292
FXUS65 KRIW 092254
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
454 PM MDT THU JUL 9 2026
KEY MESSAGES
- LESS STORM ACTIVITY FOR THIS AFTERNOON (10-15% COVERAGE).
THESE WILL BUILD AND PUSH OFF THE WINDS BY 2-3PM AND MOVE EAST
ACROSS FREMONT/NATRONA COUNTIES BY 6-7PM WITH MAIN THREATS OF
GUSTY OUTFLOW WINDS UP TO 40-50 MPH.
- RECORD HIGH TEMPERATURES ARE LIKELY THIS WEEKEND AND POSSIBLY
EARLY NEXT WEEK WITH SOME ALL TIME RECORD HIGH TEMPERATURES
POSSIBLE. THE HOTTEST DAY WILL BE SUNDAY.
- VERY LOW HUMIDITY WILL BRING ELEVATED FIRE WEATHER FRIDAY INTO
EARLY NEXT WEEK. CRITICAL FIRE WEATHER IS POSSIBLE IN NORTHERN
WYOMING SUNDAY AFTERNOON FOR THE NORTHERN BIGHORN BASIN AND
CODY FOOTHILLS.
UPDATE
ISSUED AT 1203 PM MDT THU JUL 9 2026
THUNDERSTORMS HAVE STARTED TO DEVELOP OVER THE WINDS AS MANY OF
THE HIRES MODELS HAVE SUGGESTED FROM THIS MORNING. THESE WILL
CONTINUE TO BUILD AND BEGIN TO PUSH EAST ACROSS THE WIND RIVER
BASIN TOWARDS 2-3PM BEFORE PUSHING INTO EASTERN FREMONT TO
NATRONA COUNTIES BEFORE EXITING BY 7PM THIS EVENING. THE
PRIMARY HAZARD CONTINUES TO BE GUSTY OUTFLOWS, NOT QUITE AS
STRONG AS YESTERDAY, UP TO 40-50 MPH AS DEWPOINT DEPRESSIONS
ARE A BIT LESS. OTHERWISE, HOT TEMPERATURES STILL ON THE WAY FOR
FRIDAY AND OVER THE WEEKEND, WITH SUNDAY THE HOTTEST AFTERNOON.
A EXCESSIVE HEAT WATCH HAS BEEN ISSUED FOR SATURDAY THROUGH
MONDAY WITH WIDESPREAD TRIPLE DIGITS EXPECTED FOR MANY ACROSS
THE CWA.
DISCUSSION
ISSUED AT 151 AM MDT THU JUL 9 2026
WE STILL HAVE A FEW LIGHT SHOWERS IN CENTRAL PORTIONS OF WYOMING
EARLY THIS MORNING AS WE STILL HAVE A BIT OF CAPE IN THE ATMOSPHERE.
NOTHING HEAVY, AND BARELY ANY LIGHTNING, JUST A FEW SHOWERS. AT THIS
POINT, ANY AMOUNT OF MOISTURE IS A GOOD THING.
AND IT LOOKS LIKE IT WILL BE ANOTHER DAY OF CONVECTION. THERE COULD
BE SOME THIS MORNING THOUGH, ESPECIALLY IN PORTIONS OF JOHNSON AND
NATRONA COUNTY WHERE GUIDANCE IS SHOWING SOME CAPE THIS MORNING, SO
WE ADDED AROUND A 1 IN 5 CHANCE OF A SHOWER, IT MAY END UP JUST
BEING VIRGA THOUGH. OTHERWISE, THE TREND OF DECREASING COVERAGE OF
CONVECTION CONTINUES AS PRECIPITABLE WATER VALUES CONTINUE TO DROP.
AGAIN, THE MAIN CHANCE WILL BE EAST OF THE DIVIDE WITH AREAS TO THE
WEST LARGELY DRY WITH LESS THAN A 1 IN 10 CHANCE. FOR ONCE, WE DON'T
HAVE ANY KIND OF RISK FROM THE STORM PREDICTION CENTER. THE MAIN
THREAT WILL BE, AS IT ALWAYS IS THIS TIME OF YEAR, STRONG WIND
GUSTS. MODELS SOUNDINGS CONTINUE TO SHOW INVERTED V SIGNATURES AND
WITH SOME DEW POINT DEPRESSIONS APPROACHING 50 DEGREES, WIND GUSTS
OF 50 MPH WILL BE POSSIBLE WITH ANY SHOWER OR THUNDERSTORM. THIS
LOOKS LIKE AN EARLIER SHOW WITH MOST SHOWERS ENDING AFTER SUNSET AND
ALL OVER BY MIDNIGHT. TEMPERATURES SHOULD BE SIMILAR TO
YESTERDAY, QUITE WARM BUT FAIRLY NORMAL FOR JULY.
TOMORROW IS WHERE WE BEGIN TO TRANSITION FROM THUNDERSTORMS TO HEAT.
DRIER AIR WILL CONTINUE TO PUSH EASTWARD ACROSS THE AREA, DROPPING
PRECIPITABLE WATER LEVELS EVEN MORE. THERE MAY BE JUST ENOUGH
MOISTURE AND INSTABILITY TO SQUEEZE OUT VERY ISOLATED AFTERNOON
SHOWERS AND THUNDERSTORMS, THIS WOULD BE MAINLY IN JOHNSON COUNTY
WHERE A BIT MORE MOISTURE WILL LINGER AND POSSIBLY THE MOUNTAINS
WITH A BIT OF HIGH ELEVATION HEAT SOURCE. COVERAGE WILL BE VERY
SPARSE THOUGH, WITH A CAPITAL V AND A CAPITAL S, LESS THAN 5 PERCENT
OF THE AREA. TEMPERATURES WILL ALSO BEGIN TO RISE, APPROACHING 100
IN THE WARM SPOTS LIKE THE BIGHORN BASIN AND WIDESPREAD 90S EAST OF
THE DIVIDE IN THE LOWER ELEVATIONS. THIS IS HOT, BUT NOTHING
UNUSUALLY FOR THE MIDDLE OF JULY, CLIMATOLOGICALLY THE WARMEST TIME
OF THE YEAR.
THINGS REALLY CHANGE ON SATURDAY. STRONG RIDGING OVER THE DESERT
SOUTHWEST WILL BEGIN TO BUILD NORTHWARD, WITH 500 MILLIBAR HEIGHTS
REACHING 5970 METERS BY DAYS END. AT THE SAME TIME, 700 MILLIBAR
TEMPERATURES WILL RISE TO AS HIGH AS 21 CELSIUS. THIS MEANS A VERY
HOT DAY. REASONING FOR TODAY REMAINS THE SAME, MOST LOCATIONS BELOW
5200 FEET EAST OF THE DIVIDE HAVE AT LEAST A 1 IN 2 CHANCE OF HIGH
TEMPERATURES OVER 100 DEGREES, WITH THE WARMEST SPOTS LIKE FROM
THERMOPOLIS TO GREYBULL IN THE BIGHORN BASIN HAVE AN ALMOST 100
PERCENT CHANCE. SOME RECORD HIGH TEMPERATURES ARE CERTAINLY POSSIBLE
ON THIS DAY. AND, WITH THE WARM TEMPERATURES ALOFT AND MUCH DRIER
AIR MOVING IN, THE CHANCE OF CONVECTION WILL BE BASICALLY ZERO.
BUT THIS IS ONLY THE APPETIZER, WITH THE MAIN COURSE LIKELY TO BE ON
SUNDAY. THIS IS WHEN THE RIDGE WILL BE CENTERED OVER WYOMING, WITH
SOME MODELS GIVING 500 MILLIBAR HEIGHTS AS HIGH AS 6000 METERS. THE
700 MILLIBAR TEMPERATURES MAY CLIMB AS HIGH AS 24 DEGREES CELSIUS.
ALL THIS ADDS UP TO A VERY HOT DAY, POSSIBLY ONE WE HAVEN'T SEEN IN
A LONG TIME. THE NBA ENSEMBLE GIVES A GREATER THAN 1 IN 2 CHANCE OF
100 DEGREES IN ALL LOCATIONS BELOW 6000 FEET, WITH AN ALMOST 100
PERCENT CHANCE BELOW 5500 FEET. AND THIS INCLUDES SOME PLACES
THAT DON;T SEE 100. ROCK SPRINGS HAS AROUND A 3 IN 5 CHANCE OF
OVER 100, AND EVEN JACKSON HAS A 1 IN 3 CHANCE. THE LOWER
ELEVATIONS OF THE BIGHORN BASIN HAVE AT LEAST A 4 OUT OF 5
CHANCE OF HIGH TEMPERATURES OVER 105 DEGREES ON THIS DAY. AND
THE WARMEST SPOTS, LIKE GREYBULL AND BASIN, HAVE A 1 IN 2 CHANCE
OF REACHING 110. THIS IS THE MOST LIKELY DAY TO SEE ALL TIME
RECORD HIGHS BROKEN, ESPECIALLY IN LOCATIONS THAT HAVE A SHORTER
PERIOD OF RECORD.
AS FOR HEAT HIGHLIGHTS, I HAD MIXED THOUGHTS ON THIS. THE MAIN
REASON IS THE HUMIDITY, OR MORE SPECIFICALLY THE LACK OF IT. THE
LOWER ELEVATIONS WILL HAVE WIDESPREAD SINGLE DIGIT RELATIVE
HUMIDITY, WITH SOME LOCATIONS FALLING AS A 3 PERCENT ON SUNDAY. THIS
HAS AN IMPACT ON THE APPARENT TEMPERATURES, WHICH IS WHAT WE BASE
HEAT HIGHLIGHTS ON. FOR ONE, THE APPARENT TEMPERATURE WILL BE
BELOW THE ACTUAL TEMPERATURE BY 5 OR 10 DEGREES. ALSO, WITH THE
DRY AIR, ALMOST ALL LOCATIONS SHOULD COOL OFF AT LEAST INTO THE
60S AT NIGHT. THE ONE PLACE I COULD SEE AN EXCESSIVE HEAT WATCH
IS THE BIGHORN BASIN, BUT THIS WOULD MAINLY BE FOR SUNDAY. HEAT
ADVISORIES LOOK MORE LIKELY AT THIS TIME, THERE IS STILL TIME
SO WE WILL PUNT TO DAY SHIFT TO TAKE ANOTHER LOOK.
AND THERE IS ONE MORE CONCERN FOR SUNDAY. THE NBM ENSEMBLE IS GIVING
A GREATER THAN 1 IN 2 CHANCE OF WIND GUSTS OVER 30 MPH SUNDAY
AFTERNOON NORTH OF A MEETEETSE TO WORLAND TO KAYCEE LINE. WITH THE
EXTREMELY DRY CONDITIONS, WE MAY HAVE TO CONSIDER FIRE WEATHER
HIGHLIGHTS FOR SUNDAY AFTERNOON.
THERE SHOULD BE SOME SLIGHT, AND EMPHASIS ON SLIGHT. COOLING ON
MONDAY, BE PROBABLY ONLY BY 3 TO 5 DEGREES. ONE HUNDRED DEGREE HIGH
TEMPERATURES WILL STILL BE VERY WIDESPREAD ACROSS THE LOWER
ELEVATIONS. ONE THIS DAY, THERE MAY BE JUST ENOUGH MOISTURE TO COME
AROUND THE BACKSIDE OF THE RIDGE FOR ISOLATED STORMS IN THE WESTERN
MOUNTAINS, BUT THE CHANCE IS ONLY AROUND 1 OUT OF 10. CHANCES OF
CONVECTION THEN SLOWLY INCREASE EACH DAY, STARTING MAINLY IN WESTERN
WYOMING ON TUESDAY AND THEN SPREADING EASTWARD AS THE RIDGE SLOWLY
MOVES EASTWARD AND MOISTURE ROTATES IN AROUND THE BACKSIDE OF
IT. TEMPERATURES WILL COOL AT FIRST IN THE WEST, BUT LIKELY
REMAIN WELL ABOVE NORMAL THROUGH THE FORECAST PERIOD. VERY HOT
TEMPERATURES CONTINUE TUESDAY BEFORE SOME COOLING MOVES IN FOR
MIDWEEK EAST OF THE DIVIDE. BUT EVEN WITH SOME COOLING,
TEMPERATURES SHOULD REMAIN WELL ABOVE NORMAL THROUGH MOST OF
NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 454 PM MDT THU JUL 9 2026
VFR CONDITIONS PREVAIL AT ALL TERMINALS THROUGH 00Z/SATURDAY.
ONGOING CONVECTION WANES BY 02Z/FRIDAY, WITH ONLY LINGERING MID-
LEVEL CLOUDS AND A FEW SHOWERS UNTIL 06Z/FRIDAY. CONVECTIVE GUSTY
OUTFLOW WIND 35-45KTS REMAINS THE PRIMARY HAZARD UNTIL JUST BEFORE
SUNSET. HOWEVER, BRIEF MVFR OF LESS THAN 30 MINUTES, IS POSSIBLE AT
KCPR WHERE LOW-LEVEL MOISTURE IS MORE FAVORABLE. THE MID-LEVEL
MOISTURE THAT HAS BEEN AIDING DIURNAL CONVECTIVE DEVELOPMENT
DIMINISHES FRIDAY AS DRIER AIR ARRIVES FROM THE WEST. A FEW FRIDAY
AFTERNOON SHOWERS DEVELOP OVER THE ABSAROKA, WIND RIVER, AND BIGHORN
MOUNTAINS, BUT UNFAVORABLE DYNAMICS AND LIMITED MOISTURE SHOULD LEAD
TO THESE FIZZLING QUICKLY AS THEY TRY TO MOVE INTO THE LOWER
ELEVATIONS. WESTERLY WIND 10-18KTS DECREASES BY SUNSET AT TERMINALS
WEST OF THE CONTINENTAL DIVIDE. THESE SAME TERMINALS SEE 8-15KT
WINDS BEGIN AGAIN EARLY FRIDAY AFTERNOON.
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
EXTREME HEAT WATCH FROM SATURDAY AFTERNOON THROUGH MONDAY
EVENING FOR WYZ003>006-010-011-013-016>020-023-025>030.
UPDATE...LOWE
DISCUSSION...HATTINGS
AVIATION...CNJ
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