710
FXUS65 KBOI 221049
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
349 AM MST SAT FEB 22 2025
SHORT TERM...TODAY THROUGH MONDAY NIGHT
CLOUD COVER HAS
OVERTAKEN THE FORECAST AREA AS A WEAK, SHORTWAVE TROUGH PASSES
THROUGH THIS MORNING. VERY LIGHT PRECIPITATION IS FALLING
ACROSS THE HIGHER TERRAIN OF NORTHEAST OREGON AND WEST-CENTRAL
IDAHO, MAINLY IN THE FORM OF LIGHT SNOW. THIS TROUGH WILL
PROMPTLY EXIT BY LATE THIS MORNING, YIELDING A BRIEF BREAK IN
PRECIP WITH DECREASED CLOUD COVERAGE. THE NEXT LOW PRESSURE
SYSTEM IS FORECAST TO ARRIVE TONIGHT, SPREADING AMPLE
PRECIPITATION ACROSS OREGON AND IDAHO THROUGH EARLY MONDAY.
PRECIPITABLE WATER VALUES WILL RANK WITHIN THE 95-99TH
PERCENTILE (HIGH) FOR THIS TIME OF YEAR ASSOCIATED WITH A WELL-
PRONOUNCED SUBTROPICAL MOISTURE FETCH. DUE TO THE ORIGIN OF THIS
MOISTURE, SNOW LEVELS WILL BEGIN AT ROUGHLY 3000-5000 FEET MSL
TONIGHT AND QUICKLY RISE TO 5000-8000 FEET MSL SUNDAY MORNING.
THE EXCEPTION WILL BE IN EAST-CENTRAL OREGON, THE WEISER RIVER
BASIN, AND SHELTERED MOUNTAIN VALLEY LOCATIONS, IN WHICH COLD
AIR NEAR THE SURFACE WILL BE SLOWER TO SCOUR OUT. AS A RESULT OF
THE INTRUDING WARMER AIR, THERE IS A 10-15% CHANCE OF FREEZING
RAIN DEVELOPING OVERNIGHT FOR THOSE COLDER VALLEYS BEFORE NEAR-
SURFACE TEMPERATURES ARE ABLE TO WARM ABOVE FREEZING. OTHERWISE,
RAIN OR A RAIN/SNOW MIX IS EXPECTED BELOW 5K FEET WITH THE
PRECIP ONSET THROUGH SUNDAY MORNING, BECOMING ALL RAIN BY MID-
DAY SUNDAY. HIGHER MOUNTAIN ELEVATIONS, PARTICULARLY IN THE
FAVORED UPSLOPE AREAS OF SOUTHWEST IDAHO, SHOULD SEE NOTABLE
SNOWFALL AMOUNTS OF AROUND 6-12 INCHES THROUGH EARLY MONDAY.
SURFACE WINDS WILL BECOME BREEZY SUNDAY AFTERNOON, PARTICULARLY
IN SOUTHEAST OREGON, AS THE TROUGH PROGRESSES EASTWARD.
PRECIPITATION AND WIND GUSTS WILL TAPER OFF BY MONDAY MORNING AS
THIS SYSTEM EXITS AND WEAK RIDGING DEVELOPS. HOWEVER, THIS
RIDGE WILL BE SHORT-LIVED AS THE NEXT TROUGH APPROACHES THE AREA
AND CREATES STRONG SOUTHWEST FLOW ALOFT. WHILE TEMPERATURES
WILL BECOME NOTICEABLY MILDER TODAY AND SUNDAY WITH THOSE FIRST
TWO PACIFIC TROUGHS, TEMPERATURES WILL INCREASE FURTHER ON
MONDAY DUE TO THE DEVELOPMENT OF SOUTHWEST FLOW. SURFACE WINDS
WILL INCREASE ONCE AGAIN MONDAY, PARTICULARLY NEAR THE NV BORDER
AHEAD OF THE INCOMING COLD FRONT. OVERALL, EXPECT TEMPERATURES
TO BE NEAR NORMAL THIS WEEKEND, RISING TO SEVERAL DEGREES ABOVE
NORMAL FOR MONDAY.
THE NEXT ROUND OF PRECIPITATION WILL ARRIVE MONDAY NIGHT,
SPREADING ADDITIONAL RAIN AND SNOW (60-90% CHANCE) ACROSS THE
NORTHERN PORTIONS OVERNIGHT INTO TUESDAY. SNOW LEVELS WILL
LOWER TO 4000-5500 FEET MSL WITH THE ACCOMPANYING COLD FRONT. A
FEW INCHES OF NEW SNOW CAN BE EXPECTED FOR THE MOUNTAINS OF
WEST-CENTRAL/CENTRAL IDAHO.
LONG TERM...TUESDAY THROUGH SATURDAY
AN UPPER LEVEL RIDGE
IS FORECAST TO BUILD OVER THE WEST COAST TUESDAY. THIS WILL TAPER
OFF THE PACIFIC MOISTURE STREAM OVER THE FORECAST AREA WITH
PRECIPITATION CONFINED MAINLY TO BAKER COUNTY AND THE WEST CENTRAL
AND BOISE MOUNTAINS TUESDAY WITH SNOW LEVELS AROUND 4000 FEET. AN
UPPER RIDGE WILL DOMINATE WEDNESDAY INTO NEXT WEEKEND WITH DRY
CONDITIONS PREVAILING AND TEMPERATURES ABOUT NORMAL TO 5 DEGREES
ABOVE NORMAL. FORECAST MODELS DO SHOW ANOTHER PACIFIC TROUGH
REACHING THE COAST NEAR THE END OF THE PERIOD WHICH COULD BRING SOME
PRECIPITATION (15-20% CHANCE) TO WESTERN AND NORTHERN FRINGES OF THE
FORECAST AREA.
AVIATION
MOSTLY VFR. LOCAL MVFR/IFR IN VALLEY FOG AND/OR LOW
STRATUS MAINLY NEAR KMYL, KONO, KBKE, KTWF, AND KJER EARLY SATURDAY
MORNING. LOW CHANCE (15-25%) OF MVFR IN -SHSN KBKE AND KMYL THROUGH
SATURDAY MORNING. MOUNTAINS OBSCURED. SURFACE WINDS: VARIABLE 10 KT
OR LESS EXCEPT E-SE 5-15 KT KBKE AND IN THE SNAKE RIVER PLAIN FROM
KBOI TO KJER/KTWF. WINDS ALOFT AT 10KFT MSL: W 20-30 KT.
KBOI...VFR. LOW CHANCE (10%) OF MVFR CEILINGS SATURDAY 12Z-18Z.
SURFACE WINDS: SE AROUND 10 KT.
SUNDAY OUTLOOK...ALL FLIGHT CATEGORIES EXPECTED AS WIDESPREAD PRECIP
MOVES IN TONIGHT AND CONTINUES SUNDAY. SNOW LEVELS RISING TO
6000 TO 8000 FEET MSL. MOUNTAINS OBSCURED.
HYDROLOGY
MODERATE TO HEAVY RAIN ALONG WITH LOW ELEVATION
SNOWMELT WILL CAUSE SIGNIFICANT RISES ON RIVERS, CREEKS, AND
STREAMS IN SE OREGON, AND PORTIONS OF SW IDAHO (PARTICULARLY IN
THE WEISER BASIN) BEGINNING SUNDAY AND MONDAY. SOILS ARE LIKELY
FROZEN IN SOME OF THE LOWER ELEVATIONS AS WELL WHICH WILL
ENHANCE RUNOFF. SNOW AND ICE MAY LEAD TO CLOGGED CULVERTS AND
DITCHES CAUSING PONDING OF WATER IN POOR DRAINAGE AREAS.
ADDITIONALLY, ICE JAMS COULD DEVELOP ON ANY RIVERS OR STREAMS
WITH EXISTING ICE COVER. RIVERS IN SE OREGON AND THE WEISER
RIVER WILL CONTINUE TO RUN HIGH THROUGH NEXT WEEK, POTENTIALLY
REACHING BANKFULL.
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...SH
LONG TERM....TL
AVIATION.....TL
HYDROLOGY...TL
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