/NEAR-CRITICAL FIRE WEATHER CONDITIONS WILL BE WIDESPREAD
ACROSS THE AREA THROUGH AT LEAST EARLY NEXT WEEK. AN INCOMING SYSTEM
WILL ALSO INCREASE THE LIGHTNING AND OUTFLOW WIND THREAT STARTING
SUNDAY, AS ISOLATED THUNDERSTORMS MOVE NORTHEAST ACROSS THE
AREA. THE NEAR-SURFACE CONDITIONS WILL REMAIN DRY, SO MUCH OF
THIS MAY BE VIRGA. IN ADDITION TO THE BACKGROUND GUSTY SOUTHWEST
WIND, THIS ACTIVITY COULD PRODUCE STRONG AND ERRATIC WIND GUSTS
OF 50 TO 60 MPH.
RIW WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 8 PM MDT SUNDAY FOR WYZ280.
UPDATE...MYERS
DISCUSSION...STRAUB
AVIATION...LAVOIE/GERHARDT
FIRE WEATHER...MYERS
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