Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 730 AM PST Sat Feb 14 2026 ...TRANSITION TO COOLER AND WETTER FOR THE UPCOMING WEEK... .METEOROLOGICAL CONDITIONS (SAT AM - FRI AM)... The transitory upr ridge that slid across the region yesterday is now exiting to the east over the Rocky Mountain states this morning. At the same time...a cold system has moved from the Gulf of Alaska toward the south-southeast and now resides between 130W and 140W off the west coast. Also associated with this feature is a sfc low developing in the vicinity of 40N/130W with a stationary boundary stretching northeast toward the Pacific Northwest and a cold front trailing back to the southwest. Radar imagery is picking up on some scattered very weak echoes streaming from southwest to northeast in the warm sector close to the CA/OR border. So far this morning the majority of precip gauges that have tipped are north of the CA/OR border and only a few hundredths of an inch at best. Through the rest of today...models indicate an increasing opportunity for light precip to develop across areas near and north of I-80 as the overall system nudges ever so slightly to the east. Sunday will be the day that transitions to a wetter and cooler regime across much of CA as a second disturbance begins to dive down the Alaska/BC coast and starts to kick the initial system off the west coast eastward within 130W. Initially...there is not a significant tap into any lower latitude moisture with convergence just ahead of the frontal boundary showing PW values hovering near 0.75-inch. However...given the slow progression of the overall system to the east and the favorable forcing along with orographic enhancement to the precip...precip amounts are looking to be widespread and relatively impressive. Not much has changed in the thinking for Sunday with the best precip along coastal sections between Cape Mendocino and the central CA coast and then spreading inland across the Shasta Lake drainage down the northern/central Sierra. On average...look for 1.00- to 2.00-inches in these areas with some more favorable locations nudging toward 3.00-inches. Into Presidents Day...the second system from the north will continue its journey southward...which will allow the initial system to increase its forward speed from the southwest to the northeast...crossing central and southern CA with the best precip amounts for the 24-hour period. There does become a bit more moisture entrained ahead of the frontal boundary on Monday with PW values near 1.00-inch intersecting the central and southern CA coast. Also...southerly flow ahead of the cold front will peak just shy of 50-kt at 850-mb...providing ideal upslope conditions for the transverse ranges of southern CA. This will bring amounts ranging from 2.00- to 4.00-inches between Santa Barbara to southwest San Bernardino counties. The s/wv trof will track pretty much across the southern Sierra and flow at 700-mb will turn a bit more from the southwest to provide favorable conditions for precip production from the Tuolumne River basin southward...where 2.00- to 4.00-inches will also be the norm. The one other thing to keep in mind as this dynamic s/wv trof moves across central and southern CA is the potential for convective precip...which could lead to some higher precip amounts. Currently...SPC is placing a marginal risk for severe thunderstorms from Santa Barbara county east toward Los Angeles county. It will be interesting to see how this pans out. The secondary disturbance diving down the coast will reach down to California on Tuesday before swinging inland. Moisture entrained into this system starts out rather low given its origin to the north with PW values close to 0.50-inch. As it digs a bit farther south along the CA coast...look for moisture to increase closer to the 0.75-inch mark across coastal central and southern CA. Again...given this increase in moisture and trajectory of the s/wv trof...best precip amounts will be aligned along the entire Sierra with the highest over the southern Sierra with 2.00- to 3.00-inches likely and the potential to approach 4.00-inches from the Merced River basin southward. Coastal sections will see another good shot of precip mainly from the Santa Cruz Mountains south to Point Conception and then east along the transverse range with totals for the 24-hour period adding up to 1.00- to 2.00-inches with some localized spots along the Big Sur coast and Santa Ynez/Topatopa Mountains touching 2.50-inches. Wednesday will see the system swing inland across the area with precip starting to become light to moderate over much of the region. The higher terrain will generally range from 0.25- to 0.75-inch with lower elevations staying near or less than 0.25-inch. And then finally on Thursday...continuing cyclonic flow over the region will continue showers activity mainly over the higher terrain with the best amounts over northern CA. Freezing levels are currently running from near 6000-feet at the CA/OR border to 11000-feet across southern CA. As the first wave moves across the region the passage of the cold front will usher in the first round of cooler air dropping to 2500- to 3500-feet across northern CA...4000- to 5000-feet for central CA...and then 5000- to 6000-feet for southern CA. The state of NV will generally range from 4000- to 6000-feet from north to south. The second wave moving across the region will usher in an even cooler airmass bottoming out late Wednesday or early Thursday from 2000-feet north...3000-feet along I-80...and 4000- to 4500-feet south. 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. |