Weather Synopsis – February 22, 2024

James Murakami

Thu22nd64/51Sunny afternoon with some high clouds. Scattered high clouds in the evening.
Fri23rd74/55Partly cloudy day with high clouds. Scattered high clouds in the evening.
Sat24th70/51Partly cloudy with high clouds through the evening.
Sun25th67/53Partly to mostly cloudy day. Mostly cloudy evening.
Mon26th62/52Mostly cloudy with a chance of occasional showers through the evening.


Weak high pressure aloft has developed over the state in the wake of the recent storm. Rainfall generally was in the 2-3.5 inch range away from the mountains. Some mountain locales in Santa Barbara County received 10-11 inches, however. The UCLA auto-gauge recorded 4.95 inches, but the new weather station has a history of over reporting rainfall (Auto-gauge 14.69″ for historic storm earlier in the month but in reality, it was manually measured at 12.92″). The “official” measurement will be taken on Saturday. Regardless, this month is likely to end up among the top three wettest Februaries at UCLA.

All the numerical models predict a weak, off-shore flow developing. Upper air support for widespread wind in Santa Ana wind prone areas is expected to be best in Ventura County. Still, most of the significant wind should be confined to higher elevations (isolated peak wind gusts 45-55 mph tomorrow morning). For most other areas, the main weather impact should be a noticeable, daytime warming. Unless predicted high clouds end up thicker than expected, widespread readings into the low/mid-70s are likely west of the mountains (wouldn’t rule out isolated readings into the upper 70s). This includes areas near the immediate coast due to predicted, deep layered easterly wind flow (to suppress ocean breezes until the afternoon).

A large, but elongated “cut-off” low pressure has formed well west of northern California. This low pressure is forecast to meander out there for at least a couple days (circulation center dipping southward though). Depending on which model solution verifies, the “cut-off” low pressure may not make a move toward the coast till late Sunday or Monday. While it spins about well out at sea, varying amounts of mid/high clouds are expected to reach southern California (relevant cloud could be as early as tonight). A few model solutions even depict some light showers reaching parts of the Southland Saturday afternoon. While I wouldn’t rule out sprinkles in some locales, the model consensus (today) is for no showers till late Sunday evening (west of L.A. County at first). A period of widespread showers could occur Monday night into early Tuesday. Theat of showers should end by Tuesday afternoon.

My confidence in any given weather scenario remains low. There is general consensus for wet weather sometime early next week. Most model solutions favor storm totals under half an inch away from the mountains (some much less than that). However, numerical models infrequently mishandle the future course of “cut-off” low pressures several days in advance of the event. Another uncertainty is the predicted path for an “inside slider” type trough early next week. The “inside slider” could shunt the “cut-off” low pressure too far to the south upon closest approach to the Southland (results in little shower activity over southern California). If the “inside slider” passes by more to the west, it may direct moisture from the “cut-off” more squarely over the Southland (results in a decent soaker, provided storm dynamics get strong enough…still less rain than with latest storm, however). For this forecast, I kept the risk for showers on Monday at “chance” rather than “showers likely”. There is some chance that showers could be delayed to late Monday night or Tuesday.

Regardless of the outcome early next week, there should be dry weather for the middle of next week. There is a chance for slightly warmer than normal weather for a day. However, there is good model consensus for a Gulf of Alaska storm reaching the state over the subsequent weekend (2-3 March). This should be typical, breezy, cold storm accompanied by decent amounts of precipitation (good soaking low elevations). A number of model solutions maintain an “open storm gate” after this storm passage. At the least, cool weather would prevail. So, enjoy the warmth tomorrow and Saturday.

Next issued forecast/synopsis should be on Tuesday, 27 February.