533
FXUS65 KBOI 092018
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
218 PM MDT FRI MAY 9 2025
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.
AVIATION
VFR WITH HIGH CLOUDS CONTINUING TO FILL IN ACROSS
THE REGION. ELEVATED SMOKE FROM AREA BURNS IN THE VICINITY OF
KMYL-KONO. SURFACE WINDS: E-SE 5-15 KT WITH GUSTS TO 20 KT IN
THE SNAKE PLAIN AND LONG VALLEY, ELSEWHERE VARIABLE LESS THAN 10
KT. WINDS ALOFT AT 10KFT MSL: SW 15-25 KT.
KBOI
VFR. SURFACE WINDS WILL BE E-SE 7-10 KT WITH GUSTS TO 20
KT THIS AFTERNOON, BECOMING SW 10-13 KT BY SAT/19Z.
WEEKEND OUTLOOK
SATURDAY WILL BE WARM AND DRY WITH INCREASING
CLOUDS AND A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS NEAR THE
BOISE MOUNTAINS AND ID/NV BORDER LATE AFTERNOON INTO EVENING.
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 WESTERLY WINDS, LOWERING CEILINGS, AND
MOUNTAIN OBSCURATION.
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
SHORT TERM...DG
LONG TERM....SA
AVIATION.....SA
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