833
FXUS65 KRIW 011655
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1055 AM MDT SAT AUG 1 2026
KEY MESSAGES
- IT WILL BE A NEAR-RECORD HOT WEEKEND, WITH BASINS EAST OF THE
CONTINENTAL DIVIDE SEEING HIGHS NEAR OR OVER 100 DEGREES. MANY
HIGHER-ELEVATION BASINS AND VALLEYS WEST OF THE DIVIDE WILL
SEE HIGHS INTO THE 90S.
- ELEVATED FIRE WEATHER CONDITIONS ARE LIKELY THROUGH EARLY NEXT
WEEK, WITH SUNDAY AND MONDAY BEING THE DAYS OF GREATEST
CONCERN.
- A COLD FRONT WILL PUSH THROUGH THE REGION SUNDAY NIGHT INTO
MONDAY, CAUSING TEMPERATURES TO DROP 15 TO 20 DEGREES EAST OF
THE DIVIDE, AND DROP BY ABOUT 10 DEGREES WEST OF THE DIVIDE.
DISCUSSION
ISSUED AT 1237 AM MDT SAT AUG 1 2026
WE ARE NOW OFFICIALLY TWO THIRDS OF THE WAY THROUGH METEOROLOGICAL
WINTER (IT RUNS FROM JUNE THROUGH AUGUST). AND, UNLESS YOU'VE BEEN
LIVING UNDER A ROCK, IT HAS BEEN A HOT ONE. SOME OF OUR MAJOR
CLIMATE SITES HAVE HAD THEIR WARMEST JULY ON RECORD. THIS INCLUDES
LANDER, WHICH HAS RECORDS GOING BACK TO 1892. AND THIS LOOKS TO
CONTINUE THIS WEEKEND. HOWEVER, WE MAY HAVE SOME WELCOME RELIEF ON
THE WAY FOR PORTIONS OF THE AREA EARLY NEXT WEEK.
HOWEVER, WE WILL HAVE TO RUN THE HEAT GAUNTLET THIS WEEKEND BEFORE
WE GET TO THE RELIEF. (WAS WAITING TO THROW THE WORD GAUNTLET IN, I
LOVED THAT VIDEO GAME BACK WHEN I WAS A TEENAGER IN THE 80S.)
ANYWAY, THE REASONING FOR THE FORECAST FOR THE WEEKEND REMAINS THE
SAME AS YESTERDAY. ANOTHER HEAT DOME WILL BUILD NORTHWARD OVER
WYOMING AND BRING A COUPLE OF DAYS OF VERY HOT AND IN SOME CASES
RECORD BREAKING HEAT. WE WILL STILL HAVE 700 MILLIBAR TEMPERATURES
CLIMBING TO 21 TO 22 CELSIUS ON BOTH SATURDAY AND SUNDAY, AND
THIS TRANSLATES TO ALL LOWER ELEVATIONS SEEING HIGH TEMPERATURES
AT LEAST IN THE 90S. FOR TODAY, MOST ELEVATIONS BELOW 5000 FEET
HAVE AT A MINIMUM A 1 OUT OF 2 CHANCE OF HIGH TEMPERATURES OVER
100 DEGREES, WITH THE LOWER ELEVATIONS OF THE BIGHORN BASIN
(GENERALLY BELOW 4000 FEET) HAVING A 1 OUT OF 2 CHANCE OF HIGH
TEMPERATURES OVER 105. SUNDAY STILL LOOKS LIKE THE WARMEST DAY,
AS A GUSTY SOUTHWESTERLY BREEZE DEVELOPS AHEAD OF A COLD FRONT
DROPPING TOWARD THE AREA FROM MONTANA. THIS SHOULD ALLOW
TEMPERATURES TO BE A FEW DEGREES WARMER, WITH LOCATIONS HAVING
AT LEAST A 1 IN 2 CHANCE OF HIGHS OVER 100 NOW UNDER 5500 FEET.
AND IN THE AREAS MOST PRONE TO THE DOWNSLOPE WARMING, LIKE THE
WIND RIVER BASIN, SOUTHERN BIGHORN BASIN AND EVEN AROUND CASPER,
COULD BE EVEN WARMER. THE NATIONAL BLEND OF MODEL ENSEMBLES
GIVE AT LEAST A 1 IN 3 CHANCE OF HIGHS OF 105 BELOW 5000 FEET IN
THESE AREAS. THIS IS THE DAY WHEN SOME ALL TIME HIGHS FOR THE
MONTH OF AUGUST MAY BE SET. IT DOES NOT LOOK QUITE AS HOT AS ON
JULY 12TH THOUGH, SO ALL TIME RECORD HIGHS SHOULD BE SAFE FOR
MOST. THE ONE THAT MAY BE IN JEOPARDY IS THE SWEETWATER COUNTY
AIRPORT, WHERE WE COULD REACH THE ALL TIME RECORD HIGH OF 98.
WITH THIS, WE WILL KEEP THE HEAT ADVISORIES GOING AS IS. AS FOR
PRECIPITATION, I CAN'T COMPLETELY RULE OUT A VERY ISOLATED VIRGA
SHOWER OVER THE MOUNTAINS, BUT THE CHANCE IS LESS THAN 1 OUT OF
10 AND WAS LEFT OUT OF THE FORECAST.
THE OTHER CONCERN ON SUNDAY WILL BE FIRE WEATHER. HUMIDITY WILL WILL
BE VERY LOW THROUGH THE WEEKEND, FALLING UNDER 15 PERCENT FOR MANY
AREAS AND MANY OF THE LOWER ELEVATIONS SEEING RELATIVE HUMIDITY IN
THE SINGLE DIGITS. WIND SHOULD REMAIN LIGHT TO MODERATE ON SATURDAY.
THE GUSTY SOUTHWESTERLY BREEZE THEN DEVELOPS ON SUNDAY, BRINGING
THE POSSIBILITY OF CRITICAL FIRE WEATHER. THE LOW HUMIDITY IS A
SLAM DUNK, THE WIND IS STILL BORDERLINE IN SOME AREAS THOUGH. FOR
NOW, WE WILL KEEP THE FIRE WEATHER WATCH GOING AND LET THE DAY
SHIFT TAKE ANOTHER LOOK.
AS FOR MONDAY, THOSE OF YOUR WHO ARE GEN X OR OLDER MAY REMEMBER AN
COMMERCIAL FOR ANTACID WHERE IT ASKS HOW DO YOU SPELL RELIEF? WELL,
THE RELIEF FROM THE HEAT WILL BE SPELLED C-O-L-D F-R-O-N-T. IT WILL
DROP SLOWLY INTO NORTHERN WYOMING SUNDAY NIGHT, REACHING THE
CONTINENTAL DIVIDE DURING THE DAY ON MONDAY. THIS WILL BRING SOME
COOLER TEMPERATURES, GENERALLY ABOUT 15 TO 20 DEGREES COOLER THAN ON
SUNDAY. A FEW PLACES IN FAR NORTHERN WYOMING MAY HAVE A BRIEF TASTE
OF SEPTEMBER, WITH HIGH TEMPERATURES ONLY IN THE 70S. IT WILL REMAIN
RATHER HOT ACROSS SOUTHERN WYOMING THOUGH. IN ADDITION, WITH THE
FRONT IN THE AREA, A GUSTY BREEZE WILL CONTINUE. WITH THE COOLER
TEMPERATURES AND SOMEWHAT HIGHER HUMIDITY ACROSS NORTHERN WYOMING,
FIRE WEATHER SHOULD DROP BELOW CRITICAL. HOWEVER, WITH THE GUSTY
WIND AND HUMIDITY AROUND 10 PERCENT CONTINUING IN SOUTHERN WYOMING,
CRITICAL FIRE WEATHER SHOULD CONTINUE ANOTHER DAY. SO, WE WILL
CONTINUE THE FIRE WEATHER WATCH. THE ONE THING THE FRONT WILL NOT
BRING IS MOISTURE. WE CAN'T COMPLETELY RULE OUT A SHOWER OVER THE
FAR NORTH, BUT THE CHANCE IS LESS THAN 1 OUT OF 10.
MAINLY DRY WEATHER LOOKS TO CONTINUE THROUGH MUCH OF NEXT WEEK AS
WELL. A WEAK SHORTWAVE MAY BRING A STRAY SHOWER OR STORM TO NORTHERN
WYOMING TUESDAY EVENING, BUT THE CHANCE IS LESS THAN 1 OUT OF 5
GIVEN THE LACK OF MOISTURE. THE GENERAL TREND FOR MUCH OF NEXT WEEK
WILL BE FOR THE RIDGE TO BUILD BACK NORTHWARD AND BRING WARMER
TEMPERATURES BACK TO THE AREA. ABOVE NORMAL TEMPERATURES LOOK LIKELY
TOWARD THE END OF NEXT WEEK AND NEXT WEEKEND, BUT EXTREME HEAT LOOKS
UNLIKELY AT THIS TIME, JUST TEMPERATURES RUNNING A FEW DEGREES ABOVE
SEASONAL AVERAGES.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1055 AM MDT SAT AUG 1 2026
ALL TERMINALS TO BE VFR THROUGH THE FORECAST PERIOD. LITTLE MORE
THAN SOME HIGH CLOUDS INCREASING OVERNIGHT. TERMINALS WEST OF THE
CONTINENTAL DIVIDE SEE WESTERLY 10-18KT WINDS SATURDAY AFTERNOON
UNTIL AROUND SUNSET. EAST OF THE DIVIDE TERMINALS SEE SPEEDS
12KTS OR LESS.
PLEASE SEE THE AVIATION WEATHER CENTER AND/OR CWSU ZLC AND ZDV FOR
THE LATEST INFORMATION ON SMOKE, ICING, AND TURBULENCE FORECASTS.
FIRE WEATHER
ISSUED AT 1237 AM MDT SAT AUG 1 2026
TODAY WILL BE A HOT AND DRY DAY ACROSS THE AREA. RELATIVE
HUMIDITY WILL FALL UNDER 15 PERCENT FOR MOST LOCATIONS. HOWEVER,
WIND SHOULD REMAIN LIGHT TO MODERATE EXCEPT FOR THE NORTHWESTERN
MOUNTAINS WHERE FUELS ARE NOT CRITICAL. HOWEVER, ELEVATED FIRE
WEATHER IS LIKELY THIS AFTERNOON. AN APPROACHING COLD FRONT WILL
BRING A GUSTY SOUTH TO SOUTHWESTERLY BREEZE AND COMBINED WITH
HUMIDITY FALLING INTO THE SINGLE DIGITS WILL BRING A GOOD CHANCE
OF CRITICAL FIRE WEATHER ON SUNDAY ACROSS MUCH OF THE AREA,
CONTINUING IN SOUTHERN WYOMING ON MONDAY.
RIW WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 10 PM MDT SUNDAY FOR WYZ003>006-010-011-
013-016>020-023-025>030.
FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY
EVENING FOR WYZ275-276-282-283-285.
FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY
EVENING FOR WYZ277>279-289.
DISCUSSION...HATTINGS
AVIATION...CNJ
FIRE WEATHER...HATTINGS
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