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AGUS76 KRSA 262026

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

130 PM PDT Tue Mar 26 2024



...WET PATTERN RETURNS MID WEEK THROUGH THE COMING WEEKEND AS A PAIR 

OF LOWS IMPACT THE REGION...



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



Radar imagery continues to show scattered showers across NV this 

afternoon with dry conditions over CA as an upper ridge begins to 

push into the west coast. Forecast remains on track for a 

surface/upper low to impact the region starting tomorrow and through 

the rest of the short term. A surface/upper low will continue to 

move eastward towards BC and the PacNW the rest of today sending a 

cold front towards northern CA with about 0.75-1" of moisture 

surrounding the front. The front is set to arrive offshore of the 

nrn CA coast early Wednesday morning with initial showers late 

tonight. Precip will spread inland across nrn CA and into central CA 

later Wednesday as well as into nrn NV. Showers will persist the 

rest of the near term as the low draws closer and another surface 

low and upper shortwave spin off the back side of the main system 

before moving towards the region.



Not much has changed with the models since this morning. The 

afternoon forecast was a combination of the previous forecast and 

the latest WPC guidance 12z GFS/ECMWF. This brought QPF up over nrn 

CA and the Sierra by about 0.10-0.25". Highest totals still expected 

along the north coast, over Shasta, and across the Sierra. QPF 

through 12z Fri: 1-2.75" north coast (2.50-4.50" Smith Basin/Kings 

Range), 1-2.50" Shasta/nrn/cntrl Sierra, 0.25-1+" southern Sierra, 

0.10-0.85" Bay Area/central coast, and 0.10-0.60" down the valleys 

(higher towards the foothills). 



High pressure will increase freezing levels later today to 6-8.5 kft 

north of I-80 and 7-10 kft to the south. The approaching low will 

then lower levels back down from nw to se to 5.5-8.5 kft north of I-

80 Weds am and 7-11.5 kft to the south. This downward trend will 

continue the rest of the short term to 3-4.5 kft north of I-80 Thus 

am and 4.5-11 kft to the south with lower levels spreading across 

the state into Friday as well.





.METEOROLOGICAL CONDITIONS (LONG TERM: FRI AM - SUN NIGHT)...



Not much change to the forecast thinking compared to this morning. 

Expect a vertically-stacked low to move south off the CA coast later 

Fri through the weekend and eventually across southern CA early next 

week, while a frontal system and associated moisture plume spread 

precipitation across the region. Models are a bit more consistent in 

showing heavier amounts across the transverse ranges of southern CA 

and vary regarding precip amounts down into SW CA.  With the 19 UTC 

NBM not quite available yet at the time the forecast was created, 

the latest forecast represents a blend of the 13 UTC NBM and WPC, 

which resulted in overall higher amounts for portions of southern CA 

as well as NE CA/NW NV and slightly lower amounts for portions of 

the central and northern CA coast.  Freezing level forecasts were 

largely unchanged.





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







AS/Lerman



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