308
FXUS66 KSTO 151038 CCA
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
219 AM PST FRI NOV 15 2024
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SYNOPSIS
PERIODS OF SCATTERED LIGHT TO MODERATE SNOW, RAIN, AND BREEZY
WINDS EXPECTED THROUGH FRIDAY WITH PERIODS OF MODERATE MOUNTAIN
TRAVEL IMPACTS. NORTHERN CA REMAINS IN AN ACTIVE WEATHER PATTERN
AT THE END OF THIS WEEK INTO EARLY NEXT WEEK.
DISCUSSION
THIS EVENING'S VALLEY SHOWERS AND THUNDERSTORMS HAVE WRAPPED UP
WITH LINGERING MOUNTAIN SNOW EXPECTED TO LAST INTO TOMORROW
MORNING. THE NORTHEASTERN FOOTHILLS SAW THE HIGHEST RAIN AMOUNTS
IN THE LAST 12 HOURS WITH UP TO 2 INCHES ESTIMATED AS
THUNDERSTORMS TRAINED OVER THE AREA.
CURRENT RADAR EARLY THIS MORNING SHOWS SNOW SHOWERS OCCURRING,
HEAVIEST NORTH OF INTERSTATE 80. THESE SHOWERS ARE EXPECTED TO
CONTINUE WITH AN ADDITIONAL 4 TO 8 INCHES, UP TO 12" OVER THE
PEAKS EXPECTED ACROSS THE SIERRA UNTIL FRIDAY NIGHT. AS A RESULT,
OUR WINTER WEATHER ADVISORY CONTINUES UNTIL 10 PM FRIDAY ACROSS
PORTIONS OF THE SIERRA FOR ELEVATIONS ABOVE 5500 FEET. SNOW LEVELS
THIS MORNING WILL BE AROUND 4000 TO 5000 FEET AND CONTINUE
THROUGHOUT MUCH OF THE DAY BEFORE DROPPING LATER TONIGHT AS
ACCUMULATING SNOW TAPERS OFF. HEAVIEST SNOWFALL WILL BE THIS
MORNING BEFORE GRADUALLY ENDING THROUGHOUT THE EVENING. PLAN ON
SLICK CONDITIONS, CHAIN CONTROLS, AND TRAVEL DELAYS IF PARTAKING
IN MOUNTAINOUS TRAVEL. PROBABILITIES SHOW AROUND A 70-90% CHANCE
OF AMOUNTS GREATER THAN 8 INCHES ABOVE 5500 FEET, HIGHEST ALONG
THE PEAKS SOUTH OF INTERSTATE 80.
THE THREAT OF RAIN HAS MAINLY ENDED WITH THIS WINTER SYSTEM WITH
ONLY LIGHT SHOWERS ACROSS THE SIERRA FOOTHILLS AND LOWER
ELEVATIONS OF THE MOUNTAIN. A TRACE TO JUST UNDER A QUARTER OF AN
INCH IS FORECASTED, ENDING BY THE EVENING HOURS TODAY.
AS THINGS TAPER OFF LATER TONIGHT, COLD MORNINGS FOLLOW IN THE
VALLEY SATURDAY AND SUNDAY WITH NEAR FREEZING MORNING LOWS.
COLDEST TEMPERATURES WILL BE ACROSS THE CENTRAL SACRAMENTO VALLEY
TO THE NORTHERN SAN JOAQUIN VALLEY, COLDEST SUNDAY MORNING. NBM
PROBABILITIES FOR VALLEY LOCATIONS, EAST OF I-5, HAVE 35-60%
CHANCE OF SEEING TEMPERATURES LESS THAN 35 DEG F. BREEZY NORTH
WIND GUSTS 20-30 MPH ALONG THE WEST SIDE OF THE VALLEY MAY PREVENT
SOME OF THE COLDEST FORECASTED TEMPERATURES TO BE REALIZED.
LATE SUNDAY MORNING, ANOTHER TROUGH PASSAGE WILL CONTINUE ACTIVE
WEATHER OVER NORTHERN CA, ALBEIT A MUCH WEAKER SYSTEM THAN THIS
WEEK'S WEATHER. LIGHT RAIN MOVES OVER THE COASTAL RANGE AND
NORTHERN SACRAMENTO VALLEY BEFORE SPREADING SOUTH AND EAST LATER
THAT AFTERNOON AND EVENING. ANY RESULTING PRECIPITATION IS
FORECASTED TO BE LIGHT BUT THE "HEAVIEST" PERIOD WILL BE SUNDAY
EVENING. RAIN WILL TAPER OFF IN THE VALLEY SUNDAY EVENING WITH
LINGER SNOW SHOWERS OVER THE SIERRA THROUGH MONDAY MORNING.
PROBABILITIES SHOW A 60-80 % CHANCE OF 2 INCHES OR MORE OVER THE
SIERRA FOR ELEVATIONS GREATER THAN 5500 FEET. BY MONDAY LATE
AFTERNOON, SNOW AND RAIN WILL HAVE TAPERED OFF AS WEAK RIDGING
BUILDS BACK OVER NORTHERN CA.
EXTENDED DISCUSSION (TUESDAY THROUGH FRIDAY)
MODELS HAVE TRENDED WETTER DURING THE EXTENDED FORECAST PERIOD
WITH A MORE PROGRESSIVE PATTERN. NEXT BAROCLINIC ZONE PROGGED TO
BRING A CHANCE OF LIGHT PRECIPITATION OVER FAR NW PORTIONS OF
INTERIOR NORCAL TUESDAY. PRECIP CHANCES INCREASE WEDNESDAY,
MAINLY N OF I-80. PRECIP LINE THEN PUSHES BACK NW SLIGHTLY
THURSDAY AS DOWNSTREAM UPPER RIDGING EXPANDS SLIGHTLY BACK
WESTWARD. BAROCLINIC ZONE BECOMES MORE PROGRESSIVE FRIDAY
INCREASING PRECIP CHANCES OVER MUCH OF THE CWA.
AVIATION
IN CENTRAL VLY, AREAS MVFR WITH LCL IFR AND ISOLATED LIFR POSSIBLE
IN BR/FG TIL 17Z. OTHERWISE, LCL MVFR/IFR POSSIBLE AT TIMES IN
PRECIP, MAINLY IN THE FOOTHILLS AND MTNS WITH ISOLATED LIFR OBSCRG
TRRN. SNOW LEVELS 3500-5000 FEET, LOWERING TO 2000-3000 FT BY SAT
MRNG. LCL NLY SFC WIND UP TO 15 KTS POSSIBLE IN THE CENTRAL VLY WITH
LCL NW-NE SFC WIND GUSTS UP TO 30 KTS POSSIBLE OVER MTNS.
STO WATCHES/WARNINGS/ADVISORIES
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR WEST
SLOPE NORTHERN SIERRA NEVADA-WESTERN PLUMAS COUNTY/LASSEN PARK.
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