Next rain in 9-10 days?

The NCEP model, using last evening’s global data,  produced some green pixelation in Arizona (light rain areas are green in the model run output) for Monday night into Tuesday,  November 19th-20th.  However, look below at the NOAA ensemble of spaghetti plot for that day. I don’t see any rain here.  Do you?

Cloud-maven juniors would be so scoffing at the thought of rain in Arizona in a computer prediction that is associated with a spaghetti plot like this for that same day!  For confidence in rain that far ahead here in Catalinaland, we would need a plot that shows something like you see over Japan (upper left);  the lines all squeezed together.  But you don’t see them here, do you?  They’re a mess, indicating the model is generally clueless about what will happen here in 9-10 days.  So, while it could still happen, it has to be considered a very long shot.

Forecast map for Monday, 5 PM AST.

Here’s the WRF-GFS model output, rendered by IPS Meteostar that shows rain in AZ, a model run in that had this green pixelation (areas where rain is forecast to fall in the preceding 12 h) for overnight Monday into Tuesday morning, the 19th-20th.  Nice, but wrong.  The entire model run, is rendered here in case you think I am lying about this.

I’ve added an arrow to help locate Arizona for you.



 So, in view of the ensemble of spaghetti, can’t count on green pixelation remaining in Arizona in future model runs.  Not starting out as a good day today.

Yesterday’s clouds and skies overall, how nice.

First, the “stratiform” clouds that were still “sprinkling-its not drizzle” as daybreak came.  Then the blue skies dotted with Cu.

7:36 AM. Snow showers from Altostratus/Nimbostratus envelope the Cat Mountains.
11:43 AM. Coming at you from the southwest, these small Cumulus clouds. No ice.
11:44 AM. Nice cross sections of these small Cumulus (humilis) under deep blue skies.
4:49 PM. Late in the day those Cumulus grouped together off to our north into Stratocumulus patches with a little virga (horizon).

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.