Category Archives: Catalina climate data

Cirrus altocumulus castellano-floccogenitus

We had a rare form of Cirrus yesterday, whose name I have made up in the title as a hint of where they came from, due to the very high altitude and low temperatures of some Altocumulus yesterday.   Those Ac morphed to Cirrus, hence the strange, unpronounceable  title.

Reminder,  weatherscience mavens, its more proper to say “low” temperatures; not “COLD” temperatures, FYI, though you constantly hear it.  (“Things”, like coffee, air, chairs in the sun, etc., are hot, warm, cool,  tepid, and cold; temperature is not a physical thing, and is high. moderate, or low, etc.))

Still bristling over some unexpected clouds yesterday, so I wanted to complain about something minor, bring some discipline to the field.

Mr. Cloud-maven person was not paying attention, asleep at the wheel, etc., when some Altocumulus castellanus and Cirrus castellanus came a truckin’ over the horizon and floated over Catalina after dawn yesterday, but had not been mentioned in this blog in advance.   I am sure, since they had not mentioned  from this keyboard, you may have been in some distress yesterday when they showed up and you weren’t sure what was happening.  My apologies.  It will almost never happen again.

Here are some photos of the interesting clouds that passed overhead yesterday.  I was quite excited to see them partly because I had not prepared myself mentally for them.  Now, there is something strange in the first caption.   But I wrote it that way on purpose because I REALLY want to know if YOU know WHERE the HELL you are, and where the mountains are around here.  Next, after that outrage,  some interesting banded Cirrus. Then a hint at where those Cirrus came from in the background of the 3rd shot.

First, this sunrise over the Tortolita Mountains with Cirrostratus nebulosus (vellum-like cloud) and a hint of Cirrocumulus (tiny, brighter, flocculent specs).
This banded Cirrus gave some hint as to its origin. Might be termed, Cirrus uncinus, or floccus, or fibratus, its a pretty complicated set.


Caption function not working now for this third shot in WP, so here it is:
3) A nice example of Cirrus uncinus in the foreground, tufted or hooked ice clouds trailing tiny ice crystals.  In the background, a clue to the origin of the patchy, banded Cirrus.
4) Another shot of the approaching Altocumulus castellanus (Ac cas) and (Ac floc) floccus clouds as they arrived overhead, some of which have morphed completely into ice (Cirrus) clouds, such as that larger element over the house in the foreground!  In the upper left quadrant of this shot are Ac clouds that, to this eyeball, are still liquid.
Droplet clouds have more sharply defined edges because droplet clouds have MUCH higher concentrations of particles in them than ice crystal clouds (which tend to make them “fuzzy”, ghost-like, striated, fibrous, etc.
Why this visual difference, which I want you to learn, to see for yourself and impress your friends?
There are more cloud droplet condensation nuclei than there are ice crystal nuclei.   For example, liquid Altocumulus clouds might have 100,000 to 500,ooo drops per liter in them, while ice crystal clouds may have only tens to a few thousand per liter  (and then only in newly formed elements) of ice crystals.  In general, there are more cloud condensation nuclei than ice nuclei, too.


While “Joe” is spinning up into his little hurricane-like self in some kind of weather tantrum off the California coast today before heading to Oregon, our skies over Catalina will be marked by various forms of Cirrus clouds, ice clouds well above 25,000 feet above the ground, and not much else.  BTW, you can follow Joe’s progress here from the U of WA, if interested.

If you’re interested, instead, of following our Cirrus clouds as they approach and go overhead today, go here, also from the U of WA.  You see the Cirrus clouds pealing off the main frontal band in the Pac NW and then fading as they head this way.  (I would increase the speed of the loop for maxium excitement.)

The End.


Blue skies back; some more of that Catalina rain climo, March this time

Feeling better now that the K-layer has moved on and our skies have returned to their normal deep blue. (“K” =s smoke in meteo-parlance, not a strikeout.)

No rain in models for southern AZ next 15 days.   Ugh.

In the meantime, as filler material, I will bore you with a graph of Catalina March rain climatology, thanks to our friends at Our Garden who, frankly, are a bit weather-centric.  Remember that if you buy stuff there, you will actually be supporting weather activities.


Catalina February rain climo

Its been February for awhile, Groundhog Day has passed without incident, and I suppose some climatological information might be of interest.  February has the highest average rainfall of any WINTER month, though it has come up short in promise so far with a big fat zero.  The models tell us that there is still a chance of rain this mid-week.  And, of course, as the prior rains have this winter, the coming chance of rain involves another one of those erratic cutoff lows, ones that the models have a hard time with, humans, too.  Here’s a preview from IPS Meteostar based on last evening’s data taken at 11 PM AST.  The chart below is valid for Wednesday evening at 11 PM, about the time rain chances are greatest.  As you can see, the strongest winds around this low (brownish regions) are on the west and southwest side, meaning that the low will move off to the southeast, farther away from us after Wednesday evening rather than come toward us.  “Dang!”  The Canadian model has this cut off low going off the south boundary of their forecast map, somewhere down toward the Equator, a complete miss that is just too horrible to contemplate.    In that event, maybe Acapulco will get some rain .

In the meantime, below is a chart of the days on which it has rained over the past 35 years here in Catalina.   Looks pretty noisy, no sign of a decrease in chances of rain through the whole month, no sign of any “singularities1“, short term climate deviations.  The decreasing chance of rain,  something we know is going to happen,  is not yet seen.  Hard to grasp how quickly that period where the rain chance drops off to almost zero is “bearing down” on us, as a fan of the Arizona Wildcats might put it.

The End

1A technical discussion of what climate “singularities” are and how to find SOME of them here: Mapes_climate harmonics_mapesetal


Some more of that Catalina climo

Here is a 35 year record showing what days have had measurable rain in January.  Sometimes “singularities” in weather show up in these kinds of charts of tempearture or precipitation, such as the “January thaw” that seems to occur with some regularity in the East but is “unexplained.”  You would be looking at our chart for Catalina for example,  a cluster of days with higher or lower precipitation and it MIGHT be a singularity, something that Nature likes to do at that time of the year rather than a statistical fluke that represents nothingness.  Here’s January, a month that averages 1.65 inches in Catalina.  These data are almost totally due to the careful measurements made at Our Garden organic orchard here in Catalina–only the last few years here are from measurements on East Wilds Road.

Not much to see here.  That peak on the 6th looks more like a fluke rather than a singularity.  You would never say that one day represents a singularity, but maybe 5-10 days.

The reason why I wanted to see this was because of the striking changes that were foretold by the “WRF-GFS” model 36 h ago and were shown here yesterday.  Was there a singularity that might support a greater chance of rain in SE AZ in mid-January, and therefore, cast that bit more credibility on such a huge model change?

I would have to say “no.”  And, not surprisingly, that huge change has gone bye-bye in the models.  Nothing like it is shown now, though they do have a rain situation developing for here by the end of the 15 day run (around January 20th and beyond).    But this rain comes out of the lower latitudes of the Pacific, a completely different direction than was shown just yesterday, and if the models are correct in this pattern breakdown, it means flooding in California as the flow breaks through to the coast from the Pacific.

Below, what the models came up with based on last night’s global data, again, from IPS Meteostar, whose renderings I favor.

These are exciting times for those of us who peruse the models.


These vast changes indicate that there is something far, far upwind, perhaps a data sparse zone, errors in reported measurements that is causing a problem for the models and that more changes in their outputs may come down the line until that problem is better “resolved.”  (They are never perfectly resolved.)

So, every 6 h update of the models is a “must see”, with the persuser (me) holding his breath with excitement.  In these cases, its all “good” because a rain situation is foretold for us.  Take a look at where the jet stream is compared to where it is now, up around British Columbia.   You can see it barging into southern California and major rains ALWAYS accompany this pattern.  Also, you can probably count on at least two storms breaking through before this pattern changes much.   The reservoirists in Cal will be very excited to see this pattern develop since most of their holdings have much below capacity.  And these kinds of storms usually produce significant rain in Arizona, too, though here we would be a little far south to get the brunt of those storms in this scenario.

Pretty clouds yesterday

Can’t leave without a little cloud excitement.  I wonder how many looked up and saw this little beauty go by (shown below)?  So pretty and delicate-looking, as unusually thick virga (snow) fell from this little cluster.  It would be called, “Cirrus uncinus” at this stage.

That snowfall probably began developing one-two hours before it came over us, and the cloud patch would likely have been fluffed up on top that bit and as a mostly liquid water cloud, that is, an “Altocumulus castellanus” before becoming this “uncinus.”

Below we saw the dying remnants of that patch, the snow to finally stop falling out with the parent cloud mostly gone, and that snow continuing to dry up on the way down.  Lots of nice cloud sights yesterday, in fact.







31 hundredths and counting; December total for Catalina now 2.59 inches (normal, 1.72 inches), Seattle has only had 0.25 inches this month! We had more last night than Seattle has had all month! Planet, CPC, out of control!

Pretty excited there in that title, and haven’t had that much coffee yet.   Whenever strange weather occurs, I always like to kid friends who might ask, “What’s causing this strange weather?”,  and say that the best explanation is that the “planet is out of control.”  hahahah.   Oh, well, its the best I can do.  No one really can tell you why we have had so many (great) cut off lows this year in the Southwest.  Totally unforeseen.  I didn’t expect that it would still be raining this morning at 6 AM either.

Also, remember the CPC’s (Climate Prediction Center) prediction for November, December and January made back in late October?   Due to the La Nina regime in the east Pacific, Seattle and the whole Pac NW was supposed to get hammered with excess rain and snow, and the SW was supposed to experience “intensifying drought.”

Didn’t happen, and can’t happen, even if it dries out in January.  It just goes to show that these several monthly type predictions are dicey, probably more often right than wrong, but they can’t be counted on too solidly.  Also, we know that the La Nina regimes exert their greatest influence in later winter and spring, so we could still dry out a lot after December’s excesses.

Regional precip reports are here where you can see some places got 2/3rds of an inch out of the little (cut off) guy.  How fine is that?Also, what’s really great, too, is all the rain that has and will be falling in NM and TX, taking a bite out of drought thanks to this same storm.   Below, 24 h precip totals fro the US and AZ deduced from radar from those WSI Intellicast weather guys and gals below.   Note that the Tucson area and Cat Mountains got the most of anywhere in the state.

More detail on the AZ rain can be had at the U of A rainlog site here.   BTW, joining this org as a measurer-reporter would be a nice thing to do.  How about getting a rain gauge for Christmas and joining up with the rainlog gang?

Quitting here for awhile.

Catalina summer rainfall 1977-2010: there is no trend

OK, no fooling around today with HUGE text boxes with book length ramblings, just the facts:

Catalina inches of summer rain

These data again mostly due to the friendly folks Wayne and Jenny down at Our Garden here in Catalina.  Since they are open today, Saturday, it would be great if you went down and bought everything they had as a gesture of appreciation for collecting weather data over so many years.  Its really invaluable since there are no other data in this area.  The data for 2008-2010 are from a gauge here near  where the pavement ends on E. Golder Ranch Drive, or at a somewhat higher altitude than the earlier measurements.  Note the lack of a trend, not getting droughtier in the summers. Yay!

Its always fun to look at past data and dream about excess wetness, as we had here in for two summers in the early 1980s.  Imagine, in 1983,  June through September logged over 17 inches of rain!  Our annual average is about 17.5 inches here in Catalina.  Note this annual average is considerably more than locations that are relatively close where in general, averages such as at Tucson are closer to 12 inches per year.


A welcome sight was a few evening Altocumulus clouds creeping past the Catalinas yesterday as tropical air begins making its return.  Mods have rain in the area beginning tomorrow and continuing for several days at least thereafter.  We’re just beginning the height of the summer rain season (sorry, I can’t say “monsoon”;  monsoons are in India and SE Asia.   We don’t call hurricanes,  “typhoons” do we?  Never mind;  just don’t like “monsoon.”  Its a quirk.  We all have them, so I don’t feel bad at all having quite a few quirks.)









Seattle comes to Catalina

Yes, if you’re from Seattle or the west side of the Cascade Mountains of the Pacific Northwest, you are going to feel especially at home today.   Its dark, even with the sun up, low ceilings and visibility, steady light rain mixed with snow, temperatures in the mid 30s to low 40s, well, that’s home in January.  And, here is that “home” right here in Catalina, AZ, for us to experience again!  Cloud type? Nimbostratus, often with an underlay of….Stratocumulus and Stratus fractus clouds to kind of provide that ragged, dark and gloomy, splotchy look.

As you may have experienced this morning, an extremely sharp cold front came through with a spectacular drop in temperature and a windshift at  6:30 A. M.   The temperature dropped from the upper 40s down into then upper 30s in only about 20 minutes, which it pretty unusual.  Along with the that temperature drop, the rains came in the “frontal band”, now totaling 0.80 inches here since the first period of rain began late yesterday afternoon (local weather station data here).  (BTW, this station’s wind data are averaged over 10 min, and gusts are 1 min averages.  Multiply gusts by about 1.5 to estimate the velocity of the strongest, few second duration puffs.)

This storm, still in progress,  brings the Catalina rainfall for December up to 1.93 inches.  Normal, based on a 31 year record provided by the folks at Our Garden here in Catalina, is 1.44 inches.  So with this storm, we have exceeded the normal AND crushed the monthly NOAA prediction of well below normal precip this month.  Yay!  Such predictions are partly derived from the effects of the strong La Nina now in progress-note colder than normal water along the Equator in the eastern and central Pacific.  La Ninas normally hedge the climate of the SW toward drought, and so this has been a great December if droughty conditions materialize later in the winter.  The December US-wide precip prediction, FYI:   (I should acknowledge a  bias here: I am overjoyed when droughty forecasts fail but also overjoyed when wet ones verify.)