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AGUS76 KRSA 042003

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

105 PM PDT Thu Apr 4 2024



...UNSEASONABLY COOL SYSTEM MOVING ACROSS THE AREA TO END THE WEEK...

...DRYING WITH WARMER INTO NEXT WEEK...



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



Area of low pressure continues to spin just off the coast west of 

Point Arena this afternoon with the band of precip associated with 

the frontal boundary now moving inland across northern/central CA 

with numerous showers closer to the core of the system moving 

onshore over the SF Bay Area and central CA coast. Also...the band 

of precip ahead of the upr trof axis over north-central NV down 

toward the west-central portion of the state has developed late this 

morning into the afternoon hours...just as the models had been 

indicating. Several areas of embedded convection are streaming 

northward in this feature with frequent lightning associated with 

the strongest cells. 



Through the rest of today...the area of low pressure will track 

pretty much along the I-80 corridor of CA before lifting more 

northward across northwest NV into southwest ID. Best precip will be 

focused over several areas. The first over coastal central CA and 

farther inland across the central/southern Sierra. The band of 

precip ahead of the upr trof axis over north-central NV will 

continue to see moderate amounts of precip. Finally...models have 

been picking up on another line of precip developing on the north 

side of the low pressure between Mendocino county west-northwest 

across the northern Sacramento Valley toward the northeast CA 

Plateau. From 00Z through 12Z Fri...these areas will generally see 

0.10- to 0.33-inch with some local totals from 0.50- to 0.75-inch.

After Friday 12Z...the upr trof will increase its forward speed to 

the east...while the base of the system moves across coastal 

southern CA. Look for the best precip to fall primarily over the 

southern Sierra and coastal areas between Big Sur and the CA/MX 

border. 



Into Saturday...a brief s/wv ridge will move across the 

area...drying conditions out for most areas with general west to 

northwest flow aloft. A weak disturbance moving through this flow 

will approach the northern CA coast for the afternoon and evening 

hours...which will generate some light precip across the CA/OR 

border area. 



Freezing levels continue to drop as the colder airmass filters in 

across the area. These will bottom out early Friday anywhere from 

1500- to 5000-feet from northwest to southeast. 





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



Shortwave activity over the weekend will extend shower activity over 

the mountains into early next week. While unsettled weather remains 

in place through the weekend, accumulations will be relatively low 

with a majority of locations forecast to only receive a few 

hundredths of an inch. Given the nature of the s/wv and the 

scattered characteristics of the shower activity, it is difficult to 

pin down exactly where accumulating precipitation will occur. 

Afternoon forecasts primarily followed guidance from the WPC with 

little to no change from the morning QPF. Ridging will begin to 

build behind the upper-level s/wv, leading to drier and above normal 

temperatures starting Tuesday.





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







Kozlowski/CH



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