Mostly sunny this afternoon with a few low clouds lingering at the beaches. Offshore flow continues with strengthening east winds along and below the coastal slopes of the mountains. The offshore winds will peak on Wednesday with gusts to 45 mph and isolated gusts to 55 mph before beginning to weaken on Thursday. Mid and high cloud will spread into the area from the southeast for Thursday into Friday with a slight chance of showers for the mountains late Thursday night and early Friday. There will be drying and warming for the weekend, then cooler for next Monday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Sunny and warm this afternoon, with temperatures as much as 11 degrees higher west of the mountains than at this time yesterday. High temperatures today will be around 10 degrees above seasonal averages near the coast and as much as 20 degrees above seasonal averages in the inland valleys. The mtns and deserts will be about 10-15 degrees above average. Surface pressure gradients remain offshore with -8.7 mb SAN-TPH and -3.7 SAN-DAG. The number of locations reporting easterly winds gusting 25-30 mph has increased from this morning and a few locations have reported gusts over 30 mph. A few low clouds still linger at the beaches but those will likely dissipate overnight.
From previous discussion, The offshore flow will strengthen before peaking Wed afternoon as a Rex block develops, with an upper low about 200 miles off the coast of Central Baja, an upper high over the northern Sierra and easterly flow aloft over SoCal. At its peak Wed afternoon, the offshore flow will produce easterly winds gusting to 45 mph and locally to 55 mph in the mtn passes and coastal foothills. The warming trend will continue into Wed when high temps will be in the mid to upper 80s west of the mtns, 15-20 degrees above seasonal averages.
By Thursday, the offshore flow weakens as the upper high gets displaced to the northeast in response to a low pressure trough moving in from the west, and the flow aloft becomes southeasterly. A cooling trend will begin, with high temps on Thu dropping into the 70s and low 80s west of the mtns. The circulation around the low to our southwest will draw some mid and high level moisture into SoCal, resulting in a slight chance of light showers over the San Diego County mtns for a few hours late Thu night.
The cooling trend will continue for Fri-Sat as the Rex block breaks down and an upper low moves over the region. Temps will still be 5-10 degrees above seasonal averages west of the mtns. This could also bring a return of onshore flow and marine layer low clouds/fog to the coastal areas.
A transient ridge will bring fair and warmer weather for Sunday before a more amplified low pressure trough again brings significant cooling, increasing clouds and chances for widespread precip next Mon-Tue. Forecast details for Mon-Tue remain uncertain, with a 25-45 percent chance of measurable precipitation for Tuesday. At that time, the snow level will likely be around 6,000 to 6,500 feet.
032100z, A few low clouds along the Orange County coast will continue to clear through the afternoon. Otherwise, VFR and clear skies. Gusty easterly winds in the mountains will begin around 16z Wed, with surface gusts up to 40-50 knots through mountain passes. Mod up/downdrafts near mountain peaks, and localized LLWS in the Inland Empire possible between 14z-18z Wed. Patchy BLDU possible for much of Wednesday, decreasing VIS down to 3SM at times.
No hazardous marine conditions are expected through Saturday.
Increasing northwesterly swell (270-280 degrees) and a long period (15 to 16 seconds) will bring elevated to high surf beginning Friday afternoon. Surf of 5-8 feet with locally higher sets will peak Saturday morning before slowly falling through Sunday. Impacts will be highest at west facing beaches, especially across San Diego County.
Ca, Wind Advisory from 4 AM Wednesday to noon PST Thursday for Orange County Inland Areas-Riverside County Mountains-San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Mountains- San Diego County Valleys-San Gorgonio Pass near Banning- Santa Ana Mountains and Foothills.
PZ, None.
