730
FXUS65 KPIH 212343
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
543 PM MDT TUE JUL 21 2026
KEY MESSAGES
- FLASH FLOOD RISK & ACTIVE FLOOD WATCHES: DEEP MONSOONAL
MOISTURE CARRYING PRECIPITABLE WATER (PWAT) VALUES NEAR THE
99TH PERCENTILE HAS PROMPTED A FLOOD WATCH FOR THE EASTERN AND
SOUTHEASTERN HIGHLANDS, AS WELL AS THE WAPITI BURN SCAR IN
THE CENTRAL MOUNTAINS. SLOW-MOVING THUNDERSTORMS THROUGH
WEDNESDAY WILL BE CAPABLE OF TORRENTIAL RAINFALL, LOCALIZED
FLASH FLOODING, AND DEBRIS FLOWS ON RECENT BURN SCARS.
SECONDARY STORM HAZARDS INCLUDE GUSTY OUTFLOW WINDS AND SMALL
HAIL.
- PEAK MOISTURE WINDOW TODAY & WEDNESDAY: THIS 24–36 HOUR
STRETCH REPRESENTS THE WETTEST PERIOD OF THE 7-DAY FORECAST.
EXTENSIVE CLOUD COVER WILL KEEP DAYTIME HIGHS LIMITED TO THE
80S IN LOWER ELEVATIONS AND MID-TO-UPPER 70S IN THE MOUNTAINS.
- LATE-WEEK PATTERN SHIFT & RETURNING HEAT: A DRYING AND
WARMING TREND BEGINS THURSDAY. HIGH TEMPERATURES WILL CLIMB
BACK INTO THE MID-90S ACROSS LOWER VALLEYS THIS WEEKEND AND
INTO EARLY NEXT WEEK.
DISCUSSION
ISSUED AT 147 PM MDT TUE JUL 21 2026
A ROBUST PLUME OF MONSOONAL MOISTURE CONTINUES TO SURGE INTO
EASTERN IDAHO THIS AFTERNOON, SETTING THE STAGE FOR AN ACTIVE 24
TO 36 HOURS ACROSS THE REGION. ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS WILL CONTINUE TO DEVELOP THROUGH THE REMAINDER
OF THE AFTERNOON AND PERSIST INTO THE EARLY OVERNIGHT HOURS.
WHILE A BRIEF LULL IN CONVECTIVE COVERAGE IS POSSIBLE EARLY
WEDNESDAY MORNING, A SECONDARY, POTENT WAVE OF DEEP ATMOSPHERIC
MOISTURE WILL STREAM INTO THE AREA SHORTLY THEREAFTER.
PRECIPITABLE WATER (PWAT) VALUES ON WEDNESDAY WILL CLIMB WELL
ABOVE CLIMATOLOGICAL NORMS, APPROACHING THE 99TH PERCENTILE FOR
LATE JULY. THIS ATMOSPHERIC PROFILE WILL YIELD EXCEPTIONALLY
EFFICIENT, HEAVY-RAINFALL-PRODUCING SHOWERS AND THUNDERSTORMS.
GIVEN THE SLOW MOVEMENT OF THESE STORMS AND HIGH RAIN RATES,
LOCALIZED FLASH FLOODING IS A MAJOR CONCERN. CONSEQUENTLY, A
FLOOD WATCH HAS BEEN ISSUED FOR THE EASTERN AND SOUTHEASTERN
HIGHLANDS, AS WELL AS THE WAPITI BURN SCAR ACROSS THE CENTRAL
MOUNTAINS WHERE DEBRIS FLOWS WILL BE A HEIGHTENED RISK. WHILE
THE WATCH AREA CURRENTLY ENCOMPASSES THE HIGHEST CONFIDENCE FOR
HEAVY RAIN, AREAS OUTSIDE THE WATCH ACROSS EASTERN IDAHO REMAIN
VULNERABLE TO LOCALIZED FLASH FLOODING IF SLOW-MOVING CORES
TRACK DIRECTLY OVERHEAD. WIDESPREAD CLOUD COVER AND
PRECIPITATION WILL LIMIT DIURNAL HEATING, CAPPING WEDNESDAY
HIGHS IN THE 80S FOR LOWER ELEVATIONS AND THE MID-TO-UPPER 70S
ACROSS HIGHER TERRAIN. GUSTY OUTFLOW WINDS AND SMALL HAIL WILL
ALSO ACCOMPANY STRONGER CELLS.
WEDNESDAY INTO WEDNESDAY NIGHT WILL MARK THE WETTEST PHASE OF
THE 7-DAY PERIOD. BEGINNING THURSDAY, THE MAIN MONSOONAL
MOISTURE AXIS WILL END, INITIATING A TRANSITION BACK TO A WARMER
AND DRIER PATTERN HEADING INTO THE WEEKEND AND EARLY NEXT WEEK.
WHILE LINGERING MID-LEVEL MOISTURE WILL MAINTAIN LOW-END DAILY
SHOWER AND THUNDERSTORM CHANCES OVER THE HIGHER TERRAIN, OVERALL
CONVECTIVE COVERAGE WILL BE ISOLATED. HEAT WILL QUICKLY RE-
EMERGE AS THE PRIMARY OPERATIONAL IMPACT, WITH HIGH PRESSURE
BUILDING BACK OVER THE INTERMOUNTAIN WEST TO PUSH LOWER-
ELEVATION AFTERNOON HIGHS BACK INTO THE MID-90S AS EARLY AS
FRIDAY AND CONTINUING INTO EARLY NEXT WEEK AND LIKELY MUCH
LONGER.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 526 PM MDT TUE JUL 21 2026
CURRENTLY THERE IS A STRONG THUNDERSTORM FOR DIJ CREATING
IFR/MVFR CONDITIONS ALONG WITH HEAVY RAIN. PROB30 FOR
THUNDERSTORMS REMAINS IN THE TAF AT ALL SITES EXCEPT SUN FOR
THIS EVENING. MOST STORMS THAT GET GOING WILL LIKELY JUST BE
BREEZY WITH GUSTS OF 20 TO 25 KTS. HOWEVER, ANY STRONGER STORM
THAT DOES GET GOING, COULD PRODUCE STRONG GUSTS AROUND 25 TO
35KTS. THE THUNDERSTORM OVER DIJ SHOULD BE OUT OF THE AREA IN
THE NEXT HOUR. BYI HAS THE BEST CHANCE OF STORMS DEVELOPING THE
NEXT HOUR OR TWO. HOWEVER, OUTFLOWS COULD BRING A STORM TO IDA
AND, TO A LESSER DEGREE, PIH IN THE NEXT COUPLE OF HOURS. SO,
HAVE LEFT THUNDERSTORMS CHANCES IN FOR ALL SITES EXCEPT SUN (DIJ
FOR JUST ONE MORE HOUR). EXPECT LIGHT SHOWERS MOSTLY IN THE
VICINITY FOR ALL SITES OVERNIGHT.
SHOWERS AND STORMS INCREASE IN COVERAGE TOMORROW AND STORMS ON
WEDNESDAY AREN'T EXPECTED TO PRODUCE AS STRONG OF WIND GUSTS
SINCE THEY WILL PRODUCE MORE RAIN. HAVE PUT IN A PROB 30 FOR
THUNDERSTORMS FOR ALL TAF SITES FOR TOMORROW AFTERNOON.
FIRE WEATHER
ISSUED AT 147 PM MDT TUE JUL 21 2026
MONSOON MOISTURE CONTINUES TO BRING ISOLATED TO NEARLY SCATTERED
SHOWERS AND THUNDERSTORMS TO PORTIONS OF FIRE WEATHER ZONES 413,
NORTHERN 422, 427, 475, AND 476 THIS AFTERNOON. COVERAGE ACTUALLY
BEGINS TO INCREASE LATER THIS EVENING, AFTER 1800 MDT. STRONGER
STORMS TODAY WILL BE CAPABLE OF PRODUCING STRONG WIND GUSTS OF 40 TO
50 MPH AND WILL BE A MIX OF WET AND DRY STORMS.
MOISTURE CONTENT INCREASES IN A BIG WAY ON WEDNESDAY WITH PWATS
RANGING FROM ALMOST 1.00 TO 1.50 INCHES ACROSS ALL OF OUR COVERAGE
AREA, MUCH HIGHER THAN NORMAL FOR THIS TIME OF THE YEAR. WITH THE
BETTER CHANCE FOR ANY STORM TO PRODUCE A WETTING RAIN, THE WIND
THREAT DIMINISHES FOR WEDNESDAY WITH GUSTS MORE LIKELY AROUND 35-45
MPH. GIVEN HOW WET THESE STORMS WILL BE, WE HAVE OPTED TO NOT ISSUE
A RED FLAG WARNING EVEN THOUGH WE WILL REACH "SCATTERED"
THUNDERSTORM CRITERIA AT ALMOST EVERY FIRE WEATHER ZONE ON
WEDNESDAY. SO, EXPECT SHOWERS AND THUNDERSTORMS PRODUCING LIGHTNING,
BUT ALSO PRODUCING A WETTING RAIN. WE WILL BE WATCHING THE WAPITI
BURN SCAR FOR FLASH FLOODING POTENTIAL AS WELL AS WATCHING THE OHIO
FIRE AREA FOR ANY FLASH FLOODING THERE, TOO.
ON THURSDAY, ISOLATED THUNDERSTORMS WILL LINGER IN THE CENTRAL
MOUNTAINS AND EASTERN HIGHLANDS, AND WHILE WE WON'T COMPLETELY SHUT
OFF OUR MONSOONS MOISTURE FOR FRIDAY AND THE WEEKEND, IT WILL BE
MUCH DRIER OVERALL. WINDS BEGIN TO INCREASE ON FRIDAY AND SATURDAY
AFTERNOONS WITH GUSTS OF 25 TO 35 MPH AND AFTERNOON MIN RHS FALLING
INTO THE TEENS AND 20S.
PIH WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY EVENING
FOR IDZ058>066.
DISCUSSION...MCKAUGHAN
AVIATION...TW
FIRE WEATHER...AMM
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