Pattern clouds, a few afternoon drops here, a lot over there, and a nice sunset

Pattern clouds: Cirrocumulus undulatus in odd, parallel lines.  I had not seen parallel lines like this before.  Fragments of Altocumulus are also present.

7:55 AM. Hope you saw this–I ran out of the house since these delicate patterns are usually gone in a couple of minutes.
12:21 PM. Ms. Mt. Lemmon starts to do her thing, send moist plumes of warmer air upward, with cloud remains trailing off to the NW. A southeast flow is present just above mountain top level, giving hope that later, a thunderstorm will drift off the Catalinas toward Catalina.
2:47 PM. Not a great base, but still, it holds promise of representing the bottom of a cloud that can produce measurable rain.
3:09 PM. During halftime I am able to go outside and notice that the Cumulus clouds are still trying to do something, but only light, barely visible showers have fallen toward Samaniego Ridge.
4:06 PM. After the game was over (which game? Dunno, they’re all great) I am able to go outside again and see that a giant cell has formed dropping an inch or more out there to the NW of Catalina. There are frequent cloud to ground strikes. But, there are no more Cumulus above the Catalinas! What happened? End of rain possibility story.

Though only a few drops hit the ground here in Catalina, the day ended with a pretty sunset. This marked the third day in a row where large Cumuluonimbus clouds cells at least an inch of rain in southern Arizona, but we got missed, something that also happened several times in early August.

Some of the moisture doing this is from old, former tropical storm, Elena, particularly the moist plume that resulted in yesterday’s pretty pattern clouds shown in the first photo.  Check the moist plume (whitish stream) from her here.

Looking ahead…..

While Elena was a bit of a disappointment as far as producing rain here in Catalina, her lower level moist plume too far to the west, a sibling storm is arising off Mexico, one that the models (hah!) as they did before, have calculated will cause a renewal of our summer rain season;  showers are foretold for several days beginning around the 3rd as that storm trudges up the west coast of Mexico toward Baja.  You can see the storm and the showers here in this rendering of the WRF-GFS model by IPS MeteoStar.  Remember those green areas on these maps are those in which rain is foretold to have fallen in the previous 6 h (later in the run, in the prior 12 h).  There is a LOT of green over SE Arizona after the showers begin to occur by the afternoon of the 3rd.

As is commonly heard these days from people concerned about drought, “think green”!




6:40 PM. A little hole in the clouds allows the late evening sunlight to penetrate into the aerosols we have over us, thereby producing an orange ray of sun.