Drencher! 0.75 inches total in Catalina as of 5 AM AST

More should fall before the end of this episode today, perhaps another 0.25 inches, rain that will push the total to almost an inch as another band approaches us (at 5 AM)!  What a great, needed rain, though some forecast details were off the mark.  The front and its rainband went by between 2-3 AM, dropping 0.32 inches here.  Was thinking it would be more; half inch.  The U of A Beowulf Cluster model output had the timing of that perfect, however.   The larger surprise was the 0.42 inches in the prior “pre-frontal” rainband that developed over us and to the south last evening and rained until about midnight, much more than was anticipated by the model or me.

In any event, it was fabulous to hear the rain falling on the roof.

Yesterday’s clouds

What was interesting were all the little things that went on, for example, the puff of dust when the wind picked up in mid-day (shown below). We haven’t had much wind over several weeks, and I suspect that there were a lot of very fine particles ready to blow around at the first significant wind over the deserts to the south and southwest of us, and that wind not having to be exceptional to get them in the air.   That dust puff came in about the time the first lower clouds did, then quickly moved off even as the wind increased.

First, dessert:

5:10 PM. Sunset before the storm. Wasn’t really looking that good around this time as the Cumulus and Stratocumulus clouds flattened late in the afternoon, and the virga coming out of them diminished.  It looked for a moment like I was in a crepsucular ray; felt kind of special, maybe just me being highlighted by the sun.
4:46 PM. Rainbow.  What is interesting here is that by this time the ice and virga around had decreased from mid-afternoon as the clouds flattened, but while the tops warmed to around -10 to -12 C (this from the TUS sounding) they were still able to produce a little ice/snow which melted into rain on the way down and produced this rainbow.  These cloud top temperatures are marginal for ice formation in AZ, if you care.


4:58 PM. Explanatory razzle-dazzle in photo.
12:15 PM. Dust invades Oro Valley along with the development of small Cumulus (fractus and humilis).
















3:30 PM. Heavy ice cloud emits from a modest Cumulus (mediocris). Since the top ejected in dryer air aloft, and with no cloud base below this ice plume, no rain can reach the ground. It just evaporates while settling out.  Tops here almost certainly colder than -15 C.










More rains just ahead

Yep, models coming around pretty well on the rain issue.  From Canada, two more rain spells are ahead, Saturday, and then on the following Wednesday the 19th.  The first one is marginal, range of rain from a trace to maybe 0.25 inches, tops.  The second rain is looking much more substantial, though not as much as last night, probably of the order of a third of an inch or so.  You can loop this venerable model here; haven’t looked at anything else yet.  Those two periods of rain in this model have increased in amount over time, which is a good trend.

In the longer term….

Its becoming more clear with every day that we have indeed entered a new weather regime, ending the droughty weeks of yore.  This is supported in the model runs based on last night’s data beyond the next week (beyond the time frame of the Canadian model output linked above)  as strong storms are indicated to crash into California and then march through Arizona with substantial rains.  Supported, too, in our model output “tester”, the “ensembles of spaghetti” which point to troughs and jet streams affecting us over the next 15 days.  And, if it is a regime change, they usually last longer than just the 15 days of model runs.

But how much affect will a wet spell NOW have on our spring wildflower bloom?  Will find out; forgot to do that yesterday…

The End.