433
NGUS86 KRSA 011440
HCMRSA
HYDROMETEOROLOGICAL COORDINATION MESSAGE
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
745 AM PDT TUE APR 1 2025
..PRECIP CONTINUES TODAY WITH SYSTEM ARRIVING FROM THE NORTH
..SHOWERS DECREASE THROUGH THE END OF THE WEEK
..WEAKER SYSTEM POSSIBLE BY SUNDAY INTO MONDAY MAINLY NORTH
METEOROLOGICAL CONDITIONS (SHORT TERM: TUE AM - FRI AM)
A COUPLE DISTURBANCES ROTATING AROUND A BROAD UPR TROF THAT HAS
CARVED OUT ACROSS THE WESTERN US THIS MORNING WITH ONE SHIFTING
EASTWARD TOWARD THE LOWER COLORADO RIVER BASIN AND THE OTHER
DROPPING SOUTH-SOUTHEAST FROM OFF THE PACIFIC NORTHWEST COAST TOWARD
NORTHERN CA. THIS SECOND FEATURE IS PUSHING SCATTERED SHOWERS SOUTH
AND EAST ACROSS THE NORTHERN AND PORTIONS OF CENTRAL CA THIS MORNING
WITH AUTOMATED PRECIP GAUGES SINCE 01/12Z SHOWING AMOUNTS FROM A FEW
HUNDREDTHS OF AN INCH UP TO APPROX 0.25-INCH OVER THE WETTEST
LOCATIONS OF THE NORTH COAST AND NORTHERN SIERRA.
GIVEN THE GENERAL FLOW ACROSS THE REGION AND THE NEXT SYSTEM NOW
ARRIVING FROM THE NORTH...AVAILABLE MOISTURE IS NOT OVERLY
IMPRESSIVE TODAY WITH THE 01/12Z KOAK RAOB INDICATING A SATURATED
LAYER FROM NEAR THE SFC TO JUST ABOVE 700-MB AND A RECORDED PW OF
0.65-INCH. THIS IS ABOUT AS GOOD AS IT IS GOING TO GET FOR AVAILABLE
MOISTURE WITH THIS SYSTEM.
THROUGH TODAY...THE INITIAL S/WV TROF MOVING FROM NEAR LAS VEGAS TO
THE EAST WILL RACE TOWARD THE CENTRAL PLAINS STATES BY THIS TIME
TOMORROW...WHILE THE DISTURBANCE MAKING ITS WAY TOWARD NORTHERN CA
THIS MORNING WILL CONTINUE TO DIVE TO THE SOUTH-SOUTHEAST AND
TRAVERSE MUCH OF CA BY THE MORNING HOURS ON WEDNESDAY. BEST PRECIP
LOOKS TO FALL OVER THE SIERRA FROM ABOUT THE YUBA RIVER BASIN SOUTH
THROUGH THE MERCED RIVER BASIN WITH AMOUNTS FROM 1.00- TO ALMOST
2.00-INCHES. ELSEWHERE...NORTHERN/CENTRAL CA TOTALS SHOULD BE FROM
0.25- TO 0.75-INCH FOR THE HIGHER TERRAIN AND 0.10- TO 0.33-INCH AT
LOWER ELEVATIONS. NORTHERN NV SHOULD ALSO SEE ANYWHERE FROM A FEW
HUNDREDTHS OF AN INCH TO 0.33-INCH OVER THE FAVORABLE HIGHER
TERRAIN. HOWEVER...WITH SPC PLACING MUCH OF NORTHERN AND CENTRAL CA
ALONG WITH MUCH OF NV UNDER GENERAL THUNDER...AND A MARGINAL RISK OF
SEVERE STORMS ACROSS THE SACRAMENTO AND NORTHERN SAN JOAQUIN
VALLEY...ANY CONVECTIVE CELLS THAT DO DEVELOP THIS AFTERNOON COULD
GENERATE SOME LOCALLY HEAVIER TOTALS.
FREEZING LEVELS THIS MORNING ARE STARTING OUT REASONABLY LOW FOR THE
NORTHERN TWO-THIRDS OF THE REGION...MAINLY FROM 3000- TO 6000-FEET
FROM NORTHWEST TO SOUTHEAST...EXPECTED TO ENCOMPASS THE ENTIRE
REGION BY WEDNESDAY MORNING.
FOR WEDNESDAY...THE S/WV TROF WILL ROUND THE BASE OF THE BROAD UPR
TROF AND THEN SHIFT EAST OF THE AREA ACROSS THE DESERT SOUTHWEST ON
ITS WAY TO THE NORTHERN/CENTRAL PLAINS STATES. ACROSS THE WESTERN
US...CYCLONIC FLOW ALOFT WILL CONTINUE WITH DRIER NORTHERLY FLOW
SETTING UP ACROSS THE REGION. GIVEN THE CYCLONIC FLOW...LOOK FOR THE
POTENTIAL FOR SOME SCATTERED LIGHT PRECIP TO DEVELOP...MAINLY OVER
THE LENGTH OF THE SIERRA...PORTIONS OF COASTAL SOUTHERN CA...AND THE
EASTERN TWO-THIRDS OF NV. AMOUNTS WILL BE LIGHT GIVEN THE LACK OF
SIGNIFICANT MOISTURE.
INTO THURSDAY...THE BROAD UPR TROF WILL FINALLY BEGIN TO SLOWLY
MAKING ITS WAY TO THE EAST AS A NARROW WAVELENGTH UPR RIDGE MAKES
ITS WAY FROM THE EASTERN PACIFIC TOWARD THE COASTAL WATERS. ANY
SCATTERED SHOWERS OVER THE SOUTHERN SIERRA...COASTAL SOUTHERN
CA...AND EASTERN NV SHOULD COME TO AN END AFTER SUNSET...BRINGING
DRY CONDITIONS. AS THE UPR RIDGE BEGINS TO INFLUENCE CONDITIONS
ACROSS THE WEST COAST...LOOK FOR FREEZING LEVELS TO FINALLY START TO
BUMP UP A BIT...MAINLY 5000- TO 7000-FEET (GREATEST ALONG COASTAL
AREAS AND FAR SOUTHERN NV).
METEOROLOGICAL CONDITIONS (LONG TERM: FRI AM - MON AM)
UPPER LEVEL TROUGH MOVES SE THROUGH THE REGION ON FRIDAY AS
SHORTWAVE RIDGING BUILDS IN BEHIND IT. SCATTERED LIGHT PRECIP IS
POSSIBLE OVER THE SRN SIERRA AND OVER SRN CA (MAINLY OVER SAN
BERNARDINO MTNS AND SOUTH INTO THE SAN DIEGO COUNTY MTNS) AND OVER
NV ON FRIDAY. PRECIP AMOUNTS GENERALLY EXPECTED TO BE LESS THAN A
TENTH OF AN INCH. SHORTWAVE RIDGING OVER THE REGION ON SATURDAY
BETWEEN SYSTEMS AS THE TROUGH MOVES THROUGH THE FOUR CORNERS REGION
AND ANOTHER LOW PRESSURE SYSTEM APPROACHES THE WEST COAST. DRY AND
WARMER CONDITIONS EXPECTED ON SATURDAY.
THERE IS VARIABILITY IN THE TIMING, STRENGTH AND TRACK OF THE LOW
PRESSURE SYSTEM FOR SUNDAY. THIS SYSTEM MAY TAP INTO SOME MOISTURE
WITH A PW PLUME NEAR AN INCH OF THE NRN CA COAST. THE 06Z GFS IS
FASTER AND FARTHER NORTH THAN THE 00Z EC (HAS FRONT ALONG THE NRN CA
COAST SUNDAY NIGHT) AND MOVES THE ASSOCIATED FRONT THROUGH DURING
THE DAY SUNDAY AND TROUGH INTO THE PAC NW/NRN CA SUNDAY NIGHT.
ENSEMBLE MEMBERS ALSO SHOW VARIABILITY. 24 HR QPF 50TH PERCENTILE
CLUSTERS ENDING AT 00Z TUESDAY RANGE FROM GENERALLY DRY (A TENTH OF
AN INCH OR LESS NEAR THE ORCA BORDER) OVER THE REGION IN 34% OF THE
ENSEMBLE MEMBERS (CANADIAN 25%, GFS 27% AND EC 42%) TO 0.5-1.5
INCHES ALONG THE NW CA COAST AND SRN OR CASCADES AND PRECIP INTO THE
SHASTA BASIN IN 20% OF THE ENSEMBLE MEMBERS (CANADIAN 15%, GFS 20%,
EC 22%). THE MAJORITY OF THE ENSEMBLE MEMBERS (46%- CANADIAN 60%,
GFS 53%, EC 36%) ARE IN BETWEEN WITH A HALF AN INCH OR LESS ALONG
THE NW CA COAST AND THE SRN OR CASCADES. THE FORECAST USES A BLEND
OF THE LATEST NBM WITH WPC WITH PRECIP ALONG THE NRN CA COAST DURING
THE DAY SUNDAY AND SPREADING SOUTH AND EAST OVER NRN CA (MAINLY
ALONG THE COAST AND HIGHER TERRAIN) SUNDAY NIGHT. PRECIP AMOUNTS
AROUND 0.25-0.75 INCHES ALONG THE NW CA COAST AND AROUND A QUARTER
OF AN INCH OR LESS OVER THE SRN OR CASCADES AND SHASTA BASIN AND
AROUND A TENTH OF AN INCH OR LESS FOR THE NRN SIERRA AND RUSSIAN
BASIN.
HIGH TEMPERATURES GENERALLY NEAR NORMAL TO AROUND 15 DEGREES BELOW
NORMAL (WARMEST OVER NRN CA) FRIDAY AFTERNOON AND WARM TO NEAR
NORMAL TO 10 DEGREES ABOVE NORMAL FOR NRN CA AND NEAR NORMAL TO
AROUND 10 DEGREES BELOW NORMAL FOR CENTRAL AND SRN CA AND NV
SATURDAY AND NEAR NORMAL TO AROUND 10 DEGREES ABOVE NORMAL OVER THE
REGION ON SUNDAY (A LITTLE COOLING OVER NW CA). LOW TEMPERATURES
GENERALLY NEAR NORMAL FOR THE REGION FRIDAY NIGHT AND WARM TO NEAR
NORMAL TO 10 DEGREES ABOVE NORMAL SATURDAY NIGHT AND TO ABOVE NORMAL
TO AROUND 12 DEGREES ON SUNDAY NIGHT.
FREEZING LEVELS AROUND 5000-7000 FT EXCEPT UP TO 9000 FT OVER NRN CA
COAST FRIDAY MORNING AND RISE TO AROUND 7500-11,000 FT (SE-NW) OVER
CA AND AROUND 7000-8500 FT OVER NV (HIGHEST IN THE NW) AS . THE
SHORTWAVE RIDGE MOVES INTO REGION. FREEZING LEVEL AROUND 8000-11,000
FT OVER CA/NV ON SUNDAY MORNING AND DROP TO AROUND 5500-7500 FT OVER
SRN OR AND NRN CA AND 8000-12,000 FT OVER CENTRAL AND SRN CA AND
AROUND 7500-11,000 FT OVER NV (LOWEST IN THE NW) SUNDAY NIGHT.
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/OSBORNE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page