####018003133#### AGUS76 KRSA 252022 HMDRSA Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 130 PM PDT Mon Mar 25 2024 ...DRIER CONDITIONS TODAY INTO TOMORROW... ...RETURN TO COOLER AND UNSETTLED FOR THE LATTER HALF OF THE WEEK... .METEOROLOGICAL CONDITIONS (SHORT TERM: MON PM - THU AM)... Northwesterly flow aloft will last through tomorrow afternoon as an upr ridge is upstream across the eastern Pacific along 145W and the system from this past weekend is moving downstream of the area across the Rocky Mountain states. Weak disturbances moving through this flow may touch off a few showers over the Sierra and points east across NV today into tomorrow. Then for the middle of the week...the next s/wv trof will make its way over the northeast Pacific...bringing another round of precip to the area...in particular areas near and north of I-80. Best totals of 1.00- to 2.00-inches are expected for coastal areas for the Eel River basin northward...and then across the interior from the Shasta Lake drainage down the northern/central Sierra. Freezing levels will generally be from 5000- to 7500-feet at the start of the system on Wednesday across northern CA...and then fall down to about 3000- to 5500-feet by the end of the day. .METEOROLOGICAL CONDITIONS (LONG TERM: THU AM - SUN AM)... 12 UTC model solutions tell a similar story to what was noted this morning. Expect some lingering light showers across the central CA coast, into the Sierra and NE NV along a dissipating front Thu morning, while additional post-frontal showers continue further to the north associated with weak disturbances and north or NE of an upper jet max. Expect showers to generally decrease through at least Thu evening. Model agreement is still reasonably good during this time frame. Expect freezing levels around 3000-4000 ft on the north coast and 4000-6000 ft in the northern half of the Sierra. Model agreement is much less regarding the next system expected to affect the region to close out the week. Expect a fairly stacked low pressure system to deepen and drop south off the CA coast Fri- Sat while a front and associated moisture plume bring precip across the region. Models vary widely regarding how much precip remain offshore or move inland, as well as with how quickly the main precip band will push across the region. Thus, uncertainty regarding totals is also fairly high. Some deterministic and ensemble solutions show a slow progression of fairly heavy precipitation across the transverse ranges of southern CA late in the week, while others push the band more quickly into SW CA and out of the region. The 19 UTC NBM seemed like a reasonable compromise and was used, although the potential for higher amounts exists. Expect freezing levels 4000-6000 ft in the northern half of the region and 6000- 10000 ft in the southern half. QPF graphics are available at www.cnrfc.noaa.gov/qpf.php Kozlowski/Lerman $$