| Day | Date | High/Low | Forecast |
| Mon | 24th | 70/56 | Sunny day. Some evening high clouds. |
| Tue | 25th | 74/56 | Mostly sunny day with some high clouds. Mostly clear evening. |
| Wed | 26th | 76/58 | Sunny day. Some high clouds possible in the evening. |
| Thu | 27th | 80/57 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Fri | 28th | 70/55 | Mostly sunny day with variable clouds. Partly cloudy evening. |
Synopsis
A very weak, on-shore flow returned this morning, but there was little in the way of fog/low clouds (some around the Oxnard plain but little elsewhere). The on-shore flow, however, was just effective enough for minor cooling (relative to yesterday) for many areas west of the mountains (best cooling along the coast, of course). The numerical models continue to forecast a return of weak, off-shore flow starting tomorrow (lasting through at least Thursday). Most lowland areas that typically experience breezy weather during Santa Ana wind events shouldn’t see significant winds (at least 25 mph gusts). However, at higher elevations (at or above 1500 feet), it should get breezy at times beginning sometime tomorrow. Peak wind gusts around north-south oriented canyons/passes may reach 50 mph on Wednesday morning, but it shouldn’t be widespread in areal coverage nor persistent. The peak wind gusts should switch more to east-west oriented canyons/passes on Thursday.
For most, the most salient weather feature should be much warmer than normal weather for a couple days (Wednesday-Thursday). Some valley locales may reach the mid-90s (Woodland Hills already reached at least 88 degrees today). If deep layered, easterly wind flow prevails as some model forecasts show, even areas near the coast (campus included) may warm into the low 80s on Thursday (mid/upper 80s more inland coastal plain). Unlike summertime, the dry air and longer nighttime hours (relative to summer) will promote decent cooling at night (warmer than normal, however).
All the models show a “closed”, upper level low pressure approaching southern California (from the west) Thursday night/Friday morning. The low pressure will induce cooler weather, but depending on the path the low pressure takes, there is a chance that cooling won’t be as significant as I show in this forecast. If the low pressure makes landfall over northern Baja California, the off-shore flow may decay at a slower rate than what the current model runs show. Daytime temperature falls under 10 degrees (compared with Thursday highs) might occur instead of a more precipitous drop (15-20 degrees drop for inland locales).
A path where the low pressure center passes over southern California favors the more significant cooling (back to near seasonal normals). Besides more clouds (at least partly cloud skies for a time), there would also be a chance for some scattered, instability showers (mostly around/over the higher mountains). The more southern trajectory should favor less clouds and less of a chance for showers in L.A. County (still a chance farther to the south). Regardless of outcome, storm totals from this low. pressure should be minor (well under a quarter inch…just sprinkles in many locales).
Dry weather with slightly cooler than normal temperatures are expected on Saturday. On Sunday, a different Pacific trough should affect the state. Wet weather is likely up north. At this point, showers in the Southland are probable sometime Sunday (model consensus today favors late afternoon into early evening). However, for now, it’s unclear if widespread showers will occur. Some model solutions favor mainly mountain showers. Storm totals should be modest at best (possibly quarter inch for areas away from the mountains…snow levels as low as about 5500 feet). The “storm gate” should remain open to the state for the remainder of next week (potential for a wetter, colder storm around the middle of next week). Some model solutions keep the “storm gate”open for the first two weeks of March (minor to average strength storms).
Next issued forecast/synopsis may be on Friday, 28 February.