Sprinkly clouds passed over during night; check dusty cars for drop craters and evidence of a trace of rain

Honestly, I gave up on the chance of rain overnight into this morning at sunset yesterday due to the absolutely clear skies.   And, like you, woke up to not one cloud within a 100 miles!  How could this be, given the synoptic situation?  Started slicing apples for some humble pie, but then, when looking at a radar and cloud loop (this one from IPS MeteoStar) saw that lower clouds had magically erupted to our west before midnight,  and by the time they got here in the early morning hours, had little showers coming out of them!

I did not park my own dusty car out from the carport, either. I thought I would at LEAST see a pile of clouds on Ms. Lemmon, too, this morning!  Sure wrong there.  Here are a couple of images from what has to be considered a tiny weather miracle:

201704290745_SWR 201704290830_SWR

Chances of rain increasing (imagine!), for  just over a week from now as actual model outputs begin reflecting what spaghetti (the many outputs) was indicating, i.e., a big upper trough in the West-Great Basin area.  At the time that spaghetti was indicating that, the actual model outputs were not, indicating that they were outliers.

Check this out from last night.  Since this model output is more in agreement with that crazy spaghetti plot, it inherently has more credibility, and is likely not an outlier model run.   That what the NOAA spaghetti factory is used for, getting a handle on those runs that might be wild, and those that are more likely to verify.

Its valid on the morning of May 8th and shows a trough coming out of the Pacific ahead of the one from the Pac NW, shown at this time over northern Cal.  The hope here would be that the one from the SW would have a generous amount of sub-tropical clouds with rain in them.


6:04 AM, 28 April. About the only lenticular seen. Oh, well, there were a few weak ones off to the north, but that was it. CIrrostratus is the higher cloud, too thin to be Altostratus.

Cloud shots will be posted later this morning of the next day….. (i didn’t get to is as I had planned)

12:52 PM, April 28. There can hardly be a better shot of Stratocumulus. While it looks dark, it was partly because of the Cirrostratus or Altostratus overcast; it was that thick, not thick enough to reach temperatures where ice would form in it, and rain would come out.  And no rain did, and soon this whole overcast was gone, as was the higher Cirrostratus that shadowed it.
4:09 PM. No ice came out of these clouds, but they did allow those beautiful sunny highlights on our Catalina Mountains.
4:09 PM. No ice came out of these clouds, but they did allow those beautiful sunny highlights on our Catalina Mountains.
4:40 PM. Its remarkable how after weeks and weeks of no rain that so much of our mountains and desert vegetation remains as green as it is.

Yesterday afternoon, the 29th.  Here’s what shallow, icy clouds look like, reflecting the unusually cold air above us.

4:44 PM, April 29th.
4:44 PM, April 29th.
5:43 AM this morning. In an unusually timely post, here’s a leftover ice puff from yesterday over there beyond Charouleau Gap. You’d be guessing, if you cared, that the tops of both of these icy clouds was colder than about -20° C (4°F) since there seems to be so much ice.


The End

PS:  Chance of rain still holding for the 8th.  See below for new depiction of big “cutoff” vortex over AZ from last evening’s model run:

Valid at 5 PM, May 8th.
Valid at 5 PM, May 8th.

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.