400
FXUS65 KPIH 011928
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
128 PM MDT TUE SEP 1 2026
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS CONTINUE FOR THE NEXT FEW DAYS WITH
GUSTY WINDS AND HEAVY DOWNPOURS POSSIBLE
- CRITICAL TO NEAR-CRITICAL FIRE WEATHER CONDITIONS DUE TO
THUNDERSTORMS THROUGH THIS EVENING AND WIND/HUMIDITY WEDNESDAY
- RAIN CHANCES INCREASE THIS WEEKEND AND EARLY NEXT WEEK AS
MONSOON MOISTURES INCREASES DUE TO POTENTIAL TROPICAL
CONNECTIONS
DISCUSSION
ISSUED AT 1154 AM MDT TUE SEP 1 2026
AS LOW PRESSURE SETTLES ALONG THE COAST FOR THE NEXT SEVERAL
DAYS, WE WILL SEE MULTIPLE "RIPPLES" SWING AROUND THROUGH DURING
THAT STRETCH. WE HAVE ONE OF THOSE RIPPLES CROSSING THIS STATE
THROUGH TONIGHT. THE HIGHEST CHANCES THROUGH LATE
AFTERNOON/EARLY EVENING WILL BE ACROSS THE CENTRAL MOUNTAINS
SOUTH THROUGH THE MAGIC VALLEY AND SOUTH HILLS/ALBION MOUNTAINS.
BESIDES THE POTENTIAL FOR SOME LOCALLY HEAVIER RAINFALL, THERE
IS A 50-90% CHANCE OF FOR GUSTS OVER 35 MPH WITH THE STRONGEST
STORMS. HIGH END GUSTS UP TO 45 MPH ARE POSSIBLE OVER MOST OF
EASTERN IDAHO, WITH A CORRIDOR OF GUSTS APPROACHING 60 MPH
POTENTIALLY ACROSS THE MAGIC VALLEY, LOWER SNAKE PLAIN, AND
SOUTH HILLS/ALBION MOUNTAINS. THROUGH THIS EVENING AND
OVERNIGHT, THE BETTER CHANCE OF SHOWERS AND STORMS WILL EXISTS
NORTH OF A SHOSHONE TO DRIGGS LINE. GUSTY WINDS AND A GOOD
DOWNPOUR ARE POSSIBLE WITH STORMS, EVEN PAST MIDNIGHT. THE FOCUS
QUICKLY SHIFTS TO THE CENTRAL MOUNTAINS TOMORROW. WE HAVE A
SLIGHTLY STRONGER "RIPPLE" RACING NORTHEAST. AS DRIER AIR WORKS
IN ACROSS MOST OF EASTERN IDAHO, ENOUGH MOISTURE AND PROXIMITY
TO THE LOW ITSELF WILL KEEP A DECENT CHANCE OF RAIN AND
THUNDERSTORMS ACROSS THE CENTRAL MOUNTAINS. IT IS POSSIBLE A
STORM OR TWO DEVELOPS ACROSS THE EASTERN HIGHLANDS, BUT THAT IS
STILL UNDER 20%. GUSTS OVER 35 MPH WITH STORMS IN THE CENTRAL
MOUNTAINS REMAINS POSSIBLE, ALTHOUGH TIMING SUGGESTS THE
STRONGEST WINDS DEVELOP ACROSS WESTERN MONTANA. THE MAIN IMPACT
WILL INCREASING WIND ACROSS THE REST OF EASTERN IDAHO.
SUSTAINED WINDS OF 15-30 MPH WITH HIGHER GUSTS ARE EXPECTED,
WITH A FAIRLY NARROW CORRIDOR OF SUSTAINED 30-35 MPH WITH GUSTS
CLOSER TO 45 MPH FROM CRATERS TO MONIDA PASS. WE DECIDED TO NOT
ISSUE A WIND ADVISORY FOR TOMORROW DUE TO THE LOCALIZED COVERAGE
OF HIGHEST WINDS, BUT THAT MAY NEED TO CHANGE BASED ON TRENDS
OVER THE NEXT 6-12 HOURS. WE WILL BRIEFLY REACH LAKE WIND
ADVISORY FOR AMERICAN FALLS RESERVOIR, BUT AGAIN WE WILL OPT OF
THAT FOR NOW BASED ON THE LIMITED TIMEFRAME. FOR THURSDAY, THE
PATTERN REALLY DOESN'T CHANGE MUCH FROM TOMORROW. ANY POTENTIAL
FOR SHOWERS AND STORMS IS CONFINED TO THE CENTRAL MOUNTAINS.
SOME HIGHER RESOLUTION MODELS WANT TO SPREAD THAT INTO PORTIONS
OF THE MAGIC VALLEY AND ALSO EASTERN HIGHLANDS, BUT WILL LET THE
CURRENT BLEND OF MODELS FORECAST RIDE. IT WILL BE BREEZY AGAIN,
SLIGHTLY "WEAKER" THAN WEDNESDAY. THE PATTERN WILL BRING IN
COOLER CONDITIONS, ESPECIALLY FOR THE CENTRAL MOUNTAINS. HIGHER
VALLEYS WILL ONLY BE IN THE 60S AFTER TODAY, WITH LOWER VALLEYS
RUNNING IN THE 70S TO NEAR 80.
THIS PATTERN REALLY DOESN'T BUDGE UNTIL WE GET TO SUNDAY AND
BEYOND. IN FACT, WE MAY SEE ENOUGH DRIER AIR THAT ONLY LOW
CHANCES OF SHOWERS AND STORMS OCCUR ACROSS THE CENTRAL MOUNTAINS
FRIDAY AND ESPECIALLY SATURDAY. WE DO SEE A SMALL REBOUND IN
TEMPERATURES BOTH DAYS, WITH SOME LOW 80S RETURNING FOR SOME
VALLEY LOCATIONS. THE FORECAST GETS A BIT TRICKY FOR EARLY NEXT
WEEK. THERE IS A WINDOW WHERE WE DO SEE A SURGE OF MONSOON
MOISTURE, INCLUDING TAPPING INTO WHAT'S ASSOCIATED WITH CURRENT
TROPICAL STORM MARIE. THE ECMWF AND ASSOCIATED MODELS, AS WELL
AS THE GEFS AND AIGFS, HAVE A SHORTER WINDOW WHERE WE SEE THAT
SURGE OF MOISTURE VS. THE MAIN GFS MODEL. ALL OF THE MODELS,
HOWEVER, KEEP LOW PRESSURE OVER THE WESTERN U.S. DESPITE ANY
TYPE OF INTERACTION WITH MARIE. THIS SHOULD DROP HIGHS BACK INTO
THE 60S AND 70S DURING THAT PERIOD.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1138 AM MDT TUE SEP 1 2026
SHRA AND TSRA ARE RETURNING TONIGHT WITH PROBABILITIES IN THE
PROB30 THREAT, MOSTLY. BY 01/22Z SHRA/TSRA SHOULD BE DEVELOPING
EVERYWHERE, ALTHOUGH IT CAN BE SAID THAT AT KDIJ THE SHRA HASN'T
STOPPED WITH THE ON AND OFF CIG ISSUES THIS MORNING.
NOT EXPECTING FURTHER IMPACT TO CIG ANYWHERE DURING THE
AFTERNOON AND EVENING TONIGHT. HOWEVER, OVERNIGHT KDIJ WILL BE
ONCE MORE SUSCEPTIBLE TO MARGINAL VFR DUE TO SHRA.
VSBY IN TSRA COULD BE REDUCED, BUT STILL NOT EXPECTING ANYTHING
LOWER THAN MARGINAL VFR.
WITH AN APPROACHING LOW FROM THE SOUTH, MODERATE SOUTHERLY WIND
WILL DEVELOP OVERNIGHT, WITH A GENERAL G25KT LIKELY IN THE
NORMALLY CALM OR NEAR-CALM MORNING HOURS. G45KT LIKELY IN TSRA
OUTFLOW, ALTHOUGH THE FARTHER EAST THE LOWER THE GUSTS.
FIRE WEATHER
ISSUED AT 119 PM MDT TUE SEP 1 2026
INSTEAD OF ISSUING YET ANOTHER RED FLAG WARNING FOR FWFZ 422,
HAVE EXTENDED THE CURRENT ONE, AS THUNDERSTORM ACTIVITY IN THAT
ZONE WILL INCREASE AGAIN SOMEWHERE AROUND 0600 MDT AND CONTINUE
UNTIL 1500 OR SO IN THE AFTERNOON. THE AREA OF THUNDERSTORMS
WILL PUSH FROM SOUTH TO NORTH OVER THE REGION, AND THE ACTIVITY
WILL MOVE INTO THE SALMON-CHALLIS NF BY THAT TIME.
THE RED FLAG WAS NECESSARY AS A TROUGH WITH ASSOCIATED SURFACE
FRONT MOVES IN FROM THE SOUTHWEST, PUSHING THE FRONT THROUGH
FROM SOUTH TO NORTH OVER CENTRAL IDAHO. THE RESULT WILL BE MUCH
WINDIER CONDITIONS OVER ALL OF THE FIRE WEATHER DISTRICT, AND
ISOLATED SHOWERS AND THUNDERSTORMS IN WESTERN PORTIONS
CONTINUING ALL WED, THU, AND FRI. MEANWHILE, THE EASTERN
PORTIONS HAVE MOSTLY ISOLATED THUNDERSTORM ACTIVITY FOR TONIGHT,
WEDNESDAY, AND THURSDAY. LITTLE RAINFALL, SO THE EFFECTS WILL
BE MAINLY ONE DAY OF STRONG COOLING, THEN A GRADUAL WARMING AND
DRYING. WIND WILL CONTINUE TO BE A FACTOR, STAYING MODERATE TO
STRONG. CURRENTLY, HUMIDITY READINGS ARE EXPECTED TO STAY IN THE
UPPER TEENS AND HIGHER, BUT WILL HAVE TO BE MONITORED AND COULD
CHANGE DEPENDING ON HOW MUCH PRECIPITATION DEVELOPS FROM THE
ORIGINAL LOW.
PIH WATCHES/WARNINGS/ADVISORIES
RED FLAG WARNING UNTIL 3 PM MDT WEDNESDAY FOR IDZ422.
DISCUSSION...KEYES
AVIATION...MESSICK
FIRE WEATHER...MESSICK
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