| Day | Date | High/Low | Forecast |
| Mon | 20th | 78/56 | Sunny day. Clear evening. |
| Tue | 21st | 76/55 | Mostly sunny day with some high clouds. Some evening high clouds. |
| Wed | 22nd | 69/54 | Chance of early morning low clouds; Otherwise, mostly sunny day with some mid/high clouds. Chance of evening low clouds. |
| Thu | 23rd | 72/56 | Chance of early morning low clouds; Otherwise, sunny day. Mostly clear evening. |
| Fri | 24th | 76/58 | Mostly sunny day with some high clouds possible. Chance of late evening low clouds. |
Synopsis
A weak, marginal off-shore flow has promoted slightly warmer than normal, daytime temperatures since Friday (17th). At UCLA, it got a bit warmer today than I anticipated (high so far 80 degrees). The off-shore flow is predicted to end tomorrow. Thus, it should be slightly cooler tomorrow. By tomorrow evening, there may be some return of coastal low clouds/fog south of Point Conception (foggy early today north of Point Conception). Noticeable cooling should occur on Wednesday when an upper level low pressure comes ashore somewhere around the Point Conception area (currently localed several hundred miles southwest of Los Angeles).
This sub-tropical low pressure currently has limited cloud cover associated with it (limited atmospheric instability to produce showers). However, most of the computer models show scattered, light showers developing late Tuesday into Wednesday morning (period when low pressure approaches the Southland). I decided to omit mention of showers in the campus forecast since predicted, atmospheric instability looks marginal (chances for isolated, brief-lived thunderstorms look remote too). In a worst case scenario (for my forecast), “sprinkle showers” may occur in the L.A. Basin (sometime Tuesday night-Wednesday morning).
A new, marginal off-shore flow is expected to follow the passage of the low pressure (starting weakly late Wednesday night or early Thursday). While no widespread, significant wind in Santa Ana wind prone areas are expected (confined mostly to higher elevations), a warming trend is likely. Seasonable to slightly warmer than normal weather is expected on Friday and Saturday. At this point, this warming cycle shouldn’t get as high as with the most recent warming.
Most model solutions show a couple of storms affecting northern California this weekend (areas of wet weather). The storms should take an “inside slider” path. Thus, no precipitation is predicted to reach southern California according to most model forecasts. However, there are some solutions showing marine layer induced showers Sunday morning (coastal areas to the east and south of L.A. County. As with some “inside sliders”, it may get breezy in the interior for a time.
With the predicted wind flow pattern, slightly cooler than normal weather is expected (Sunday-Monday). Another warming cycle should follow, however. Some models show a weak off-shore flow that can promote widespread, 80 degree weather (by Wednesday next week). A cooling trend should follow over the subsequent weekend (a few solutions showing a minor threat of wet weather reaching southern California).
Next issued forecast/synopsis should be on Monday, 27 October.