| Day | Date | High/Low | Forecast |
| Mon | 28th | 77/64 | Sunny remainder of day. Mostly clear evening. |
| Tue | 29th | 86/66 | Sunny day. Clear evening. |
| Wed | 30th | 82/66 | Chance of patchy, early morning low clouds; Otherwise, sunny day. Clear evening. |
| Thu | 1st October | 84/67 | Sunny day. |
| Fri | 2nd | 88/69 | Mostly sunny day with some high clouds. Some evening high clouds. |
Synopsis
A very warm and muggy weekend occurred. There were even some sprinkles in parts of L.A. County yesterday…minor, measurable rain to the east and south of L.A. County. That resulted from funneling of hurricane moisture into the Southland by an upper level low pressure (center crossing the southern San Joaquin Valley today). Due to the close proximity of the low pressure, seasonable, daytime temperatures have returned to most of southern California (less muggy too).
Just don’t get use to it. The aforementioned low pressure should cross into Arizona early tomorrow (lower Great Plains midweek). Deep layered, northerly winds are forecast to develop over much of the Southland by tomorrow (low pressure also responsible for this afternoon’s brisk, westerly winds in places). If most computer model forecasts are right, breezy conditions should occur in Santa Ana wind prone areas (mostly higher elevation locales). Peak gusts in the higher mountains could reach 45 mph for a time early tomorrow. Santa Ana wind prone areas in the lowland will probably not exceed 20 mph, for the most part. Winds should tail off quite a bit by the afternoon hours (upper air support forecast to wane quickly).
Even where no relevant wind occurs tomorrow, the predicted off-shore flow should lead to noticeable warming, including near the coast. Widespread temperatures into the 80s (potentially flirting with 90 degrees in parts of the inland coastal plain) are likely. A caveat to this predicted warming is if a sea breeze manages to develop at some beaches (counter current to the off-shore flow). Those locales may stay several degrees lower than some nearby locales affected by the off-shore flow.
Marginal off-shore flow conditions should prevail on Wednesday. Ocean breezes that develop that day should lower daytime temperatures near the coast somewhat (relative to what’s expected tomorrow). Still, warmer than normal temperatures are expected. Strengthening high pressure aloft over the Southland should promote warmer weather after Wednesday. In fact, much warmer than normal weather is forecast late this week through most or all of next week (good potential for heat wave…widespread 90 degree weather for several consecutive days…some chance even of triple digit heat in the inland, coastal plain as well as coastal valleys). In addition, another increase in muggy weather is possible at some point…as early as late this week. This is due partly from the influence of the still much warmer than normal ocean locally. Some model forecasts also predict a new “monsoon” moisture incursion into the Southland sometime next week (including chance to funnel moisture from future hurricane Rachel into the region…just a chance, for now).
If some longer range models are right, warmer than normal weather may prevail over most of the state through the first three weeks of October. Lingering episodes of muggy weather may also prevail. Of course, looking this far into the future should be considered more speculation than actual forecast.
Next issued forecast/synopsis should be on Monday, 5 October.