Clouds And Storms On An Atypical SoCal Day


I’m doing a little radar watching this afternoon. The weather is decidedly not SoCal-ish! It is hot. It is {sigh} sticky. Nearby John Wayne Airport hit 97&#176 with a dew point of 66&#176–and that’s with a seabreeze!

That’s the kind of heat and humidity we left Connecticut to escape!

This is a good day for me to brush up on my forecasting skills. Weather everywhere is created by the same forces through the same laws of physics. However, most places have special circumstances which make certain types of weather more or less likely.

That’s climatology and it’s helpful to consider while forecasting.

I saw this singular towering cumulus cloud (above) as we drove toward the house this afternoon. It’s on the far side of a mountain range. The mountains, some nearly 6,000 feet tall, are 10-15 miles from here. That big cloud is another 15 miles out.

Radar shows it’s a prodigious rainfall producer. There’s a Severe Thunderstorm Warning plus a Flash Flood Warning for the desert communities it will pass over. Moreno Valley has nearly 200,000 people. It’s not all barren out there.

Because the storms are hardly moving, all the rain will be concentrated in a small area. Flash flooding is a major concern in the desert where rainfall doesn’t seep into the ground as easily as it does in other places and where steep canyon walls funnels water into a few low lying spots.


Most likely there will be no storms where I live. There are mountains between me and the thunder. It’s unlikely (not impossible) any will fire up on the coastal side.

During the winter these mountains will create a rain shadow to the east. Showers here will often fall apart before they get to the desert.

I’ll also be able to look from our bedroom window and see snow on the highest nearby peaks a few times each winter, even when it’s shirtsleeve weather here!

I’ve got to get used to these microclimates if I’m going to stay current as a forecasters.

Yes, the weather here is usually gentler than back east, but there are a huge number of microclimate zones that allow very different weather over a very short space. Knowing them will take practice.

2 thoughts on “Clouds And Storms On An Atypical SoCal Day”

  1. Here the temperature can vary as much as 15 degrees from one side of town to another. It can be 65 here and 70 on the Embarcadero just 2.5 miles due east. But out at the beach, just 4.5 miles due west it might be 55. Or if the marine layer is shallow and not making it over the hills it could be 60 and breezy at my friends’ in Cole Valley (a little less than a mile walk from here, but with 600′ in elevation gain at the crest), and 68 here with little breeze. You need to bring clothing options even for a trip cross town.
    I go to Weather Underground (which you turned me on to) a lot because i can look at weather stations all over town, and because the hills are steep and ride quickly to almost 1000′ in places, even rainfall will vary wildly from place to place in town.

  2. Geoff,
    We had flash floods in two areas on Thursday–Torrington streets got torn up so bad that some folks could not get out of or into their homes on several streets. Same thing downtown Middletown and parts of Portland.
    As far as your heat and humidity, they have been predicting this (out here) for you folks for a few days now. Also, because you all are so dry—the forest fire up in Yosemite continues to be moving rapidly, although they are about 30% contained now. Sure did mess up a lot of folks vacations out there!
    So, are you getting bored, or is Helene ready for you to get out of her hair!?

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