766
FXUS65 KPIH 290350
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
950 PM MDT MON SEP 28 2026
KEY MESSAGES
- ISOLATED LATE AFTERNOON/EVENING STORMS EAST OF I-15:
LINGERING CLOUDINESS AND WEAK SHORTWAVE ENERGY WILL SPARK
ISOLATED SHOWERS AND A STRAY THUNDERSTORM LATE THIS AFTERNOON
AND EVENING, PRIMARILY FOCUSED EAST OF THE I-15 CORRIDOR.
- SEASONABLE TEMPERATURES EARLY THIS WEEK: HIGH TEMPERATURES
MONDAY THROUGH WEDNESDAY WILL HOVER NEAR SEASONAL AVERAGES,
REACHING THE UPPER 60S TO LOWER 70S ACROSS LOWER ELEVATIONS.
- UNSEASONABLY WARM EARLY OCTOBER: UPPER-LEVEL RIDGING BUILDS
OVER THE INTERMOUNTAIN WEST STARTING THURSDAY, BRINGING HIGH
CONFIDENCE IN DRY WEATHER AND TEMPERATURES 7 TO 10 DEGREES
ABOVE NORMAL (MID-TO-UPPER 70S, WITH LOCALIZED SPOTS TOUCHING
80°F).
DISCUSSION
ISSUED AT 127 PM MDT MON SEP 28 2026
CLOUD COVER CONTINUES TO GRADUALLY DECREASE FROM WEST TO EAST
ACROSS THE REGION THIS AFTERNOON AS A WEAK LOW-PRESSURE SYSTEM
POSITIONED TO OUR SOUTH LOSES ITS INFLUENCE ON EASTERN IDAHO'S
WEATHER. LINGERING MOISTURE AND CLOUDINESS REMAIN ANCHORED OVER
FAR EASTERN AND SOUTHEASTERN ZONES. HIGH-RESOLUTION CONVECTIVE-
ALLOWING MODELS (CAMS) INDICATE SUFFICIENT INSTABILITY TO
GENERATE ISOLATED SHOWERS AND PERHAPS A STRAY THUNDERSTORM LATER
THIS AFTERNOON AND EVENING, GENERALLY FOCUSED EAST OF THE I-15
CORRIDOR. PRECIPITATION CHANCES WILL DIMINISH RAPIDLY LATE THIS
EVENING, BECOMING NON-EXISTENT BY MIDNIGHT AS ATMOSPHERIC DRYING
TAKES HOLD. OVERNIGHT LOWS WILL REMAIN SEASONABLY COOL UNDER
CLEARING SKIES.
A BROAD, TRANQUIL WEATHER REGIME TAKES OVER ACROSS EASTERN
IDAHO FOR THE FIRST HALF OF THE WORKWEEK. WITH THE DEPARTING
SYSTEM WELL TO THE SOUTH AND HIGH PRESSURE BEGINNING TO
ORGANIZE TO THE WEST, PRECIPITATION CHANCES REMAIN NEAR ZERO.
DAYTIME HIGH TEMPERATURES TUESDAY AND WEDNESDAY WILL HOVER RIGHT
AROUND LATE- SEPTEMBER CLIMATOLOGICAL NORMS, TOPPING OUT IN THE
UPPER 60S TO LOWER 70S ACROSS LOWER-ELEVATION VALLEYS.
CONFIDENCE REMAINS VERY HIGH IN A PROLONGED DRY AND UNSEASONABLY
WARM WEATHER PATTERN DEVELOPING THURSDAY AND EXTENDING INTO THE
FIRST WEEK OF OCTOBER. GLOBAL MODEL ENSEMBLES ARE IN STRONG
AGREEMENT THAT AN UPPER-LEVEL RIDGE WILL BUILD DIRECTLY OVER THE
INTERMOUNTAIN WEST ON THURSDAY AND REMAIN ANCHORED OVER THE
REGION THROUGH THE WEEKEND. RISING 500 MB HEIGHTS AND SUBSIDENCE
WILL DRIVE A NOTICEABLE WARMING TREND, PUSHING DAYTIME MAXIMUM
TEMPERATURES 7 TO 10 DEGREES ABOVE SEASONAL AVERAGES. LOWER-
ELEVATION VALLEYS WILL WIDESPREAD REACH THE MID-TO-UPPER 70S
STARTING THURSDAY, WITH LOCALIZED SPOTS LIKELY TOPPING 80°F
DURING PEAK DIURNAL HEATING. GIVEN THE STRENGTH AND POSITIONING
OF THE RIDGE, MEASURABLE PRECIPITATION IS HIGHLY UNLIKELY
THROUGH THE UPCOMING WEEKEND AND LIKELY THROUGH MUCH OF THE
FOLLOWING WEEK AS WELL.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 950 PM MDT MON SEP 28 2026
WINDS HAVE GONE LIGHT IN MANY AREAS FOR THE NIGHT. WILL PROBABLY
SEE UP TO 10KTS OVERNIGHT AND INTO TUESDAY AT PIH/BYI. SHOWERS
ARE CONTINUING TO WEAKEN AS THE EVENING GOES ON AND ANTICIPATE
CLEAR OR MOSTLY CLEAR SKIES FOR OVERNIGHT.
FIRE WEATHER
ISSUED AT 127 PM MDT MON SEP 28 2026
UPPER LEVEL LOW AND TROUGHING CONTINUE TO MOVE EASTWARD THROUGH THE
REST OF TODAY AND TONIGHT. THIS KEEPS MOST OF THE SHOWER AND
ISOLATED THUNDERSTORM ACTIVITY CONFINED TO THE EASTERN AND
SOUTHEASTERN HIGHLANDS, BUT SOME ISOLATED ACTIVITY CONTINUES IN THE
CENTRAL MOUNTAINS THROUGH THE EVENING. BY TOMORROW AFTERNOON, WEAK
HIGH PRESSURE BEGINS TO BUILD BACK IN OVER THE AREA AND A SLOW,
MODEST WARMING TREND STARTS. HIGHS ON TUESDAY WILL GENERALLY BE IN
THE UPPER 60S TO LOW 70S ACROSS THE AREA WITH AFTERNOON WIND GUSTS
AROUND 15 TO 20 MPH WITH GUSTS TO 25 MPH IN PARTS OF THE SOUTH HILLS
AND EASTERN MAGIC VALLEY. MIN RHS WILL BE DRIER ON TUESDAY, RANGING
FROM THE MID 20S TO LOW 30S THROUGH MOST OF THE EASTERN MAGIC
VALLEY, SOUTH HILLS, CENTRAL MOUNTAINS, AND SNAKE RIVER PLAIN.
HOWEVER, MOISTURE LINGERS A BIT LONGER IN THE EAST WITH MIN RHS
AROUND 35 TO 40 PERCENT. THROUGHOUT MOST OF THE WEEK, EXPECT
AFTERNOON RHS TO RANGE FROM 20-35 PERCENT AND HIGHS WILL PEAK ON
FRIDAY WITH THE LOWER ELEVATIONS MAKE IT BACK INTO THE UPPER 70S AND
LOW 80S, WHICH IS ABOUT 10 DEGREES ABOVE OUR "NORMALS" FOR THIS TIME
OF YEAR. AFTER OUR PRECIPITATION TODAY, THE REST OF THE WEEK LOOKS
DRY.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...MCKAUGHAN
AVIATION...13
FIRE WEATHER...AMM
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