“Come together, right now, over me” (that is, those divergent computer models, please!)

Every morning when I get up, I start thinking about those old lyrics, reprised in the title,  from the Beatles song about (USC) Trojan football, go to the internet, and hope that the Canadian model has changed course, and come together with our WRF-GFS model, which has had a lot of rain in AZ for several days now.

I haven’t looked yet, but thought as a game, I would blindly post the Enviro Can model run from last night and see what it looks like for 6 days out (144h), next Saturday afternoon when our model had so much AZ rain.

Answer?  Nope.

Still no rain in AZ foretold by the Canadians based on last night’s run.  What is the matter with them?  I’ll try not to be sharp with my Canadian relatives.

The arrow in the upper panel points to the remnants of hurricane Miriam. The panel below the one with the arrow is the areas of rain predicted and has NONE in AZ for the 12 h ending at 5 PM AST on Saturday, the 29th. Pretty Discouraging.

Now I will go look and see if the WRF-GFS model (from IPS MeteoStar again) still has rain predicted for us.  What if the models have “come together” and BOTH now show NO RAIN?  How awful would that be?  It would be exactly as awful as that Duck/Wildcat fubball game last Saturday evening;  that’s how bad it would be.

The last time I looked, the run from 5 AM yesterday morning’s data, it still had a lot of rain coming into AZ, AND, it rained all over AZ for several days as the tropical air hung around and was “motivated” into forming showers and thunderstorms by an upper low center stalled over us.  It could not have been a more joyful run!  But with the Canadian model diverging in its prediction so vastly, it really wasn’t time to pop open the bottle of fizzy grape juice.  OK, here’s my next surprise, holding breath.  Adding some dramatic waiting music here, like the kind you hear on TEEVEE quiz shows:

There it is! The WRF-GFS, valid for 5 PM AST on Saturday the 29th,  still has plenty of rain falling here, and that rain even begins in this model run 24 h earlier, on Thursday afternoon, the 28th. Not only that, the tropical air that gets here gets hung up in a stationary upper low that helps wring out more showers and thunderstorms in this area through October 1st.  How great is that?!

This dichomoty, this bifurcation concerning Miriam, now a hurricane,  in these models,  is troubling to be honest. You just can’t yet hang your hat on either model right now.  I can’t remember two more divergent sets of predictions this close to the “real event”, beginning this Thursday.

Why this huge discrepancy?

Once again it involves the weak winds aloft, those ones that steer poor Miriam, who doesn’t know which way to go, and we probably won’t know for sure that she’s coming until a day or two before, like a surprise visit from a Canadian relative who comes because its too cold where he lives.  So, and this is for me, too, don’t “fall in love” with this WRF-GFS forecast so fast.  It may yet break your heart.    Your favorite TEEVEE weather presenter should point this out, too.

Now some cloud babble

We’ve had several interesting days in a row, including today, from a science viewpoint.  The atmosphere has pretty much remained the same, and our cloud top and cloud base temperatures and in otherwise virtually identical clouds, have changed only slightly.

First we had tops at -10 C to 11 C, and there no indication of ice forming in them for sure.  That day was followed by almost exactly the same set of clouds, except that top temperatures were a just a few degrees colder, at -15 C (5 F) or so, and you could see that with that small decrease in temperature out came the snow virga, and even an isolated drop of rain to the ground here and there.

Yesterday was a perfect match for those prior two days because again, the clouds were virtually identical except that cloud top temperature was slightly warmer at -10 to -12 C (about 12 F), pretty much the same top temperature as two days before. maybe just a tad lower.  And the “results” were the same as two days ago.  Little or no ice formed in yesterday’s clouds, kind of what is expected here in AZ in “continental” Cumulus clouds (ones having higher droplet concentrations than ones over the ocean (maritime Cumulus clouds) and that have colder cloud bases.  Of late, our cloud base temperatures have been colder than -5 C (23 F).

Here is a sunset shot, since the SD card was not in my camera until evening and I don’t have a single afternoon cloud shot!

6:17 PM. This shows two levels of Cirrus clouds, the high bright ones, at probably 35,000 feet or more, the the lowered colored fallstreak one in the center, likely at 25,000 to 30,000 feet. It may have originated as an Altocumulus cloud, judging by those similar colored specs to the left of it.  Altocumulus clouds dot the horizon below the Cirrus.