Weather Synopsis – February 15, 2024

James Murakami

UCLA 5 Day Forecast

Thu15th62/50Mostly sunny afternoon with variable high clouds. Becoming partly cloudy in the evening.
Fri16th68/52Mostly sunny day with some high clouds. Some high clouds in the evening.
Sat17th66/53Partly cloudy day. Mostly cloudy evening with a slight chance of sprinkles late evening.
Sun18th64/54Mostly cloudy through the evening. Chance of light showers by evening.
Mon19th60/55Rain likely and possibly breezy at times. Rain, possibly heavy at times late day/evening.


A weakened storm brought modest precipitation to northern California overnight. Rain got as far south as western Santa Barbara County along the coast (Southland storm totals mostly under a tenth inch). For the rest of southern California, tranquil weather continued.

High pressure aloft will build across the Southland later today through tomorrow. A marginal, surface off-shore flow is predicted, which should promote some warming over today’s readings (some areas away from the coast may get slightly warmer than normal). No widespread, significant wind in Santa Ana wind prone areas is expected (relevant wind mostly higher elevations and only for a short time). How much warming will depend on how much high clouds from a distant storm passes through the high pressure aloft (referred to as a “dirty ridge”). The off-shore flow should fade away on Saturday, and an increase in high clouds appears likely, but daytime temperatures shouldn’t drop off much from Friday’s readings.

For several days, the numerical models had been predicting a return of widespread, wet weather in southern California by the President’s Day weekend. More recent model runs have backed off on that scenario somewhat. Wet weather is expected on Saturday for areas north of Point Conception (rainfall mostly under a half inch). There is a chance that light showers could reach L.A. County Saturday evening or the early hours of Sunday, but no widespread, measurable rainfall is currently anticipated through much of Sunday(based on model consensus).

A large storm is forecast to get close enough for widespread, wet weather in L.A. County by Monday morning, but model consensus remains poor on when any episodes of heavy rainfall will occur. It may occur as early as the morning hours, but it could hold off till Tuesday (areas west of L.A County stand a better chance of occasional, heavy rainfall by Monday morning). An atmospheric river tap is forecast by all the models, but the forecasts differ on when good storm dynamics will move over L.A. County when the atmospheric river is overhead. One thing looks likely. The predicted storm dynamics at its height shouldn’t reach the levels of last week’s deluging storm (UCLA received a whopping 10.40 inches on the 5th). This one should be a good soaking storm, but more in line with most other, strong storms of the past.

Tuesday should be a mainly wet day like Monday. The storm should finally exit the region Wednesday morning (most showers gone in lowland, L.A. County by sunrise). Storm totals by that point should add up in the 1.5 – 3.5 inch range for lowland areas away from the mountains (twice as much possible for some south facing, coastal mountains/foothills…maybe more in Santa Barbara County). The cold core of the storm may remain north of the Southland. So, snow levels may not drop much below 7000 feet for most of the wet period. Only a few inches of “wet” snow may fall down to 6000 feet, but potentially, several feet could fall in some locales above 7000 feet.

Dry weather should prevail for the latter half of next week (temperatures returning to seasonable levels). A number of model solutions show a “cut-off” low pressure approaching the Southland sometime over the subsequent weekend (24th-25th). However, there is no clear consensus on whether widespread, wet weather will accompany this low pressure (leaning toward a minor rain event at this point).

The next issued forecast/synopsis should be on Tuesday, 20 February.