873
FXUS65 KPIH 061935
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
135 PM MDT TUE OCT 6 2026
KEY MESSAGES
- QUIET & UNSEASONABLY WARM THROUGH FRIDAY: AFTERNOON SATELLITE
IMAGERY REMAINS CLEAR, WITH ABNORMALLY WARM OCTOBER
TEMPERATURES AND ZERO PRECIPITATION CHANCES CONTINUING THROUGH
THE END OF THE WORKWEEK.
- BREEZY & COOLER SATURDAY SHIFT: A TIGHTENING PRESSURE
GRADIENT AHEAD OF AN APPROACHING PACIFIC LOW WILL BOOST WINDS
ON SATURDAY WHILE LOWERING TEMPERATURES, THOUGH READINGS WILL
REMAIN SLIGHTLY ABOVE NORMAL UNTIL LATE AFTERNOON RAIN
ARRIVES.
- CUTOFF LOW EVOLUTION (SUNDAY–EARLY NEXT WEEK): MODELS ARE
TRENDING TOWARD A CUTOFF LOW OVER CENTRAL CALIFORNIA AND
NEVADA SUNDAY INTO MONDAY. THIS SETUP WILL TAP INTO MOIST
SOUTHERLY FLOW, BRINGING PERSISTENT RAIN AND MOUNTAIN SNOW
ACROSS EASTERN IDAHO.
- DRASTIC FALL COOLDOWN & SNOW POTENTIAL: HIGH CONFIDENCE
REMAINS IN A MAJOR SHIFT TO COOL, WET WEATHER. HIGH-ELEVATION
SNOW IS LIKELY, WITH A NON-ZERO POTENTIAL FOR SNOWFLAKES
REACHING THE SNAKE PLAIN AND MAGIC VALLEY FLOOR DEPENDING ON
EXACT LOW PLACEMENT.
DISCUSSION
ISSUED AT 128 PM MDT TUE OCT 6 2026
AFTERNOON SATELLITE IMAGERY SHOWS VIRTUALLY NO CLOUD COVER
ACROSS EASTERN IDAHO AS QUIET AND ABNORMALLY WARM OCTOBER
WEATHER CONTINUES. A STABLE SYNOPTIC REGIME WILL MAINTAIN THIS
PATTERN THROUGH THE END OF THE WORKWEEK, WITH ONLY SUBTLE DAY-
TO-DAY TEMPERATURE FLUCTUATIONS AND NO APPRECIABLE CHANCES FOR
PRECIPITATION. HIGHS WILL RUN WELL ABOVE SEASONAL CLIMATOLOGICAL
NORMS, ACCOMPANIED BY LIGHT WINDS AND CLEAR OVERNIGHT SKIES.
WEATHER CONDITIONS BEGIN TO TRANSITION DRASTICALLY ON SATURDAY
AS A POTENT UPPER-LEVEL TROUGH APPROACHES THE INTERMOUNTAIN
WEST. SURFACE WINDS WILL PICK UP NOTICEABLY DURING THE DAY AS
THE REGIONAL PRESSURE GRADIENT TIGHTENS. INCREASED CLOUD COVER
AND WIND MIXING WILL INITIATE A COOLING TREND, THOUGH DAYTIME
MAXIMUM TEMPERATURES WILL STILL MANAGE TO HOLD A FEW DEGREES
ABOVE SEASONAL AVERAGES ACROSS MOST VALLEYS. CLOUD COVER AND
PRECIPITATION PROBABILITIES WILL INCREASE RAPIDLY DURING THE
SECOND HALF OF SATURDAY, SPREADING FROM SOUTHWEST TO NORTHEAST.
A MAJOR AIRMASS CHANGE OVERSPREADS EASTERN IDAHO FOR THE SECOND
HALF OF THE WEEKEND INTO EARLY NEXT WEEK, DROPPING TEMPERATURES
WELL BELOW SEASONAL NORMALS. OPERATIONAL MODELS AND HAVE TRENDED
TOWARD CONSOLIDATING A CUTOFF LOW OVER CENTRAL CALIFORNIA AND
NEVADA SUNDAY INTO MONDAY BUT VARIOUS ENSEMBLES STILL HAVE
SLIGHTLY DIFFERENT OPINIONS ON WHERE THE LOW EVENTUALLY GOES.
ASSUMING THE FORMER SOLUTIONS PANS OUT, THIS SYNOPTIC EVOLUTION
WOULD LOCK A MOIST SOUTHERLY TO SOUTHWESTERLY FLOW OVER EASTERN
IDAHO, MAINTAINING PERSISTENT PRECIPITATION CHANCES THROUGH
EARLY NEXT WEEK. WHILE A CUTOFF LOW TRAJECTORY CAN RESULT IN
SLIGHTLY MILDER THERMAL PROFILES COMPARED TO A DEEP OPEN TROUGH,
IT SIGNIFICANTLY INCREASES QPF POTENTIAL AND DURATION. HIGH-
ELEVATION SNOWFALL IS LOOKING INCREASINGLY LIKELY, AND DEPENDING
ON HOW DYNAMICALLY COLD AIR IS PULLED INTO THE LOW'S
CIRCULATION, SNOW COULD POTENTIALLY MIX DOWN TO THE VALLEY
FLOORS OF THE SNAKE PLAIN AND MAGIC VALLEY. WHILE MINOR
UNCERTAINTY REMAINS REGARDING THE EXACT TRACK AND TIMING OF THE
LOW, CONFIDENCE IS VERY HIGH IN A PROLONGED TRANSITION TO A
COOL, WET AUTUMN PATTERN. BELOW-NORMAL TEMPERATURES AND PERIODIC
RAIN/SNOW SHOWERS WILL PERSIST INTO NEXT WEEK. FORECAST UPDATES
WILL REFINE SNOW LEVELS AND QPF TOTALS AS GUIDANCE CONVERGES
OVER THE COMING DAYS.
AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 1121 AM MDT TUE OCT 6 2026
NO AVIATION IMPACTS EXPECTED THROUGH WEDNESDAY MORNING. MAINLY
CLEAR SKIES WITH LIGHT WINDS MAINLY UNDER 10 KNOTS. WILL HAVE
THE DIURNAL WIND SHIFTS AT SUN THROUGH THE PERIOD. AFTERNOON
WINDS AT THE OTHER SITES APPROACHING 10 KNOTS AFTER 18Z.
FIRE WEATHER
ISSUED AT 128 PM MDT TUE OCT 6 2026
TREND THROUGH FRIDAY REMAINS VERY HOT WITH DRY CONDITIONS WITH
MINIMUM HUMIDITY IN THE 15 TO 25 PERCENT RANGE WITH SEVERAL
LOCATIONS DROPPING BELOW 15 PERCENT AND HIGHS IN THE 70S AND 80S FOR
THE MOST PART. GENERALLY 15 TO 20 DEGREES ABOVE NORMAL FOR THE HIGH
TEMPERATURES. NO PRECIPITATION IS EXPECTED THROUGH FRIDAY WITH
WINDS INCREASING AND GUSTS FRIDAY IN THE 20 TO 35 MPH RANGE.
THE BIG PATTERN CHANCE WILL BEGIN TO TAKE SHAPE SATURDAY WITH
WIDESPREAD RAIN MOVING INTO THE REGION MAIN SATURDAY NIGHT.
THERE IS AT LEAST A 50 PERCENT CHANCE OR GREATER OF WETTING
RAINS ALL LOCATIONS SATURDAY EVENING THROUGH MONDAY EVENING.
WILL START TO SEE COOLING TEMPERATURES SATURDAY WITH MUCH
COOLER CONDITIONS SUNDAY AND MONDAY WITH THE EXTENSIVE
PRECIPIATION EXPECTED. HIGHS LIKELY DOWN TO THE 40S MOUNTAINS
AND 50S TO LOWER 60S VALLEYS.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MCKAUGHAN
AVIATION...GK
FIRE WEATHER...GK
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