Version:  Current  |  Back 1  |  Back 2  |  Back 3  |  Back 4  |  Back 5  |
Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PDT Thu Sep 21 2023

...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE CASCADES 
AND SIERRA AND EAST OVER NEVADA TODAY AND OVER NE NV FRIDAY...
...PRECIP OVER NW CA SAT NIGHT INTO SUNDAY SPREADING SOUTH AND EAST 
OVER SRN OR AND NRN CA MONDAY AND SHOWERS POSSIBLE OVER NRN CA 
TUESDAY...

.METEOROLOGICAL CONDITIONS (THU AM - WED AM)...

Low pressure centered over Eastern Oregon this morning with 
associated trough over the region. The low weakens and wobbles 
around to near the CA/OR/NV tonight then shifts east along the 
OR/NV/ID border during the day Friday and east of the region by 
Friday evening.  Scattered showers and isolated thunderstorms over 
Srn Oregon Cascades and along the Sierra and over NV today then 
lingering showers possible over NE NV into Friday afternoon. 
Drizzle/light rain (few hundredths or less) possible over Srn CA 
this morning with a deepening marine layer and onshore flow with the 
trough over the region. 

The trough shifts to the east later Friday as weak ridge moves over 
the area between systems bringing dry conditions Friday night into 
the day Saturday. A weak disturbance moves through Srn CA Saturday 
but not expected to bring any precipitation. Another trough digs 
over the Eastern Pacific Saturday night into Sunday and the cold 
front moves onto the west coast Monday. Light precipitation possible 
along the NW CA coast Saturday night into Sunday then increasing and 
spreading south and east across Srn OR and Nrn CA Sunday night into 
Monday as cold front moves across the area. Showers possible on 
Tuesday over Srn OR and Nrn CA, mainly along the NW Coast and over 
the higher terrain. PW around 1.5 inches along Nrn CA coast Sunday 
night into Monday and dropping south to off the Central Coast 
Tuesday. Highest precipitation amounts expected over NW CA (around 
Cape Mendocino and north) with 2-4 inches (highest for the Smith 
Basin) and 1-3 inches over the Shasta Basin and around 0.5-1.5 
inches for the Northern Sierra. 

Max temperatures generally around 5 to 20 degrees below normal today 
with the trough over the region. Max Temperatures near normal to 15 
degrees below normal Friday and Saturday then cooling to 5 to 20 
degrees below normal for Srn OR and Nrn CA Sunday into Tuesday. Low 
temperatures generally near normal to 10 degree below normal warming 
to near normal to 10 degrees above normal Sunday and Monday 
mornings.  


Please Note: This product may NOT be routinely updated Friday
through Sunday between Jun 1 and Oct 1. Please refer to
www.cnrfc.noaa.gov/dailyBriefing.php for a graphical summary of
weather and hydrologic conditions.