Old “Joe Trough”; cool temperatures move into Catalina later today

Mr. Cloud Maven person tried to trick you by titling his “piece” (“piece”, hah!) using a popular but not quite proper weatherspeak phrase, “cool temperatures”; something he ranted about a few days ago.   Properly, and we try to be quite proper here, but probably aren’t, its cool “air” that’s moving toward Catalina.

As a demonstration of this assertion about cooler air moving thisaway, here, from our friends at Intellicast  Inc., ones who hate Accuweather I’ve heard, is today’s 24 h temperature change chart (like to throw in some gossip from time to time, helps build ratings):

That blob of blue is associated with the encroachment of a cold front, where cooler air is replacing warmer air. Its the cold front that came ashore with Joe Trough (that trough that was so well predicted in its path across the Pacific Ocean for more than a week in advance) and his big low pressure center that brought hurricane force winds to some portions of the Oregon coast yesterday.

Unfortunately, both the warm side of the cold front (east of the cold front’s windshift line) and the incoming Pacifc air are both too dry for precip here.   However, there should be a few small Cumulus later in the day as that cooler and more moist air arrives here in Catland.  Also with a bit of moisture at mid and high levels, we could also see an Ac or Cc lenticular–keep an eye toward the NE and downstream from Mt. Sara L.   Expecting a nice gold-lined small Cu sunset.

"Joe Trough", the one we've been following, goes from Vancouver Island to San Diego here.
Joe Low, or just J-Lo, is trying to reform around Tonopah, but the main center is way over there in eastern Montana.

Where Joe T is this morning, brought to you by the U. of WA, is shown in the next panel, and the third one shows that Joe’s Low, or “J-Lo” for short, is all the way into eastern Montana!  However, a second low is attempting to form around Tonopah, of course.

As Joe Trough ages, moving SLOWLY across the Southwest today (passes over Catalina at 8 PM AST), it will cast off by the main jet stream and will eventually become an isolated, enfeeble-ized meandering cut off low with a weak circulation over Texas, finally ending up, like so many old things, in Florida six days from now.

Not a great way to go, but with more moisture rising up from the Gulf of Mexico, this moisture being something of an age enhancer for “Joe”, huge amounts of precip will fall in the southern Plains food basket of the US.  You don’t need so much strength as a weather system to generate huge clouds when you have Gulf air to play with.   Think of our summers.  No lows required, just that high dewpoint air and a blazing early sun for a good downpour here and there.

Note the new header today, along with an AZ Cat color scheme implemented by my web page person, Jenny Rink.  She’s great!  Go Wildcats!  Huskies, too, though.

Speaking of summer and humid air….

Longer range models have something akin to a summer rain regime breaking out on April 10th, blazing hot with lots of tropical clouds streaming up from Mexico.   Rains in SE AZ for three days, ended by a sharp trough and cold front on the 13th.  Something to keep an eye on, dream about.

Will have some April precip climo tomorrow.

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.