April precip climo; yesterday’s cloud

Well, no surprises here.  The chance of rain continues to diminish overall in April, with an especially dry period in the current 35 year record in the middle of April.  It has not rained on the 9th and 19th in all those years!  Odd.

Since rain at this time of year has to be associated with cold troughs (like the Joe T of yesterday), these frequencies also tell you when a passing trough is more likely.   We had one go by yesterday evening, and its still nearby, fitting the pattern above of an enhanced chance of rain day or trough passage in the first few days of April.

BTW, most of these data are from the folks at Our Garden in Catalina, who happen to be very weathercentric, thank heavens.  You should really go there and buy everything they have as a “thank you.”  (hahahah, sort of.)

Today’s upper level configuration from the U of WA is shown below.  You can see that “Joe” is still around; in fact, he’s in the process of forming a closed center just over the horizon in New Mexico.   This will eventually be a great rain producer, as mentioned yesterday, for portions of the southern Plains States.  It would be great to be there during those downpours.  Anyone for a road trip to OK?  (hahahahah, sort of#2).

Yesterday’s cloud and its shadow

Here it is, in case you missed it.  Well, OK, there was more than ONE, but not too many more.   And, disappointingly, they faded before sunset!  What were those clouds?  Cumulus fractus, maybe as “large” a one that it could be termed a Cumulus humilis, but that was it.  No ice, of course, not cold enough, only about 32 F at top; just droplet clouds.

 The weather ahead?  Dry now

That mid-April chance of rain has disappeared on the models, now seeming to fit the 35-year climatology of it being VERY hard to get measurable rain here in mid-April.  Dang.  Nothing in sight now for the next two weeks in the latest model calcs.

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.