Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 610 AM PDT Tue May 12 2026 ...LIGHT PRECIP NEAR THE CA/OR BORDER AND OVER THE N COAST LATE TONIGHT THROUGH WEDS AM... ...SEASONABLY WARM AND DRY THROUGH FRIDAY BEFORE TEMPERATURES MODERATE OVER THE WEEKEND... .METEOROLOGICAL CONDITIONS (TUE AM - MON AM)... A strong upper ridge remains over the Four Corners this morning keeping dry conditions for most areas across the region for today along with well above normal temperatures away from the coast. Anomalies expected to be around +10 to +20 deg F, locally higher over ne NV. An upper low approaching the PacNW will then usher in some chances of light precip along the nrn CA/OR border into the north coast late tonight through Wednesday morning. Amounts look lighter than yesterday, so QPF was brought down to generally 0.10" or less (up to 0.20" Smith Basin). The trough will also push the ridge further inland mid to late week allowing for some moderation of temperatures. Still expecting above normal conditions for most areas with anomalies at +5 to +15 deg F as 500 mb heights remain quite high (>580 dm). Another system then looks to approach the PacNW on Friday sending troughing into the west coast for the coming weekend. This should act to lower temperatures back down near seasonal normals. There is some disagreement between the ECMWF and the GFS on the depth of this trough as well as its positioning. The GFS has a low descending into nrn NV on Sunday with a core of 555 dm while the ECMWF has a shallower trough centered over ID and 500 mb heights over NV and CA in the 570s dm. The stronger low out of the GFS also generates some showers over NV as it passes through while the ECMWF does not. To summarize, dry conditions for most of the period aside from some potential showers over the north coast and CA/OR border late tonight through Wednesday morning. Continued above normal conditions into the end of the week before returning closer to near normal over the weekend (though some uncertainty due to model differences). 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. |