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AGUS76 KRSA 222052

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

1255 PM PST Thu Feb 22 2024



...DRY CONDITIONS THROUGH MOST OF SUNDAY AS HIGH PRESSURE BUILDS...

...PRECIPITATION CHANCES RETURN LATE SUNDAY THROUGH EARLY NEXT 

WEEK...



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



Forecast remains on track with no updates to the QPF in the near 

term. Ridging over the west coast is expected to keep conditions 

mostly dry through Sunday morning as a surface/upper low pressure 

system slowly approach from the west. The northeastern edge of the 

low will elongate and get close enough to the north coast this 

evening/tonight to potentially introduce a few showers, but nothing 

significant. The low then retreats westward later Friday pulling any 

precip well offshore. The system is forecast remain over the Pacific 

the rest of the near term keeping CA/NV dry.



Freezing levels 5-7.5 kft north of I-80 and 7-9.5 kft to the south 

this afternoon. Higher freezing levels to continue to spread 

northward the rest of today. By this evening, expecting 6-8 kft 

north of I-80 and 8-10 kft to the south. High pressure overhead will 

further increase levels Friday with all of CA above 8 kft by the 

late afternoon and remaining 8-10.5 kft or so the rest of the short 

term.





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



Guidance continues to suggest the return to a wet pattern beginning 

Sunday night and lasting through Monday as a digging s/wv over the 

northeast Pacific swings over the forecast region and absorbs a 

stagnant cutoff just off the California Coast. The digging s/wv 

trough will likely bring colder temperatures with it, resulting in 

lowered freezing levels (down to 4,000 feet on Tuesday morning) 

across the higher terrain and contributions to the snowpack in the 

Sierra.



Uncertainty continues to persist within the phasing between the s/wv 

trough and the cutoff low and, therefore, the timing and amplitude 

of the system as it moves onshore. Current GFS forecasts are 

predicting much higher accumulations across the Southern Sierra 

(upwards of 4 inches) where upslope moisture flux is stronger within 

a moisture plume extending inland from the Pacific that was 

originally being drawn poleward around the base of the cutoff. The 

EC, on the other hand, only has a few hundredths of an inch over the 

southern Sierra. Cluster analysis show that over 60% of the 

ensembles favor the wetter southern Sierra regime, which also falls 

in line with the NBM. Afternoon RFC forecasts generally followed the 

guidance from the NBM and WPC, increasing accumulations in the 

southern Sierra by up to .65 inches with slight decreases over 

southern California and the Smith basing (generally <0.1 inches).  





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







AS/CH



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