Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 735 AM PST Sun Feb 15 2026 ...COOLER AND WETTER FOR THE WEEK AHEAD... .METEOROLOGICAL CONDITIONS (SUN AM - SAT AM)... High pressure continues to shift downstream of the region moving off the Rocky Mountains eastward to the Great Plains states. Across the eastern Pacific...a deepening system has made its way from the Gulf of Alaska toward the south-southeast and now resides off the west coast. A sfc low is situated in the vicinity of 40N/130W with a stationary boundary extending to the northeast across the Pacific Northwest while a cold front is aligned southward generally along 125W. IR imagery shows the amount of cold air entrained into the system behind the frontal boundary with cellular cloud mass down to about 30N outside of 130W. Radar imagery is showing the leading edge of precip associated with this slow moving system affecting coastal locations of northern and central CA with the overall movement of precip from south-to-north. Precip gauges since 15/12Z indicate anywhere from a few hundredths of an inch to 0.33-inch over the most favorable terrain of the lower Russian River basin. Through the rest of today...look for slow progress of the overall system to the east with coastal areas seeing the best precip and inland areas finally seeing precip pick up in coverage and intensity after sunset and overnight into Monday. The thinking continues to be the best precip remaining along coastal sections between Cape Mendocino and Point Conception with 1.00- to 2.00-inches locally higher for the lower Russian River basin...Santa Cruz Mountains and Big Sur coast. Inland the precip will be best from the Shasta Lake drainage south across the northern/central Sierra with similar totals of 1.00- to 2.00-inches. Into Presidents Day...a secondary system diving south along the Alaska and BC coast will track southward along the Pacific Northwest and eventually CA coast. This feature will act as the kicker system for the initial system just off the west coast...opening up and increasing its forward speed to the east. The trajectory of this s/wv trof will bring the best precip amounts along coastal sections from the Santa Cruz Mountains southward and over the length of the Sierra (heaviest for the southern half of the range). Also...moisture entrained along and ahead of the cold front...which starts close to 0.75-inch PW on Sunday will see a slight increase to 1.00-inch intersecting the central and southern CA coast. Southerly flow ahead of the cold front will ramp up to just shy of 50-kt at 850-mb...which will transport the moisture inland and up the south facing slopes of the transverse mountains...enhancing precip between Santa Barbara and southwest San Bernardino counties. For the southern Sierra the s/wv trof will track overhead during the later morning and afternoon hours with added enhancement from 700-mb winds switching to a more southwesterly direction providing upslope conditions. Finally...one thing that may bring some added fuel to overall totals will be the potential for convection just ahead of the cold front. SPC has drawn a Marginal risk of severe thunderstorms in an area along the immediate central CA coast down to Point Conception and then east toward Los Angeles. Precip totals on Monday will range from 1.00- to 3.00-inches with some locations over the transverse ranges and southern Sierra nearing 4.00- or possibly 5.00-inches. For Tuesday...the initial s/wv trof will race off toward the east and be replaced by the deepening secondary system stretching along the west coast. Only late in the evening on Tuesday or even early Wednesday will this system begin to swing inland as it bottoms out over central/southern CA. Again...with its origin to the north...moisture will not be overly ample with PW values just shy of 0.50-inch intersecting the northern CA coast with only slightly higher available moisture closer to 0.75-inch crossing the central and southern CA coast. Precip will once again ramp up with this feature and given its trajectory across the region the best precip will fall over coastal areas between the Santa Cruz Mountains down to Point Conception and then east along the transverse ranges of southern CA. Inland...the entire Sierra will see a good helping of precip with the highest totals over the southern half of the range. Wednesday will see the entire system swing inland with scattered showers continuing across much of the region focused over upslope areas of the coastal mountains and Sierra with broad cyclonic westerly onshore flow. Amounts should average somewhere from 0.25- to 0.75-inch. Then for the end of the week...models are showing the potential of another disturbance rotating through the flow on Thursday before the possibility of drying conditions through Friday. Freezing levels will be lower with this series of storms given the origin of the disturbances from the north. Today...in the warmer sector of the storm freezing levels are starting between 5500- and 7000-feet near the CA/OR border down to the I-80 corridor increasing to 9000- to 12000-feet across southern CA and extreme southern NV. After the first wave passes to the east...dragging the cold front across the region...the initial shot of cooler air will bring freezing levels down to 2500- to 3500-feet across northern CA...4000- to 5000-feet for central CA...and 5500- to 6500-feet over southern CA. The state of NV will range from 3000-feet northwest to 6000-feet south. The next s/wv trof will bring another surge of cooler air across the region on Wednesday with 1500- to 3000-feet across areas near and north of I-80...3000- to 4000-feet for central areas...and 4000- to 5000-feet southern sections. 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. |