| Day | Date | High/Low | Forecast |
| Thu | 26th | 77/63 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Fri | 27th | 87/63 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Sat | 28th | 82/59 | Mostly sunny day with some high clouds. Some evening high clouds. |
| Sun | 1st March | 74/56 | Chance of some early morning low clouds; Otherwise, mostly sunny day. Chance of evening low clouds. |
| Mon | 2nd | 69/55 | Chance of morning low clouds; Otherwise, mostly sunny day. Chance of some evening low clouds. |
Synopsis
High pressure aloft is strengthening over the state today. It has started a noticeable, low level, northerly wind flow through the San Fernando Valley (brisk winds promoting temperatures well into the 80s there). The various, computer models predict some modest, upper air support for stronger northerly winds tonight. Some peak gusts at higher elevations to 50 mph will be possible. It’s less clear (to me) whether the stronger winds will translate to low elevations prone to San Ana winds. In any case, the upper air support is forecast to diminish tomorrow (still gusty winds in Santa Ana wind prone areas but less wind than it gets tonight).
Minor to modest daytime warming has occurred in most areas west of the mountains today. UCLA, however, hasn’t yet joined with the warming trend (as of this writing). It can be tricky forecast temperatures near the coast in the beginning phase of off-shore flow (ocean breezes starting unexpectedly early). For this forecast, I ramped up the predicted high for Friday from my previous, conservative one. The surface off-shore flow should be strong enough to delay ocean breezes tomorrow (in theory). With high pressure aloft reaching peak strength tomorrow and being of sub-tropical origin, there should be well inland areas reaching the low/mid-90s. Record temperatures for the date may be at least tied. At UCLA, the current record high for 27 February is 85 degrees (set way back last year). The current, record high minimum for the date is 61 degrees (first set in 2020 and tied last year).
The off-shore flow is expected to weaken some on Saturday (marginally on-shore by Sunday). High pressure aloft will also weaken and get displaced southward by an approaching Pacific, upper air trough (will bring some light precipitation to parts of northern California over the weekend). In southern California, modest cooling should begin on Saturday. A more noticeable cooling should occur on Sunday and Monday (latter expected to be the coolest of the next several days).
The aforementioned trough should get close enough to promote widespread, marine layer clouds west of the mountains. However, no widespread blanket of low clouds are currently anticipated (trough may stir up atmosphere too much). In any case, temperatures that day should be back to near normal.
Mostly sunny and slight warming is expected on Tuesday. The predicted, northwest wind flow aloft should allow for multiple, “inside slider” type troughs to pass through the state next week. Although the model consensus favors warmer than normal weather next week, the predicted wind flow may not permit any significant warming cycles (in between, passing “inside sliders”). Some model solutions, in fact, favor some cooler than normal days and even a chance for showers with the “inside sliders” (showers mainly around the mountains). For the time being, I’m keeping the chances for wet weather next week rather low (first chance not before the 5th of March). Even among “wet” solutions, rain totals would be mostly under a quarter inch (snow levels potentially as low as 5000 feet).
Next issued forecast/synopsis should be on Monday, 2 March.