####018003253#### AGUS76 KRSA 121535 HMDRSA 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 IN THE AFTERNOON AND EVENINGS THROUGH WEDNESDAY... .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. QPF graphics are available at www.cnrfc.noaa.gov/qpf.php Osborne $$ ####018003269#### AGUS76 KRSA 121538 HMDRSA 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. QPF graphics are available at www.cnrfc.noaa.gov/qpf.php Osborne $$