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AGUS76 KRSA 131437

HMDRSA



Hydrometeorological Discussion

National Weather Service / California Nevada RFC / Sacramento CA

735 AM PDT Sat Apr 13 2024



...COOLER AND UNSETTLED CONDITIONS THIS WEEKEND...

...DRYING THROUGH NEXT WEEK WITH TEMPERATURES REBOUNDING...



.METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)...



This weekend will see the most impactful conditions in terms of 

precip as an area of low pressure is spinning west of the SF Bay 

Area generally along 125.5W this morning. The line of precip 

associated with the frontal boundary is currently arching from near 

Cape Mendocino back across the northern CA coastal mountains and 

then through the SF Bay Area and down to the central CA coast. Since 

13/12Z...precip gauges show the best totals ranging from 0.10- to 

0.25-inch with some localized higher amounts. Favorable upslope flow 

is occurring along the west side of the Sacramento Valley and 

adjacent coastal mountains as southeast low- to mid-level flow 

exists in the northeast quadrant to the area of low pressure.



Models are in reasonable agreement with the progression of the 

system today with primary circulation slowly dropping toward the 

southeast before eventually moving inland somewhere along the 

Monterey county coast Sunday morning. The line of precip will shift 

inland and southward this afternoon with the best amounts focused 

from the American River basin down to the upper portions of the San 

Joaquin River basin and across areas near Point Conception...which 

include the Santa Ynez Mountains where a brief period of southerly 

flow exists ahead of the frontal boundary. Also...a mid-level vort 

max will rotate through the cyclonic flow...which will enhance 

precip across this area. By the evening and overnight...precip will 

focus over areas in the vicinity of the primary circulation near the 

SF Bay Area and central CA coast...the southern Sierra along with 

the San Gabriel and San Bernardino mountains where the frontal 

boundary will be traversing...and then near the CA/OR border in an 

area of convergent flow. 



Sunday will see the area of low pressure track inland toward 

southern NV with precip tapering off as the new work week starts. A 

couple disturbances moving through the cyclonic flow will bring the 

best precip to areas near Point Conception and far southern Sierra 

with the other being in the vicinity of the CA/OR border. 



Overall totals from this morning through Monday morning 12Z...the 

next 48 hours...will generally be from 0.75- to 1.50-inch with a few 

localized areas closer to 2.00-inches across the higher terrain from 

areas near the CA/OR border down to the transverse ranges of 

southern CA. Central Valley locations may be slightly less...with 

approx 0.33- to 0.75-inch with some areas on the east side of the 

San Joaquin Valley approaching 1.00-inch.



Freezing levels are starting today with an tight east-to-west 

gradient...from 9000- to 11500-feet across much of NV and southern 

CA...while the cooler airmass near the area of low pressure is down 

to 3500- to 5500-feet across coastal northern CA down through the SF 

Bay Area and Monterey Bay area. As the area of low pressure moves 

inland later today into early Sunday...these will bottom out with 

3500- to 5500-feet across much of northern and central CA and then 

eventually 5500- to 7000-feet for NV down toward southern CA.



After this system moves downstream of the area on Monday...dry 

conditions are expected to set up shop for the rest of the week as 

modest high pressure builds over the area...and temperatures warm 

back to or just above normal.





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







Kozlowski



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