Rain, inches of it, still foretold for Catalina Mountains; and, an inch or more for Catalina itself!

In case you don’t believe me, here’s the model crunch from our very own Banner University of Arizona Weather Department (aka, Hydromet and Atmos Sci Dept).  You can watch the storm play out hour by hour here.

The large totals of rainfall expected by mid-day this Monday, November 21st. This output based on the global data from 5 PM AST last evening.
The large totals of rainfall expected by mid-day this Monday, November 21st. This output based on the global data from 5 PM AST last evening.  As you can see, I hope, Ms. Lemmon is supposed to get over 3 inches!  Wow.  How great would that be? I put some writing on this image to help you understand where you are.

However, as you can see, to throw cold water on such a great prediction, we are in the HEART of a rather narrow band of heavy precip, which raises the uncertaintly level a lot on just how much rain will actually fall.    Somewhere, these days, there is a Gaussian like distribution of the rainfall at point locations so you can see just what the model spread is in the rain predictions, but I haven’t located it and am too lazy to look right now.  If I come up with that, will post it.

So, just as good as that, I will say that measurable rain will fall in Catalina between Sunday evening and mid-day Monday that the least likely amount is 0.15 inches (10% chance of less), which would be a real poop, and the most, 1.00 inches (10% chance of more, a luxuriant rain, washing so much dust off stuff).

The average of those extremes is usually is closer to the actual total, which in this case would be 0.625 (correction! 0.575!  Egad, dividing by 2 is still pretty hard for me) inches at my house.  The idea here is that we meteorologists often know what’s NOT going to happen better than what is,  in the domain of precip forecasts,  and so by starting with extrema, to be erudite there for a second, we can narrow our predictions down, not get too carried away as often happens here.

BTW, if you want really great, professional level forecasting besides that by the TUS NWS , see Bob’s discussions!  He’s always got great stuff.

The first high clouds ought to be arriving later this afternoon.  Have cameras ready.  Should be a nice sunset to go with them since there shouldn’t be a total overcast to the west.

Really looking forward to this rain!

The End