572
FXUS65 KBOI 261524
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
924 AM MDT FRI APR 26 2024
DISCUSSION
SHOWERS CONTINUE THIS MORNING IN SOUTH-CENTRAL IDAHO
BUT SHOULD EXIT EAST BEFORE NOON. MORE SHOWERS, AND ISOLATED
THUNDERSTORMS, IN OUR CWA THIS AFTERNOON MAINLY OVER HIGHER TERRAIN
AS A COOL UPPER TROUGH MOVES IN FROM THE NORTHWEST. GUSTY WEST WINDS
TO 35 MPH IN SOUTH-CENTRAL IDAHO THIS AFTERNOON AND THROUGH THE
NIGHT. EVEN WINDIER SATURDAY, GUSTS 40 TO 45 MPH. LITTLE CHANGE
IN TEMPERATURES THROUGH SUNDAY. CURRENT FORECAST IN GOOD SHAPE
ON ALL THIS. NO UPDATES.
AVIATION
GENERALLY VFR. ISOLATED THUNDERSTORMS AND SCATTERED TO
NUMEROUS SHOWERS IN SE OR AND THE HIGHER TERRAIN OF SOUTHWEST ID
AFTER 18Z. SNOW LEVELS 5000-6500 FT MSL. MOUNTAINS OBSCURED DURING
SHOWERS. SURFACE WINDS: W TO NW 5-15 KT THIS MORNING, INCREASING TO
10-20 KT WITH GUSTS TO 25-30 KT THIS AFTERNOON. WINDS ALOFT AT 10KFT
MSL: N TO NW 10-20 KT.
KBOI...VFR WITH SCATTERED MID AND HIGH CLOUDS, WITH ONLY A 10%
CHANCE OF A SHOWER THIS AFT/EVE. SURFACE WINDS: NW 5-15 KT,
INCREASING TO 10-20 KT WITH GUSTS AROUND 25 KT AFTER 18Z.
WEEKEND OUTLOOK...ISOLATED TO SCATTERED SHOWERS SATURDAY OVER THE
MOUNTAINS, WITH MOSTLY DRY CONDITIONS AND DECREASING CLOUDS
ELSEWHERE. MOSTLY DRY SUNDAY. MOUNTAINS OBSCURED DURING SHOWERS.
SNOW LEVELS: 4000-6000 FT MSL SATURDAY, 6000-7000 FT MSL SUNDAY.
SURFACE WINDS GENERALLY W-NW 10-25 KT. GUSTS 30-40 KT FROM KMUO TO
KJER/KTWF SATURDAY, THEN 20-30 KT SUNDAY.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...THE FRONTAL SYSTEM
AND ASSOCIATED SHOWER ACTIVITY CONTINUES OVER THE HIGHER
ELEVATIONS OF SW IDAHO, INCLUDING MCCALL AND THE SOUTHWEST
HIGHLANDS NEAR THE NEVADA BORDER. THE SHOWERS ARE EXPECTED TO
MOVE OUT OF THE AREA BY MID-MORNING. MEANWHILE, THE CORE OF AN
UPPER TROUGH SITUATED TO OUR WEST WILL BRING ANOTHER ROUND OF
SHOWERS THIS AFTERNOON. THE DAYTIME HEATING WILL HELP TO
INITIATE CONVECTION OVER THE HIGHER ELEVATIONS, INCLUDING
ISOLATED THUNDERSTORMS. THE THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING GUSTY WINDS, SMALL HAIL, AND HEAVY RAIN. TEMPERATURES
WILL RUN A FEW DEGREES COOLER TODAY - CLOSE TO SEASONAL
NORMALS. MOST OF THE ENERGY WITHIN THE TROUGH WILL DEVELOP INTO
A LOW PRESSURE SYSTEM TO OUR SOUTH WHERE THE BULK OF THE SHOWERS
ARE EXPECTED. HOWEVER, LINGERING MOISTURE IN SW IDAHO WILL
ALLOW FOR A 30-60 PERCENT CHANCE OF SHOWERS OVER THE HIGHER
ELEVATIONS - MAINLY IN CENTRAL IDAHO. SNOW LEVELS LOWER ENOUGH
FOR LOCAL LIGHT SNOW ACCUMULATIONS IN THE MOUNTAINS ABOVE
6500-7000 FEET. THE SURFACE PRESSURE GRADIENT WILL BECOME
ENHANCED AND LEAD TO INCREASING WINDS LATE TONIGHT THAT WILL
PERSIST THROUGH SATURDAY. MODELS ARE SHOWING SOMEWHAT LIGHTER
WINDS, SO NOW THERE IS LESS THAN A 30 PERCENT CHANCE OF
SUSTAINED WINDS REACHING AT LEAST 30 MPH ON THE SNAKE PLAIN EAST
OF BOISE, WHICH INCLUDES THE I-84 CORRIDOR FROM MOUNTAIN HOME
TO TWIN FALLS. DRIER CONDITIONS AND WEAKER WINDS ARE ANTICIPATED
FOR SUNDAY, ALTHOUGH ANOTHER PACIFIC TROUGH WILL ENTER THE
NORTHWEST AND COULD BRING ENOUGH MOISTURE IN THE NORTH FOR A
15-30 PERCENT CHANCE OF SHOWERS TO THE WEST CENTRAL MOUNTAINS.
LITTLE DAY-TO-DAY CHANGES IN TEMPERATURES ARE EXPECTED OVER THE
WEEKEND, AVERAGING WITHIN A COUPLE DEGREES OF NORMAL.
LONG TERM...MONDAY THROUGH FRIDAY...AN UPPER LEVEL LOW LOOKS
TO DIP DOWN INTO THE PACIFIC NORTHWEST FROM THE BRITISH COLUMBIA
COAST ON MONDAY. THIS WILL BRING A COLD FRONT INTO THE REGION
BY MONDAY AFTERNOON, BRINGING SLIGHTLY BELOW NORMAL
TEMPERATURES, BREEZY WINDS, AND A CHANCE OF SHOWERS, MAINLY OVER
HIGHER TERRAIN IN BAKER COUNTY, OR AND THE WEST CENTRAL
MOUNTAINS. SNOW LEVELS WILL BE THE LOWEST OVER THE MONDAY-
TUESDAY PERIOD, AROUND 4000-5000 FEET. THIS, COMBINED WITH
OVERNIGHT LOWS NEAR FREEZING WILL SUPPORT SNOWFALL IN MOST OF
THE MOUNTAIN VALLEYS IN SOUTHEAST OREGON AND SOUTHWEST IDAHO.
THE LONG VALLEY IN ID, INCLUDING, MCCALL, HAS A 30-40% CHANCE OF
SEEING AT LEAST A TRACE OF SNOWFALL OVERNIGHT MONDAY-TUESDAY.
DAYTIME HIGHS WILL ALLOW FOR ANY ACCUMULATING SNOW TO MELT
QUICKLY BELOW ABOUT 6000-7000 FEET BY TUESDAY. THIS LOW THEN
LOOKS TO PASS TO OUR NORTH, OVER THE IDAHO PANHANDLE BY TUESDAY
EVENING. FORECAST MODEL AGREEMENT REMAINS HIGH THROUGH THE
MIDDLE OF THE WEEK.
BY WEDNESDAY EVENING'S FORECAST, MODELS BEGIN TO DIVERGE. SOME
CLUSTERS SHOW THE LOW DIVING TO OUR EAST AS A RIDGE BUILDS IN
QUICKLY BY THURSDAY MORNING. THEN, SOME SHOW THIS RIDGE
LINGERING THROUGH THE END OF THE WORK WEEK, WHILE OTHERS ADVANCE
ANOTHER DEEP UPPER LEVEL LOW INTO THE REGION. THEREFORE,
FORECAST UNCERTAINTY IS QUITE HIGH FROM WEDNESDAY-THURSDAY DUE
TO THE VARIABILITY IN BOTH DETERMINISTIC AND ENSEMBLE FORECAST
SOLUTIONS.
BOI WATCHES/WARNINGS/ADVISORIES
ID...NONE.
OR...NONE.
WWW.WEATHER.GOV/BOISE
INTERACT WITH US VIA SOCIAL MEDIA:
WWW.FACEBOOK.COM/NWSBOISE
WWW.TWITTER.COM/NWSBOISE
DISCUSSION...LC
AVIATION.....SP
SHORT TERM...BW
LONG TERM....SA
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