CNRFC Hydrometeorological Discussion Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 705 AM PST Fri Feb 13 2026 ...MAINLY DRY TODAY... ...PATTERN SHIFT TO COOLER/WETTER THIS WEEKEND INTO NEXT WEEK... .METEOROLOGICAL CONDITIONS (SHORT TERM: FRI AM - MON AM)... Latest setup shows an elongated upr trof crossing 120W this this morning with scattered showers primarily impacting the Colorado River basin. There is the potential for some light precip this morning over far southeast CA through the afternoon hours...but otherwise a positively tilted s/wv ridge is expected to slide across the area bringing dry conditions and near or slightly above normal temperatures for Friday. This upr ridge will be quick to move off toward the east on Saturday...reaching the Rocky Mountain states and then the Great Plains states. As this occurs...attention turns to a polar system diving south-southeast out of the Gulf of Alaska toward the eastern Pacific settling just off the CA coast. Initially...a warm front aligned across Oregon will bring the chance of some light precip near the CA/OR border on Saturday before lifting northward. Then once the broad upr trof reaches its farthest south point...it will slowly start to make its way to the east waiting for an upstream system diving down the west coast to kick the first disturbance inland. Overall...models are getting a bit more settled on a solution timing the precip across the region with this first system. Look for precip to initially reach coastal sections of northern and central CA during the late night hours of Saturday or early morning hours of Sunday. For Sunday...this will be the transition day to a wetter period across the region as the axis of this first system moves within 130W and spreads precip inland across much of CA. Current thinking places the best precip along coastal sections between Cape Mendocino and the Santa Lucia Mountains with 1.00- to 2.00-inches...and then shifting inland over the Shasta Lake drainage down across the northern Sierra with similar totals. Models show slightly elevated available moisture ahead of this initial frontal boundary with PW values hovering near or just above 0.75-inch...which will contribute to the moderate to heavy precip amounts. Freezing levels will start generally from 6000- to 7500-feet across northern CA and 8000- to 10000-feet for central CA on Saturday before slowly dropping on Sunday as the frontal boundary and cooler airmass begins to usher across the region. By late Sunday into early Monday...look for these to be down to 4500- to 5500-feet across northern CA and 6000- to 7000-feet for central CA. .METEOROLOGICAL CONDITIONS (LONG TERM: MON AM - THU AM)... Monday morning, the surface low offshore will begin to push inland as the upper trough is nudged southeastward towards the CA coast by the next low dropping in from the Gulf of Alaska. This will spread precip inland and across central/southern coastal areas. There are some timing and positional differences between the GFS/ECMWF for Monday morning with the GFS more quickly progressing precip across the Transverse Range while the ECMWF is a bit slower. By the late afternoon, troughing from the next upper low will merge with the current system leaving CA/NV under a broad troughing pattern. This will allow showers to persist across the region with the coastal mountains and Sierra receiving the bulk of the precip. The offshore low will continue to descend offshore of the PacNW on Tuesday while the broader pattern shifts eastward. Expect continued precip throughout the day Tuesday, particularly along the central/srn CA coastal mountains and over the Sierra due to terrain effects. Wednesday, the system will push inland across CA and into NV with precip diminishing from west to east as it does so. There is uncertainty in the precip for next week, mainly as some slight timing and positional differences on the placement/path of the low exist. There is decent confidence that the central coast mountains, Transverse Range, and Sierra will see the highest totals. Ensembles are divided now mainly on how much precip will fall along the coast north of the Golden Gate inland into Shasta. These disagreements are not slanted towards any one parent model, as in each QPF cluster is not dominated by one set of members. There is just a decent spread of values. 24 hour QPF spreads at Arcata for Tuesday/Wednesday are about 1.50". The official forecast mainly went with the NBM, but blended in either the EC based west WRF or the GFS based west WRF over parts of the Transverse Range/srn Sierra depending on which was closer timing wise to the NBM. This was done in order to get in a little terrain enhancement that the broader models will not yet capture. QPF 12z Mon-12z Thurs: 3-7.50" Transverse/Sierra, 2.50-6" central coast mountains, 2-3.50" Shasta, 1.50-3" CA coastal areas and down the valleys. Freezing levels starting out 4-7 kft across the Sierra Monday morning lowering into Tuesday down to 3-5 kft. The entire region by that point should be below 7 kft. Lower freezing levels will push further to the south into Wednesday down to 2.5-3.5 kft north of I- 80 and 3-4.5 kft from I-80 to the southern Sierra. Most of the region, north of San Diego, should remain below 5.5 kft through the period. 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. |
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