Scattered showers coming to a mountain near you

I wanted to get your day going on the right foot, one filled with the thoughts of a few scattered Cumulus and Cumulonimbus clouds next week, with almost a certainty of hearing thunder in Catalinaland, along with brilliantly colored sunsets, and some shafts of rain.

How do I know this so confidently, and am feeling good about myself also having those thoughts whizzing around?

Model “convergence.”

Both the USA (!) and the Canadian model (a version of the European Center for Medium range Forecasting, “ECMWF”) are both showing rain around here, and the little baby low center that forms going along the same track, one to the south of us.

BTW, a quite illustrative cartoon discussion of models (USA vs European) after Dreamworks has been released recently.  You’ll want to bone up on models here, perhaps before reading on.  This cartoon was brought to my attention by Mark Albright, the former WA State Climatologist who wants to live in AZ but can’t make up his mind on a house, to give credit where credit is due.  This is so funny; brilliant!

The GFS (the US Global Forecast System) explained.  Rated “R” due to language near the end.

Contnuing on to what the models are saying, the chances of rain falling here are more better when the low center is a little to the south and moisture from the tropics can wrap around the low from the east side of it.  Here are two prediction maps for about the same time.  The first from IPS Meteostar for Wednesday May 9th, midday.

You can see a low center at 500 mb (18,000 feet or so in the atmosphere) is over the north portion of the Gulf of Baja California, Sea of Cortez.  The green represents moisture at that level streaming in from the east on that day.  Cool!  We will certainly get a boatload of Ac cas with this, something that Mr. Cloud-maven person likes to see and frequently, as a result, forecasts its occurrence wrongly because he is not being objective, but SUBjective, which as the name applies, is below “objective” and being “disinterested” in what you are talking about, to go on and on about it.  It happens in science.  Remember when…, oh, never mind.

OK, below this chart, from Enviro Can, is also one for Wednesday, May 9th at 5 AM AST-PDT.  The low center at 500 mb is shown by the little red dot in the upper left panel.  You can see that both models have now (after being “divergent”) have put the low center in the same spot.  The USA model had it farther north for several model runs, which were quite bad for rain here in Catalina.

 Yesterday’s clouds

Just a few Cirrus ice clouds floated over as the upper level winds start turning from the southwest at high levels.  These kinds of clouds should be seen over the next few days.