735
NGUS86 KRSA 211504
HCMRSA
HYDROMETEOROLOGICAL COORDINATION MESSAGE
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
705 AM PST SAT DEC 21 2024
..SERIES OF SYSTEMS TO IMPACT THE REGION THROUGH THE WEEK AHEAD
METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)
THE FIRST OF A SERIES OF DISTURBANCES AFFECTING THE WEST COAST IS
MOVING FROM SOUTHWEST TO NORTHEAST JUST OFF THE NORTHERN CA COAST
THIS MORNING...ON ITS WAY TOWARD THE PACIFIC NORTHWEST LATER THIS
AFTERNOON. PRECIP ASSOCIATED WITH THE COLD FRONT AND MOISTURE PLUME
ENTRAINED AHEAD OF THE BOUNDARY IS CURRENTLY IMPACTING THE NORTHERN
CA COASTAL MOUNTAINS...SPREADING INLAND ACROSS THE SHASTA LAKE
DRAINAGE AREA AND SACRAMENTO VALLEY. AUTOMATED PRECIP GAUGES SHOW
AREAS FROM THE EEL RIVER BASIN NORTHWARD TO THE CA/OR BORDER WITH
THE BEST AMOUNTS SO FAR...GENERALLY FROM 0.25- TO 0.50-INCH. THROUGH
THE REST OF TODAY...PRECIP WILL CONTINUE TO MOVE INLAND TOWARD THE
NORTHERN SIERRA AND SOUTHWARD TO THE I-80 CORRIDOR BEFORE STARTING
TO TAPER OFF AS THE SFC COLD FRONT BECOMES DIVORCED FROM THE BETTER
MID-LEVEL FORCING TO THE NORTH. FREEZING LEVELS WILL RANGE FROM
5500-FEET OR SO NEAR THE CA/OR BORDER...AND 8000- TO 9500-FEET ALONG
THE I-80 CORRIDOR.
SOME LIGHT PRECIP MAY LINGER THROUGH THE EVENING AND OVERNIGHT UNDER
MOIST ONSHORE FLOW NEAR THE VICINITY OF THE WEAKENED FRONTAL
BOUNDARY FROM THE SF BAY AREA INLAND ACROSS THE CENTRAL SIERRA AND
PORTIONS OF NORTHWEST NV. THIS IS AHEAD OF THE NEXT S/WV TROF TO
IMPACT THE REGION ON LATER SUNDAY INTO EARLY MONDAY. THE TRAJECTORY
OF THE MID-LEVEL SYSTEM WILL MOVE WEST-SOUTHWEST TO EAST-NORTHEAST
MAINLY ACROSS THE PACIFIC NORTHWEST...CLIPPING NORTHERN CA. AMOUNTS
WITH THIS QUICK MOVING SYSTEM WILL BE LIMITED...EVEN THOUGH
AVAILABLE MOISTURE IS DECENT...GIVEN THE DURATION OF THE PRECIP.
BEST AMOUNTS WILL REMAIN OVER THE HIGHER TERRAIN FROM ABOUT I-80
NORTHWARD WITH 0.25- TO 0.75-INCH. LOWER ELEVATIONS WILL GENERALLY
RANGE FROM 0.10- TO 0.33-INCH. FREEZING LEVELS WILL REMAIN ELEVATED
WITH THIS SYSTEM AS WELL...FROM 6000- TO 7500-FEET NEAR THE CA/OR
BORDER TO 8000- TO 9500-FEET ALONG THE I-80 CORRIDOR.
THE THIRD S/WV TROF MAKING ITS WAY TOWARD THE WEST COAST LOOKS TO BE
A BIT MORE IMPRESSIVE...SHARPENING A AND ELONGATING BEFORE CROSSING
THE COAST. LOOK FOR PRECIP TO SPREAD ACROSS THE REGION FROM
NORTHWEST TO SOUTHEAST STARTING MONDAY AFTERNOON AND THEN LINGERING
THROUGH THE EARLY EVENING HOURS ON TUESDAY. ALTHOUGH NORTHERN CA
WILL SEE THE HIGHEST TOTALS FROM THIS SYSTEM...CENTRAL CA WILL SEE
WIDESPREAD MODERATE AMOUNTS...WHILE EVEN SOUTHERN CA IS EXPECTED TO
PICK UP SOME MAINLY LIGHT PRECIP. SOME TIMING AND STRENGTH OF THE
SYSTEM DIFFERENCES AMONGST THE 21/00Z MODELS...BUT THIS FAR OUT THE
GENERAL PATTERN IS HANDLED WELL ENOUGH TO HAVE MEDIUM CONFIDENCE IN
OVERALL PRECIP TOTALS. LOOK FOR THE HIGHER TERRAIN OF NORTHERN CA TO
RANGE FROM 1.00- TO 3.00-INCHES WITH A FEW LOCALIZED HIGHER AMOUNTS
FOR THE SMITH RIVER BASIN AND KING RANGE. SACRAMENTO VALLEY
LOCATIONS WILL SEE CLOSE TO 1.00-INCH SOUTH NEAR SACRAMENTO TO
ALMOST 2.00-INCHES AROUND THE REDDING AREA. CENTRAL CA WILL ADD UP
0.75- TO 1.50-INCHES ACROSS THE HIGHER TERRAIN WITH THE SAN JOAQUIN
VALLEY RANGING FROM 0.10-INCH OR SO NEAR BAKERSFIELD TO 0.75-INCH
AROUND STOCKTON. AREAS SOUTH OF POINT CONCEPTION WILL GENERALLY BE
NEAR OR LESS THAN 0.10-INCH. FOR NV...TOTALS WILL BE BEST OVER THE
NORTHERN HALF OF THE STATE WITH 0.10-INCH FOR LOWER ELEVATIONS AND
0.50-INCH OVER FAVORABLE TERRAIN...WHILE THE SOUTHERN HALF OF THE
STATE WILL GENERALLY BE NEAR OR LESS THAN 0.10-INCH EVERYWHERE.
FREEZING LEVELS WILL START REASONABLY ELEVATED FROM NEAR 8000-FEET
TO AS HIGH AS 13000-FEET (NORTHEAST TO SOUTHWEST GRADIENT). BEHIND
THE FRONTAL BOUNDARY...THESE WILL FALL AS THE CORE OF THE S/WV TROF
MOVES OVERHEAD...DOWN TO 3500- TO 4500-FEET NORTH...WITH 5500- TO
7500-FEET CENTRAL...AND ABOVE 8000-FEET TO 12500-FEET SOUTH.
AFTER THIS SYSTEM EXITS THE REGION TO THE EAST EARLY ON CHRISTMAS
DAY...CONDITIONS WILL BE PRIMARILY DRY FOR THE HOLIDAY. THE NEXT
DISTURBANCE WILL ARRIVE ON THURSDAY WITH ANOTHER ROUND OF PRECIP
MAINLY FOCUSED ACROSS NORTHERN CA AND TAPERING OFF ACROSS CENTRAL
CA.
QPF GRAPHICS ARE AVAILABLE AT WWW.CNRFC.NOAA.GOV/QPF.PHP
*********************** CONTACT INFORMATION ************************
CNRFC OFFICE HOURS PHONE: 1 (916) 979-3056 EXTENSION 338
AFTER-HOURS CALLING SERVICE: 1 (800) 218-0858
LEAVE NAME...OFFICE...AND PHONE NUMBER
KOZLOWSKI
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page