| Day | Date | High/Low | Forecast |
| Mon | 31st | 78/63 | Some lingering morning clouds but mostly sunny day. Mostly clear evening. |
| Tue | 1st Sep | 78/63 | Chance of early morning low clouds; Otherwise, mostly sunny day. Mostly clear evening. |
| Wed | 2nd | 78/64 | Chance of early morning low clouds; Otherwise, mostly sunny day. Mostly clear evening. |
| Thu | 3rd | 78/65 | Chance of early morning low clouds; Otherwise, mostly sunny day. Some evening low clouds possible. |
| Fri | 4th | 79/67 | Chance of early morning low clouds; Otherwise, mostly sunny day. Some evening clouds possible. |
Synopsis
Last week didn’t get as hot at UCLA as I predicted (peak readings 90 degrees on three of five work days). Warm overnight low temperatures (low/mid-70s) and humid air did contribute to an uncomfortable week though. This month will go down as the warmest August in campus history (average of daily maximum and minimum temperatures during the month).
Upper level low pressure along the West Coast has finally promoted noticeable cooling across southern California (UCLA not forecast to reach at least 80 degrees…first time since the 16th). Subtle, small scale wind flow changes may influence temperatures slightly up or down from today’s readings. All the computer models show a marine layer presence this week, but so far, areal coverage of low clouds has been haphazard (futile to forecast accurately where solid overcast may occur on a given day). The marine layer though, should continue to promote muggier than usual weather west of the mountains (due to warmer than normal ocean…as high as mid-70s water off of San Diego County). At least, the absence of “monsoonal” moisture means less humid conditions this week compared with last week (water vapor content last Thursday was comparable to many Gulf Coast cities for a time).
Astronomical summer is due to end in 22 days, but summer weather is far from over. Currently, a tropical disturbance is organizing several hundred miles southwest of Acapulco, Mexico. Forecast models predict this will become tropical storm Marie as early as tomorrow. Many model forecasts show it becoming a hurricane later in the week. High surf should directed at Southland, south facing beaches by the weekend. The predicted wind flow pattern should also import a fresh batch of “monsoonal” moisture into southern California this Labor Day weekend (parts of the Southwest, for that matter). In short, the holiday weekend should be very warm and humid across most or all of the Southland.
The predicted details of weather, however, are uncertain at this time. A number of model solutions predict future hurricane Marie moisture reaching the the Southland as early as Saturday (could be delayed to Sunday or even Monday). A few solutions even predict Marie reaching Southland waters as a tropical storm (winds at least 39 mph). That last scenario is a small, model minority (at least, for now). A more plausible scenario is one that has hurricane moisture getting stripped from the storm while it’s still in the tropics (low level circulation should remain down there). This “Monsoon” surge brings variable clouds and scattered showers and isolated thunderstorms (latter mostly in the mountains and desert) sometime over the holiday weekend. This scenario has played out in the past. On the other hand, hurricane Doreen in August,1977 did “die” near San Clemente Island. It triggered heavy rains and breezy conditions across many areas, including the L.A. Basin.
Time permitting, I will issue a Thursday (3 Sep) forecast this week.