Weather Synopsis – May 21, 2024

James Murakami

Tue21st66/54Partly cloudy remainder of morning; Mostly sunny afternoon. Chance of late evening low clouds.
Wed22nd67/56Good chance of morning low clouds; Otherwise, mostly sunny day. Chance of evening low clouds.
Thu23rd66/57Morning low clouds likely but mostly sunny afternoon. Evening low clouds likely.
Fri24th65/57Morning low clouds likely but mostly sunny afternoon. Evening low clouds likely.
Sat25th65/57Morning low clouds likely but mostly sunny afternoon. Evening low clouds likely.


Despite a weaker on-shore flow today, low clouds were still widespread this morning (not necessarily as a solid overcast all the while though). Only in a few spots (mostly parts of coastal Santa Barbara County) did low clouds linger till early afternoon. The computer models continue to show only minor day to day changes in our weather pattern this week. The on-shore flow should remain weaker for one more day, and that may lessen the areal coverage and persistence of low clouds tomorrow morning. Daytime temperatures should edge upward in most areas (compared with today). Most of the that warming (modest) should occur in well inland areas. For Thursday through Saturday, another cycle of stronger on-shore flow and attendant cooling (mostly west of the mountains) should occur (“inside slider” troughs exerting more influence on the wind flow pattern affecting southern California). Even a little patchy, early morning mist/drizzle is possible (mainly up against coastal facing foothills/mountains). Temperature-wise, it shouldn’t get any cooler than it got in recent days.

For the remainder of the Memorial Day weekend, high pressure aloft should begin a modest mount over the Southwest. So, the seemingly month long period of “May Gray” weather west of the mountains may end (for a time, at least). The model consensus do show some weak, upper level troughs passing through or nearby, but they should be quite a bit weaker than most of the troughs this month. That should result in an overall, shallower marine layer and weak on-shore flow (relative to recent weeks). Temperatures next week in most areas should reach on a consistent basis seasonable or slightly above normal levels (particularly well inland areas).

One caveat is the potential effects of a shallow but well defined, marine layer. This shouldn’t effect the coastal valleys so much, but areas near the coast (campus included) could be shielded from a general warming trend next week. Any potential, coastal eddy may help keep the marine layer solid enough to prevent a noticeable warming trend near the coast (“May Gray” may continue there for much of next week). Also, at least forecast-wise, none of the models predict a persistent, Southwest high pressure aloft in the next couple of weeks (characteristic of summer). That would leave the door open for any “May Gray” to transition into “June Gloom” for the coastal plain.

Next issued forecast/synopsis should be on Thursday, 23 May.