Author: Art Rangno

So, I am just going to ignore them until the next model runs, and not say anything right now.  Feeling chastened (once again) after all the rain enthusiasm I had.

Clouds?  Look for a lot of Altostratus/Cirrostratus (ice clouds) way up there; might look dark at times, but too high to precip, namely the kind of clouds we saw yesterday afternoon around 5 PM LST (see below).   Might be some nice sunrise/sunset photo ops.

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PS:  After looking at this loop from the University of Washington for the western hemisphere, it looks like the As/Cs clouds will be eventually accompanied by some Altocumulus clouds (mostly comprised of droplets clouds) because they are lower and warmer than As/Cs.  And since they are ejecting from the tropics toward us, a good bet is for some “Ac cas”  (Altocumulus with turrets -“castellanus”).  I like Ac cas.   They will help ease the pain of these latest model runs….

First, lots of cirrus clouds overhead.  Get ready for a great sunrise photo.

AZ incoming storm update:  Yay! (overall impression)

Now that the US and Canadian models are “converging” a bit to a similar depiction of where the highs and lows and upper level features will be come this Saturday,  a good rain seems in the bag for at least SE AZ.  Both models were having quite a headache trying to figure out where this low off the West Coast now was going to end up, and still do, as shown below.  However, both have significant rain here in SE AZ, though when it happens Sunday or Monday, is still a conundrum.

But with that next rain, and there may be some strong winds again, our November rainfall should be substantially higher than normal.  Seems like another half inch will materialize over the weekend into Monday, as this system passes by.  That should bring us (here in Catalina Land) to around a 1.50 inches total.  Average over the past 33 years here (not in Tucson!) is just under an inch.  You can go here to see how Enviro Can (the Canadians) depict this storm situation, and here for the US version.

You will see that in the Canadian version, a trough from the Pac NW and our incoming storm off Cal now “mesh” into a single trough as both combine over the interior of the West Coast.   They do this in time for a major storm in AZ in that model with lots of wind.  In the US model, the Pac NW trough bypasses our incoming low, and so they don’t combine into a larger storm system;  rather the Cal system muddles across us a day later but still brings significant rain, though mostly to southern AZ and us.  No doubt, that in the next model run or so, these discrepancies between Enviro Can and the US model with be healed.  Still, it seems we are assured of a good rain no matter what happens at this point (he sez).  Yay#2.   Below a couple of snapshots from these runs, first the less-potent-AZ storm depicted in the US “GFS” run:

Note in the first panel that you have a trough over ID and one off San Diego.  If they combine, look out!  A much more potent storm results for us.   If they bypass one another, then things ain’t quite so good.  But see what happens?  In the US prediction, the low dawdles off Baja while the ID trough is, only a day later, over the the Corn Palace in Mitchell, SD!   Not so good for us, though that Baja low DOES dribble over us on Monday bringing some rain.

The next two panels are from the Environment Canada model run, a model based on the European Center for Medium Range Forecasting model.  Here’s what that model came up with for these same two times shown above for the US GFS one.

The difference between the US and Canadian runs are pretty subtle for Saturday morning (leftmost panels).  But look at the difference for Sunday morning; they’re gigantic!

The Canadians think that the Pac NW trough will inject itself southward into our Cal-Baja trough, meshing for a stronger storm over AZ as all that Pac moisture from the system off Baja is swept into Arizona.

The Canadian model is therefore the preferred solution to our storm dilemma.  In sum, though, rain appears in the bag for SE AZ, not so much confidence elsewhere in AZ unless these troughs combine rather than bypass one another.

Hope this is comprehensible (as usual).  Local advice:  clean out your rain gauges of dust and bugs.

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A second nice rain here in droughty Catalina!  Thought 25 hundredths would be great from that little rainband, but no, we milked that system, appropriate language for rural regions, for no less than 45 hundredths, both here on Wilds Road and in Sutherland Heights.   Very Seattle-like morning, too, with DARK low hanging clouds.  Now our November rainfall is almost at our Catalina average of 0.97 inches with 0.93 having fallen already!

And if you were watching closely, and I suspect you were, you might have seen a little “graupel” (tiny snowballs) fall out of some of the Cumulus congestus (second shot below)-Cumulonimbus clouds (third shot)  yesterday afternoon here.  Historical query:  wasn’t there a song decades ago by the farmer, Don Hoe,  about tiny snowballs?  Sounds familiar anyway.

Graupel,  and hail for that matter, often show up as strands, or fiber-like regions of precip falling out the bottom of clouds, and you could see those from time to time yesterday afternoon.   That last shot is a shot taken by someone while at the same time they were driving (good grief!) down Tangerine looking toward the Catalina Mountains.   If you look hard you can see “strandedness” in the shaft to the left of the short rainbow.  (The little rainbow terminates, of course, where the precip becomes ice and not rain.

Continuing about strands from cloud bases, that’s is definitely the base area of the cloud you want to be under to see things bouncing off the ground or your car or the biggest drops.  Saw some graupel (also called,  “soft hail”) yesterday myself at Golder Ranch Drive and Oracle.

Such a pretty day, too, with the mountains so white in the morning, capped by nice orographic clouds in the afternoon.  See some of this photogenic day below.

Canadian teaser

How exciting it was to wake up this morning and see that the Canadians had provided all of Arizona with a MAMMOTH, drought-denting storm in their overnight model run for November 12-14th.   Check out these model images below, valid for the mornings of November 12th and 13th, respectively.   (The entire original series can be found here.) 

In comparison for these two output times below, I reprise the Canadian model output based on the data but 12 h earlier than those just shown below them.  In yesterday morning’s model output, rain had not even gotten to San Diego by the morning of the 13th, and a pleasant, but really kind of decrepit (just a couple of isobars around it) low center is shown STILL offshore.  

But in last night’s run for November 12th, a giant low is centered in California, 994 millibars central pressure no less, with MANY isobars around it covered the whole western US practically!  The low is nowwhere near San Diego anymore, but rather over “Sacramenta”, CA!  

Those many isobars in the latest model run mean lots of wind, and with that wind,  huge amounts of cloud laden air are going to be smashed into the coasts of California and Baja California, and with that, lots of rain as that wind drives in against the mountains.  And you can see that happens in those colored regions, lower right panel of the 4-panel model output), that’s what happens on the 12th and 13th.  

This was SO EXCITING to see!  I wanted to call all my friends and let them know about this.

But alas, this very wet scenario is likely just a teaser since there was too much change from the prior model run.  In hoping it will actually happen you may just as well be hoping that your horse, last by 6 lengths in the far turn, will spurt to the front by the finish line.  Too, this drought denting scenario was not at all seen in the US models (seen here).   Rather, our NCEP model run  resembles the old Canadian model from yesterday morning, one that showed a relatively weakly precipitation system go over us.  Dang.  Still, they all do show more rain ahead, that’s the upside of this whole blog today.

So, some kind of  bad data likely got into the Canadian model.  Still, its not impossible that the Canadian model is on to something, and that’s where the final ray of hope lies, is that somehow later today, the Canadian model sees the same rain drenching result over AZ on the 12th and 13th, and also, the US models see it as well.  So, lots of anticipation today to see how things change.   A more reasonable guess, one that I would make,  is that the Canadian model is not completely goofy, and that the US models will strengthen the storm on the 12-13th when they ingest this morning’s data.

Will post likely disappointing new results (trying to be objective here)  later in day when progs come out based on data taken globally about right now (4:40 AM AZ time).

Just on the horizon.  You were probably worried when you got up at 2:30 AM and saw only a big moon and no clouds.  “Where’s the rain?”, you wondered.   “She’ll be coming around the mountains when she comes” , to quote the lyrics from that old western song about Clementine (the Tortolitas and those mountains SW of us, in this case) in just an hour or so (its 4:30 AM now), certainly before daylight it should be dark and showery.  Yay!  Might get a quarter of an inch or so, which would be great!   Check this radar-satellite imagery out from IPS Meteostar for approaching cloud and precip details.

Mods continue to show a couple of more rain events in the days ahead with some sunny, cool breaks, biggest one on the 13th.  Hope these materialize into monsters, because as many of you know (“many”, hahaha, exaggerating readership again;  actually it should be, “as both of you know”)  we are in a La Nina oceanographic regime.    A La Nina regime is usually thought of as a “storm deflector” for the SW.  However, its magical powers are most pronounced in the LATE winter and spring, so we got to get us all the rain and mountain snowpacks we can NOW to avoid a really droughty year!  However, even the “best” La Nina’s  don’t positively mean this; the correlation coefficient between droughts here and a La Nina is not 1.00, that is perfectly correlated.

As we know, in semi-arid climates, too, it only takes a few good storms to make a good year, and those can slip in during La Nina regimes anyway.  Fingers crossed for mammoth rain and snowstorms this month.

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Maybe….  (Keep in mind those models like to tease us that far out, but, plenty of reason to be excited some more again 🙂

But what a great, potent storm that was last night!  Producing O.48 inches here in Catalina at Golder Ranch road above the bridge, it was “all it could be” I’d say.  Another hundredth or two are possible at the very tail of this rainband as very light rain continues to fall.  Estimated wind gusts around here, in those less than one second “puffs” last night  that blasted up against the house and took the power out, 60 mph. The rain should end by 7 AM in Catalina, though.  The Catalina Mountains, though some reports are missing, seem to have gotten an inch or so.  Check here.

But hang on, the models have some very un-Arizona weather ahead.  Sorry snowbirds.  The National Center for Environmental Models (NCEP) continue to show some powerful storms for AZ and Catalina in the days ahead.  So what’s happening?

Persistence.   The jet stream its river-like steering of highs and lows like logs in the water likes to get stuck at times so that the same kinds of storms recur for a period of weeks in a region, something meteorologists have known for decades and we call that tendency “persistence.”   Droughty periods in winter occur  when the jet stream is away from us, or the flow in out of the NW or N even when its close.   Rainy spells here occur when the core of the jet at mid-levels circumscribes Arizona (that is, is located to the S of us),  and the flow is from the southwest, plus or minus some, as it was last night and now.

Last night’s model runs for about mid-way (mid-levels we might also say) in the “troposphere”, the domain where clouds occur, really shows this tendency since almost the EXACT same configuration of the jet stream over us this very minute is shown AGAIN EIGHT days from now, a configuration that would also be associated with a powerful storm then.    How great is that unless you are a snowbird?

These bends in the winds such as we have going by over us now are called “troughs”, air rises, producing clouds and precip occurs mostly on the east side of the bend, and clearing conditions on the west side.

Check these two “twin” maps out from IPS Meteostar:  The first is for right now, 5 AM this morning, and the second map is for 5 pM this November 13th!  And there are gobs of precip from other “troughs” that go by even before this, the next one as you know from the local forecasts, goes over us this Monday.  That trough, too,  also caught in the same overall pattern where the flow comes down the West Coast from the northwest, reaches the “bottom” over Arizona (that is, the jets most southerly latitude in a trough) and then heads off toward the northeast into the Plains States and Upper Midwest.

Weather with this pattern, one that is more typical of spring?

Colder and wetter than normal in the West, warmer than normal back in the East overall for the period that this “persistence” pattern holds up.

Well, lots of reasons for excitement here.  We should really be building snowpacks over the next two weeks or so, maybe put a little dent in our drought.

Hope this is partly intelligible.

The End.

You have to see this for yourself, from IPS Meteostar!  Its unbelievable.  The National Center for Environmental Prediction (NCEP) and its “zuperkomputors” have blessed us in their billions of calculations with not one, not two, but four-five days of rain in the next 15 days!  FOUR different storms (!) bring rain and snow to AZ !  I am so happy!  I am tired of dust here in Catalina land!   Two of these events, the storm late today into tomorrow, and the one on Monday, are pretty much “in the bag”, so at least two storms can give us something in the way of rain.

The following two, storms three and four,  are “out there”, November 12th (Saturday), and the last, WAY out there,  also on fubball day ,  Saturday, November 19th.  These last two, both depicted as major storms, are of course, dubious and lots of things get falsified in the model predictions that far in advance.  The highs and low pressure areas are almost never where they are predicted to be that far out.  ONLY if a bunch of ensemble runs shows the same thing can we weather anticipators have any confidence that far out.  Remember the big, bad storm of January 2010 in which Cat Land got almost three inches in 48 hours?  Well, that storm was predicted consistently in “ensemble” runs, where slight modifications of starting conditions usually produce lots of different outcomes one to two weeks in advance.  But with that huge storm, the ensembles were not so scattered all over in their predictions; they were all saying a giant low was to strike the California coast and go into Arizona.   So in THOSE cases,  the “signal”, the upwind pattern is so strong that the storm keeps appearing in nearly the same place in those “ensemble” runs even when there are “tweaks”.  Believe me, that usually doesn’t happen, but it gave us a lot of warning about that “Frankenstorm” as someone called it.  These ones for us, confidence not so great.

OK, back to the present:  STILL, to see storms even show up in the models, combined with these first two storms “bearing down” on us (didn’t an Arizona football coach say something about that?), makes you think that the climate pendulum may be finally swinging back into a wet, cold regime here in AZ after so many droughty months and winter seasons (except for the winter of 2009-10).

Of course, if you and that other person who reads this blog knows anything at all from it, it is that I get overly optimistic when rain is predicted, and now that excitement that I have has led to a a bit of hyperbole regarding the end of the Arizona drought.  I am SICK of drought and so I like to say it looks like its going to end;  to HECK with the La Nina down there in the eastern Pacific (specifically, “region 3.4” of the Pacific, as La Nina acolytes know about) and those droughty predictions for this rain season!  Here’s where “region 3.4” is in the Pacific, FYI.

Science note:  People like me is why we have double blind randomized trials in our experimentation to prevent people from seeing only what they want and biasing outcomes of experiments, if even inadvertently, and with really good intentions.  (You can do that with evaluations of people, too–hahahahaha, sort of).

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Cloud scenario today:

And with today’s strong storm rapidly approaching, and tremendous influx of mid and high moisture beforehand with near 100 mph jet stream as low as around 20,000 feet, we should see some great Altocumulus lenticularis clouds, and maybe some delicate Cirrocumulus clouds with finely granulated patterns before the cold front gets here today. In plain language, it should be a fantastic day to look up in the sky and see lots of interesting patterns.  They will change by the minute.  Some examples of what I hope to see today in the “pre-storm” stage, the first Ac len, the second Cc.  And, there’ll be wind here at the ground later today, gusts likely to momentarily hit 40 mph this afternoon on our Catalina hill tops.

Have a nice cloud day!  And talk to you tomorrow morning in the rain.

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