####018003548#### AGUS76 KRSA 212008 HMDRSA Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 130 PM PDT Thu Mar 21 2024 ...A LOW PRESSURE SYSTEM WILL BRING PRECIP TO THE REGION FRIDAY INTO THE WEEKEND... ...ANOTHER SYSTEM WILL BRING ADDITIONAL PRECIP CHANCES TO THE NORTH EARLY TO MID NEXT WEEK... .METEOROLOGICAL CONDITIONS (SHORT TERM: THU AM - SUN AM)... Little change to the afternoon forecast with a little decrease in amounts over NW CA overnight into Friday morning with the front possibly a tad slower and increase amounts a little over Nrn and Central CA for Saturday night as low moves inland over nrn CA/Oregon. A low pressure system currently around 42N and 140W, strengthens a little as it approaches the west coast tonight with the cold front reaching the Nrn CA coast Friday morning and moving through the region into Saturday. The low is off the Pac NW coast Saturday with trough moving into the region and low moves onshore NrnCa/OR Saturday night. Moisture plume about an inch along the CA coast ahead of this system. Light precip along the NW CA coast early Friday morning then increasing and spreading south and east across the region as the front moves through. Precip spreads to around the I-80 corridor Friday afternoon and into Central CA and Srn Sierra and Nrn Nv Friday night and into Srn CA and Ern NV on Saturday as weakening front moves through the region. Precipitation amounts through Saturday night are expected to generally be around 1.5-3.5 inches with local amounts to around 4 inches along the NW CA coast and 1-3 inches for the Shasta Basin and Nrn and Central Sierra and 1- 2 inches for the Srn Sierra and 0.5-1.5 with local amounts up to 2 inches for the Central Coast and 0.25-0.75 for Sac Valley and 0.1- 0.75 for SJ Valley and generally half an inch or less for Srn CA. Freezing levels around 6500 ft over NW CA coast and around 7000-8000 ft for the Nrn Sierra and 8000ft and higher elsewhere Friday morning and dropping to around 3500-5000 ft behind the cold front over Nrn and Central CA Friday night and around 5000-8000 ft over Srn CA and NV Saturday dropping to around 3500-5500 ft over most of the region Saturday night. .METEOROLOGICAL CONDITIONS (LONG TERM: SUN AM - WED AM)... Precipitation will linger into Sunday as s/wv activity embedded in the upstream portion of the broader large scale trof digs southward over California. Accumulations on sunday will be relatively modest across much of the forecast region (<0.25 inches) but could approach 0.75 inches over coastal southern California where dynamics are most favorable. A majority of the region is forecast to remain dry on Monday outside of the northern portions of California and Nevada where pockets of PVA are forecast to produce light precipitation. The chance for heavier precipitation across the north returns Tuesday as another system approaches and makes landfall over northern California, though guidance differs on exact timing and magnitude of numerous features that will play a role on the precipitation. Afternoon forecasts generally followed guidance from the WPC with little change from the morning. Southern California saw the largest changes, increasing amounts by up to 0.2 inches with the system on Sunday. QPF graphics are available at www.cnrfc.noaa.gov/qpf.php Osborne/CH $$