A weak low pressure system moving inland through central and southern California today will bring a few more degrees of cooling and maintain a marine layer deep enough for night and morning coastal low clouds to cover much for the coast and valleys into Tuesday morning. Strengthening high pressure to the east and weak offshore flow in the mountains for Wednesday and Thursday will bring warming of high temperatures to within a few degrees of average on Wednesday with more gradual warming for Thursday into the weekend.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
(today through Wednesday), A weak upper level low pressure system will move inland through central and southern California today with high temperatures a few to around 5 degrees cooler than Sunday and as much as 5 to 10 degrees below average for the valleys. High temperatures for today will range from the lower to mid 70s near the coast to the lower 80s for the Inland Empire with the lower deserts in the mid to upper 90s.
The upper level low pressure system will weaken and move east on Tuesday with high pressure to the east strengthening for Wednesday into next weekend. There will be east winds gusting to 15 to 25 mph for the mountains during the morning on Wednesday and Thursday.
High temperatures on Tuesday will warm a few to around 5 degrees with the greatest warming for the inland valleys. Warming will continue on Wednesday with high temperatures as much as another 4 to 8 degrees warmer for the Inland Empire. With the warming, high temperatures on Wednesday will be within a few degrees of average for most areas. High temperatures on Wednesday will range from the mid to upper 70s near the coast to the upper 80s to mid 90s for the Inland Empire with the lower deserts around 100.
The marine layer will remain around 3000 to 3500 feet deep into Tuesday morning with night and morning coastal low clouds spreading inland across most of the coast and valleys overnight. The marine layer will become shallower on Wednesday and Thursday with coastal low clouds not spreading nearly as far into the valleys.
(Thursday through Sunday), High pressure aloft will remain across northern Mexico and adjacent southwest states through the weekend with high temperatures warming to around 5 degrees above average for Thursday and Friday, and possibly to 5 to 10 degrees above average for the coast and valleys on Saturday with an increase in surface dewpoints into the mid to upper 60s for coastal areas on Saturday.
Tropical Storm Polo, off the southwest coast of Mexico, is forecast by the National Hurricane center to become a major hurricane over the new few days with a track eventually and generally toward the west northwest which might put the center a few hundred miles south of the southern tip of Baja on late Friday afternoon. The track uncertainty is even greater beyond Friday. There could eventually be at least some peripheral impacts to portions of southern California for late in the weekend into early next week.
211130z, Coast/Valleys, Low clouds with bases around 1800-2800 feet MSL filling the coastal basin, will gradually clear this morning around 17-20Z. Patchy low clouds could persist near the coast thereafter. Low clouds with similar bases will spread inland after 23Z, starting around KSAN and moving northward overnight into Tuesday.
Otherwise, BKN clouds AOA 15000 feet MSL over the southeast part of the region will gradually clear from west to east this morning. Then mostly clear skies with unrestricted VIS after 17Z through tonight.
No hazardous marine conditions are expected through Friday.
Ca, None. PZ, None.
