568
FXUS65 KPIH 051908
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
108 PM MDT MON OCT 5 2026
KEY MESSAGES
- NEAR-RECORD HEAT TODAY: UNSEASONABLY WARM OCTOBER WEATHER
CONTINUES TODAY WITH VALLEY HIGHS IN THE LOWER-TO-MID 80S.
ISOLATED AFTERNOON SHOWERS OR STORMS IN THE SOUTH HILLS AND ALONG
THE MONTANA DIVIDE COULD PRODUCE GUSTY WINDS, THOUGH MOST
AREAS STAY DRY.
- CONTINUED WARM MID-WEEK: THE SOUTHERN RIDGE GETS SUPPRESSED
SLIGHTLY TUESDAY THROUGH FRIDAY, COOLING HIGHS BY A FEW
DEGREES WHILE REMAINING 10 TO 15 DEGREES ABOVE NORMAL UNDER
ZONAL FLOW ALOFT
- BREEZY SATURDAY TRANSITION: WINDS WILL INCREASE ON SATURDAY
AS THE REGIONAL PRESSURE GRADIENT TIGHTENS AHEAD OF AN
APPROACHING PACIFIC NORTHWEST TROUGH, HOLDING HIGHS IN THE 60S
AND 70S.
- DRASTIC COOLDOWN & RAIN/SNOW (SUNDAY–EARLY NEXT WEEK): HIGH
CONFIDENCE IN A MAJOR FALL PATTERN SHIFT SUNDAY AND MONDAY,
BRINGING A SHARP TEMPERATURE DROP, RAIN, MOUNTAIN SNOW, AND
EVEN THE POTENTIAL FOR VALLEY SNOW FLAKES DEPENDING ON THE
FINAL EVOLUTION OF THE SYSTEM
DISCUSSION
ISSUED AT 106 PM MDT MON OCT 5 2026
AN UNUSUALLY WARM OCTOBER WEATHER PATTERN REMAINS FIRMLY
ESTABLISHED ACROSS EASTERN IDAHO TODAY. AFTERNOON SATELLITE
IMAGERY DISPLAYS MID-TO-HIGH LEVEL CLOUDINESS DRIFTING OVERHEAD,
BUT NEAR-RECORD TO RECORD HIGH TEMPERATURES ARE STILL EXPECTED
AS LOWER-ELEVATION VALLEYS CLIMB INTO THE LOWER-TO-MID 80S.
HIGH-RESOLUTION CONVECTIVE-ALLOWING MODELS (CAMS) INDICATE A
LOW-END CHANCE FOR AN ISOLATED SHOWER OR THUNDERSTORM TO DEVELOP
LATER THIS AFTERNOON ACROSS THE SOUTH HILLS OR ALONG THE
MONTANA DIVIDE. WHILE ATMOSPHERIC MOISTURE IS LIMITED—KEEPING
PRECIPITATION ACCUMULATION MINIMAL—PASSING CELLS WILL BE CAPABLE
OF GENERATING LOCALIZED GUSTY DOWNDRAFT WINDS. THE VAST
MAJORITY OF EASTERN IDAHO WILL REMAIN DRY AND UNSEASONABLY HOT.
THE UPPER-LEVEL RIDGE ANCHORED TO OUR SOUTH GETS SUPPRESSED ON
TUESDAY AS 500 MB HEIGHTS DIP SLIGHTLY ACROSS THE INTERMOUNTAIN
WEST. IN RESPONSE, DAYTIME MAXIMUM TEMPERATURES WILL DROP A FEW
DEGREES TUESDAY THROUGH FRIDAY UNDER A PREDOMINANTLY ZONAL FLOW
REGIME. DESPITE THIS MINOR TEMPERATURE REDUCTION, AFTERNOON
HIGHS WILL CONTINUE TO RUN 10 TO 15 DEGREES ABOVE SEASONAL
CLIMATOLOGICAL NORMS. DRY CONDITIONS AND LIGHT-TO-MODERATE
SURFACE WINDS WILL PREVAIL THROUGH THE END OF THE WORKWEEK.
WEATHER CONDITIONS BEGIN TO TRANSITION ON SATURDAY AS GLOBAL
GUIDANCE TRACKS A POTENT UPPER-LEVEL LOW DIGGING INTO THE
PACIFIC NORTHWEST. AS THE REGIONAL PRESSURE GRADIENT TIGHTENS
AHEAD OF THE APPROACHING TROUGH, SURFACE WINDS WILL INCREASE
MARKEDLY ACROSS THE SNAKE PLAIN AND HIGHER TERRAIN. INCREASED
CLOUD SHADING AND WIND MIXING WILL CAP SATURDAY HIGH
TEMPERATURES IN THE 60S AND 70S. WHILE THESE READINGS REMAIN
SLIGHTLY ABOVE SEASONAL AVERAGES, SATURDAY MARKS THE LEADING
EDGE OF A SIGNIFICANT AIRMASS CHANGE.
CONFIDENCE CONTINUES TO INCREASE IN A DRASTIC COOLDOWN ARRIVING
SUNDAY AND EXTENDING INTO EARLY NEXT WEEK AS THE PARENT UPPER
LOW CROSSES THE REGION. WHILE ENSEMBLE GUIDANCE EXHIBITS ONGOING
SPREAD REGARDING THE EXACT DEPTH AND TRACK OF THE SYSTEM,
SIGNIFICANT COLD ADVECTION, WIDESPREAD PRECIPITATION, AND
ELEVATED WINDS APPEAR INCREASINGLY LIKELY. CURRENT NATIONAL
BLEND OF MODELS (NBM) THERMAL GUIDANCE APPEARS TO SIT ON THE
WARM SIDE OF LATEST MODEL RUNS, SUGGESTING DAILY HIGH
TEMPERATURES MAY TREND EVEN LOWER IN UPCOMING FORECAST CYCLES.
HIGH-ELEVATION MOUNTAIN SNOW IS LOOKING INCREASINGLY PROBABLE
SUNDAY NIGHT INTO MONDAY, WITH GUIDANCE INDICATING A NON-ZERO
POSSIBILITY FOR VALLEY SNOW FLAKES DEPENDING ON HOW RAPIDLY COLD
AIR FILLS IN BEHIND THE FRONT. ADDITIONALLY, VALLEY FROST/FREEZE
CONDITIONS APPEAR POSSIBLE FOR EARLY NEXT WEEK. FORECAST DETAILS
WILL BE REFINED OVER THE COMING DAYS AS GUIDANCE CONVERGES, BUT
A DEFINITIVE SHIFT TOWARD TRUE FALL WEATHER IS ON THE HORIZON.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1043 AM MDT MON OCT 5 2026
OVERALL MINIMAL IMPACTS EXPECTED. THERE IS A VERY SLIGHT CHANCE
OF SOME CONVECTIVE ACTIVITY AND HAVE VICINITY OVERNIGHT AT BYI
AND SUN BUT LOW CONFIDENCE IN OCCURRING ON SITE. WINDS GENERALLY
REMAIN LIGHT AND MOSTLY UNDER 10 KNOTS THROUGH TUESDAY MORNING.
FIRE WEATHER
ISSUED AT 106 PM MDT MON OCT 5 2026
TREND THROUGH FRIDAY REMAINS VERY HOT WITH DRY CONDITIONS WITH
MINIMUM HUMIDITY IN THE 15 TO 25 PERCENT RANGE AND HIGHS IN THE 70S
AND 80S FOR THE MOST PART. GENERALLY 15 TO 20 DEGREES ABOVE NORMAL
FOR THE HIGH TEMPERATURES. THERE REMAINS A VERY SLIGHT CHANCE OF
CONVECTIVE ACTIVITY LATE TODAY AND TONIGHT INTO TUESDAY MAINLY IN
ZONES 427, 413, 422 AND 476 BUT VERY LOW CONFIDENCE IN ANY
PRECIPITATION. WINDS NOT FORECAST TO BE VERY STRONG THIS WEEK
THROUGH THURSDAY WITH SOME HIGH ELEVATION 15 TO 25 MPH GUSTS THE
HIGHEST. WILL SEE A PATTERN CHANGE FRIDAY INTO THE WEEKEND WITH
WINDS INCREASING FRIDAY AND SATURDAY AHEAD OF AN UPPER LEVEL TROF
AND SURFACE COLD FRONT WHICH MAY BRING SOME MUCH NEEDED
PRECIPITATION SUNDAY INTO NEXT MONDAY WITH MUCH COOLER TEMPERATURES.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MCKAUGHAN
AVIATION...GK
FIRE WEATHER...GK
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