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AGUS76 KRSA 111933

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

130 PM PDT Mon Mar 11 2024



...A TROUGH WILL BRING PRECIPITATION TO NRN/CNTRL CA AND NRN NV THRU 

TUES WITH LINGERING SHOWERS POSSIBLE ON WEDS, MAINLY OVER NV...

...BUILDING HIGH PRESSURE TO RETURN DRY CONDITIONS TO THE REGION MID-

WEEK THRU THE REST OF THE PERIOD...



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



Forecast remains on track with no big changes to the afternoon 

update. The upper trough has moved into NV this afternoon while the 

next round of showers has arrived along the north coast. An upper 

low is moving through the Gulf of Alaska and will be the main driver 

of precip the rest of today. More moderate showers in the 

afternoon/evening period still expected along the north coast as the 

low draws nearer traveling south offshore of BC. Troughing from this 

system is still progged to move through the region late today and 

Tuesday before deepening into a closed low into Wednesday and 

shifting to a southerly trajectory through eastern NV the rest of 

the short term. Meanwhile, mid-week a strong upper ridge will build 

in over the eastern Pacific drying conditions out over CA the rest 

of the short term.



Majority of the precip expected is forecast for the rest of today 

and Tuesday before diminishing to lighter scattered showers that 

will become more confined to NV on Wednesday. Afternoon forecast 

went with the updated WPC guidance amounting to very little change 

from the morning amounts. QPF went up by 0.10-0.25" for parts of the 

Sierra with less than 0.10" change elsewhere. Best chances of precip 

still north of I-80 and particularly along the north coast over the 

Smith Basin/Kings Range. QPF for the short term: 0.50-1" nrn CA 

coast Sonoma northward (1-2" Smith Basin/Kings Range), 0.75-1.50" 

Shasta/northern Sierra, 0.10-0.75" central Sierra, 0.10-0.50" Bay 

Area, and a few hundredths to 0.25" or so down the valleys.



Freezing levels this afternoon 4-6.5 kft north of I-80 and 6-10 kft 

to the south fluctuating between 3.5-6.5 kft through tomorrow. 

Higher freezing levels then expected to develop along the CA coast 

as high pressure builds offshore up to 8-11 kft from Cape Mendocino 

southward mid Weds morning. Levels will decrease further inland as 

the low digs across the region the rest of the short term down to 

3.5-5.5 kft E to W from NV through much of the Sierra and 6-10 kft E 

to W to the coast early Thursday.





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



The end of the week will feature an amplified pattern with a high 

pressure ridge either just off or along the west coast stretching 

northward into western Canada...and then an upr low spinning over 

the lower Colorado River basin. This will generate mainly dry north 

to northeast flow across CA and NV with the possibility of a few 

showers rotating around the area of low pressure into far southern 

NV and portions of southern CA...mainly desert locations or 

north/east upslope areas. Any precip is expected to be light and 

very scattered across these areas. Freezing levels will show a sharp 

gradient from northwest (10000- to 11000-feet) to southeast (5500- 

to 7000-feet)...fluctuating as the pattern slowly evolves.





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







AS/Kozlowski



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