National Weather Service California Nevada River Forecast Center Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

Printer Version
CNRFC Hydrometeorological Discussion

Version:  Current  |  Back 1  |  Back 2  |  Back 3  |  Back 4  |  Back 5  |
Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
130 PM PST Mon Mar 4 2024

...PRECIP MAINLY OVER SRN OR AND NRN CA AND NRN NV TODAY INTO EARLY 
TUESDAY AND SPREADING SOUTH INTO CENTRAL CA LATER TUESDAY AND INTO 
SRN CA AND SRN NV WEDNESDAY...

...DRIER CONDITIONS EXPECTED THURSDAY AND FRIDAY THEN ANOTHER SYSTEM 
MOVES INTO NORTH BRINGING PRECIP TO SRN OR AND NRN CA SATURDAY...

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

No big changes to the precip amounts for early this week. Decreased 
amounts a little into tonight over NW CA and increased amounts a 
little over Nrn CA coast and Srn OR and Shasta Area for Tuesday and 
Srn CA for Wednesday afternoon and night.  

Upper level low off the B.C. coast weakens and moves into the Pac NW 
today into Tuesday. Another low system over the Eastern Pacific 
approaches the west coast to around 140W 40N this afternoon and 
around 130W 37N Tuesday afternoon and offshore of the Central Ca 
coast Wednesday morning and off Srn CA coast by Wednesday evening 
and onshore into Srn CA overnight. 12Z models a little closer to the 
coast and moving inland over Srn CA so increased amounts later 
Wednesday. Moisture plume almost an inch aims at Srn CA coast on 
Wednesday ahead of this system. Precip will increase and be mainly 
over Srn OR and Nrn CA and Nrn NV this afternoon into tonight and 
continue over Srn OR and Nrn CA and Nrn NV on Tuesday. Precip will 
decrease over the north and spread south into Central and Srn CA and 
Srn NV later Tuesday into Wednesday as the low gets closer to the 
coast (still varying solutions on track).  Precip amounts for Monday 
through Wednesday are expected to generally be around 2-5 inches for 
the NW CA coast (around Cape Mendo and north) and 1-3 inches for 
Shasta and Feather Basins and generally 0.25-0.75 inches (possibly 
locally higher over Santa Barbara and Ventura County) along the CA 
coast from the Russian Basin down to San Diego and generally a 
quarter of an inch or less for the Central Valley and Srn Sierra and 
over NV (except up to an inch over Nrn Nv higher mtns).  Freezing 
levels are around 3000 ft near the ORCA border and 4000 ft around I-
80 and 6000 ft for the Srn Sierra and rise to around 4500 ft near 
the ORCA border and 5500 ft near I-80 on Tuesday and around 5000-
7000 ft over most of the region on Wednesday. Although some cold air 
from the weekend system could get trapped in some valleys for 
locally lower snow levels today into tonight. 

Max temperatures forecast to be around 5 to 20 degrees below normal 
today then near normal to 15 degrees below normal for Tuesday and 
Wednesday. Overnight temperatures generally near normal for Tuesday 
then near normal to 10 degrees above normal for Wednesday morning 
and near normal to around 10 degrees below normal (coldest in the 
north) for Thursday morning. 


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

Thinking remains similar to this morning as an upr trof is exiting 
to the east on Thursday...while a positively tilted upr ridge over 
the eastern Pacific makes its way over the west coast. A few 
lingering showers across the southern Sierra down toward coastal 
southern CA and then eastward over southern/eastern NV will amount 
to about 0.10-inch or less. 

Dry conditions will persist through Friday as a weakening 
disturbance making its way toward the west coast will arrive on 
Saturday from the Pacific Northwest down across northern CA. The 
04/12Z EC has come more in line with the weaker GFS and CMC with 
reference to this system. Mainly light to locally moderate precip is 
expected across portions of northern CA and the upper Klamath River 
basin with the best totals along coastal areas near and north of 
Cape Mendocino. Freezing levels will range from 3000- to 6000-feet 
where precip is expected...lowest north and west.