Examples of “good” and “bad” model runs at 144 hours from this morning

First, let us examine the National Center for Environmental Prediction (NCEP) model that came out based on this morning’s data from around the globe.  This first panel is for the winds around 500 mb (millibars, or “hectopascals”) and is at about 16,ooo to 20,ooo feet in the atmosphere, depending on how high or low the point at which a pressure of 500 is reached.  The winds blow along the lines, and the strength is noted by colors; red  and purple are real strong.  The colors tell you where the jet stream is, and storms are steered  by and develop/dissipate along it.

This panel below is for 144 hours from now or is valid Tuesday, October 4th in normal speak.  Note the area off southern California, where the winds are light, come on to the coast and then turn to the NE over Arizona.  Where the winds turn like that is called a “trough.”   The air tends to rise on east side of a trough, and descend on the west side.   This particular “trough” over southern California would be considered rather weak.  However, some tropical moisture is still around and some spotty showers are forecast for eastern Arizona (not shown) with this pattern.

This is not a particular “good” model output; perhaps it could be considered even quite “bad” since we need a lot of rain, and this trough, according to THIS model, is quite weak, and can’t do the job.

So, we start looking around to see if there is a “good” model run that for this same forecast hour, 144 h from now, on Tuesday morning, October 4th, which shows that there will be a LOT of rain.

Sure enough, Environment Canada has supplied what we are looking for based on the SAME data taken around the globe, but using a version of the European Center for Medium Range Forecasting model.  The next figure shows the “classic” four panel projection for that time from the Canadians.  Here, the jet stream part of the forecast is the upper left hand corner, and LOOK at the difference along the West Coast!  Instead of a jet stream ramming into Oregony and northern Califiornia as it does in the US model, its going into Juneau, AK!  And more importantly, that Canadian jet stream map shows a whole low pressure center along the California coast!  And with a low center there, and tropical air to the east of that low, it acts like a pully system to bring a gush of that tropical air across Arizona with substantial rain, as predicted as noted by the green areas in the panel in the lower right.  Not shown is the rain even more substantial rain that PRECEDES this map, also substantial for the 24 h prior to this map.  The heavier rain is due to the low center along the California coast being a stronger, better organizer of the storms in the tropical air over us.

Thus, the Environment Canada model output for 144 h,  would be called a “good” model prediction since we need rain and this model run “delivers.”

So, this is what forecasters deal with a lot of the time, though the differences shown here would be considered a little out of the ordinary as great as they are in this “model divergence.”

In real life the models are perturbed slightly at the beginning of the prediction period to assess how different the results could be, and a whole group of predictions is obtained from the SAME model having slightly different starting conditions.   The resulting outputs are called “ensembles”.   The more likely a situation will be observed in the future is in how LITTLE the ensembles vary.  Here, to be serious for a second, this :model divergence” for the situation in the SW means that neither model output can be relied upon heavily.

Darn.

The End.


Nice!

These, and lots more of them yesterday.  I think one of the lightning strikes associated with photo No. 2 down there was about 8 inches from the house!  Also, there one particularly dangerous stroke from a thin anvil cloud just after 12 Noon yesterday as the first thunder began to be heard from a Cumulonimbus cloud raining on Mt. Lemmon (where they received over an inch of rain).  However the strike was a near vertical cloud to ground strike many miles from the rain area, and out of a fairly innocuous anvil cloud.  See photo number 3 below.  The cloud-to-ground stroke came down about a mile away, perhaps in or near the Sutherland Heights development east of Lago del Oro road,  and behind the mesquite tree humped up in the center of the foreground area of this photo.  I just could not believe it and it does tell you to be cautious about lightning.  I might well have been outside up there in the Sutherland Heights area being a little too non-chalant about where lightning will hit next when looking up at that anvil cloud.

 

However, the 0.13 inches received was a little disappointing considering the behemoth of a storm that was approaching about 4 PM.  Actually, only about an hour earlier I had told a neighbor, after looking at the mostly glaciated skies, that it probably wasn’t going to rain here after all, so maybe I should be happy with a few “crumbs” of rain!

The End.

Likable model runs continue; one of the best overnight!

Tired of being dry?  Tired of having dry washes?  Tired of seeing dust raised on your gravel road?  Maybe too much dust on your late model car?  Maybe you’ve been thinking about wanting some more humidity and cloud cover with RAIN to make to make you lose that feeling of fatigue and boredom?  Well, then this model run’s  for you!

Yes, that’s right, Hilary will cure your blues and blue skies!   Yes, that’s right no more fatigue, lack of interest in life, and overall dullness due to too much sun and blue sky with last night’s model run!   See below, from IPS Meteostar:

Only 108 h (morning of October 1st),  top panel.  Hilary (small purple blob and low pressure) is cruising into central Baja, and some rain has already spread into AZ.

Second panel, valid in 144 h, valid for Sunday afternoon, October 2nd, a tiny purple blob can be seen over my house here in Catalina, SE Arizona. How great is this?  Lets hope nothing changes in these model runs for the next 144 hours!  (Technical Note:  that’s not possible, but to HELL with that anyway! )   This model output looks great now, and it’s what I want to believe will happen.  Maybe I just won’t look at the later model runs; HELL they go back and forth anyway on Hilary and where she will go.)

Lastly, there are some cloud shots below with a bit of science, mostly from yesterday.

Now even yesterday, some rain “appetizers” were around by evening.  I am sure you noticed.  Now its gonna take a coupla days for this to “develop” and this wetting will be due to the remains of Hurricane to tropical storm, Hilary, there down Mexico way right now.  According to the word on the model street, Hilary crashed across mid-Baja while turning toward the northeast and then goes over my house as a rain blob in 144 h 12 minutes (hahah), or in normal speak about six days from now (see below).  Still dicey that far out, but its what to believe in.

In the meantime, some of yesterday’s surprisingly (to me, anyway) active Cumulus clouds, beginning with a baby cloud over Charoleau Gap, NE of Catalina.  Since it was before 11 AM, this was a sign in the sky that we were going to have an active day of Cumulus clouds, ending with a nice sunset with a mixture of Stratocumulus, Cumulus, and shallow Cumulonimbus clouds, the latter responsible for the light rain off to the south and west of Catalina shown in the second two photos.

Technical information:   The first cloud photo was taken on Sunday, not yesterday, Monday as it is written above, but there COULD HAVE BEEN a cloud like that yesterday and so I used it anyway (haha, sort of).

Second with areas of rain dropping out of these higher based clouds (14,000 feet or so above sea level, 10-11 Kft above ground level) and with base temperatures of about -5 C (23 F), it was actually SNOW falling out of these clouds right at base, melting into rain below that.

Quiz:  How cold were cloud tops to produce virga/snow/rain this thick as you see in the second two photos?  Probably lower than -20 C (-4 F).  At say, -15 C (5 F) there almost certainly would not have been this much “stuff” coming out.  This assertion from your writer and self-proclaimd “expert” in ice formation in Cumulus clouds (“hey”, I got journal pubs!)

Its back! After going away on the model runs for a couple of days and I didn’t want to tell you about it thinking it could come back because the models can be kind of dicey on these things and it did


That vexious tropical storm is once again shown to move northward into Baja Cal and then its remnants move into the SW, combine with a winter-like upper air trough, and together produce some good AZ rains.  After a period of depression about this tropical depression going to the west and dying instead of into AZ as I had mentioned in two earlier “statements” here, I can be happy again.

Here are a couple of examples from last night’s NCEP model runs from IPS Meteor Star:  The areas of color are areas of rain.  It takes a couple of more days (last panel) for that tropical air to be bound up and wrung out by that winter-like cool trough (last panel).

In the meantime, we can be thrilled, I tell you, with interesting Altocumulus castellanus and floccus with virga here and there today and maybe tomorrow, too.  Those clouds make for great sunrise and sunset color.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

“Good” model runs continue, ones that bring substantial rain to AZ

I thought sure that late September-early October tropical storm entry into AZ and Catalina land would disappear; too good to be true.   But today,  after several more model runs, there it is, the remnant practically over where we live the afternoon of October 1st (2nd panel)!  (These are National Center for Environmental Prediction (NCEP) model runs repackaged by IPS Meteostar.

So, something to look forward to along with an occasional Cumulus humilis cloud until then it seems.  I hope you’re happy now.

The End

Good model

I like this model output from “12Z” this morning, and so I thought my other reader besides me would like it, too.

These are the latest gov’t models as repackaged by IPS Meteostar–they do a great job at presenting weather stuff.

These are for the afternoons of September 29th and 30th, respectively.  Note hurricane (low center) passing over Cabo San Lucas on the 29th.  Fantastic.   It is not the same low they had in the Mexican Pacific before of which I spoke.  Its an even better (stronger) one.  Not only that, in the days after I mentioned the possibility of AZ rain from a tropical storm, there were some “bad” model runs which either had no tropical storm, or showed a tropical storm moving off into the Pacific and not moving this way.   That made which those model runs quite bad, and not even worth mentioning.  But now I am happy again.

A note of explanation:  the areas of colors from green to blue to pink are where the model thinks it has rained during the past 12 h.  Blue and pink are where a lot more rain than in green areas is forecast to fall.  Note all the green in droughty AZ and NM!  This could be a really nice rain, one that might keep the remaining green weeds green for a little longer, IF the models verify.

Lastly, a picture of some greenish weeds around the State Trust Lands above Catalina land yesterday FYI.

The End


The Tucson storm passes by Catalina like so many other September storms

With continuous thunder and threatening skies for Catalina, the mammoth Tucson storm that dropped a record 2.83 inches for the wettest day ever in September at the International Airport passed by Catalina early yesterday afternoon.  Here’s what a fraction of it looked like (using a bad ISO setting, darn it).  Also at the TUS AP it has become the wettest September of record halfway through the month with over FIVE and a half inches!

Of course, we here in Catalina land have been missed by most of those heavy September rains and have had only a crummy 1.17 inches.  Still, better than nothin’.   And there have been some fabulous sights during these past days.  Below are a couple of shots from yesterday.  That easily visible roiling motion in that last shot, if you saw that Cumulus congestus-going-to-Cumulonimbus, was a real indicator of how unstable the air was, that is, how easily it could go upward yesterday.  This situation us due to the cooler air aloft we have right now, along with mid-80 temperatures at the ground.   This is the kind of roiling, churning action you see in those big boys in the Plains States, East, and South when severe weather lurks.

Mods think we have a chance for rain today, too.  Maybe it will be our time, we will win the rain lottery today.

Below, thanks to the U of AZ, we have a time lapse movie of part of the storm, anyway, to the right side of the image.

Dreamy weather ahead:

Of particular excitement in the longer range NCEP (“government”) models, although almost certainly wrong as they usually are that far in advance, is that a tropical storm advances toward Arizony in early October.  Mark your calendars.  Might as well.


 

 

 

 

 

 

 


Another summer thunderstorm day!

We’re on the cusp, of course, for the end of the summer rain season, and so every day like yesterday is a particular treasure.  Take a gander here at the bulging morning Cumulus congestus and Cumulonimbus (albeit, marginal ones) clouds early on over the Cat Mountains.  Note detached top of small Cb to left with virga.   Some science:  note, too, that it appears to be a droplet cloud with snow virga underneath.   The presence of a droplet cloud tells you that the cloud top did not get excessively cold, probably no lower than about -20 C.   Those big boys of the afternoon and their all ice, spreading anvils would have tops colder than at least -30 C.

Did you notice, too, how much lower the cloud bases were yesterday than the prior day?  (Com’on!  You’re supposed to notice things like that as a nascent cloud assessor!)  So, all in all, I was very happy yesterday.  Note in the second photo, this tiny start up Cumulus cloud seems to be making an unseemly gesture to the clear sky above, as though it will alone fill in that overly blue sky.  Well, it was joined by its big brothers later in the day to produce some nice showers, 0nly 0.05 inches here in Catalina “Heights”, but 0.16 inches just a mile N in the Sutherland “Heights” district.  Here’s what it looked like later on yesterday afternoon from Sutherland Heights:

Lastly, another one of our glorious sunsets to top off another exciting weather day.

Scattered rain in AZ forecast next ten days!

Last night’s model runs continue to indicate a showery spell of no less than 10 days duration in the State of AZ.  IPS Meteostar, a private weather provider,  has repackaged the National Center for Environmental Prediction numerical model predictions here.  No one cannot be excited by this prospect in view of our droughty August.  What’s REALLY interesting, though likely in some error, is that a tropical storm moves up the Baja Coast , dies, but its remnant moves into AZ in 10 days (see model forecast below valid for September 14th).   As a forecaster type of person, as well as a cloud-maven kind of person, this would be like Christmas in September to have something like this happen where maybe an inch or two of rain spreads over parts of the State.  This is because we are supposed to be getting drier and drier as the summer rain season withers in September, and so this would be an anomaly.  I’ve always liked weather anomalies, and this might be a real good one.  However, as mentioned in prior writeups, these kinds of things come and go in the models, and so its best to think of it as like in a dream right now, but a pleasant one.

Some cloud shots below from yesterday.  It was SO NICE to see that first little Cumulus cloud pop up over the Catalina Mountains in the early afternoon!  While the depth of the Cumulonimbus clouds locally was limited by dry air and an inversion (temperature reversal aloft) and they could not produce strong rainshafts as a result, still in was nice to see ANYTHING dropping out of those clouds!  Here we were lucky enough to register 0.o2 inches, enough to cut the dust some on our gravelly neighborhood roads.