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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PDT Fri Sep 22 2023

...ISOLATED SHOWERS AND THUNDERSTORMS OVER NE NV TODAY...
...PRECIP OVER NW CA SUNDAY SPREADING SOUTH AND EAST OVER SRN OR AND 
NRN CA MONDAY AND SHOWERS POSSIBLE OVER SRN OR AND FAR NRN CA 
TUESDAY AND WEDNESDAY...

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

Low pressure centered near the border of CA/OR/ID this morning with 
a few showers over NE NV. This system will continue to shift east of 
the region by this evening ending the showers over NE NV. Meanwhile 
a weak disturbance and some tropical moisture from the remnants of 
tropical storm Kenneth (now post-tropical cyclone) are offshore of 
Baja and streaming towards Srn CA. The moisture increases during the 
day today with PW rising to around 1.25 inches this evening. Light 
rain and sprinkles are possible over Srn CA today and into Srn NV 
overnight. Saturday should generally be a dry day across the region 
before the next system arrives. 

A 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 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. PW around 1.5 
inches along Nrn CA coast Monday and weakening and dropping south to 
off the  Bay Area Monday night. Highest precipitation amounts Sunday 
and Monday expected over NW CA (around Cape Mendocino and north) 
with 2-4 inches (highest for the Smith Basin) and 1-2.5 inches over 
the Shasta Basin and around 0.5-1 inches for the Northern Sierra. 

Another disturbance moves into the PAC NW late Tuesday into 
Wednesday. About a 1.3 inch PW plume off the Nrn CA coast Tuesday 
night into Wednesday morning.  06Z EC is farther north and weaker 
with the system than the 06Z GFS late Tuesday into Wednesday. The 
forecast leans to more of a southerly route with showers possible 
over Srn OR and NW CA on Wednesday. Showers possible on Tuesday and 
Wednesday over Srn OR and Nrn CA, mainly over Srn OR and along the 
NW Coast and over the higher terrain. Precipitation totals for 
Tuesday into Wednesday around 0.25-0.75 for the Smith Basin and Srn 
Or Cascades and generally around a tenth of an inch or less for the 
Shasta and Eel Basins. 

Max Temperatures near normal to 15 degrees below normal today and 
Saturday then cooling to 5 to 20 degrees below normal for Srn OR and 
Nrn CA and generally near normal to 10 degree below elsewhere 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.