| Day | Date | High/Low | Forecast |
| Mon | 1st | 71/51 | Mostly sunny day with some high clouds. Some evening high clouds. |
| Tue | 2nd | 69/52 | Mostly sunny day with some high clouds. Chance of late evening low clouds. |
| Wed | 3rd | 66/51 | Chance of morning low clouds; Otherwise, mostly sunny day with some high clouds. Mostly clear evening and possibly. breezy at times late. |
| Thu | 4th | 72/54 | Mostly sunny day with some high clouds; Possibly breezy at times early. Mostly clear evening. |
| Fri | 5th | 71/52 | Mostly sunny day with some high clouds possible. Scattered evening high clouds possible. |
Synopsis
Weak off-shore flow prevails today, which eliminated marine layer clouds over land in the overnight hours. Temperatures today got a little warmer than I expected in some locales (namely UCLA…peaked at 73 degrees noon hour). The passage of an “inside slider” trough produced some breezy weather in the usual, Santa Ana wind prone areas (still present as of this writing, albeit less windy now). Peak wind gust reached the low 40s in some higher mountains, but to my knowledge, low elevation locales saw gusts stay under 30 mph.
Weak on-shore flow is expected to return tomorrow afternoon, but it won’t last long. A minor to modest cooling trend should develop tomorrow/Wednesday. All the computer models predict another “inside slider” passage by Wednesday afternoon. A brief return of marine layer, low clouds is likely for areas west of the mountains along with a slight risk for spotty, marine layer mist (some models last week had predicted widespread wet weather with this system). Santa Ana winds should return to the wind prone areas as early as late Wednesday morning (higher elevations at first). Breeziest weather should occur late Wednesday evening into Thursday morning. Peak wind gusts in the mountains may reach 60 mph although some model solutions show nothing worse than with today’s event. Some Santa Ana wind prone areas at lower elevations may see gusts over 45 mph, but gusts should be mostly under 40 mph. I wrote in a chance for breezy weather for the campus area, but confidence isn’t great (predicted, deep layered northeast wind direction not always a reliable wind producer).
The off-shore flow should wane appreciably Thursday night. Marginal on-shore flow is expected Friday and weak on-shore flow is anticipated for Saturday. Thursday should be the warmest day for this next off-shore flow. I left the campus temperature forecast unchanged form my morning issuance, but since it reached 73 degrees today, it might get solidly into the mid-70s on Thursday (still expecting slight cool down Friday). Some isolated 80 degree readings are possible, but the predicted position of high pressure aloft isn’t the best for that much warmth (not in December). Seasonable readings should prevail for Saturday.
Most models favor high pressure aloft building right over the Southwest early next week. If deep layered, easterly wind flow develops (not explicitly being forecast at this time), widespread 80 degree weather is possible for a day or two early next week. The accompanying off-shore flow should not have upper air support for widespread, significant wind. The off-shore flow should gradually decay. Weak on-shore flow should return by the second half of next week (temperatures at or slightly below normal, depending on how well defined a marine layer return gets).
The longer range models have been inconsistent at best with regard to wet weather chances in the state. The latest trend now keeps California dry through the 11th (a good number of solutions extend that through the 12th). A majority consensus favors an opening of the “storm gate” to the state sometime after the 12th (14th, if you accept today’s consensus). These storms would be typical Gulf of Alaska storms (cold with modest precipitation). Since there are still some model solutions keeping at least southern California dry (through mid-month), I’m not ready to accept a mid-month return to wet weather…just yet.
Next issued forecast/synopsis should be on Monday, 8 December.