Weather Synopsis – May 14, 2024

James Murakami

Tue14th66/58Partial afternoon clearing. Low clouds likely again in the evening.
Wed15th65/57Mostly cloudy through the evening.
Thu16th67/56Morning low clouds likely but mostly sunny afternoon. Evening low clouds likely.
Fri17th68/56Morning low clouds likely but sunny afternoon. Chance of evening low clouds.
Sat18th68/56Good chance of early morning low clouds; Otherwise, mostly sunny day. Chance of late evening low clouds.


A moderately strong on-shore flow continues over southern California. That, along with an intermittent, coastal eddy circulation, has promoted widespread, marine layer clouds (mostly night through late morning hours over land). Subtle wind flow pattern shifts on a small scale have dictated how quickly low clouds form or dissipate on a given day (difficult to forecast accurately). None of the numerical models are forecasting any major changes to the wind flow pattern (affecting southern California). Thus, one should expect more “May Gray” weather for several more days (possibly up to the beginning of the Memorial Day weekend). Day to day temperature changes should be minor in the coastal plain (modest farther inland).

While I show minor day to day changes in the campus forecast, in reality, the actual low cloud pattern each day may vary more than I show (complexities of marine layer physics). An elongated, weak, upper level low pressure should bring variable mid/high clouds tomorrow (above the marine layer blanket). So, afternoon sunshine may be more muted tomorrow than it is today. It won’t affect areas west of the mountains, but the aforementioned low pressure may trigger isolated, afternoon showers today and tomorrow (a little more widespread tomorrow). Atmospheric instability should be insufficient to support thunderstorms, but the chance won’t be zero percent (especially tomorrow afternoon). Any rain in the interior, however, should be minor (rain falling into a dry layer beneath the cloud base). With the low pressure moving inland tomorrow night, the threat for additional showers should quickly end.

High pressure aloft should bring some warming to well inland areas Thursday through Saturday. Although low clouds may become less widespread during the same period, little temperature change is anticipated in near the coast (as happened this past weekend with healthy, on-shore flow). A new though weak, upper level trough should bring about more widespread, low clouds again next week. I wouldn’t rule out patchy drizzle with the expected, persistent low clouds. Some of the model solutions do favor a disruption of the low cloud field some time next week (mid or latter half of next week). The predicted, upper level trough over the state wouldn’t promote any relevant warming trend, however. At least, not until the Memorial Day weekend comes around. Of course, much could change between now and later next week.

Next issued forecast/synopsis may occur on Thursday, 16 May.