Wednesday's Synopsis

NOTE: Weather Conditions at sites below--
Current UCLA Data at a Glance
Current UCLA Data Summary

Notice: The AOS department has decided on not updating the weather page (been broken for some time now), This includes the five day, campus forecast and synopsis. The page with current UCLA weather conditions will continue, however (it's a Davis Instruments site). Thus, today's synopsis will be the final one unless there is a demand for periodic synopses/blogs. Please let me know (James Murakami: tenki@atmos.ucla.edu) if you would like to see the synopses continue (would likely get moved to a separate page within the AOS revamped site).

High pressure aloft that brought a warming cycle in the state is weakening. It brought more warming to much of the Southland than I anticipated last week (a marginal, low level, off-shore flow developed). Today's variable high clouds come from a weak, sub-tropical jet stream, but it didn't put much of a damper on daytime temperatures (most of the coastal plain a little warmer today than yesterday). Cooler weather is expected after today when a Pacific Northwest trough deepens southward into the state. The cooling should be minor for well inland areas at first, but the cooling trend should accelerate on Friday. Some of the coolest weather since spring is expected this weekend.

If today's computer model consensus is right, there will be some weather accompanying a trough this weekend. It will be mostly a marine layer induced rain event (drizzle some areas, mainly light rain showers other areas). This should occur mainly Saturday morning, but showers around the mountains may occur all day (intermittently). There is also some chance at lingering showers Sunday morning (amended campus forecast from preliminary one). Storm totals should be under a quarter inch in most areas though values of a tenth inch or less should be more common away from the mountains (some favored, coastal slope mountains may receive up to half an inch rain).

Dry weather should return to the Southland after Sunday. If today's model consensus is right, a marginal, off-shore flow may occur by the middle of next week. Slightly warmer than normal weather is probable. In addition, some breezy weather is probable around Santa Ana wind prone areas (possible first Santa Ana wind event of the new season). Another cooling cycle should occur by the subsequent weekend.

UCLA Forecasts and analyses are written by James Murakami

– posted: 2023-09-27