Hydrometeorological Discussion National Weather Service / California Nevada RFC / Sacramento CA 730 AM PDT Wed May 8 2024 ...WARMING THROUGHOUT THE WEEK AS HIGH PRESSURE BUILDS OFFSHORE... ...GENERALLY DRY CONDITIONS ASIDE FROM ISOLATED SHOWERS/T-STORMS OVER NV THURS, THE SIERRA AND NV FRI AFTN/EVE & SUN/MON... .METEOROLOGICAL CONDITIONS (WED AM - TUE AM)... A large upper low resides over the north central US this morning with building high pressure over the eastern Pacific. The low will begin to separate later today with the back half breaking off and retrograding back towards CA/NV into Thursday. This will push the southern half of the ridge offshore while the northern half wraps around into the PacNW. This may generate some isolated showers and thunderstorms in the afternoons/evenings, mainly over north/east NV. The upper low will back into NV on Friday with the core of the system over srn NV. This will bring better chances of isolated showers and thunderstorms in the afternoon/evening with the best chances east of the Sierra. Friday night, the low will shift its trajectory eastward pulling out of the region on Saturday and allowing the ridge to move back in. Models then show a weak trough developing west of CA throughout Sunday impacting the region through the rest of the period. There are some differences between the models and amongst the ensembles as to the relative strength and positioning of this troughing. Depending on how strong the offshore ridging is and how much influence the trough has, there is a chance of some isolated showers Sunday and Monday, mainly over the Sierra and into NV. In either case, no significant precipitation is anticipated as the official QPF for days 1-6 has at most 0.10-0.25" over the Sierra and generally a few hundredths to a tenth of an inch under any other areas that receive showers. Locally higher amounts possible should any thunderstorms develop. The large upper low over the north central US will keep temperatures moderated today at 5-15 deg F below normal for most of the region with some warmer temperatures over the coast thanks to the offshore ridge. Warming from west to east is then expected the rest of the week and into the weekend as high pressure builds offshore. Northern and central coastal CA can expect above normal temperatures beginning tomorrow with these conditions spreading across the region the rest of the week. Expecting widespread above normal temperatures Friday through Monday by 5-10+ deg F (most prominent away from the coast). Freezing levels 6-8 kft over NV today and 7-12.5 kft over CA with higher freezing levels spreading across the region the rest of the period. Generally 8-12 kft the rest of the week with the region generally above 10 kft by Saturday remaining around 10-12 kft the rest of the period. |