035
FXUS65 KBOI 100303
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
903 PM MDT FRI MAY 9 2025
DISCUSSION
SOUTHWEST FLOW ALOFT WILL CONTINUE TO BRING
ABOVE-NORMAL TEMPERATURES TO THE REGION ON SATURDAY WITH
RECORD/NEAR RECORD HIGHS POSSIBLE. SOME AREAS COULD EVEN
SURPASS 90F IN THE AFTERNOON, INCLUDING PORTIONS OF THE SNAKE
PLAIN. MODELS CONTINUE TO DEPICT LIMITED MOISTURE MOVING
NORTHEAST FROM EASTERN NEVADA LATER IN THE AFTERNOON INTO THE
EVENING WHICH COULD LEAD TO THUNDERSTORMS. LITTLE PRECIP IS
EXPECTED WITH THE STORMS, BUT THERE IS THE POTENTIAL FOR STRONG
WIND GUSTS TO AROUND 50 MPH. THE THREAT APPEARS TO REMAIN WELL
EAST AND SOUTH OF BOISE, TARGETING S-CENTRAL IDAHO (FAIRFIELD
SOUTH TO TWIN FALLS AND TO THE ID/NV BORDER). FORECAST IS ON
TRACK, NO UPDATES.
AVIATION
VFR WITH HIGH CLOUDS FILLING IN FRIDAY EVENING.
SURFACE WINDS: E-SE 5-15 KT IN THE SNAKE PLAIN, ELSEWHERE
VARIABLE LESS THAN 10 KT. LLWS LIKELY FOR KONO AND KJER TONIGHT.
WINDS ALOFT AT 10KFT MSL: SW 15-25 KT.
KBOI...VFR. E-SE WINDS 5-10 KT FRIDAY EVENING THROUGH SATURDAY
MORNING, BECOMING SW AT 10-15 KT WITH GUSTS UP TO 20 KT SATURDAY
AFTERNOON.
SUNDAY OUTLOOK...ON SUNDAY AFTERNOON, A COLD FRONT WILL MOVE
FROM SE OR INTO SW ID, BRINGING A CHANCE OF SHOWERS AND
THUNDERSTORMS (40-50% CHANCE) WITH GUSTY SOUTHWESTERLY WINDS,
LOWERING CEILINGS, AND MOUNTAIN OBSCURATION.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT...DRY AND MILD
CONDITIONS TONIGHT WILL SET UP FOR ANOTHER UNSEASONABLY HOT DAY
ON SATURDAY. SOME LOWER ELEVATION SITES WILL SEE NEAR RECORD
HIGHS. INCREASED SOUTHWEST FLOW WILL DRAW MID-LEVEL MOISTURE
INTO IDAHO DURING THE DAY WHICH WILL OVERLAP WITH SURFACE ENERGY
AND ELEVATED INSTABILITY TO SUPPORT SHOWER AND THUNDERSTORM
DEVELOPMENT. DRY LOW LEVELS WILL MAKE STRONG TO LOCALLY SEVERE
GUSTY OUTFLOW WINDS THE MAIN ATTRIBUTE ACCOMPANYING
SHOWERS/STORMS THAT DEVELOP. INITIATION WILL BE FAVORED ACROSS
S-CENTRAL IDAHO FROM THE SOUTHERN BOISE MTNS TO THE ID/NV BORDER
(MTN HOME AND POINTS EAST IN THE SNAKE PLAIN). FOR NOW WILL
CONTINUE TO CARRY A 20-30% CHANCE OF SHOWERS AND STORMS FOR
THIS AREA. SOME BUILDUPS ARE POSSIBLE IN THE W-CENTRAL MTNS,
BUT EXPECT MOST OF THE ACTIVITY TO BE NORTH OF THE SALMON
IF/WHEN IT GETS GOING. NOT SEEING A GREAT 0-6KM SHEAR
ENVIRONMENT ACROSS SOUTHERN AREAS, BUT 30+ KTS NORTH OF THE
SNAKE PLAIN WOULD BE ENOUGH TO ENHANCE DEVELOPMENT IN THE MTNS.
ON SUNDAY AREAL COVERAGE EXPANDS INTO HIGHER TERRAIN OF THE
W-CENTRAL ID MTNS AND SE OREGON (MAINLY BAKER COUNTY AND
NORTHERN HARNEY AND MALHEUR COUNTIES) AS INSTABILITY AND DYNAMIC
SUPPORT INCREASES AHEAD OF AN UPPER LOW. MID-LEVEL MOISTURE
DROPS SOME, BUT IS SUFFICIENT ENOUGH TO SUPPORT A 30-50% CHANCE
OF PRECIPITATION IN THESE AREAS. SOUTHWEST FLOW ALOFT WILL
TRANSLATE WINDY CONDITIONS TO OPEN TERRAIN OF SE OREGON AND SW
IDAHO BY SUNDAY AFTERNOON. GUSTS OF 40-45 MPH WILL BE POSSIBLE
ALONG THE NV BORDER WHICH COULD STIR UP DUST. ON TOP OF THE
GENERALLY BREEZY/WINDY CONDITIONS, STRONG GUSTY OUTFLOW WINDS
REMAIN THE MOST LIKELY THREAT FROM SHOWERS AND STORMS THROUGH
SUNDAY EVENING. INCREASED CLOUDS AND COOLING ALOFT WITH TAKE
7-12 DEGREES OFF OF HIGH TEMPERATURES FROM SATURDAY TO SUNDAY
WITH A COLD FRONTAL PASSAGE LATER IN THE DAY/EVENING.
LONG TERM...MONDAY THROUGH FRIDAY...A DEEP UPPER LEVEL LOW WILL
MOVE INTO THE REGION ON MONDAY, WITH GUSTY WINDS CONTINUING
THROUGH TUESDAY. MUCH COOLER TEMPERATURES AND WIDESPREAD
PRECIPITATION WILL MOVE IN LATE MONDAY WITH PERIODS OF RAIN
SHOWERS THROUGH THURSDAY. THE STRONGEST WINDS WILL STAY OVER THE
OWYHEE MOUNTAINS WITH GUSTS UP TO 40-50 MPH. COOLER
TEMPERATURES WILL ALLOW FOR LOWERING SNOW LEVELS, WITH MINIMAL
ACCUMULATIONS ANTICIPATED ABOVE ~6000 FEET. INSTABILITY WILL
REMAIN BEST OVER BAKER COUNTY, OR AND HIGH TERRAIN IN SOUTHWEST
AND SOUTH CENTRAL IDAHO ON MONDAY. THIS INTRODUCES ABOUT A
20-30% CHANCE OF THUNDERSTORMS ON MONDAY EVENING. MODEL
AGREEMENT REMAINS EXCELLENT IN THE STORM TRACK THROUGH
WEDNESDAY, WITH HIGH CONFIDENCE IN PRECIPITATION, ESPECIALLY
OVER HIGHER TERRAIN. A WARMING AND DRYING TREND WILL BEGIN BY
LATE THURSDAY, WITH SOME MODEL DISAGREEMENT ON EXTENT OF THE
RIDGE. A FEW ENSEMBLE MEMBERS ARE SHOWING A WEAK TROUGH MOVING
IN LATE FRIDAY, BRINGING ELEVATED CHANCES OF PRECIPITATION.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.X.COM/NWSBOISE
DISCUSSION...BW
AVIATION.....JY
SHORT TERM...DG
LONG TERM....SA
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