| Day | Date | High/Low | Forecast |
| Wed | 30th | 73/61 | Sunny day. Mostly clear evening. |
| Thu | 31st | 74/61 | Chance of some early morning low clouds; Otherwise, sunny day. Clear evening. |
| Fri | 1 August | 75/61 | Chance of some early morning low clouds; Otherwise, sunny day. Clear evening. |
| Sat | 2nd | 76/62 | Clear day. Some evening high clouds possible. |
| Sun | 3rd | 77/64 | Mostly sunny day with some high clouds. Variable evening high clouds. |
Synopsis
A relatively mild July should spill over into the first few days of August. Warming cycles this month (at least, in the coastal plain) have been minor (rarely reaching or exceeding seasonal normals). At UCLA, it got a little warmer than I anticipated (briefly reached 76 degrees during the 3 PM hour), but that’s still a couple degrees lower than the normal for late July. Well inland areas have been quite hot from time to time, but there have also been numerous “mild” episodes. Chalk it up to upper level low pressure frequently aiding a healthy, low level on-shore flow pattern (reason for consistent, marine layer clouds most of July in the coastal plain).
The latest, upper level trough is forecast to weaken and move inland. That should permit high pressure aloft to our south to nudge northward. Over the next few days, that should also allow high pressure aloft to be better established in the Southwest. Yet another upper air trough passing through the Pacific Northwest states should displace the Southwest high pressure, but it should only last a day or two early next week. After that, most numerical model forecasts show a moderately strong high pressure establishing itself somewhere around Arizona (possibly lasting till mid-month).
The consequence of the aforementioned pressure changes (aloft) should be to promote more consistent warmth for well inland areas (seasonable to warmer than normal). A heat spell is probable sometime next week for much of the Southland, assuming the center of high pressure aloft gets close to southern California. The one exception might be for areas near the coast. For most of July, a shallow but defined marine layer (with or without extensive low clouds) has kept warming cycles to a minimum. Even the inland coastal plain has benefited (just modest warming cycles…at or below seasonal normal temperatures). I’ve over predicted campus temperatures at times, albeit only slightly due to the unexpected marine layer influence. For this forecast, I left the temperature forecast unchanged despite today’s higher than expected maximum temperature (might be fluke).
Should the marine layer get extremely shallow or greatly diluted, it’s possible that the campus area will experience more significant warmth next week than this July (lasting at least through the subsequent weekend). It shouldn’t reach 90 degrees at UCLA, but consistent 80 degree weather is definitely possible (more consistent with what expects in August).
For the time being, most of the longer range models don’t show any relevant, “monsoon” moisture incursion reaching southern California (time period covers next two weeks). An occasional surge of Gulf of California air may reach parts of the southern desert region (Coachella Valley, for instance), but it should be too short-lived and shallow to pose a threat of “monsoon” showers/thunderstorms (this side of the state). Some high level clouds from the sub-tropics are possible at times (like this weekend), but it shouldn’t mix down to the ground to promote muggy weather. Of course, I’ve infrequently stated that a small error in predicted winds can result in significant weather changes (with regard to “monsoon” incursions). So, confidence in a “no monsoon incursion” is relatively low at this time.
Next issued forecast may be on Monday, 4 August (On call for jury duty that week, however).