993
FXUS65 KPIH 100842
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
242 AM MDT WED AUG 10 2022
SHORT TERM
TODAY THROUGH THURSDAY NIGHT.
A DYNAMIC WEATHER DAY IS IN STORE ACROSS EASTERN IDAHO TODAY WITH A
CLOSED UPPER LEVEL LOW OFF THE PACIFIC COAST AND BROAD HIGH PRESSURE
CENTERED OVER THE CENTRAL UNITED STATES DRIVING STRONG MONSOONAL
MOISTURE UP THROUGH THE GREAT BASIN. BEING IN A FAVORED MOISTURE
TRANSPORT REGION TODAY IN BETWEEN THESE TWO UPPER LEVEL FEATURES,
MOIST SOUTHWEST FLOW WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS ALONG WITH THE POTENTIAL FOR FLASH FLOODING CONCERNS
AND POTENTIALLY SEVERE GUSTY OUTFLOW BOUNDARIES. THE WEATHER
PREDICTION CENTER HAS ISSUED A SLIGHT 15 PERCENT RISK FOR
EXCESSIVE RAINFALL EXCEEDING FLASH FLOOD GUIDELINES EXTENDING FROM
THE NEVADA/UTAH BORDER REGION IN SOUTH-CENTRAL IDAHO UP THROUGH
THE FRANK CHURCH WITH A MARGINAL 5 PERCENT RISK FOR THE REMAINDER
OF SOUTHEAST IDAHO. PWATS BETWEEN 0.75 AND 1.50 INCHES WILL
APPROACH 3 TO 5 SIGMA ABOVE NORMAL NEARING 200 TO 300 PERCENT OF
NORMAL FOR THIE TIME OF YEAR ACROSS THE REGION THIS AFTERNOON AND
EVENING. PRECIPITATION WILL START OFF TODAY IN WESTERN IDAHO,
GRADUALLY WORKING EAST THROUGHOUT THE DAY WITH AFTERNOON
CONVECTION HELPING TO INITIATE AND DEVELOP STRONG THUNDERSTORMS.
THE MAIN CONCERN WITH THUNDERSTORMS TODAY WILL BE LOCALIZED FLASH
FLOODING CONCERNS, STRONG GUSTY OUTFLOW WINDS, AND HAIL UP TO
AROUND HALF-INCH TO QUARTER SIZE WITH SUFFICIENTLY AVAILABLE
DCAPE/CAPE IN ADDITION TO 30 TO 50 KTS OF 0 TO 6 KM SHEAR
ENABLING THE ENVIRONMENT TODAY TO PRODUCE STRONG THUNDERSTORMS.
THE DEVELOPMENT OF MODERATE TO HEAVY PRECIPITATION ASSOCIATED WITH
AREAS OF CONVECTION WILL BEGIN MID-AFTERNOON BETWEEN 2 TO 4PM AND
EXTEND THROUGH ABOUT MIDNIGHT WITH LINGERING SHOWERS OVERNIGHT
ACROSS THE HIGHER TERRAIN NORTH AND EAST AND ACROSS THE EASTERN
SNAKE PLAIN. AFTER A BRIEF BREAK TOMORROW MORNING FROM
PRECIPITATION, THERE WILL BE THE POTENTIAL FOR PATCHY FOG
DEVELOPMENT ACROSS THE SNAKE PLAIN GIVEN SATURATED LOWER LAYERS AND
QUIETER WINDS BUT WITH CLOUD COVER OVERHEAD, THIS COULD STIFLE ANY
SIGNIFICANT FOG DEVELOPMENT. IN AREAS THAT DO GET TO SEE THOSE CLEAR
SKIES, CHANCES WILL INCREASE GIVEN MORE EFFECTIVE RADIATIVE COOLING.
KEEP AN EYE ON THE SKY THROUGHOUT THURSDAY MORNING AND YOU WILL SEE
TOWERING CUMULUS BUILDING OVER THE HIGHER TERRAIN FOR ANOTHER DAY OF
AFTERNOON SHOWERS AND THUNDERSTORMS BUT WITH SCATTERED COVERAGE
REMAINING OVER THE HIGHER TERRAIN AS MORE ISOLATED COVERAGE MOVES IN
FOR THE SNAKE PLAIN AND MAGIC VALLEY. THE WPC HAS AGAIN ISSUED A
MARGINAL 5 PERCENT RISK FOR EXCESSIVE RAINFALL EXCEEDING FLASH
FLOOD GUIDANCE FOR THURSDAY ACROSS ALL OF SOUTHEAST IDAHO WITH A
PREDOMINANT FOCUS ON THE HIGHER TERRAIN. TEMPERATURES THROUGH THE
PERIOD WILL REMAIN NEAR NORMAL IF NOT ABOVE NORMAL TODAY IN THE
80S TO MID 90S, COOLING SLIGHTLY FOR THURSDAY INTO THE 80S TO LOW
90S. SYNOPTIC WINDS OUTSIDE OF CONVECTION BE UP TO AROUND 20 TO 30
MPH WITH THUNDERSTORMS CAPABLE OF PRODUCING WINDS IN EXCESS OF 40
TO 50 MPH. MACKAY
LONG TERM
FRIDAY THROUGH NEXT WEDNESDAY.
THE MODELS AND CLUSTER FORECASTS ARE FAIRLY CONSISTENT ON MONSOON
MOISTURE REMAINING ACROSS CENTRAL AND EASTERN IDAHO INTO NEXT
WEEK. THERE WILL BE SOME DAILY FLUCTUATIONS IN WHERE THE BEST
CHANCE AND ALSO WHERE HEAVIER RAINFALL WILL OCCUR, BUT THE GENERAL
IDEA IS OVER THE HIGHER ELEVATIONS...ESPECIALLY THE SOUTHERN AND
EASTERN HIGHLANDS. THIS PATTERN IS ALSO CONDUCIVE TO POTENTIALLY
SEE AN UPTICK ACROSS THE CENTRAL MOUNTAINS FROM THE WOOD RIVER
VALLEY TO AROUND GILMORE SUMMIT. WE WILL HAVE TO MONITOR HOW MUCH
RAIN FALLS IN THE COMING DAYS TO SEE WHERE ANY RISK FROM FLASH
FLOODING/DEBRIS FLOWS EVOLVES AS WHERE GET INTO THE WEEKEND AND
NEXT WEEK. AFTERNOON TEMPERATURES WILL GENERALLY BE AT OR JUST
BELOW AVERAGE BASED ON THE BLEND OF MODELS. HOWEVER, A LOT OF THAT
WILL BE FLUCTUATING DAY TO DAY BASED ON WHERE WE SEE MORE SUN VS
CLOUDS DOWN THE ROAD.
AVIATION
THE START OF MORE MONSOONAL MOISTURE MAKES IT INTO THE AREA TODAY.
RAIN CHANCES INCREASE AT KSUN IN THE FIRST HALF OF THE DAY BEFORE
MOISTURE SPREADS FARTHER EAST WITH MORE WIDESPREAD RAIN AND STORMS
HEADING TOWARDS KBYI, KPIH, KIDA, AND KDIJ AROUND 23Z WEDNESDAY.
CONDITIONS COULD DROP TO MVFR OR EVEN IFR AS RAIN PASSES OVER THE
TERMINALS DUE TO REDUCED VISIBILITY. MOST OF THE ACTIVITY WRAPS UP
AROUND 09Z THURSDAY. WITH LIGHT WINDS EARLY THURSDAY, THERE IS THE
POTENTIAL FOR SOME DEVELOPMENT OF LIGHT MIST, THOUGH CONFIDENCE IS
NOT HIGH DUE TO SOME DISAGREEMENT BETWEEN CAMS.
FIRE WEATHER
TODAY BEGINS SEVERAL DAYS OF SHOWERS AND THUNDERSTORMS ACROSS
CENTRAL AND EASTERN IDAHO, AS MONSOON MOISTURE CONTINUES TO STREAM
INTO OUR AREA. THE FOCUS FOR HEAVIER RAINFALL WILL BE ACROSS THE
WESTERN HALF OF OUR FIRE FORECASTING AREA, MEANING ZONES 475, 476,
422, 425, 427, AND 410/411 WEST OF I-15. THERE IS A 40-60% CHANCE
OF WETTING RAINS, ESPECIALLY WHERE WE CAN MULTIPLE STORMS TO
TRACK OVER THE SAME LOCATIONS, ACROSS THOSE ZONES. IN FACT, THERE
IS A 20-30% CHANCE OF SEEING BETWEEN 0.25-0.5" IN SOME OF THOSE
SAME LOCATIONS. THE PROBABILITY OF MORE THAN 0.50" RAPIDLY DROPS
OFF TO 10% OR LESS. THIS FITS THE CURRENT TREND WHERE BETTER AND
DEEPER MOISTURE ARRIVES WITH THE MONSOON PUSH LATER TODAY. THAT
SAID, IT DOES LOOK LIKE ONCE YOU GET TOWARD THE NORTHERN END OF
475 AND THE MOOSE FIRE, WETTING RAINS LOOK LESS LIKELY...MAYBE
ONLY AS HIGH AS 30%. IN FACT, ONCE YOU GET FARTHER EAST...THE
PROBABILITY BARELY PUSHES ABOVE 30% AS THE PUSH OF DEEPEST
MOISTURE DOESN'T SHIFT FAR ENOUGH EAST UNTIL TONIGHT AND FRIDAY.
SOME OF THESE STORMS TODAY MAY PRODUCE WINDS OVER 40 MPH AND SMALL
HAIL. THE GREATEST RISK OF HIGHER WINDS WILL BE WITH STORMS THAT
ARE INITIALLY "DRIER" ACROSS PORTIONS OF THE SNAKE PLAIN (410),
MAGIC VALLEY(425), AND SOUTH HILLS(427). WITH THE SHIFT IN BETTER
MOISTURE EAST THURSDAY, SCATTERED COVERAGE LOOKS TO BE MAINLY
ACROSS 476 IN THE CENTRAL MOUNTAINS, THE SNAKE PLAIN AND
SOUTHERN/EASTERN HIGHLANDS(410/411/413). WETTING RAIN POTENTIAL IS
HIGHEST ACROSS ZONE 413 AT 30-50%. ELSEWHERE, THE CHANCE IS 30%
OR LOWER. AMOUNTS OVER 0.25 WILL BE SPOTTY, BUT STILL POSSIBLE
ACROSS PORTIONS OF ZONES 476, 411 AND 413 WHERE THE PROBABILITY
EXCEEDS 20%. THE RISK OF STRONG WINDS DROPS OFF TOMORROW, BUT SOME
STORMS MAY STILL EEK OUT WINDS OVER 30 MPH. BEYOND THAT, THE
PATTERN REMAINS IN PLACE. WE WILL NEED TO MONITOR TRENDS,
ESPECIALLY WHEN WE CAN GET HIGHER RESOLUTION DATA IN THE MIX, TO
SEE WHERE WE CAN TARGET HIGHER CHANCES AND HIGHER RAINFALL.
PIH WATCHES/WARNINGS/ADVISORIES
NONE.
WWW.WEATHER.GOV/POCATELLO
WWW.FACEBOOK.COM/NWSPOCATELLO
WWW.TWITTER.COM/NWSPOCATELLO
SHORT TERM...MACKAY
LONG TERM...KEYES
AVIATION...AMM/KEYES
FIRE WEATHER...KEYES
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