| Day | Date | High/Low | Forecast |
| Fri | 1st | 67/54 | Some high clouds but mostly sunny afternoon. Chance of evening low clouds. |
| Sat | 2nd | 65/53 | Partly cloudy through early evening. Then, clearing. Possibly breezy at times. |
| Sun | 3rd | 70/55 | Sunny day and possibly breezy at times. Clear evening and possibly breezy at times. |
| Mon | 4th | 74/54 | Sunny day and possibly breezy at times early. Clear evening. |
| Tue | 5th | 72/54 | Mostly sunny day with some high clouds. Chance of evening low clouds. |
Synopsis (delayed by network problems)
A broad area of low pressure aloft exists along the West Coast today. On a smaller scale, an embedded, “short wave” trough was diving south from the Oregon coast. For days the numerical models were struggling with forecast track the trough would take through the state (“inside slider” vs “outside slider” or mostly dry vs wet). Well, the models have finally come to agreement favoring an “inside slider” trough (mainly a dry, wind storm by the time it reaches southern California). Spotty, mainly, early morning drizzle still can’t be ruled out when a deep marine layer forms (for a short time tomorrow). There could also be some cold air instability showers over and adjacent to the higher mountains (favoring mostly north facing slopes except coastal facing slopes in San Diego County). This would be similar to what occurred on Monday (most measurable showers fell in the evening).
Today has been a little cooler day than I anticipated (so far). On-shore flow is pretty weak, but this morning’s coastal eddy appears to have developed a better defined marine layer than I thought earlier (too diluted for much in the way of low clouds, however). The on-shore flow is predicted to strengthen tonight into tomorrow morning. So, with the approach of the “inside slider” trough, on-shore flow should increase markedly tonight into tomorrow (increasing winds for the interior). A deepening, more moist marine layer should support widespread low clouds. However, I’m unsure whether it will take the form of a widespread, blanket of low clouds (leaned today’s forecast with “partly cloudy”). In any case, the deep marine layer and trough should support a little more cooling tomorrow west of the mountains.
Sunny weather should prevail across the Southland on Sunday. Most of the models favor widespread, breezy weather (as early as Saturday night in Santa Ana wind prone areas). However, some model solutions limit significant wind (25 mph or higher speeds) to the traditional, Santa Ana wind prone areas. The campus area potentially could see peak gusts approaching 35 mph, but confidence isn’t the greatest (similar event early this week wasn’t as breezy as I expected, based on model solutions at the time). If today’s model consensus is right, breezy weather in Santa Ana wind prone areas could continue into Monday (just less windy than what should occur on Sunday). By Tuesday, weak on-shore flow should develop (wind pattern returning to the mundane).
Most of the longer range models show a new, “inside slider” trough developing in the Southwest around Wednesday. It’s a “closed low” circulation (similar to a “cut-off” low but one that isn’t semi-stationary in position). Thus, it could pose a forecast headache. If the low pressure center winds up close to the Southland, cold air instability showers would be possible (not limited to mountain/desert region). At this time, the model consensus favors mostly just a wind storm in southern California. Off-shore flow winds on Wednesday/Thursday should result in slightly warmer than normal weather for most areas west of the mountains (possibility of wind speeds reaching 65 mph in the mountains). More tranquil weather should follow by the subsequent weekend. At this point, there are a few model solutions showing a minor threat of wet weather nearing Veteran’s Day (11th).
Next issued forecast should be on Tuesday, 5 November.
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