Dry and warm weather continues into Tuesday with increased Santa Ana winds across the mountains and western valleys. Cloudier skies will enter the region by Tuesday as low pressure systems across the Pacific move over our area. This will bring chances for periods of rain and showers for New Year's Eve into the weekend.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
This morning, Under variable high clouds, sfc pressure gradients - with some support from northeast winds aloft below 18000 ft - continue to produce gusty Santa Ana winds. In the last hour, some of the wind-prone areas have reported northeast to east winds gusting 45-55 mph with local gusts of 65+ mph.
With an upper-level high pressure ridge to the north and a closed upper low over the SoCal Bight retrograding to the southwest, dry and warm weather will continue through Tuesday. Periods of gusty Santa Ana winds will also continue through Tuesday. Northeast to east winds will continue to gust 45-55 mph with locally higher gusts in winds-prone areas. Tuesday will likely be the warmest day with temperatures in the 70s to near 80 west of the mtns. Most areas will be near to as much as 11 degrees above seasonal averages. The temperature forecast for Tuesday may be complicated by high clouds moving in from the southwest and reducing daytime solar heating but the increasing heights and thicknesses will tend to raise temperatures.
BY Tuesday, the retrograding upper-levelclosed low just off the coast will merge with the closed low about 1200 miles southwest of San Diego. By Wednesday this new low will begin to move northeast toward SoCal as a low pressure system moves southward out of the Gulf of AK. These systems will bring us periods of rain/showers from late Wed through the weekend. This will likely occur in two distinct phases. The first phase will be the low to the southwest ejecting to the northeast and becoming an open wave over SoCal on Thu. During this phase, relatively warm, moist air from the tropics will result in widespread rain/showers before a dynamic ridge moves over the region on Friday. This ridge could bring a break in the precipitation until the low from the Gulf of AK arrives with colder air and more rain/showers for Sat through Monday. Snow levels will remain above 8,000 ft through Friday then fall to around 7,500 ft on Sat and 6,500 ft on 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 1"-1.9" in the coastal areas, 1.1"-1.8" in the inland valleys, 0.2"-0.6" in the low deserts, 0.25"-0.8" in the high desert, 1.3"-3" in the San Diego and Riverside County mtns and 1.5"-4.5" 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.
291630z, VFR conditions through the TAF period with few to scattered high clouds around 25,000 ft MSL. Gusty winds will continue out of the north to northeast and will gradually strengthen into the afternoon with gusts of 35-45 kts for the coastal mountain slopes and mountain passes and 20-30 kt gusts stretching below mountain passes into inland valleys. Localized areas of reduced VIS due to BLDU is possible, especially near the mountains. Gusty northerly winds below Cajon pass could produce crosswinds on approach/takeoff within the Inland Empire along with 25-35 kts of low level wind shear. Widespread mod up/downdrafts expected, especially near mountains and mountain passes. Strong offshore winds prevail through Tuesday morning.
No hazardous marine weather conditions expected through Saturday.
Ca, Wind Advisory until 1 PM PST Tuesday for 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.
