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AGUS76 KRSA 221951

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

1250 PM PDT Fri Mar 22 2024



...AN UNSETTLED WEEKEND INTO NEXT WEEK AHEAD...



.METEOROLOGICAL CONDITIONS (SHORT TERM: FRI PM - MON AM)...



Precip continues to stream onshore along the northern CA coast early 

this afternoon...as the offshore upr trof located over the northeast 

Pacific approaches the region and the upr ridge nudges farther 

downstream. This is all part of a pattern shift from the spring-like 

weather across the region for the past several days...to one that 

promises to bring cooler temperatures and widespread precip (except 

desert locations of southeast CA). The previous 6-hour period came 

in a touch wetter across coastal locations between the Smith River 

basin and the Eel River basin...in particular locations in the 

vicinity of the King Range (1.00- to 1.50-inches). Precip will 

slowly make its way inland and southward as the upr trof spreads 

across the western US and rotates through several disturbances this 

weekend...before finally moving downstream on Monday. Best precip 

still looks to fall over coastal areas from the upper Russian River 

basin northward and then inland over the Shasta Lake drainage down 

across much of the Sierra with 1.00- to 3.00-inches. Freezing levels 

will also drop from current levels as the cooler airmass filters 

across the region...bottoming out early Sunday from 3500-feet 

northwest...4000- to 4500-feet along I-80...and 4500- to 5500-feet 

for southern CA into southern NV. 





.METEOROLOGICAL CONDITIONS (LONG TERM: MON AM - THU AM)...



Forecast remains on track for another surface/upper low to impact 

the region mid to late next week. Lingering showers for 

Monday/Tuesday across parts of nrn CA/NV and srn OR before initial 

precip from the low arrives late Tuesday night. There is still some 

uncertainty with the positioning and timing of the low, but nothing 

has changed substantially since this morning. Precip is expected to 

spread across nrn CA Weds am reaching central CA in the 

afternoon/evening as the offshore trough starts to move inland. 

Precip for the most part expected to remain confined to nrn/central 

CA with some light showers possible into Santa Barbara County south 

of Point Conception. The afternoon update blended in the latest WPC 

guidance and a little of the 12z GFS/ECMWF into the previous 

forecast. This led to minor overall changes with about 0.10-0.25" 

increase for parts of the Sierra and the central coast. Majority of 

the QPF is still expected on Weds with the highest totals along the 

north coast, Shasta, and the Sierra. QPF for Weds: 1-2" north coast 

(locally 2-2.50" Smith Basin/Kings Range), 1-1.75" Shasta, 0.75-2" 

Sierra, and 0.10-0.75" Bay Area/central coast/down the valleys 

(locally closer to 1" in the foothills). Not expecting much precip 

to make it south of Point Conception.



Freezing levels Monday 4.5-7.5 kft n to s across the region rising 

across southern areas Tuesday up to 6-9 kft south of I-80. Higher 

freezing levels will spread with the brief ridging up to 5.5-8.5 kft 

north of I-80 and 8.5-11 kft to the south by Weds am. The 

approaching low and front will lower freezing levels nw to se the 

rest of the period down to 3-4 kft north of I-80 and 3.5-6.5 kft 

from I-80 to Point Conception.





QPF graphics are available at www.cnrfc.noaa.gov/qpf.php







Kozlowski/AS



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