588
NGUS86 KRSA 221525
HCMRSA
HYDROMETEOROLOGICAL COORDINATION MESSAGE
NATIONAL WEATHER SERVICE / CALIFORNIA NEVADA RFC / SACRAMENTO CA
830 AM PDT WED OCT 22 2025
...SCATTERED SHOWERS/T-STORMS OVER THE CENTRAL COAST, VALLEY, SRN
SIERRA/NV TODAY AS A LOW MOVES THROUGH...
...MORE WIDESPREAD PRECIP EXPECTED FRI-MON ACROSS NRN CA AS TROPICAL
MOISTURE IS STEERED TOWARDS THE WEST COAST...
METEOROLOGICAL CONDITIONS (WED AM - TUE AM)
SATELLITE AND RADAR IMAGERY SHOW A LOW PRESSURE SYSTEM CENTERED JUST
OFFSHORE OF POINT CONCEPTION THIS MORNING THAT IS GENERATING SHOWERS
AND THUNDERSTORMS ACROSS PARTS OF THE CENTRAL COAST AND INLAND INTO
SE CA/SRN NV. THE LOW WILL MAKE ITS WAY INLAND ACROSS SRN CA LATER
TODAY CONTINUING TO GENERATE SHOWERS AND THUNDERSTORMS AS IT HEADS
FOR NV INTO THIS EVENING. THE SYSTEM WILL EXIT INTO AZ EARLY
THURSDAY MORNING WITH LINGERING SHOWERS ALONG THE BACK EDGE OF THE
SYSTEM POSSIBLE. THE MAIN EVENT FOR THE FORECAST PERIOD REMAINS
APPROACHING TROPICAL MOISTURE FOR THE END OF THE WEEK AND THROUGH
THE WEEKEND. MODELS CONTINUE TO SHOW A STREAM OF TROPICAL MOISTURE
BEING DRAWN INTO THE WEST COAST BY AN UPPER LOW IN THE GULF OF
ALASKA AND A RIDGE JUST NORTH OF THE HAWAIIAN ISLANDS. THIS MOISTURE
LOOKS TO GET WRAPPED FIRST AROUND A COLD FRONT HEADED FOR THE PACNW
AND NRN CA ON FRIDAY. A SLOWER TIME FRAME SEEMS INCREASINGLY LIKELY
WITH ARRIVAL OF SHOWERS PROBABLY IN THE EARLY AFTERNOON. THE ECMWF
IS STILL A BIT AHEAD OF THE GFS AT BRINGING IN PRECIP BUT THE
OVERALL DETAILS ARE FAIRLY CONSISTENT. EXPECT PRECIP TO SPREAD
INLAND TO THE SOUTHEAST FRIDAY EVENING MOVING INTO THE NORTHERN
SIERRA BY EARLY SATURDAY MORNING.
SATURDAY, ANOTHER SURFACE/UPPER LOW WILL MOVE OFFSHORE OF THE PACNW
DRAWING IN ADDITIONAL TROPICAL MOISTURE. TROUGHING FROM THE OVERALL
LARGER SYSTEM WILL PUSH SOUTHWARD ACROSS CA THE REST OF SATURDAY
SENDING ADDITIONAL PRECIP INTO THE NORTH BAY AREA THROUGH TO THE
CENTRAL SIERRA. THE OVERALL FLOW PATTERN WILL CONTINUE TO RESULT IN
TROPICAL MOISTURE BEING CARRIED INTO THE AREA BY SOME ADDITIONAL
EMBEDDED DISTURBANCES ON SUNDAY AND INTO MONDAY. THIS OFFSHORE
MOISTURE LOOKS TO FINALLY GET CUT OFF FROM ITS TROPICAL ORIGINS
LATER IN THE DAY MONDAY WITH SOME RIDGING PUSHING ANY SUBSEQUENT
MOISTURE AWAY. OTHER THAN SOME LINGERING SHOWERS ALONG THE NORTH
COAST OVERNIGHT THINGS LOOK TO DRY OUT FOR THE END OF THE PERIOD.
OFFICIAL QPF WAS A BLEND OF WPC GUIDANCE AND THE NBM. QPF TODAY
SHOULD BE AROUND 0.10-0.50" OVER THE CENTRAL/SOUTHERN SIERRA AND
LESSER AMOUNTS ACROSS THE REST OF CENTRAL/SRN CA/NV. EXPECT HIGHER
TOTALS UNDER THUNDERSTORMS. FOR THE REST OF THE PERIOD (FRIDAY-
MONDAY): 2.50-4.50" NORTH COAST (3.50-5.50" SMITH BASIN), 1.50-2.50"
SHASTA, 0.75-1.75" NORTHERN SIERRA, 0.25-1" CENTRAL SIERRA, 0.10-
0.75", AND A FEW HUNDREDTHS TO 0.25" FOR THE BAY AREA AND SOUTHERN
SIERRA.
FREEZING LEVELS TO START FRIDAY STILL NORTH OF 12.5 KFT FOR MOST OF
THE REGION LOWERING INTO SATURDAY TO 6-11 KFT NORTH OF I-80 AND 10-
13.5 KFT FROM I-80 TO THE SOUTHERN SIERRA. LOWER LEVELS WILL SPREAD
A BIT FURTHER SOUTH THE REST OF SATURDAY DOWN TO 5-9 KFT NORTH OF I-
80 IN THE EVENING AND HOVERING AROUND THERE THROUGH SUNDAY. HIGHER
FREEZING LEVELS WILL BEGIN TO BUILD BACK IN FROM WEST TO EAST INTO
MONDAY.
PLEASE NOTE: THIS PRODUCT MAY NOT BE ROUTINELY UPDATED THIS
SUMMER. PLEASE REFER TO THE FOLLOWING PRODUCT ISSUED BY THE CNRFC
WWW.CNRFC.NOAA.GOV/DAILY-BRIEFING FOR A GRAPHICAL SUMMARY OF
WEATHER AND HYDROLOGIC CONDITIONS.
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
AS
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