Weather Synopsis – November 16, 2023

James Murakami

NOTE: Weather Conditions at sites below–

Current UCLA Data at a Glance

Current UCLA Data Summary UCLA Five Day Forecast 16 Nov (Thu) 72/57 Partly cloudy through the evening with a slight chance of a few light showers. 17 Nov (Fri) 71/58 Partly to mostly cloudy day with a slight chance of afternoon showers. Mostly cloudy evening with rain becoming likely by late evening. 18 Nov (Sat) 67/56 Cloudy day with rain likely. Decreasing clouds in the evening with a decreasing chance of rain 19 Nov (Sun) 69/53 Some clouds in the morning but mostly sunny day; Possibly breezy at times, mainly in the morning. Clear evening 20 Nov (Mon) 74/54 Sunny day. Mostly clear evening.

Sorry everyone who have missed my forecasts and synopses. The level of care my elderly father needs increased substantially recently. Based on responses in the previous weeks, I’ve decided there is enough interest to continue my forecasts and synopses. However, the issuance frequency will be intermittent, depending on how occupied I get (no two days have been the same lately). You’ll just have to tune in non-holiday weekdays to see if a forecast was issued (potentially late afternoon). I may need to embed the five day forecast within the synopsis so that it doesn’t “disappear” the following day (reminder that the department doesn’t plan on fixing the current weather page…not enough available, human resources to overhaul the site).

Time Permitting, a new synopsis may follow later today.

Synopsis from last week: I didn’t have a whole lot of time to peruse the maps, but here goes…

The passage of a typical, “inside slider” type, upper level trough promoted gusty, Santa Ana winds in places (the usual suspects). At UCLA, it hasn’t been all that breezy (peak gusts 20 mph daytime hours today…26 mph peak gusts late last night though). However, some higher elevation locales reported gusts exceeding 50 mph (mostly under 40 mph in wind prone areas lower elevations). Winds tonight may reach similar levels to last night, but winds should lessen more quickly by mid-morning tomorrow (compared with today). Another, weaker, “inside slider” may produce another increase in winds late Friday into early Saturday, but peak gusts in most locales should be less than today’s peaks.

Warmer than normal weather should continue through the weekend thanks to the off-shore flow. The approach of the aforementioned, weak trough should produce some cooling on Friday, but temperatures in most areas should be slightly above normal levels (immediate coast possibly may cool to normal for a day). The rest of the Veteran’s Day weekend should be distinctly warmer (widespread 80 degree weather…flirting with 90 degrees in a few spots).

Cooler weather should develop by Monday of next week. The off-shore flow should be a decay phase, and variable high clouds from an approaching trough are expected. The longer range, computer models haven’t been in great agreement on details of the wind flow pattern next week. However, most solutions are favoring significant, wet weather at some point in the state. Some solutions show showers affecting the northwest area of southern California by Tuesday night (i.e. San Luis Obispo/western Santa Barbara Counties). Other model solutions don’t show a relevant chance of rain reaching L.A. County till late Wednesday. Potentially, it could get rather soggy over much of the Southland late Thursday into early Friday next week. Dry weather should return sometime over the subsequent weekend.

Let me caution that the above scenario is the latest model consensus. Some models show a “cut-off” low pressure that will develop next week, which could portend much, model uncertainties in timing and strength of predicted, wet weather (throughout the state). I’m relatively confident we’ll see the first good soaking storm of the autumn in southern California (potential for first good snow dump all higher mountains in the state). At some point, the trough should tap into rich, water vapor laden air in the tropics (atmospheric river connection). How wet the storm actually gets remains to be seen, but an initial estimate of 1.5 – 2.5 inches of rain the lowlands away from the mountains would be plausible. Snowfall at higher elevations (above 7000 feet) could reach 2 feet (dependent on how much tropical air gets thrust in the Southland).

Next issued synopsis….???