Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 840 AM PDT Thu Jun 4 2026 ...WARM AND DRY THROUGH FRIDAY... ...TURNING COOLER THIS WEEKEND INTO EARLY NEXT WEEK... ...PRECIP CHANCES INCREASE FOR NORTHERN CA AND NORTHERN NV MON-TUE... .METEOROLOGICAL CONDITIONS (THU AM - WED AM)... The s/wv trof that moved across the Pacific Northwest yesterday has shifted off toward the east and is now making its way across the northern Rockies this morning. The deep upr low over the northeast Pacific has shifted a bit to the east as well and now currently resides in the vicinity of 52N/138W. At the same time...the upr ridge to the southwest of the CA coast is building across the region and will bring dry and above average temperatures for the next couple days...peaking on Friday. Anomalies are currently expected to be anywhere from plus 5- to plus 20-degF over seasonal normals for afternoon high temperatures. By this weekend...the system over the northeast Pacific will slowly make its way eastward and become a bit more elongated...bringing troffing to the west coast. This will result in temperatures cooling and initially some scattered light precip from the southern Sierra up toward northeast NV on Saturday and Sunday. As this system rotates inland later Sunday...the next disturbance making its way across the Pacific will replace this first one. Also...this feature will have a tap into some lower latitude moisture that is advecting northeast over the central Pacific into the mid-latitudes and then riding east generally just north of 40N. This moisture plume actually has some impressive PW values that are over 2.00-inches initially...and around the 1.00-inch mark as it intersects the west coast early on Monday from the SF Bay Area up to about Cape Mendocino. Models are continuing to hint at an increasing chance of widespread light to moderate precip mainly over areas from I-80 northward on Monday into Tuesday. The latest NBM is picking up on this precip as well...and for the morning forecast was used with a blend of the 04/00Z EC and latest WPC QPF. This brings totals of 0.25- to 0.75-inch over the higher terrain of northern CA and the southern OR Cascades...as well as 0.10- to 0.33-inch for wetter locations of northern NV. This feature will slowly move out through the middle of next week with an upr ridge building over the eastern Pacific nudging toward the west coast the following weekend. Freezing levels today into tomorrow will range from 13000-feet for areas near the CA/OR border to 17000-feet for central and southern CA. These will dip this weekend with the arrival of the first system along the west coast...down to about 8000- to 10000-feet near the CA/OR border to 15500-feet close to the CA/MX border. Then as the second system arrives...these will drop a bit more for areas near the CA/OR border from 6500- to 8000-feet...but remain relatively elevated across central and southern CA. 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. |