490
FXUS65 KPIH 101955
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
155 PM MDT SAT OCT 10 2026
KEY MESSAGES
- FLOOD WATCH IN EFFECT: A FLOOD WATCH REMAINS ACTIVE ACROSS
MUCH OF EASTERN IDAHO FOR A MULTI-DAY RAINFALL EVENT.
WIDESPREAD TOTALS OF 1.0 TO 2.0 INCHES ARE EXPECTED ACROSS THE
MAGIC VALLEY, SNAKE PLAIN, AND EASTERN HIGHLANDS, WITH
LOCALIZED AMOUNTS UP TO 3.0 INCHES POSSIBLE. NBM GUIDANCE
SHOWS 70% TO 100% PROBABILITIES FOR RAINFALL EXCEEDING 1.0
INCH IN THE AFOREMENTIONED AREAS. PROBABILITIES FOR EXCEEDING
2.0 INCHES RANGE FROM 20% TO 50%, PEAKING AT 60% TO 80% AROUND
ISLAND PARK.
- SHARP WEEKEND COOLDOWN: TEMPERATURES TODAY ARE ALREADY 15 TO
20 DEGREES COOLER THAN 24 HOURS AGO. ANOTHER 10 TO 15-DEGREE
DROP IS EXPECTED FOR SUNDAY, CAPPING HIGHS IN THE UPPER 40S TO
UPPER 50S.
- LINGERING COOL & WET PATTERN: PRECIPITATION AND WELL-BELOW-
NORMAL TEMPERATURES WILL PERSIST INTO THE MIDDLE OF NEXT WEEK
AS AN UPPER LOW SLOWLY CROSSES THE INTERMOUNTAIN WEST.
DISCUSSION
ISSUED AT 149 PM MDT SAT OCT 10 2026
AFTERNOON SATELLITE IMAGERY SHOWS CLOUD COVER INCREASING ACROSS
EASTERN IDAHO AS AN UPPER-LEVEL TROUGH CONTINUES TO DIG INTO
THE PACIFIC NORTHWEST. WELL TO OUR SOUTH, TROPICAL MOISTURE
ASSOCIATED WITH TROPICAL STORM RACHEL IS SURGING NORTHWARD INTO
CALIFORNIA AND THE SOUTHERN GREAT BASIN. WE COULD SEE JUST
ENOUGH BREAKS IN CLOUD COVER THIS AFTERNOON TO YIELD MARGINAL
INSTABILITY, SUPPORTING AN ISOLATED THUNDERSTORM THREAT LATER
TODAY, THOUGH THE VAST MAJORITY OF PRECIPITATION IS EXPECTED TO
FALL AS SHOWERS. A FLOOD WATCH BECAME EFFECTIVE EARLIER THIS
AFTERNOON AND CONTINUES ACROSS MUCH OF EASTERN IDAHO. THE BULK
OF THE PRECIPITATION WILL OVERSPREAD THE AREA DURING THE
OVERNIGHT HOURS AND CONTINUE THROUGHOUT THE DAY TOMORROW.
TEMPERATURES TODAY ARE ALREADY 15 TO 20 DEGREES COOLER THAN 24
HOURS AGO.
RAINFALL WILL PEAK ON SUNDAY AS TROPICAL MOISTURE INTERACTS
WITH THE INCOMING TROUGH. FORECAST PRECIPITATION AMOUNTS REMAIN
LARGELY ON TRACK, WITH A BROAD SWATH OF 1.0 TO 2.0 INCHES
EXPECTED ACROSS THE MAGIC VALLEY, THE SNAKE PLAIN, AND INTO THE
EASTERN HIGHLANDS. NATIONAL BLEND OF MODELS (NBM) PROBABILITIES
REMAIN HIGH, SHOWING A 70% TO 100% CHANCE OF EXCEEDING 1.0 INCH
IN THESE AREAS. PROBABILITIES FOR EXCEEDING 2.0 INCHES ARE
GENERALLY COMING IN LOWER AROUND 20% TO 50%, THOUGH THEY PEAK AT
60% TO 80% AROUND ISLAND PARK. BEFORE ALL IS SAID AND DONE,
LOCALIZED TOTALS COULD CERTAINLY CLIMB ABOVE 2.0 TO 3.0 INCHES,
ESPECIALLY ACROSS THE EASTERN HIGHLANDS AND HIGHER TERRAIN WHERE
OROGRAPHIC LIFT WILL BE MAXIMIZED. MEANWHILE, TOTALS ACROSS THE
CENTRAL MOUNTAINS ARE CURRENTLY RUNNING IN THE 0.33 TO 0.66
INCH RANGE, THOUGH THERE IS STILL A BIT THAT CAN CHANGE.
IN ADDITION TO THE HEAVY RAIN, TEMPERATURES WILL DROP ANOTHER
10 TO 15 DEGREES AS WE MOVE INTO SUNDAY. DAYTIME HIGHS TOMORROW
WILL ONLY TOP OUT IN THE UPPER 40S TO UPPER 50S ACROSS THE
REGION. DESPITE THE COLD SURFACE TEMPERATURES, SNOW LEVELS WILL
REMAIN HIGH ENOUGH TO LIMIT ANY FROZEN PRECIPITATION STRICTLY TO
THE HIGHEST TERRAIN AND MOUNTAIN PEAKS.
PRECIPITATION CHANCES WILL LINGER INTO THE EARLY PART OF THE
WORKWEEK AS THE LOW WILL BE SLOW TO DEPART THE AREA. MODELS KEEP
THE LOW MOVING SLOWLY ACROSS THE INTERMOUNTAIN WEST UNTIL
WEDNESDAY OR THURSDAY. THIS WILL RESULT IN TEMPERATURES STAYING
WELL BELOW SEASONAL NORMS, WITH HIGHS MAINLY IN THE 50S UNTIL
PERHAPS THURSDAY. BY THURSDAY, RIDGING SLOWLY BUILDS OVER THE
AREA, FINALLY REPLACING THE PERSISTENT TROUGHINESS OVER THE
PACIFIC NORTHWEST AND ALLOWING CONDITIONS TO MODERATE.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1203 PM MDT SAT OCT 10 2026
A LINE OF -SHRA EXTENDS FROM JUST SOUTH OF BYI TO NORTH OF DIJ.
POCKETS OF CLEARING BEHIND THIS BAND HAS THE POTENTIAL TO
GENERATE ENOUGH INSTABILITY FOR TSRA FORMATION. WINDS ARE ALSO
LOCALLY QUITE GUSTY ACROSS PORTIONS OF EAST IDAHO, WITH GUSTS
AROUND 35KTS. CLEARING HAS THE POTENTIAL TO INCREASE THE
COVERAGE OF THESE WINDS THIS AFTERNOON BEFORE THE WINDS DECREASE
OVERNIGHT. MORE WIDESPREAD RA DEVELOPS OVERNIGHT AND CONTINUES
THROUGH SUNDAY ACROSS MOST OF THE REGION, THOUGH SUN AND BYI MAY
FLIRT WITH THE WESTERN EDGE OF THE MAIN EVENT. CIGS DECREASE TO
MVFR WITH POTENTIAL FOR VIS TO DROP THAT LOW AS WELL.
FIRE WEATHER
ISSUED AT 149 PM MDT SAT OCT 10 2026
THE SHIFT TO A MORE FALL PATTERN HAS BEGUN ACROSS EAST IDAHO.
SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD THROUGH
THE EVENING AND OVERNIGHT. SUNDAY AND SUNDAY NIGHT ARE STILL
EXPECTED TO BE THE MAIN EVENT WITH RESPECT TO PRECIPITATION
TOTALS ACROSS THE ENTIRETY OF THE REGION, WITH MOST OF THE
RAINFALL ACROSS THE SNAKE PLAIN AND EASTERN HIGHLANDS. FORECAST
PROBABILITIES STILL SUPPORT 1.0-2.0" IN THESE AREAS WITH LOCALLY
HIGHER AMOUNTS. TEMPERATURES WILL CONTINUE TO DROP INTO SUNDAY,
WITH POTENTIAL FOR LIGHT ACCUMULATING SNOW ABOVE 7500 FT SUNDAY
NIGHT, AND LIGHT SNOWFALL BUT NO ACCUMULATION AT MID-SLOPES OR
BELOW. THE PRECIPITATION WILL LINGER INTO MIDWEEK AS THE LOW IS
SLOW TO EXIT THE REGION, THOUGH PRECIPITATION WILL DECREASE IN
INTENSITY AND COVERAGE AFTER MONDAY. HIGH PRESSURE IS STILL
EXPECTED TO REBUILD LATE IN THE WEEK INTO THE WEEKEND, WITH A
SLOW WARMING TREND.
PIH WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH MONDAY AFTERNOON FOR IDZ051>067-073-075.
DISCUSSION...MCKAUGHAN
AVIATION...DMH
FIRE WEATHER...DMH
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