Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 630 AM PDT Fri May 15 2026 ...PRECIP CHANCES INCREASE OVER NORTHERN/EASTERN NV ON SUN... ...COOLER TEMPS THIS WEEKEND WARM TO ABOVE NORMAL BY NEXT WED-THU... .METEOROLOGICAL CONDITIONS (FRI AM - THU AM)... Zonal onshore flow is generally focused between 40N and 50N this morning with a s/wv trof along 135W making its way toward the Pacific Northwest and southwest BC. A flattened upr ridge resides off the CA coast pretty much along 140W. Through today...the pattern will begin to start to buckle as the s/wv trof shifts inland with the opportunity for some light precip making its way down to the crest of the southern OR Cascades. For this weekend...look for this overall system to dig over the interior on its way toward the Great Basin...bringing an area of mainly light precip to northern and eastern NV on Sunday. Amounts will generally remain near or less than 0.25-inch. Given this flow regime on Sunday...dry northerly flow will develop across CA as the area is sandwiched between the digging s/wv trof over the Great Basin and a building upr ridge offshore between 130W and 140W. Into next work week...the general troffing over the interior will shift farther to the east...while the offshore upr ridge becomes quite broad and stretches over much of the eastern Pacific and the western US. This will allow temperatures to rebound from being mainly below normal this weekend to anywhere from plus 5- to plus 15-degF over seasonal normals by Wednesday into Thursday. Freezing levels currently range from 8000- to 11000-feet over the northern portion of the region to 12000- to 14000-feet across the southern half. As the system digs from the Pacific Northwest to the Great Basin...the freezing level gradient becomes more northeast to southwest oriented with a range of 6000- to 7000-feet over the Humboldt River basin to 13000- to 14000-feet along the southern CA coast. These will become a bit more uniform by the middle of next week under high pressure with 12500- to 13500-feet throughout the area. 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. |