UCLA Weather

from the Department of Atmospheric and Oceanic Sciences.

Sunday - 9:45pm

f

69°

High - 83°

Low - 67°

Today:

Five Day Forecast

Latest Average Hourly Temperatures

NOTE: SPURIOUS TEMPERATURE/HUMIDITY SENSOR READINGS BECAME CHRONIC BY THE MEMORIAL DAY WEEKEND. THE SENSORS WERE CLEANED AND WIRING ADJUSTED, WHICH APPEARED TO CORRECT THE PROBLEM. HOWEVER, FURTHER SPURIOUS READINGS ARE PROBABLE TO RETURN IN THE COMING WEEKS, BASED ON PAST ADJUSTMENTS.

High pressure aloft was centered over Colorado this morning. Like a top, the center has wobbled somewhere around the Four Corner states for weeks (common for mid-summer). Today's computer model runs show it sticking around Colorado for a couple days. After that, it may wander closer to Nevada.

Despite its center remaining well east of our region, it's western half circulation has imported "monsoon" moisture into southern California at times. A minor uptick in moisture occurred overnight. A minor decrease is expected tomorrow (i.e. less threat for afternoon thunderstorms southern mountains and eastern desert). Some model forecasts show yet another increase in moisture by Friday. There isn't the greatest of model agreement on when relevant, "monsoon" moisture surges will enter southern California, but it's safe to say that no complete drying out will occur anytime soon. Expect periodic episodes of mountain/desert showers and thunderstorms for the foreseeable future (up to two weeks). West of the mountains, there may be some periods with more mid/high clouds than other times. If an unexpected disturbance ripples to the coast from the interior (something numerical models are poor with beyond a half day period), sprinkles/light showers may fall in some areas west of the mountains at times (won't venture to guess when/if that may happen within the next week).

With relatively warm ocean temperatures and occasional "monsoon" surges occurring, the marine layer has been mostly diluted and shallow (i.e. insufficient water vapor for a widespread blanket of low clouds). Areal, inland coverage of low clouds typically is less than earlier in the summer (due to aforementioned reasons), but even the coastal waters have been unusually clear of low clouds lately. Based on the model consensus, marine layer clouds aren't expected to make any relevant comeback for some time (at least, south of Point Conception).

Without a defined marine layer, most beaches have been slightly warmer than normal (warmer than normal ocean helps). Warmer than normal conditions also prevail for the rest of the coastal plain and many coastal valleys. However, while the center of high pressure stays well to the east, interior temperatures have been seasonable or even slightly cooler than normal (i.e. "monsoon" weather related). For this issuance, I've indicated a "flat lined", temperature forecast. In reality, some days may be a little higher while other days may be a little lower. Subtle differences in the wind flow pattern are varying the vertical air mixing from one day to the next. Today is a little warmer than I predicted, but tomorrow could end up more like my forecast shows (maybe). In any case, I didn't want to nitpick with numbers that may end up leaning in the wrong direction (predicting warming one day when it actually cools off). If today's model consensus is right, there may be a small trend toward cooler weather next week, but it should be minor in magnitude.

Next issued forecast/synopsis should be on Wednesday, 17 August. I am switching to once a week issued forecasts. There may be some weather events that warrant a couple of forecasts in a week, but that'll be announced in advance.

UCLA Forecasts and analyses are written by James Murakami

– posted: 2022-08-09

Data and technology is provided by UCLA's Department of Atmospheric and Oceanic Sciences

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