777
FXUS65 KBOI 210341
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
841 PM MST THU FEB 20 2025
DISCUSSION
MOSTLY CLEAR SKIES AND CALMING WINDS UNDER AN
UPPER RIDGE WILL ALLOW RADIATIONAL COOLING TONIGHT BUT ALSO
DEVELOP AREAS OF VALLEY FOG AND LOW STRATUS OVERNIGHT AND
FRIDAY MORNING. A PACIFIC TROUGH WILL WEAKEN AS IT MOVES INLAND
THROUGH THE LARGER SCALE UPPER RIDGE LATE FRIDAY NIGHT THROUGH
SATURDAY, BUT WILL STILL BRING LIGHT RAIN AND SNOW TO THE
NORTHERN HALF OF OUR CWA, WITH SNOW LEVEL NEAR 5000 FEET MSL.
A STRONGER PACIFIC TROUGH AND GREATER MOISTURE WILL MOVE IN
SUNDAY AND SUNDAY NIGHT, CLEARING BUT BREEZY ON MONDAY.
CURRENT FORECAST LOOKS GOOD ON ALL THIS. NO UPDATES.
AVIATION
MOSTLY VFR. PATCHY MVFR/IFR VALLEY FOG AND LOW
STRATUS EXPECTED TO DEVELOP LATE TONIGHT, THEN DISSIPATE BY
FRI/18Z. SURFACE WINDS: VARIABLE 10 KT OR LESS THROUGH FRIDAY.
WINDS ALOFT AT 10KFT MSL: NW-N 10-20 KT TONIGHT, BECOMING
W 5-15 KT FRIDAY.
KBOI...VFR, THEN MVFR FOG AND/OR LOW STRATUS POSSIBLE (50%
CHANCE) AFTER 06Z. SURFACE WINDS: VARIABLE 5 KT OR LESS
OVERNIGHT.
WEEKEND OUTLOOK...MOSTLY VFR SATURDAY, THEN ALL CATEGORIES
DUE TO CEILINGS AND VISIBILITY SATURDAY NIGHT AND SUNDAY AS
PRECIPITATION MOVES IN. HIGH SNOW LEVELS FAVOR RAIN AT ALL
TERMINALS, EXCEPT FOR PERIODS OF A RAIN/SNOW MIX AT KMYL
SATURDAY EVENING THROUGH SUNDAY MORNING. MOUNTAINS OBSCURED
LATE SATURDAY-SUNDAY. SURFACE WINDS: E-S 5-15 KT SATURDAY,
THEN SE- SW SE 5-15 KT SUNDAY.
PREV DISCUSSION
SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...THE SUNSHINE AND
WIND ARE FINALLY SCOURING OUT THE LOW CLOUDS AND FOG THAT
PERSISTED THROUGH EARLY THIS AFTERNOON. AN UPPER RIDGE BUILDING
IN FROM THE WEST WILL BE ACCOMPANIED BY MOSTLY CLEAR SKIES AND
LIGHT WINDS THAT COULD LEAD TO ANOTHER ROUND OF VALLEY FOG AND
LOW CLOUDS LATE TONIGHT THROUGH FRIDAY MORNING, INCLUDING THE
SNAKE PLAIN. VISIBILITIES MAY BE LOCALLY AT OR BELOW 1/4 MILE.
THE UPPER RIDGE WILL CONTINUE TO BRING DRY CONDITIONS ON FRIDAY
WITH FOG EXPECTED TO DISSIPATE BY THE AFTERNOON. TEMPERATURES
WILL BE SLIGHTLY BELOW NORMAL.
A WEAK PACIFIC TROUGH MOVES INTO OUR AREA LATE FRIDAY NIGHT
THROUGH SATURDAY FOR A 15 TO 40 PERCENT CHANCE OF LIGHT SNOW
ACROSS OUR NORTHERN AREAS, INCLUDING BAKER COUNTY AND CENTRAL
IDAHO. THIS WILL BE FOLLOWED BY THE LEADING EDGE OF A MOIST
PACIFIC PLUME SATURDAY NIGHT AS PRECIPITATION BECOMES
WIDESPREAD LATE SATURDAY NIGHT. THE HIGHEST PRECIP TOTALS WILL
BE ACROSS THE NORTHERN HIGH TERRAIN, WITH LITTLE OR NO PRECIP
ALONG THE NEVADA BORDER. SNOW LEVELS RISE TO AROUND 5000 FEET,
SO MOST OF THE ACCUMULATING SNOW WILL BE LIMITED TO THE
MOUNTAINS. TEMPERATURES WILL BE A LITTLE WARMER, BUT STILL
SLIGHTLY BELOW NORMAL.
LONG TERM...SUNDAY THROUGH THURSDAY...PRECIPITATION CONTINUES
INTO THE EARLY LONG-TERM, WITH RAIN CONTINUING SUNDAY BEFORE
TAPERING OFF LATE SUNDAY NIGHT INTO THE EARLY HOURS MONDAY.
THE WEST CENTRAL MOUNTAINS WILL SEE THE HIGHEST ADDITIONAL
PRECIPITATION AMOUNTS, WITH A GREATER THAN 70% CHANCE OF
LOCATIONS ABOVE 4500 FEET MSL SEEING MORE THAN A HALF INCH
OF PRECIPITATION. LOCATIONS IN THE SNAKE PLANE AND LOWER THIRD
OF OUR AREA WON'T SEE AS MUCH ADDITIONAL PRECIPITATION, WITH
AMOUNTS UNDER 0.20 INCH IN THE TREASURE VALLEY AND AMOUNTS
UNDER 0.05 INCH SOUTH OF MOUNTAIN HOME. SNOW LEVELS STAY ABOVE
6000 FEET MSL, WILL NEED TO MONITOR FOR RIVER RESPONSE TO THIS
NEW LIQUID QPF AND MELTING LOW ELEVATION SNOW. MONDAY PROVIDES
A BRIEF BREAK IN PRECIPITATION FOR LOWER ELEVATIONS AS A LOW
AMPLITUDE RIDGE BUILDS INTO THE AREA. MONDAY NIGHT INTO EARLY
TUESDAY A SHORTWAVE MOVES THROUGH WITH INCREASING PRECIPITATION
CHANCES. THERE IS BEGINNING TO BE MORE OF A MODEL CONSENSUS OF
THE SHORTWAVE SKIMMING OUR NORTHERN AREA, PRECIPITATION CHANCES
ARE INCREASED TO 50%-60% IN BOISE, VALLEY, AND ADAMS COUNTIES.
BEYOND TUESDAY, MODEL ENSEMBLES ARE IN GOOD AGREEMENT OF A RIDGE
BUILDING INTO OUR AREA WITH A BLOCKING PATTERN ALLOWING DRY AND
WARM CONDITIONS TO PREVAIL THROUGH THE REST OF THE LONG TERM.
HIGH TEMPERATURES LEANING ABOVE AVERAGE THROUGH THE LONG TERM,
WITH LOWER ELEVATIONS RANGING FROM UPPER 40S TO UPPER 50S
(GENERALLY INCREASING AS YOU MOVE SOUTH), AND HIGHER ELEVATIONS
IN THE MID TO UPPER 30S.
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...LC
AVIATION.....SP
SHORT TERM...BW
LONG TERM....NF
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