| Day | Date | High/Low | Forecast |
| Mon | 4th | 74/61 | Hazy sunshine remainder of day. Some evening high clouds. |
| Tue | 5th | 78/63 | Chance of some early morning low clouds; Otherwise, mostly sunny day with some high clouds. Variable evening high clouds. |
| Wed | 6th | 79/63 | Mostly sunny day with variable mid/high clouds. Scattered evening mid/high clouds. |
| Thu | 7th | 79/64 | Mostly sunny day with some high clouds. Some evening high clouds possible. |
| Fri | 8th | 78/63 | Mostly sunny day with some high clouds possible. Some evening high clouds possible. |
Synopsis
Slowly but surely, the weather pattern in the Southwest is headed toward a sustained heat spell. Just not today. Yet another, upper level trough over the Pacific Northwest states is keeping high pressure aloft from exerting full weather influence on southern California. It’s been warmer, in general, for well inland areas recently, but temperatures west of the mountains have mostly been slightly below normal (exception in parts of Inland Empire…seasonably hot there). Closer to the coast (campus included), on-shore flow has stayed just strong enough to keep any warming cycles on the “mild” side.
The various, computer models predict a weakening of the Pacific Northwest trough as the week progresses. Most model solutions show a modest but noticeable warming trend through the work week. The models have mostly over forecast warming cycles for the coastal plain this summer. However, for this forecast, I decided to lean the campus forecast on the warmer side (reaching seasonable levels, for a change). IF the low level, on-shore flow stays stronger than most of the models predict, a shallow but defined marine layer could hinder the warming trend (less so for well inland areas though).
August is the mostly likely month in southern California for a “monsoon” moisture incursion, but at least this week, it doesn’t look likely for any relevant incursion to happen (excepts minor but shallow, brief surges from the Gulf of California into parts of the low desert). Some sub-tropical, high clouds on occasion, should be the closest thing to “monsoon” incursion. If some of the models are right, a significant moisture incursion is possible toward mid-month (sometime 13th to the 16th). IF true, that’s when mountain/desert thunderstorms (mainly afternoon hours) will be possible. A few scenarios include areas west of the mountains, but it’s not a serious consideration (for now).
Most of the models show a ridge of high pressure forming west of the Pacific Northwest states this weekend. This should allow for the Southwest ridge to better establish itself in the region. A more prolonged foothold should allow for longer duration heat in the Southland (this weekend through most or all of next week). Minor shifts in the position/strength of the high pressure could produce minor ups and downs in temperature, but it’s looking probable that a long duration period of warmer than normal weather will finally occur. Of course, a stronger than expected on-shore flow could temper any warming trend near the coast (i.e. shallow but effective marine layer shielding the coastal zone). However, I’m reasonably confident that the campus areas will warm well into the 80s next week.
Next issued forecast/synopsis may be on Monday, 11 August (I requested a change of venue to my jury duty. So, the next issuance is tentative.)