| Day | Date | High/Low | Forecast |
| Mon | 23rd | 72/58 | Mostly sunny remainder of day. Evening low clouds returning. |
| Tue | 24th | 71/59 | Morning low clouds likely but mostly sunny by late morning. Chance of late evening low clouds. |
| Wed | 25th | 74/60 | Good chance of early morning low clouds; Otherwise, mostly sunny day. Chance of late evening low clouds. |
| Thu | 26th | 75/61 | Chance of early morning low clouds; Otherwise, mostly sunny day. Clear evening. |
| Fri | 27th | 76/62 | Chance of early morning low clouds; Otherwise, mostly sunny day. Clear evening. |
Synopsis
An upper level trough remains over the state today (responsible for recent cool down across the state), and it’s forecast to stick around through tomorrow. After that, high pressure aloft should begin encroaching on southern California for the remainder of this week. For now, it’s unclear whether high pressure aloft will become entrenched in the Southwest this weekend and beyond.
We’ve reached the time of year when small scale, wind flow changes can greatly influence the “behavior” of the local, low cloud field. The aforementioned trough is expected to weaken relative to today, but the computer models still expect the low level, on-shore flow will increase a little (over today’s readings). Even if low clouds aren’t solidly overcast tomorrow morning in most areas, on-shore flow may still support slight cooling (relative to today) in most locales west of the mountains. All the models support the aforementioned trough moving east of the state on Wednesday. That, along with predicted weaker on-shore flow, should result in some warmer weather that day (coastal low clouds may also clear away more quickly and completely).
High pressure aloft in the sub-tropics should exert more influence on Southland weather in the second half of this week. However, a couple of weak troughs passing by well to our north may prevent much warming for this work week (temperatures staying close to seasonal normals). Most models do show the marine layer getting progressively shallower, but at this point, the models don’t show the marine layer getting too diluted (i.e. coastal low clouds should remain a daily, weather fixture along most of the coast).
Some model solutions do show high pressure aloft building into the desert Southwest over the weekend and lasting into early next week. Warmer than normal weather should result, but not all models show significant warming for the coastal plain. Potentially, enough of a marine layer may remain to keep temperatures from getting much above normal levels. There are also some model solutions showing weak, upper level troughing near or over the state by the beginning of July (Tuesday). That scenario keeps a trough in the “neighborhood” through the beginning of the 4th of July weekend (temperatures at or slightly below normal in the Southland). High pressure aloft may strengthen back in the Southwest late in the holiday weekend (favors distinctly warmer than normal weather), but that scenario is far from unanimous. Based on today’s model consensus, no “monsoon” moisture incursion into the Southland is forecast (for the next two weeks).
Next issued forecast/synopsis should be on Monday, 30 June.