The final round of rain, snow, and gusty winds will be Thursday, with the main cold front moving through the area late Thursday morning through the early evening. There is a slight chance of thunderstorms Thursday afternoon and evening. Showers will diminish overnight Thursday with gusty winds diminishing by Friday morning. Frost is possible Friday and Saturday mornings. Dry conditions looking like they will prevail through the weekend. Chances of precipitation increase again mid-next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, New Aviation and Marine Discussion For the 00z TAF Package,
Key Points:
*Gusty and potentially damaging west winds along the mountain crests and adjacent desert slopes Thursday into Friday morning. Gusty westerly winds expected for the coast and valleys during the day Thursday.
*3-8 inches of additional snow expected Thursday into Friday morning. Additional snow plus strong winds may result in blowing snow and limited visibility. Snow levels as low as 3500 to 4000 ft Thursday may result in light accumulations through the Cajon Pass.
*Light to moderate rain is expected Thursday. Ponding of water on roads and minor street flooding in urban areas possible. Thunderstorms may bring locally heavy rain, stronger winds, and small hail.
At 1 PM a few isolated showers were moving across the coastal basin. Any lingering showers this afternoon will produce light rain, with hourly rates less than 0.10" per hour. Winds are still gusting over the mountains and into the deserts. Gusts this afternoon are mainly 35-55 mph. A lull in the winds is expected overnight, but winds are still expected to increase again Thursday peaking in the afternoon and evening, continuing into early Friday morning. For the mountain ridges and desert mountain slopes peak gusts of 60 to 70 mph, potentially up to 75 mph in wind prone locations are expected. Wind gusts in the deserts will be 45 to 65 mph with the strongest winds near the mountain foothills. For the coast and valleys, peak gusts of 30 to 45 mph are expected. Winds for the coast and valleys are expected to peak with the passage of the cold front. The front will start to move through Orange County/San Bernardino County mid- morning, reaching San Diego county by the early afternoon.
Light to moderate precipitation is expected Thursday with the heaviest precipitation expected with the frontal passage or where any thunderstorms develop. For the coast and valleys and additional 0.25 to 0.50" of rain are possible with 0.10" or less in the deserts. Snow levels for through Thursday are expected to be 3500- 5000 ft with an additional 3 to 8 inches of snow expected across area mountains. Current forecast has a 60% chance of accumulating snow on I-15 at the summit of the Cajon Pass.
Dry conditions are expected by Friday, with diminishing winds. Dry conditions will prevail through the weekend. Conditions may be cold enough Friday and Saturday morning for patchy frost to develop in the valleys and High Desert. High temperatures will warm each day for Friday through Monday with high temperatures on Monday around 5 degrees above average. Shower chances begin to increase again Monday evening into Tuesday, with the highest chances of precipitation currently Wednesday.
190030z, SCT-BKN clouds 3,000-6,000 feet MSL through Thursday morning west of the mountains. Winds gusting 25-40 kts along east-facing desert slopes and through mtn passes will weaken 03-06Z Thu. Clouds begin to fill in and lower after 18Z Thu as yet another round of light to moderate precip moves into the area. Current guidance indicates the main precip band will move northwest to southeast through the coastal basin from 18Z Thu to 02Z Fri. A few hours of MVFR cigs/vis is expected for the coasts/valleys with mtns shrouded in FG through Thu evening. Winds turn southwest and strengthen again late Thursday morning and into the afternoon. Gusts 25-35 kts through the coastal basin (locally 40 kts at the coast), 35-45 kts widespread for the mtns and deserts, and 50-65 kts along desert slopes.
Winds gusting to 20 kts may create hazardous conditions for small craft through early this evening. Winds and associated seas will calm down briefly overnight, but hazardous conditions will redevelop ahead of the next system on Thursday. Gusts reaching 25 to 30 knots in the afternoon. Conditions will improve Friday.
High surf of 4 to 7 feet is expected with sets as high as 8 feet, highest in San Diego County today. A lull is expected tonight before high surf returns Thursday afternoon. Dangerous swimming and surfing conditions and localized beach erosion can be expected. A High Surf Advisory is in effect through Friday and contains more details.
Ca, High Surf Advisory until 10 PM PST Friday for Orange County Coastal Areas-San Diego County Coastal Areas.
Wind Advisory from 9 AM Thursday to 2 AM PST Friday for Orange County Coastal Areas-Orange County Inland Areas-San Bernardino and Riverside County Valleys-The Inland Empire- San Diego County Coastal Areas-San Diego County Valleys- Santa Ana Mountains and Foothills.
Winter Storm Warning until 9 AM PST Friday for Riverside County Mountains-San Bernardino County Mountains.
Winter Weather Advisory until 9 AM PST Friday for San Diego County Mountains.
Wind Advisory until 9 AM PST Friday for Apple and Lucerne Valleys-Coachella Valley-San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, Small Craft Advisory until 10 AM PST Friday for Coastal Waters from San Mateo Point to the Mexican Border and out to 10 nm- Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.
