Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 750 AM PST Mon Feb 16 2026 ...COOL AND WET PATTERN THIS WEEK AS A SERIES OF LOWS MOVE IN FROM THE NORTHWEST... .METEOROLOGICAL CONDITIONS (MON AM - SUN AM)... A low sits just offshore of the central coast this morning along with a cold front. This is sending a surge of roughly 0.75-1" PW of moisture into southern CA around Point Conception. Radar imagery shows a wide band of precipitation from about the Golden Gate northeastward across the I-80 corridor into the northern Sierra and through the central coast into western Santa Barbara County. Over the past 24 hours about 1-3.50" of precip has fallen along the coastal mountains from Cape Mendocino to Big Sur with locally up to 5" reported over the Big Sur mountains. Inland about 0.75-2" has been reported across the northern Sierra into Shasta with up to 1.50" down the nrn Sacramento Valley. The focus of the precip will shift south along with the low the rest of this morning moving soon into the western Transverse Range. Models have this area underneath a 120-140 kt jet streak mid to late morning along with 850 mb winds around 40 kt and southerly, enhancing orographics over that area into mid morning. The GFS rotates the winds a bit more southwesterly by about 18z shifting those southerly winds further eastward out of Santa Barbara/Ventura counties. HREF exceedance probabilities predict 60-90% chance of exceeding 0.50"/hr rain rates and a 10-30% chance of exceeding 1"/hr rain rates around Point Conception into the western Transverse the rest of the morning. These chances will shift southeastward across srn CA this afternoon all while the system also generates some convection. Chances of thunderstorms, particularly along central/srn CA coast south of the Monterey Bay. Heavier convective precip bands that may drop higher rain rates are also possible. The low will open into a trough later this afternoon before shifting inland across srn CA into this evening. This will re-focus precip across the mountains east of San Diego and over the southern Sierra. Overnight, the trough will get absorbed into the broader upper level pattern allowing precip that isn't terrain driven to diminish. Models still have precip across coastal srn CA and across the Sierra. Precip totals today look generally 1-4", lower down the SJ valley and north of I-80 and approaching 5" over parts of the Transverse and southern Sierra. Just behind the current low, another upper low will drop in tonight from the northwest sending additional precip into the nrn CA coast as it lessens over srn CA. The low will descend into CA tomorrow morning spreading precip into the central coast and across the Sierra in the afternoon. Rain rates look less intense for Tuesday at more scattered chances of 0.50"/hr (10-30%) compared to today as it does not have the same source of moisture currently being pulled into srn CA. The low will open into a trough by Tuesday evening before beginning to swing inland. The main focus of precip will again be along the coastal mountains from Santa Cruz through the Transverse along with the southern Sierra at about 1-3.50". General chances of thunderstorms again across much of nrn/central CA and coastal srn CA. Wednesday, that same system will continue to push inland across CA/NV producing showers across the state. Uncertainty grows beyond Wednesday. Both the det GFS and the ECMWF favor a continued active pattern with more precip on and off the rest of the forecast period due to additional lows dropping in from the northwest. There are differences on the timing of each of these systems and some other details that make for low confidence in the precip in the extended. Went with a blend of the morning WPC guidance and the latest NBM for days 4-6. QPF 12z Thurs-12z Sun: 1-3" nrn CA coast into Shasta, 1-2" nrn Sierra/central coast mountains, and 0.30-1" for the rest of nrn/central CA, and 0.10-0.75" for coastal srn CA. Freezing levels 4-7.5 kft north of Point Conception this morning lowering through out the day to 2.5-5.5 kft by this evening. Levels will hover around there through Tuesday lowering further down to 2.5- 4.5 kft late Wednesday afternoon. Lower freezing levels for most of the week beginning to rise from sw to ne into the weekend up to 6- 8.5 kft for srn CA Friday evening and 6.5-8.5 kft south of I-80 late Saturday afternoon. Some uncertainty later in the period again due to timing differences on those next lows. Please Note: This product may NOT be routinely updated. Please refer to the following product issued by the CNRFC www.cnrfc.noaa.gov/Daily-Briefing for a graphical summary of weather and hydrologic conditions. |