256
FXUS65 KBOI 141626
AFDBOI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE ID
926 AM MST THU NOV 14 2024
DISCUSSION
AN UPPER-LEVEL TROUGH OFF THE PACIFIC NORTHWEST
COAST THIS MORNING IS STILL EXPECTED TO MOVE INLAND THIS
EVENING, PASSING ACROSS THE FORECAST AREA FROM FRIDAY THROUGH
FRIDAY NIGHT. A BRIEF BREAK IN PRECIPITATION IS ANTICIPATED THIS
MORNING, WITH CONVECTIVE SHOWERS LIKELY TO DEVELOP BY EARLY
AFTERNOON, ESPECIALLY IN SOUTHEAST OREGON. STRONGER SHOWERS
COULD BRING BRIEF PERIODS OF HAIL OR GRAUPEL, ALONG WITH LIGHT
RAIN BELOW 5,000 FEET. LIGHT SNOW MAY FALL ABOVE 5,000 FEET,
THOUGH ACCUMULATION IS EXPECTED TO BE MINIMAL.
ON FRIDAY MORNING, LIGHT SNOWFALL MAY OCCUR ACROSS SOUTHWEST
OREGON WITH THE TROUGH'S PASSAGE. ENSEMBLE MODELS CONSISTENTLY
SHOW AN UPPER-LEVEL LOW FORMING OVER NORTHEAST NEVADA AND SOUTH-
CENTRAL IDAHO BY FRIDAY AFTERNOON AND EVENING, CREATING
FAVORABLE CONDITIONS FOR A PRECIPITATION BAND TO FORM ON THE
LOW'S BACKSIDE. THIS COULD RESULT IN MODERATE SNOWFALL ALONG THE
IDAHO/NEVADA BORDER. ALTHOUGH SOME MODELS SHIFT THIS BAND
NORTHWARD INTO THE EASTERN TREASURE VALLEY AND WESTERN MAGIC
VALLEY, THESE REMAIN OUTLIERS. CURRENT GUIDANCE SUGGESTS AN 80%
CHANCE OF 2-4 INCHES OF SNOWFALL ALONG THE IDAHO/NEVADA BORDER
ON FRIDAY NIGHT, POTENTIALLY IMPACTING TRAVEL ON US-93 AND STATE
HIGHWAY 51.
MINOR UPDATES HAVE BEEN MADE TO THE PROBABILITY OF PRECIPITATION
FOR TODAY’S FORECAST, WITH FURTHER UPDATES FOR FRIDAY’S EVENT
EXPECTED IN THE AFTERNOON FORECAST PACKAGE.
AVIATION
MAINLY VFR. ISOLATED RAIN/SNOW SHOWERS TODAY CAUSING
BRIEF MVFR/IFR CONDITIONS. LOW CLOUDS AND PATCHY FOG CREATING
MOUNTAIN OBSCURATION. SNOW LEVELS 4K-5K FEET MSL. SNOW ENTERING SE
OREGON INCLUDING KBNO THIS AFTERNOON, WITH RAIN-SNOW EXPANDING INTO
SOUTHEAST OR AND SOUTHWEST ID AFTER 15/13Z. SNOW LEVELS 3000-4000
FEET MSL. MVFR TO LIFR IN SNOW. MOUNTAIN OBSCURATION.. SURFACE
WINDS: SE-SW 6-12 KT SHIFTING TO NW 10-20 KT WITH GUSTS TO 30 KT IN
THE SNAKE RIVER VALLEY AFTER 15/14Z. WINDS ALOFT AT 10KFT MSL: W-SW
10-20 KT.
KBOI...GENERALLY VFR. PERIODS OF LIGHT RAIN SHOWERS THIS MORNING AND
AFTERNOON. SURFACE WINDS: VARIABLE LESS THAN 10 KT BECOMING NW 5-10
KT 15/12Z.
WEEKEND OUTLOOK... SATURDAY: LINGERING LOW CLOUDS/PATCHY MOUNTAIN
VALLEY FOG IN THE MORNING, THEN VFR. SURFACE WINDS W-NW 5-15 KT,
AFTERNOON GUSTS TO 15-25 KT. SUNDAY: RAIN/SNOW MOVING IN FROM NW,
BECOMING WIDESPREAD BY SUN NIGHT. MVFR TO LIFR IN PRECIP. SURFACE
WINDS SW-SE 5-15 KT, AFTERNOON GUSTS 20-25 KT. MOUNTAIN OBSCURATION.
SNOW LEVELS OSCILLATING BETWEEN 2500-5500 FT MSL, LOWERING NEAR/AT
VALLEY FLOORS EARLY MON.
PREV DISCUSSION
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...COOL, MOIST
SOUTHWESTERLY FLOW ALOFT CONTINUES OVER OUR CWA THIS MORNING
WITH UPPER TROUGH AXIS ALONG THE COAST, BUT FEW IF ANY SHOWERS
WERE OCCURRING AT 3 AM MST. HIGHEST POPS AND MOST NUMEROUS SNOW
SHOWERS TODAY ARE SLATED FOR THE CENTRAL IDAHO MOUNTAINS. AS
THE UPPER TROUGH MOVES INLAND PCPN WILL INCREASE IN SOUTHEAST
OREGON THIS AFTERNOON AND TONIGHT, THEN IN SOUTHWEST IDAHO IN
OWYHEE AND TWIN FALLS COUNTIES FRIDAY THROUGH SATURDAY MORNING.
SNOW WILL ACCUMULATE 3 TO 6 INCHES NEAR THE ID/NV BORDER,
ALMOST ENOUGH FOR A WINTER WEATHER ADVISORY. THE WESTERN MAGIC
VALLEY MAY GET UP TO ONE INCH OF WET SNOW. MEANWHILE, CENTRAL
AND NORTHERN PARTS OF OUR CWA SHOULD HAVE ONLY LIGHT PCPN,
MAINLY IN THE FORM OF SNOW, WITH UP TO TWO INCHES IN THE CENTRAL
IDAHO MOUNTAINS TODAY, BUT ONLY ANOTHER INCH OR LESS FRIDAY
THROUGH SATURDAY NIGHT. HIGH TEMPS TODAY WILL BE SIMILAR TO
YESTERDAY'S HIGHS BUT FRIDAY SHOULD BE 3 TO 6 DEGREES COLDER AS
THE UPPER TROUGH COMES IN, AND SATURDAY ANOTHER 2 TO 4 DEGREES
COLDER. SATURDAY NIGHT LOOKS QUITE COLD IN CENTRAL AND NORTHERN
AREAS AS SKIES PARTIALLY CLEAR, WITH LOWS IN THE TEENS TO MID 20S.
FRIDAY AFTERNOON THROUGH SATURDAY WILL ALSO BE WINDY FROM THE
NORTHWEST WITH SPEEDS 15 TO 30 MPH.
LONG TERM...SUNDAY THROUGH THURSDAY...A SIGNIFICANT GULF OF
ALASKA TROUGH WILL BRING A MODERATE TO HIGH CHANCE (60-90%) OF
RAIN/SNOW FOR THE FORECAST AREA BEGINNING SUNDAY. BREEZY
SOUTHWEST-SOUTHEAST SURFACE WINDS DURING THE DAY WILL TRANSITION
TO WEST-NORTHWEST AS THE COLD FRONT ARRIVES SUNDAY NIGHT. SNOW
LEVELS WILL OSCILLATE BETWEEN 2500-5500 FT MSL ON SUNDAY,
CREATING A CHALLENGING FORECAST SCENARIO FOR ESTIMATING SNOWFALL
AMOUNTS AT THIS TIME. AS THE TROUGH MOVES SOUTHEAST MONDAY,
SHOWERS ARE EXPECTED TO CONTINUE IN BREEZY, UNSTABLE NORTHWEST
FLOW. SNOW LEVELS WILL LOWER TO NEAR/AT VALLEY FLOORS BY MONDAY
MORNING, RESULTING IN SNOW POTENTIAL FOR MOST AREAS.
ACCUMULATIONS IN THE LOWEST ELEVATIONS ARE CURRENTLY FORECAST TO
BE LITTLE TO NONE, BUT MOUNTAINS SHOULD SEE SEVERAL INCHES OF
STORM TOTAL SNOWFALL SUN-MON. PRECIPITATION WILL QUICKLY END
TUESDAY THROUGH THE REST OF THE WEEK AS A STRONG, AMPLIFIED
UPPER RIDGE BUILDS OVER THE WESTERN U.S. THIS WILL PROMOTE A
WARMING TREND FOR THE MOUNTAINS WHILE KEEPING VALLEY
TEMPERATURES RELATIVELY COLD FROM DEVELOPING TEMPERATURE
INVERSIONS. VALLEY AIR STAGNATION WILL BECOME LIKELY.
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...JDS
AVIATION.....SA
SHORT TERM...LC
LONG TERM....SH
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