A trace of rain was officially recorded in Catalina at this site ending prospects of a rainless October. It fell from high-based Cumulonimbus clouds in a band, partially lining the NW horizon that could be seen as the sun rose yesterday. Some ants were injured by the falling drops, ones that reached millimeter sizes and fell at 5-8 mph, though in some areas, winds of 10-15 mph added to drop impacts. Flying insects, while obliged to avoid the watery missiles, were able to do so with ease due to the appreciable spacing between the drops of several feet.
Due to the short-lived hydrometeor events, many humans were unaware that rain had fallen in Catalina on more than one occasion yesterday. That’s why we blog here. Weather and cloud news you can rely on.
How high were the bases of those precipitating clouds spewing snow virga that melted to rain? Higher than the freezing level! Haha.. The balloon sounding profile started with the Altocumulus perlucidus layer at 18,000 feet above sea level, 15,000 feet above Catalina, bases at -11°C. By evening the lowest moist level had lowered to 14,000 feet ASL (11,000 feet AGL) and -3°C. However, that last moist level had to be a bit lower than those snowy cloud bases IMO–we know that the moist level almost always lowers.
So cloud maven person will make the definitive call that the rainy (well, sprinkly) cloud bases were at 16,000 ASL (13,000 feet AGL) when they passed over, if that makes any sense or is anything you really care about.
As rain fell……this sky, 12:30 to 1 PM:
Kind of pathetic really; no shafting whatsoever, much less virga than on the horizon yesterday morning. So our end of that band was so weak it was just barely able to get some drops to the ground.
Looks like this is it for rain in October 2017. However, November 2017 appears to look much brighter for substantial, dust-removing rains in Catalina beginning in the first 10 days!
The End (I missed the sunset due to a social engagement–hope you saw it wherever you were). Probably was pretty nice.
Another pretty cloud day ahead. Though most of the Altocumulus clouds are flat, there are some whoppers off to the north now, Ac cas so large they might have to be called Cumulonimbus, certainly large enough to produce radar echoes, maybe a sprinkle at the ground.
Lots of wind tomorrow, as you likely know, but no rain in sight still. So, October almost surely will end as a rainless month. Our average for October is just over an inch of rain!
A warm, rainless October appears to be our fate, much like last year when only 0.01 inches fell. Oh, me. Our dryness since the end of July, with so many cloudless skies, continues on and on. Tough to take if you’re cloud-centric.
However, this month, though likely rainless, promises to deliver some great sunrises and sunsets as weak regions of rising air pass above us in the days ahead, that rising air showing up as lots of middle and upper level clouds like Altocumulus, Altostratus with virga, and CIrrus over many of the remaining days. Those kinds of clouds can be associated with the most spectacular ones sunrises and sunsets.
I guess that’s something.
Below, a sample pretty scene for cloud-starved readers.
Again, pardon the links to ads. I have nothing to do with them. Will make them go away via $$ in the days ahead.
As here, just to reinforce that assertion a bit. Its a link to a recent blog by my cloud-obsessed friend and author, Maria Mudd Ruth. I strongly recommend buying a few of her books. Really, I do!
But in viewing our deep blue skies, pocked with little fluffy Cumulus clouds over the past two or three days, you would not need convincing that even tiny clouds are beguiling, a wonderful attribute for a planet to have. Having mountains on a planet is great, too, and watching the interplay of clouds and their shadows on them is a never ending pleasure. We’re pretty lucky when you think about it to be on a planet like this one. Hope you think so, too.
No rain ahead, glumly, though some sprinkles are out there this morning as frontal cloud band passes over. Just a little too high off the ground for real rain. And the cloud tops aren’t quite cold enough to form much ice, too. Those cloud tops get colder going to the NE, and so higher terrain up thataway (e.g., Show Low) are getting some light rain this morning. Right now, there’s a little sprinkle just beyond Romero Canyon, so we got a little ice this morning in them clouds.
What was interesting is that I never saw no ice yesterday, to continue the slang of rock and roll, in another cheap attempt to reach out to another demographic. The clouds were just a bit too warm for ice-formation, tops running in the -4°C to -5°C range according to yesterday afternoon’s Banner University of Arizona’s balloon sounding. Some may have bulged up to nearly -10°C, but still not quite there. I looked constantly for signs of ice and never saw none, and neither did you, of course.
Bases were cool, at about 4°C, at 11, 000 feet above sea level, or 8,000 feet above Catalina. Tops, about 15,000 feet above sea level. So, they were running around 3,000-4,000 feet thick with no ice. This was a situation where dropping dry ice into those clouds would have created snowfall, then sprinkles, that would not have fallen naturally. Doubtful anything would have reached the ground anywhere near our elevation, however, but up at Ms. Mt. Lemmon, something would have likely even measured from doing that far enough upwind.
In summary, yes, there are some fairly rare times you can get some precip out of clouds by seeding them and yesterday was one of them1.
Today the clouds are thicker, drop sizes therefore larger in those tops of a cloud band similar to the one we had yesterday evening. As drop sizes increase, the temperature at which they freeze also increases. Well, at least that’s what we found over and over again at the U of Washington.
The result, some ice has formed even though they’re hardly colder than just -9°C or -10°C (14°F). Check the radar:
Here are some cloud shots from the past couple of days. Should be some more great scenes today:
Due to time constraints, we now move ahead in the action. Well, its not really “action” is it?
Well, not that much, just a day ahead….
Moving ahead to yesterday and the day long cloud band….
Oh, well. When you’re sloppy and asleep at the wheel, think you know more that you really do, that’s what happens, “weather surprises” that shouldn’t be.
But, what a gorgeous day again! Really, with the smoky skies gone I am so appreciating a blue sky pocked with Cumulus and Cumulonimbus clouds!
Lettuce reprise yesterday in all its unexpected glory:
Since I was clueless yesterday, will remain quiet about today’s weather, though we do have low level moisture around as clouds are again topping the Cat Mountains.
We’ll still get into some early winter like weather in only a week–that’s pretty much in the bag. Probably no rain, though, just a bit of a very windy day or two and very cold air for the time of year plopping over us. Our TEEVEE weather folks are surely all over this!
It was quite a surprise to this observer who claims to be a “cloud maven”, but whose credentials must be questioned, even if I do say so myself. Was thinking plain old small to moderate Cu, hold the ice.
But in a long cloud street, appearing to emanate from Kitt Peak, some ice started to show up in the cloud row upwind of us. Wonder if you saw it? The first ice happened around 3:45 PM, followed by a couple drops at 3:59 PM. Well, as Rob Reiner might say, enough of my yammering, lets get on with the cloudumentary:
Yesterday’s clouds, lot of ’em
Enough lower level moisture for Cumulus again today, but even smaller ones than yesterday. Since the wind is already noticeable now at 6:26 AM, better mention that we could have noticeable winds again today. (Much windier yesterday than anticipated by CMP; wind was not on my radar if wind could be seen by radar (well, of course it can when they are raindrops or bugs. Hah!)
Big intrusion of unusually cold air still coming into the West in about a week. Some of that will reach right here in Catalina really giving the sense that its truly football season.
First, I will shamelessly plug a book on clouds, “A Sideways Look at Clouds”, by a well-published and acclaimed author friend, Maria Mudd Ruth. Its about her odyssey into them, mentally and physically, after she realized they were something she really had not paid much attention to before mid-life, then she had to know EVERYTHING about them! Its a great read, infused here and there with humorous anecdotes.
Not that there have been that many rainstorms since the end of July.
But it would seem that today marks the meteorological end of the summer rain season as dry westerly winds sweep our remaining tropical air to the east today. The mods think there is a chance for a couple of high-based thunderstorms in the area around Catalina late in the day. But bases will be so high that not a lot of rain will reach the ground even if one passes right over us. And, they’ll be moving in from the SW or W today due to encroaching westerlies.
In a little over a week, too, you’ll be hearing about early snow in the Rockies and West! We’ll have a day or two of those gusty, dry southwest winds that accompany our winter storms as well. You’ll get a real feel for the season change then.
Check out this plot from the NOAA spaghetti factory showing (blue lines) that an unusually strong upper trough will absolutely dominate the West in just over a week