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Hydrometeorological Discussion
National Weather Service / California Nevada RFC / Sacramento CA
830 AM PDT Sun May 12 2024

...WARM TEMPERATURES INTO MID WEEK NEXT WEEK THEN SOME COOLING NEXT 
WEEKEND...
...ISOLATED SHOWERS/T-STORMS MAINLY OVER CENTRAL AND SRN SIERRA AND 
EAST OVER NV AND NEAR THE ORCA BORDER THIS AFTERNOON/EVENING THEN 
MAINLY OVER CENTRAL AND SRN SIERRA AND INTO NV MONDAY INTO WED...

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

Ridge of high pressure over the region with a weak trough off the CA 
coast around 130W and a shortwave trough approaching the Pac NW 
today. Shortwave trough moves inland through PAC NW tonight into 
Monday brushing by far northern portion of the region. Weak trough 
forms weak closed low off the Central CA coast Monday and moves 
inland into Srn CA/Baja Tuesday into Wednesday as ridge of high 
pressure over the Eastern Pacific moves into the region. Isolated 
showers/thunderstorms mainly over Central and Srn Sierra and near 
the ORCA border this afternoon/evening and a little better chance 
over Central and Srn Sierra and into NV on Monday afternoon/evening 
and chances lessen Tuesday and Wednesday afternoons and evenings. 
QPF amounts will be variable due to convective nature, but generally 
a tenth of an inch or less with locally higher amounts (up to around 
0.5 inches) possible in heavier showers and thunderstorms. Drizzle/ 
light rain possible along the coast  in the nights/morning into 
Tuesday. Freezing levels generally 10000-14000 ft.
High pressure builds over the region from the Eastern Pacific on 
Wednesday and Thursday. Ridge weakens Friday with another shortwave 
trough moving into the Pac NW/B.C. and a low offshore the CA coast. 
Although the details are still uncertain with various strength and 
tracks of the trough/lows.  There are various solutions with the 
timing and track and strength of these two systems (det GFS farther 
north and quicker with trough over NW and stronger with low off 
Point Conception on Saturday and EC stronger and farther south with 
shortwave trough that mergers with weaker low to the south and some 
Ensemble solutions just weakening the ridge) so details are uncertain 
but at least temps should be a little cooler next weekend. 

Max temperatures generally above normal up to 15 degrees over most 
of the region this afternoon and similar on Monday except near 
normal along the CA coast (with deepening marine layer). Temps cool 
over the Central and Srn CA coast up to 10 degrees below normal on 
Tuesday. Max temps rise to 5 to 20 degrees above normal on Wednesday 
except near to around 10 degrees below normal over the Central and 
Srn CA coast and generally a little warmer on Thursday. Cooler 
temperatures over Srn OR and Nrn CA and into Central CA on Friday 
with max temps near normal to around 15 degrees above normal. More 
widespread cooling expected over the weekend a low/trough moves 
through. Overnight temps generally near normal to around 15 degrees 
above normal tonight into Friday night.