A few degrees of warming today, with continued below average temperatures. A gradual warming trend will continue through the end of the week. The marine layer will bring night and morning low clouds to coastal areas through the rest of the week. The marine layer is expected to become shallower, with less low cloud coverage in the valleys by the end of the week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Visible satellite at 1 PM, was showing low clouds had cleared the coast and valleys, with areas of high clouds moving west to east across the Inland Empire. Low clouds will start to spread east towards land this evening, and are expected to reach into the valleys overnight. The marine layer is expected to remain 2000 to 2500 ft deep through Wednesday while we remain under cyclonic flow aloft as a trough moves across the West Coast.
Highs Wednesday will be 4 to 8 degrees warmer than today for the mountains, deserts, and inland valleys. An additional few degrees of warming are expected into Thursday. The warming trend will bring temperatures back to right around average for Thursday.
An area of high pressure from south of the border will build near the Four Corners region for the end of the week into the weekend. This will result in a more noticeable warming for the deserts Friday through Monday. Chances of the low deserts exceeding 110 degrees are highest on Sunday and Monday at 60 to 80 percent. There are some indications that the position of the high pressure would allow for a moisture surge from the southeast into the low deserts over the weekend or early next week. If that were to occur, that would keep high temperature readings on the lower side of guidance. For Sunday and Monday, there is a 7 degree difference between the warmest and coolest solutions with the coolest solutions staying right around 105 degrees and the warmest exceeding 110 degrees.
Conditions are also expected to warm up west of the mountains, but an upper level weak trough lingering off the coast of Southern California is expected to keep the aforementioned high pressure from moving too far west. Chances of the Inland Empire exceeding 100 degrees on Sunday and Monday are mostly 20 to 30 percent, locally up to 50 percent in the eastern portion of the Inland Empire. For the eastern San Diego valleys, chances for temperatures to exceed 90 degrees are 30 to 50 percent. Chances of inland Orange County exceeding 90 degrees on Sunday and Monday are closer to 10 to 20 percent. The low is expected to be close enough to maintain marine layer low clouds and fog along the coast but influence from the high pressure aloft should keep the marine layer shallower and less likely to reach the inland valleys.
242015. Coast/Valleys, SCT250 this afternoon. Low clouds begin to return to the coastal areas around 01Z Wed, reaching coastal TAF sites 03Z-05Z Wed with bases lowering to around 1500 ft MSL. Patchy clouds likely to reach into parts of the IE again 10-12z Wed. Clearing to the coast 17Z-19Z Wed.
.Mountains/Deserts, Clear skies with unrestricted VIS through Wednesday morning.
No hazardous marine conditions are expected through Saturday.
Ca, None. PZ, None.
