Warmer and drier through Tuesday with periods of moderate gusty Santa Ana winds. A low pressure system from the southwest will likely bring a return of precipitation for Wednesday through next weekend, though exact timing and precipitation amounts are still uncertain.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
The patches of shallow radiation fog from earlier this morning have lifted and we're mostly sunny with variable high clouds. The clear skies overnight allowed low temperatures to drop into the low 30s in some inland valley locations. Sfc pressure gradients are trending stronger offshore and are currently -7.1 mb SAN-TPH and -4.0 mb SAN-DAG. Winds have turned offshore and the windiest locations are reporting northeast to east winds with gusts 35-45 mph.
A pattern of high pressure to the north and a closed upper low to the southwest will bring warm and dry conditions with periods of gusty Santa Ana winds through Tuesday. The offshore flow gets some upper level support on Mon and Tue with northeast winds aloft. The offshore flow will likely be strongest on Tuesday, producing gusty Santa Ana winds in the mtns and lower elevations west of the mtns. Northeast to east winds gusting 35-45 mph - with local gusts of 55-60 mph - will be possible in the favored locations. Tuesday will also be the warmest day, with high temps in the 70s west of the mtns and most areas seeing temps near or above seasonal averages. Coastal and valley areas could be as much as 9 degrees above average while the mtns and deserts will be near or just a few degrees above. Relative humidities could fall into the teens for some inland areas Monday and Tuesday afternoons but the recent rains will mitigate fire weather concerns.
Chances for rain and mountain snow will return for Wed through next weekend as a low pressure system moves in from the Gulf of Alaska, causing the closed low to our southwest to become an open wave as it is drawn into the mean westerly flow over the Southwest US. Forecast details are still uncertain but numerical model solutions are coming into better agreement with respect to the synoptic pattern. Precipitation could move in as early as Wed afternoon with periods of rain and showers continuing (with breaks) through next Sunday. Precip amounts will be greatest in the northern areas (Orange and San Bernardino Counties) and less in southern San Diego County. Current rainfall estimates are for totals of 0.6"-1.2" in the coastal areas, 0.7"-0.8" in the inland valleys, 0.05"-0.4" in the low deserts, 0.15"-0.4" in the high desert, 0.55"-1.6" in the San Diego and Riverside County mtns and 1.5"-3.5" in the San Bernardino Mountains. The snow level will remain above 8,000 ft through Friday before lowering to around 6,500 ft on Saturday. Most of the precipitation will likely fall before next weekend so snowfall amounts at resort levels and below will be limited.
281630z, VFR conditions are expected through the TAF period with a few to scattered clouds around 25,000 ft MSL. Offshore winds out of the north to northeast will gradually strengthen through the day with wind gusts of 25-30kts expected for the coastal slopes of the mountains and mountain passes, spreading below mountain passes and into the inland valleys after 18Z. While gusts may not surface at terminals like KONT or KSBD until late tonight or Monday morning, gusty northerly winds below Cajon pass could produce crosswinds on approach/takeoff within the Inland Empire this afternoon. LLWS may be possible, especially late tonight, for Inland Empire airports. Gusts strengthen to 35-45 kts for the coastal mountain slopes and passes after 00-02Z Monday with mod up/downdrafts expected. Strong offshore winds prevail into Monday evening.
No hazardous marine weather conditions expected through Friday.
Ca, High Wind Watch from this evening through Tuesday afternoon for San Bernardino County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Gorgonio Pass near Banning-Santa Ana Mountains and Foothills.
High Wind Watch from late tonight through Tuesday afternoon for San Diego County Mountains-San Diego County Valleys.
PZ, None.
