| Day | Date | High/Low | Forecast |
| Mon | 24th | 89/69 | Mostly sunny day with some high clouds. Some evening high clouds. |
| Tue | 25th | 91/71 | Mostly sunny day with some high clouds. Mostly clear evening. |
| Wed | 26th | 93/73 | Mostly sunny day with some afternoon high clouds. Some evening high clouds. |
| Thu | 27th | 94/73 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Fri | 28th | 92/70 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
Synopsis
High pressure aloft dominates most of the western states today (center over New Mexico). It will strengthen some, and its center should get as far west as eastern Arizona by Thursday. Already, surface on-shore flow has weakened enough to allow widespread triple digit heat in the valleys (close to that in spots of inland, coastal plain). At UCLA, the temperature reached 90 degrees around 11:30 AM (first time since 17 March). If the on-shore flow weakens further, possibly a marginal, off-shore flow morning hours, then the campus area should experience 90 degree heat for the rest of the work week (five 90 degree days would be the most since 2020 when five such days occurred). Besides the chance of record maximum temperatures (for the date), some record high minimums may be tied or set (expect some “warm” overnight low temperatures in most areas away from the immediate coast).
Some “monsoon” moisture aloft continues to reach southern California occasionally (mainly in the form of variable, high clouds). A couple of thunderstorms were over southern mountains this afternoon (largest near Big Bear). Earlier in the morning, radar did detect a few light showers (sprinkles) in the San Diego area. All the computer models show some decrease in atmospheric instability for the next couple of days (not expecting any mountain/desert thunderstorms in the Southland tomorrow/Wednesday). Some models show upper level moisture from current, tropical storm Iselle (about 580 miles west-southwest of the southern tip of Baja California early this afternoon) getting directed toward central California late this week. Most model solutions keep any shower threat north of Point Conception (mostly in the form of sprinkles away from the higher mountains).
High pressure aloft should weaken and slowly migrate east again by this weekend. An upper level trough west of the Pacific Northwest states is forecast to strengthen along the West Coast by Sunday. If this scenario holds true, a good cooling trend should develop over the weekend (modest start on Saturday). By Monday, most areas should see near seasonable temperatures (UCLA normal high for the end of August is 80 degrees). A return of widespread, early morning low clouds by the coast can be expected early next week. Some minor warming may return later next week as some models show high pressure aloft trying to nose back into southern California. Some model solutions keep an upper trough in the neighborhood though. That would support little or no warming trend, especially for the coastal plain.
Next issued forecast/synopsis should be on Monday, 31 August.