448
FXUS65 KRIW 090412
AFDRIW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1012 PM MDT WED JUL 8 2026
KEY MESSAGES
- SCATTERED RAIN SHOWERS AND ISOLATED THUNDERSTORMS WILL SLOWLY
TAPER OFF THIS EVENING, WITH MOST ACTIVITY DONE BY 9 PM MDT.
UNTIL THEN GUSTY OUTFLOW WIND OF 45 TO 55 MPH WILL REMAIN
POSSIBLE.
- WARMING TREND THROUGH THE WEEKEND WITH A DOWNWARD TREND FOR
THUNDERSTORM ACTIVITY AS DRIER AIR MOVES INTO THE REGION.
- THE HOTTEST WEATHER OF THE YEAR ARRIVES THIS WEEKEND, WITH
MANY ALL-TIME RECORD HIGH TEMPERATURES POSSIBLE. THE BEST
CHANCE OF ALL TIME RECORD HIGH TEMPERATURES WILL BE SUNDAY
AFTERNOON.
- THE EXTREMELY HOT AND DRY CONDITIONS WILL RESULT IN NEAR-
CRITICAL FIRE WEATHER CONDITIONS FOR THE END OF THIS WEEK INTO
EARLY NEXT WEEK.
UPDATE
ISSUED AT 1230 PM MDT WED JUL 8 2026
MORE CLEARING FROM THE OVERNIGHT HOURS THAN YESTERDAY THAT WILL
GIVE WAY TO A BIT BETTER INSTABILITY FROM SWEETWATER TO NATRONA
COUNTIES. RADAR IS STARTING TO INCREASE IN ACTIVITY OFF THE
UINTAS THAT WILL EVENTUALLY PUSH INTO SOUTHERN SWEETWATER COUNTY
IN THE NEXT HOUR AND EXPAND NORTH AND EAST THROUGH THE
REMAINDER OF THE AFTERNOON. EASTERN FREMONT TO NATRONA COUNTIES
WILL BE OF CONCERN FROM 1600-1800L PUSHING EAST OF THE CWA BY
1900L. THE OTHER AREA OF NOTE CONTINUES TO BE JOHNSON COUNTY FOR
LATER IN THE AFTERNOON BEFORE SUNSET WITH STORMS COMING IN OFF
THE BIGHORNS FROM MONTANA. HOWEVER, THE INSTABILITY MAY NOT BE
QUITE AS HIGH WITH HIRES MODELS COMPLETELY MISSING THE EARLY
MORNING CONVECTION THAT ROLLED IN FROM YELLOWSTONE STRAIGHT
EAST INTO JOHNSON COUNTY THAT LOOKS TO BE FINALLY DISSIPATING AS
IT MOVES INTO EASTERN PORTIONS OF THE COUNTY. MAIN THREATS
STILL WILL BE OUTFLOW WINDS AS PER USUAL OVER 50 MPH BEING
POSSIBLE. DEWPOINT DEPRESSIONS DON'T LOOK QUITE AS GOOD AS
YESTERDAY BUT SEVERE GUSTS ALWAYS STILL POSSIBLE, EVEN WITH THE
GREEN BLOBS OUT OF RADAR RANGE. HEAT STILL ON FOR THE WEEKEND
INTO NEXT WEEK WITH NBM STILL PINGING THE WIDESPREAD TRIPLE
DIGITS, STAY TUNED!
DISCUSSION
ISSUED AT 245 AM MDT WED JUL 8 2026
I HAVE A QUESTION FOR YOU THIS MORNING. WHAT DO THESE THINGS HAVE IN
COMMON: GAS PRESSURE AND VOLUME, SUPPLY AND DEMAND AND SPEED AND
TRAVEL TIME. IF YOU ANSWERED INVERSE RELATIONSHIPS, YOU WOULD BE
RIGHT. AND THAT IS WHAT WE WILL HAVE OVER THE NEXT WEEK, AS THE
TEMPERATURE GOES UP, THE CHANCE OF CONVECTION GOES DOWN.
TODAY WILL BE SOMEWHAT SIMILAR TO YESTERDAY. ANOTHER SHORTWAVE WILL
BE MOVING THROUGH THE AREA. WE ALSO CONTINUE TO HAVE FAIRY STEEP LOW
AND MID LEVEL LAPSE RATES. INSTABILITY VALUES ARE ALSO DECENT, WITH
SOME PORTIONS OF THE AREA (MAINLY THE NORTHEASTERN PORTIONS OF THE
AREA) HAVING OVER 1000 J/KG OF CAPE AND LIFTED INDICES AS LOW AS
MINUS 5. THERE WILL BE ONE DIFFERENCE THOUGH, AND THIS WILL BE A
TREND OVER THE NEXT FEW DAYS. AND THAT IS THAT PRECIPITABLE WATER
VALUES ARE A LOWER THAN YESTERDAY, ESPECIALLY WEST OF THE DIVIDE.
BUT EVEN EAST OF THE DIVIDE, VALUES ARE 10 TO 20 PERCENT LOWER. IT
IS STILL AROUND 130 PERCENT OF NORMAL THOUGH. AS A RESULT, IT WILL
BE ANOTHER DAY ANYWHERE FROM A 1 IN 5 TO 2 OUT OF 5 CHANCE OF A
SHOWER OR THUNDERSTORM, WITH THE BEST CHANCE IN THE AFTERNOON AND
EVENING AND ACROSS NORTHERN AND FAR SOUTHERN WYOMING. THE LOWEST
CHANCE WILL BE ACROSS THE WEST WITH LESS THAN A 1 IN 10 CHANCE.
TEMPERATURES WILL BE SIMILAR TO YESTERDAY, NEAR TO SOMEWHAT ABOVE
NORMAL. AS FOR ANY STRONGER STORMS, THE BEST CHANCE WOULD BE OVER
JOHNSON COUNTY WHERE THERE IS A MARGINAL RISK, WITH STRONG WIND
GUSTS AND MARGINALLY SEVERE HAIL THE MAIN THREATS. STRONG WIND GUSTS
WILL BE A THREAT WITH ANY SHOWER OR THUNDERSTORM THOUGH, EVEN
FURTHER WEST WHERE DEW POINT DEPRESSIONS WILL BE LARGER.
THE DOWNWARD TREND IN CONVECTION CONTINUES ON THURSDAY AS DRIER
WORKS A LITTLE FURTHER EAST. THERE WILL STILL BE SOME CONVECTION
AROUND, BUT MOST WOULD BE CONFINED TO EAST OF THE DIVIDE AGAIN AND
ESPECIALLY IN JOHNSON AND NATRONA COUNTIES WHERE THE DEEPEST
MOISTURE WILL REMAIN. TEMPERATURES LOOK LARGELY SIMILAR TO TODAY.
THE INVERSE RELATIONSHIP REALLY BEGINS ON FRIDAY AS RIDGING OVER THE
DESERT SOUTHWEST BEGINS TO PUSH NORTHWARD WITH RISING HEIGHTS AND
TEMPERATURES ALOFT. THIS IS THE DAY WHEN BELOW NORMAL PRECIPITABLE
WATERS WILL PUSH ACROSS THE ENTIRE AREA. WE CAN'T RULE OUT A STRAY
SHOWER OR THUNDERSTORM, MAINLY OVER THE NORTHERN MOUNTAINS, BUT EVEN
HERE THE CHANCE IS LESS THAN 1 OUT OF 5. TEMPERATURES WILL ALSO
BEGIN TO REALLY RISE, WITH THE NORMALLY WARMER SPOTS SEEING HIGH
TEMPERATURES APPROACHING 100.
IT IS SATURDAY WHEN WE REALLY BEGIN TO THROW SOME COAL INTO THE
BLAST FURNACE, OTHERWISE KNOWN AS A DEATH RIDGE. HEIGHTS ACROSS THE
AREA WILL CLIMB TO OVER 5950 METERS AT 500 MILLIBARS, AND BRING
DEFINITELY THE HOTTEST WEATHER OF THE YEAR. THE NBM ENSEMBLE GIVES A
GREATER THAN 1 OUT OF 2 CHANCE OF HIGH TEMPERATURES ABOVE 100
DEGREES IN LOCATIONS 5200 FEET OR BELOW, WITH A NEARLY 100 PERCENT
CHANCE IN THE WARMER SPOTS LIKELY FROM THERMOPOLIS UP TO GREYBULL.
ALL LOCATIONS BELOW 6500 FEET HAVE A 4 OUT OF 5 CHANCE OF
TEMPERATURES OVER 90 DEGREES. SOME RECORDS WILL LIKELY FALL ON THIS
DAY. WITH THE DRY AIR IN PLACE AND WARM TEMPERATURES ALOFT, THE
CHANCE OF CONVECTION LOOKS JUST ABOUT NIL.
HOWEVER, THE HEAT LOOKS TO PEAK ON MONDAY. THIS MORNINGS GUIDANCE
SHOWS 700 MILLIBAR TEMPERATURES CLIMBING AS HIGH AS 24 DEGREES
CELSIUS. THIS COMBINED WITH NEARLY FULL SUNSHINE WILL LEAD TO ONE
OF THE HOTTEST DAYS IN QUITE A WHILE. ENSEMBLE GUIDANCE SHOWS A
NEARLY 100 PERCENT CHANCE OF HIGH TEMPERATURES OVER 100 DEGREES
BELOW 5500 FEET, AND PLACES LIKE ROCK SPRINGS, GREEN RIVER AND
EVEN JACKSON HAVE A GREATER THAN 1 OUT 3 CHANCE OF HIGH TEMPERATURES
OVER 100 DEGREES. WHEN WE GO UP TO 105 DEGREES, ENSEMBLE GUIDANCE
GIVES A GREATER THAN 4 OUT OF 5 CHANCE OF THIS FROM THERMOPOLIS TO
GREYBULL, WITH RIVERTON EVEN HAVING A 1 OUT OF 2 CHANCE. AND GOING
UP EVEN FURTHER, TO 110, THERE IS A 2 OUT OF 5 CHANCE A PLACE LIKE
GREYBULL OR WORLAND COULD REACH THIS TEMPERATURE. WE COULD SEE SOME
ALL TIME HIGH TEMPERATURES FALL ON THIS DAY AS THE 5980 500 MILLIBAR
RIDGE WILL BE CENTERED JUST ABOUT OVER WYOMING.
WE SHOULD BEGIN TO TAKE A COUPLE OF DEGREES OFF OF THE HIGHS ON
MONDAY AS THE RIDGE RETREATS TO THE EAST JUST A BIT. HOWEVER, MOST
AREAS BELOW 5500 FEET WILL AGAIN HAVE AT LEAST A 1 IN 2 CHANCE OF
HIGH TEMPERATURES ABOVE 100 DEGREES. AND WITH THE RIDGE MOVING EAST,
SOME MOISTURE, MAINLY OF THE MID LEVEL VARIETY WILL BEGIN TO COME
AROUND THE BACK SIDE OF THE RIDGE. A COUPLE OF STORMS ARE POSSIBLE
ON MONDAY, BUT CHANCES INCREASE MORE ON TUESDAY AND INTO WEDNESDAY.
WITH THE LOW LEVELS REMAINING RATHER DRY, THESE THUNDERSTORMS WOULD
PRODUCE MORE WIND THAN RAIN THOUGH. CONVECTION SHOULD BE ON THE
ISOLATED SIDE THOUGH WITH MOST LOCATIONS NOT SEEING ONE ON ANY GIVEN
DAY. TEMPERATURES WILL DROP SOMEWHAT FROM THE BLAST FURNACE LEVELS
OF THE WEEKEND, BUT LOOK TO REMAIN ABOVE NORMAL THROUGH THE MIDDLE
OF NEXT WEEK.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1000 PM MDT WED JUL 8 2026
VFR CONDITIONS PREVAIL OVER THE NEXT 24 HOURS FOR MOST SITES. A FEW
ISOLATED SHOWERS LINGER THIS EVENING, BUT THESE SHOULD LARGELY
END BY MIDNIGHT (09/0600Z). MID-LEVEL CLOUD DECKS HANG AROUND
IN CENTRAL WYOMING OVERNIGHT INTO THE MORNING HOURS, AND BY
MID-MORNING, CPR COULD SEE SOME VIRGA (LIGHT SHOWERS EVAPORATING
BEFORE THEY HIT THE GROUND). THESE COULD LEAD TO SOME UNEXPECTED
GUSTS FROM VARIABLE DIRECTIONS AT (AND ABOVE) CPR DURING THE
MORNING HOURS.
DURING THE AFTERNOON HOURS, LND AND RIW EACH HAVE A SLIGHT
CHANCE (PROB30 GROUPS ADDED) OF AFTERNOON THUNDERSTORMS WITH
ERRATIC, GUSTY (35 TO 45 KT) WINDS. OTHER SITES HAVE A SMALLER
BUT NON-ZERO CHANCE OF AN ISOLATED STORM NEARING THE AIRPORT,
SO ADDED BKN AND OVC DECKS AT THESE SITES TO HINT AT THE
POSSIBILITY. RKS NOW LOOKS TO REMAIN SOUTH OF THE BETTER LIFT,
SO REMOVED THE PROB30 AT THAT LOCATION FOR THE 06Z SET OF TAFS.
ANY ISOLATED STORMS AND SHOWERS QUICKLY END AFTER SUNSET
THURSDAY.
RIW WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...LOWE
DISCUSSION...HATTINGS
AVIATION...VANDENBOOGART
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