Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 130 PM PDT Fri Apr 10 2026 ...WET AND UNSETTLED WEATHER TO CONTINUE THROUGH THE WEEKEND AS MULTIPLE UPPER LOWS SWING ONSHORE... .METEOROLOGICAL CONDITIONS (SHORT TERM: FRI PM - MON AM)... The upper level trough and cutoff have begun to negatively tilt and shift to the east. Showers and thunderstorms have continued to develop across northern California, spreading from the northern San Joaquin Valley/Central Coast to the Oregon state line. Things continue to look on track for this upper low to open and shift eastward through this evening and another stronger low to swing in from the Gulf of Alaska through Sunday. No major changes from this morning's QPF with minor adjustments made with latest WPC, NBM, and some HRRR guidance. Largest increase was made over the Sierra, north of the I-80 corridor (~0.5 inches through the first 3-days). Freezing levels have lowered under the current low to below 8k feet along the North Coast while remaining above 11k feet across the south. Levels will continue to lower through the weekend to below 6k feet across the north on Monday morning and 8k feet across the south. .METEOROLOGICAL CONDITIONS (LONG TERM: MON AM - THU AM)... Still anticipating the weekend upr low to be shifting inland on Monday...crossing the northern Sierra on its way to the Great Basin. Best precip totals will be ahead of the primary circulation over portions of eastern NV with amounts over the favorable higher terrain from 0.10- to 0.33-inch. Otherwise...look for some remnant shower activity mainly over the southern Cascades and length of the Sierra with amounts generally remaining at 0.10-inch or less. After this system exits to the east toward the central Rockies...brief ridging will slide across the region bringing primarily dry conditions on Tuesday. This is all ahead of another area of low pressure dropping southeast from the Gulf of Alaska toward southern BC and the Pacific Northwest. The 10/12Z models are showing a little better agreement in terms of the depth of this s/wv trof moving inland and clipping the northern tier of the region. After incorporating the latest WPC QPF and 10/13Z NBM...precip amounts remained relatively consistent with the morning forecast...which shows 0.25- to 0.50-inch over the Smith River basin down to near the mouth of the Klamath River and then inland over the crest of the southern OR Cascades. Lesser totals more in the range of 0.10- to 0.25-inch are forecast over the Shasta Lake drainage over to far northern NV close to the OR and ID border. Farther south across northern CA...0.10-inch or less will fall across the Eel River basin for coastal sections and the northern Sierra for inland locations. Freezing levels will generally be from 5000- to 7000-feet where precip is expected. |