| Day | Date | High/Low | Forecast |
| Mon | 30th | 73/60 | Sunny remainder of day; Clear evening. |
| Tue | 1st July | 72/60 | Good chance of early morning low clouds; Otherwise, mostly sunny day. Chance of evening low clouds. |
| Wed | 2nd | 72/60 | Early morning low clouds likely; Otherwise, mostly sunny day. Evening low clouds likely. |
| Thu | 3rd | 73/60 | Early morning low clouds likely; Otherwise, mostly sunny day. Chance of late evening low clouds. |
| Fri | 4th | 75/61 | Mostly sunny day except chance of early morning low clouds. Mostly clear evening. |
Synopsis
June is coming to an end. Weather-wise, the first month of summer, meteorologically speaking, was fairly mild (most of southern California). The warmest it got at UCLA was 79 degrees (1st and 18th). The campus averages about three 80 degree days in June. Based on the latest, computer model forecasts, a continuation of relatively mild temperatures should prevail through at least the 4th of July (Friday).
An upper level low pressure of some sort has been a common theme along or just west of the state this month. High pressures have covered the state from time to time, but they haven’t stuck around for more than a few days at a time. That, however, is likely to change by next week (more on this in a bit). Of course, subtle day to day changes in the low level, on-shore flow pattern have produced some variability in temperatures (more pronounced for well inland areas). My forecast today shows almost no day to day changes in temperature, but it could vary by a few degrees.
The latest, upper low pressure (west of the state) is forecast to move inland on Wednesday. It should promote a little greater on-shore flow tomorrow/Wednesday. So, marine layer clouds should be more extensive again for a couple of mornings. However, with the seasonal warming of the local ocean, the marine layer has become warmer than it was last month. Unless the marine layer gets much deeper than expected (inducing “June Gloom” like weather), daily clearing of low clouds should be relatively quick (by mid-morning most areas). Less marine layer coverage is anticipated by the 4th of July weekend.
While some modest warming is expected for the holiday weekend (more so away from the coast), the trend of the model forecasts is showing a large, strong high pressure aloft in the Southwest next week. If this scenario holds up, an extended period of much warmer than normal weather is likely (potentially beginning as early as Monday for well inland areas). Even the beaches could be much warmer than normal for at least a few days (minimal marine layer expected). Widespread triple digit heat for the valleys is probable for most of next week. Potentially, the campus could approach the 90 degree mark for a day or two.
In addition, the predicted wind flow pattern aloft could allow for a “monsoon” moisture incursion into southern California (by the middle of next week). Even before that (late this week), occasional, shallow surges of humid, Gulf of California air may reach the lower Colorado River valley. If some model solutions are right showing some deep layered, moisture next week, chances of afternoon showers and thunderstorms would be probable in Southland mountain/desert region. It even possible that muggy weather my reach the coastal plain for a couple days (L.A. standards…still considered “dry” by Gulf Coast residents). At this point, moisture from current, tropical storm Flossie (a couple hundred miles southwest of Acapulco this afternoon) isn’t forecast to reach southern California (some of that storm air mass could eventually move up the Gulf of California though…if some model solutions are right).
If some of the models are right, much warmer than normal weather may continue beyond the subsequent weekend (BTW– weekend of July 12th-13th might be blistering hot for most areas). There are some signs in the model runs favoring persistent high pressure encompassing southern California. Of course, this would be nothing unusual for July (Death Valley infrequently sees its hottest weather in July). How hot it actually gets remains to be seen, but strings of 90 degree days in the inland coastal plain may be in our near future. Enjoy the current “mild” weather while you can.
Next issued forecast/synopsis should be on Monday, 7 July.