Time permitting, a new synopsis should follow by 3 PM.
Previous synopsis from Friday:
Some rain showers started last night in portions of southern California(8-10 PM period in the campus area), which I didn't expect(sorry for those who got caught unprepared). A few of those showers produced brief, heavy intensity rain. Snow also fell in the San Bernardino mountains(started in the late afternoon and just kept going). This may have been caused by an undetected disturbance, but it wasn't clear from available data.
The second in a series of three storms barreled through L.A. County this morning(partial clearing now, as of this writing). Occasional intense rain fell at UCLA from early this morning till shortly after noon. The episode around noon was the most intense(in terms of rainfall rates...nearly an inch an hour for a ten minute period). It was windy too(peak gust 31 mph) The storm total at UCLA stood at 1.88 inches(includes last night's showers). In general, the storm occurred as predicted(isolated thunderstorms though not in the campus area...one possible, severe thunderstorm came ashore around Huntington Beach area just before 1 PM). The barometric pressure also fell to 1000 millibars(29.53 inches) or lower in L.A. County, a very rare feat in southern California.
Although the main storm front has passed L.A. County, numerous showers should continue well into the evening hours(most showers should be light in intensity though). Shower activity should diminish by late tonight and by tomorrow morning, even activity in the mountains should be winding down(already well over a foot of snow reported at resort level for this storm). For the most part, tomorrow should be no worse than partly cloudy.
The third and possibly final storm of the series will bring a soggy Sunday to southern California. There is some chance of hors d'oeuvre showers starting late tomorrow night, but the main course should occur during the daytime hours on Sunday. Steady rain from this storm, however, might continue well into the afternoon hours in L.A. County. Showery weather is expected Sunday night into Monday morning. Shower activity should become more confined to the mountain areas by the afternoon hours(Monday).
Like today's storm, good storm dynamics are predicted(favoring wind and heavy precipitation). Chances for isolated thunderstorms look less than with today's storm, but some intense showers should be embedded within the main frontal storm. This storm should produce a longer period of precipitation than the current one, and it's predicted to have a higher water vapor content. So, believe it or not, storm totals for the Sunday-Monday period may exceed storm totals from the current storm(haven't seen latest readings but suspect widespread totals 1.25 -2.25 inches). UCLA has a chance to make the top ten in terms of wettest Januarys for the campus(currently ranked 19th wettest).
A secondary storm is predicted to pass through the Southland on Tuesday. Most model solutions show cold air instability showers for the mountains(snow level may fall to 3000 feet in the morning). There could be showers over the coastal waters, but most of those should head for southern Orange/San Diego Counties. So, I show only a slight risk of showers for the morning hours(should be sunny in the afternoon in the L.A. County, coastal plain).
Dry weather should prevail for the remainder of the month. Off-shore flow is predicted for most of that period, but in the beginning, high pressure aloft isn't forecast to be well developed. Warmer than normal may not come till the end of the next week or even later. At this point, warmest readings probably won't exceed the mid-70s. There is fair model consensus for a storm to reach the Southland sometime after the second of February, but the predicted storm would be minor with no tap into an atmospheric river(a ho-hum storm oompared with the recent series of storms)., It also may not form a series of storms passing through the state.
UCLA Forecasts and analyses are written by James Murakami
– posted: 2017-01-23