Aside from a few stray showers this afternoon, the lull in unsettled weather ends this evening as wrap around precipitation fills back in this evening, with additional rain and snow showers favoring the eastern/southern mountain slopes. Snow levels will remain near 6500 ft through Saturday morning. Drier weather with a gradual warming trend sets in for early next week with temperatures returning above normal by Wednesday/Thursday. There is the potential for weak Santa Ana winds by the middle of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
While there are still a few very scattered showers across the area, particularly the high deserts this afternoon, the radar is much quieter now compared to this morning. However, current satellite and 500mb RAP analysis shows the upper low over the California Bight, but a vort max diving southward will pull the closed southward into northern Baja tonight into Saturday. As this occurs, wrap around precipitation is set to fill back into the area this evening into the overnight hours, favoring the deserts and southern/eastern mountain slopes, especially in San Diego County. This precipitation will generally be light, with rates up to 0.1-0.2"/hr though localized enhancements, particularly along the San Diego County desert mountain slopes, are possible. Additional rainfall totals from this wrap around will be 0.2" or less for the coasts/valleys, 0.75-1" in the mountains (though eastern slopes could see additional totals closer to 1.5-1.75"), and 0.25-0.5" in the deserts. Snow levels remain near 6500ft through tonight but gradually rise to ~7000ft Saturday afternoon. Additional snowfall above 6500ft through Saturday morning range from 2-5", with locally up to 9" on eastern mountain slopes. Snowfall rates could be 1-1.5"/hr at times and given the expected additional snowfall, the Winter Storm Warning has been extended through 10 AM Saturday for mountain elevations in San Bernardino County and Riverside County >6500ft.
The wrap around precipitation eventually tapers off by Saturday afternoon as the upper low begins to lift northeastward and dry northwesterly flow aloft returns for Sunday into Monday. Temperatures slowly respond with a subtle warming trend that returns afternoon highs to seasonable norms by Monday/Tuesday. Ensembles are consistent with a trough digging from the Pacific Northwest through the Great Basin, aiding to strengthen to the offshore pressure gradient Tuesday into Wednesday. Currently there is about a 40% chance of a weak to moderate Santa Ana event mid-next week, likely peaking around Wednesday. Between the offshore winds and an upper ridge peaking Thursday, temperatures warm to 5-10 degrees above normal for Wednesday into Thursday.
Looking into the far extended, ensembles continue to hint on another storm system late next week that could bring another round of rain. Significant uncertainty remains in the timing and track of this next trough, so it's not something to get too excited about just yet.
212130z, Coasts/Valleys, BKN low clouds based 3000-5000 ft MSL will become more SCT this evening through the coastal basin along with SHRA and associated cig/vis reductions becoming isolated. Light -RA increasing in coverage again over just San Diego County from 06- 12Z Sat. East to southeast winds gusting 25-35 knots after 00Z in coastal foothills and locally into inland valleys.
Deserts/Mtns, BKN-OVC low clouds 4000-6000 ft MSL currently. SHRA will become more persistent and widespread in the low deserts with MVFR cig/vis reductions at times. Slight chance TSRA in the San Diego County deserts/mtns 00-06Z Sat. SCT FG/SHRA/SN in the mtns through Saturday morning, especially along the eastern slopes, where precip will be favored. Conditions slowly improving after 12Z everywhere with any precip becoming more SCT and intermittent.
No hazardous marine conditions are expected through Wednesday.
Ca, Winter Storm Warning until 10 AM PST Saturday for Riverside County Mountains-San Bernardino County Mountains.
PZ, None.
