Later yesterday morning, some interesting “Altocumulocirrus”, a rare breed indeed, mocking/mimicking Altocumulus.
Maybe Cirrus floccus would come closest to the true name, but to every eye but that of a genuine cloud maven person, it would be deemed just “Altocumulus”. Check these out to see how good you were–and NO correcting your cloud diaries!!!!
Haha, most readers won’t even notice! But maybe some cow-centric, instead of cloud-centric, folks will drop by, raising the worth of this blog to above $35 if sold….that according to a “biz” site.
Had a rainbow yesterday. Hope you noticed. It was pretty early and overhead west. I think the clouds did not have ice in them. The rain echoes were not showing up on the radar, suggesting the beam went over the tops. Sounding suggested tops might have been as cool as -5°C. In any case, the drops were able to tip the bucket a couple of more times, and along with yesterday afternoon’s brief, light rain showers our total has climbed to 0.37 inches for the storm. Not bad, though as in money, you always want more.
These storm breakup days are always our prettiest, and that’s often what this site is about, being pretty. Yesterday had some fabulous scenes; couldn’t stop shuttering cam. It is a real neurotic compulsive behavior pattern, as afflicts some of us cloud and storm-centric folk. Check Mr. Olbinsky’s work; his work goes beyond phenomenal whether you want a wedding photographer or want to see a storm chasing video. But it takes that kind of eccentric energy to be special, to stand out as he does.
Here, though, we let the storms and cloud scenes, such as they are, hope for the best, and let them come to us…. Kind of a lazy storm chaser’s attitude.
Still cold aloft, so having some nice Cumulus today is in the bag, the early Stratocumulus devolving into Cu, that is.
At this hour, a small, pin-wheeling, galaxy-like vortex is drifting toward Catalina. Last night the town was ravaged by 0.30 inches of rain and winds to 50 mph around 2 AM as one of its pin-wheeling bands came through, likely with a big arcus cloud fronting it.
This was the first measurable rain in Catalina since I don’t know when. You probably don’t remember, either, its been that long.
More rain is expected as the little pin-wheeling vortex moves overhead of the little village of Catalina today and on to New Mexico tomorrow.
Plunked below is the Pima County ALERT rain map amounts with the Sutherland Heights amount plunked on it as well. We did pretty well it appears, compared to surrounding amounts. Yay. Our desert will love this! The greatest amount here is 0.46 inches at Dan Saddle in the CDO upper watershed. I guess he hasn’t found it yet.
And if you mention our desert vegetation, as I have, how can you not exult over the fabulous blooms on one of the most horrible plants on earth (haha), as far as spines and glockets go, the prickly pear!
The Weather Way Ahead
Our models, supported by those ensemble “spaghetti” maps are making most of May look pretty darn nice, at least through 20th-25th as the upper air configuration reprises troughs twixt now and then. They’re looking like dry cool fronts, though, no rain in ’em. Snowbirds done left too soon!
A Cumulus cloud! Then traces of ice spewing from them as they deepened and spread over the sky! Then masses of VIRGA, snow drifting downward toward the parched desert, which is mostly parched all the time anyway. What a day, Mr. and Mrs. Catalina!
How high up were the bottoms of those Cumulus clouds with all that ice? Oh, about 17,000 feet above sea level, 14,000 feet above Catalina by mid-to late afternoon. The base temperatures, as you could tell with all that snow virga hanging down, had to be way below freezing, about -9°C, about 16° F.
Now, with all that ice, can you guess how low the temperatures had to be up around the tops of those clouds? Remember, if the top is about -12°C in a thin cloud, the droplets are very small because they haven’t been lifted upward much, 1000 to 1500 feet or so, there’s probably not going to be any ice. The smaller the drops, the harder it is for nature to create an ice crystal. So guessing that the tops were 1000-1500 feet above the base would be a good starting point, but horribly WRONG for those clouds with a lot of ice! A cloudwise neighbor, hearing that estimate, might start laughing, or at least sniggle.
With all that ice up there, and cold based clouds, a good estimate would have been -22.3°C, because adding the decimal would make it appear that you know more than you really do. Here’s the sounding from the U of AZ for yesterday afternoon when all the ice was in full display, down thataway as well as here:
So you can see that tops were about -25°C, about right for all the ice we saw come out of those clouds.
As you know, the actual rain from this incoming system doesn’t get here until late tomorrow. We have to go through a dry slot aloft before the Pacific moisture gets here. The U of AZ Beowulf Cluster output is suggesting that we here in Catalinaland should get at least a tenth of an inch as an upper level vortex goes by (run is not complete as of this writing). But, because this vortex aloft that’s going to affect us is rather small, a slight position error could mean much more than that. It would seem the potential rain amount here might range from a least amount of 0.05 inches to ten times that amount, or 0.50 inches, more uncertainty than usual! Good chance of some thunder with this situation, too, to remind us that the summer rain season is getting closer.
The NOAA spaghetti factory had indicated this situation and the chances of rain on the 8th more than 10 days ago, and that is the power of those crazy maps, to give us some insight farther out in time than we normally can do any reliability. The scenario of “troughiness” over us continues well into May in those plots, and that should mean temperatures are moderate, not “ovenly” as we like to say here. Check it out here.
But that also means very windy at times, too, along with a chance for additional rain.
This is great news, heard here first of course (haha), after a pitiful April with no measurable rain. Poor desert.
Its been suggested by the NOAA spaghetti factory for some time, but now actual precipitation is showing up in the models pretty regularly for around May 8th and thereafter, and so we can gleefully start dusting off our umbrellas, seeing if we have enough change for the car wash afterwards, etc.
Even WU (Weather Underground) is starting to catch up, showing about a 3% (THREE percent!) chance of rain at that time from last night’s model output. Its “waymore better” (a nice name for someone) than that, I think, though its not 100% yet. That percentage should be climbing as the days get closer.
BTW, Have never seen such a pronounced “retrogression” as that shown today over such a vast region of the globe in those spaghetti plots, and that’s why I’ve taken to the air today.
The good news for AZ-ians is that we get placed in a trough in the lower latitudes, albeit a weak one; a dip in “jetty jet stream” to the south over us (meaning cooler temperatures than average aloft should prevail) with some enhanced chances for rain after our main chances coming right up on the 8th and beyond for a couple of days.
As you know already, ovenly weather for this time of year, with temperatures far above average, is just ahead, which takes a big, fat high pressure dome aloft over us. That high will dissipate as “troughy” conditions begin to shape up toward the weekend.
So, venturing farther, it would seem a reasonable temperature first half of May is ahead, with RAIN, after the “meltdown” later this week.
Time for a random thought before closing:
A cactus can be a beautiful thing, can’t it?The End
Honestly, I gave up on the chance of rain overnight into this morning at sunset yesterday due to the absolutely clear skies. And, like you, woke up to not one cloud within a 100 miles! How could this be, given the synoptic situation? Started slicing apples for some humble pie, but then, when looking at a radar and cloud loop (this one from IPS MeteoStar) saw that lower clouds had magically erupted to our west before midnight, and by the time they got here in the early morning hours, had little showers coming out of them!
I did not park my own dusty car out from the carport, either. I thought I would at LEAST see a pile of clouds on Ms. Lemmon, too, this morning! Sure wrong there. Here are a couple of images from what has to be considered a tiny weather miracle:
Chances of rain increasing (imagine!), for just over a week from now as actual model outputs begin reflecting what spaghetti (the many outputs) was indicating, i.e., a big upper trough in the West-Great Basin area. At the time that spaghetti was indicating that, the actual model outputs were not, indicating that they were outliers.
Check this out from last night. Since this model output is more in agreement with that crazy spaghetti plot, it inherently has more credibility, and is likely not an outlier model run. That what the NOAA spaghetti factory is used for, getting a handle on those runs that might be wild, and those that are more likely to verify.
Its valid on the morning of May 8th and shows a trough coming out of the Pacific ahead of the one from the Pac NW, shown at this time over northern Cal. The hope here would be that the one from the SW would have a generous amount of sub-tropical clouds with rain in them.
Cloud shots will be posted later this morning of the next day….. (i didn’t get to is as I had planned)
Yesterday afternoon, the 29th. Here’s what shallow, icy clouds look like, reflecting the unusually cold air above us.
PS: Chance of rain still holding for the 8th. See below for new depiction of big “cutoff” vortex over AZ from last evening’s model run:
April’s been kind of a weather dud here in Catalina so far (no rain so far, and the chance on the 20th, mentioned here some weeks ago, has receded to Utah and points north), so lets take a look at how May is shaping up, only two weeks ahead:
I thought you’d be pretty happy when you saw this, as I was.
Its possible there is a photo from Catalina, Arizona! I have not checked yet. Its just been published by the World Meteorological Organization of the United Nations. Still needs a little work, but overall is VERY, very nice. Came out out on March 23rd, so we’re a little behind here as usual. The thing that makes it different from prior and sometimes flawed atlases is that each photo is accompanied by some weather data and in many cases maps, radar or satellite imagery at the time of the photo.
Some new expressions to toss around to your fellow cloud-centric folk are things like “Cirrus anthrogenitus”–Cirrus evolved from contrails and “Cumulus flammogenitus”, a Cumulus formed at the top of a fire, something we used to call, “pyrocumulus”, an unofficial term that somehow seems preferable to “flammo”.
However, something that has drawn great attention over the past 20 years or so was not given a name, aircraft-produced ice in Altocumulus and Cirrocumulus clouds, which have been referred to by Heymsfield and colleagues as “hole punch clouds.”1
Ice canals amid Altocumulus are also fairly common. Ironically, a hole punch cloud with ice in the center, and an ice canal in an Altocumulus cloud layer can be readily seen on the new International Cloud Atlas submission site, now closed. They’ve mistakenly, IMO, referred to “ice canal” photos as “distrails” without mentioning the ice canal “cirrus” down the middle. Formerly, distrails were clearings produced by aircraft in thin clouds without any change of phase in the cloud induced by the aircraft, unlike those holes and clearings produced when the ice-phase is triggered by an aircraft passage.
Certainly a “hole punch” cloud is not a distrail, a linear feature, and should have a separate nomenclature.
In keeping with the new terminology regarding “anthro” effects, maybe it should be, since we’re talking about the Cirrus induced by an aircraft, albeit at much lower levels than true Cirrus clouds:
“CIrrus Altocumuloanthroglaciogenitus.” (??)
Here’s a classic one of those that erupted over Catalina, posted here last January:
——————————————- 1It should be pointed out immediately if not sooner that Catalina’s Cloud Maven Person had plenty of time to rectify, or suggest changes to the Atlas as he could have been part of this process, but didn’t really do anything except submit some images for consideration.
I could literally hear the cameras clicking all over Catalina and Oro Valley as these patterns showed up, moving in from the southwest as the increasing numbers of cloud-centric folk lost control of themselves. Reflecting that general loss of control, which affected yours truly, too many photos will be posted here. Below holey clouds with icy centers, but not ones caused by aircraft:
And look closely at the fine patterns, lines and granulations in these shots! Truly mesmerizing.
But what’s missing in this photo above? There was no iridescence seen around the sun where we normally look for it suggesting that those Cirrocumulus clouds nearest the sun were composed of ice crystals, and not tiny droplets. Iridescence is rarely seen next to the sun due to ice crystals because they are usually the result of the freezing of existing droplets, that then grow rapidly as ice particles to sizes too large to produce diffraction phenomenon close to the sun. Where’s my Lear jet, so’s I can confirm these speculations?!! I would very much like to have one on “stand by”, in case I think of something. Below, a wonderful example of no iridescence even though newly formed clouds are by the sun:
A jet runs through it
Or so I thought. In this chapter of cloud-maven.com, we inspect the photos of a commercial jet flying at or near the level of these clouds and determine what happened. I was quite excited to see this happen because we would now determine whether there were any liquid droplets in what to the eye of the amateur cloud watching person would be a liquid droplet Altocumulus clouds. Here the size of the elements are just a bit too large to lump it into the Cirrocumulus category, if you care. So, with heart pounding, took this sequence of photos:
Let is go zooming:
By the way, if you caught it, there were a couple of standard, aircraft-produced, “hole punch” clouds at the very upwind, formative portion of this patch of clouds before it got here. These photos pretty much prove that the Cc at the formative end at that time was composed of highly supercooled droplets and that the passage of an aircraft produced ice, that caused a fall out hole.
In particular, those Altocumulus clouds, “cold” Cirrocumulus (ones that transform to ice immediately), and those “Altocumulocirrus” clouds combining with scenes of “regular” cirriform clouds. Lots of interesting sights to have seen yesterday. All these the result of marginal moisture aloft and strong winds, up around 100 mph at the highest Cirrus levels.
Let us begin as cloud maven folk by examining the late afternoon sounding launched from our Wildcat balloon launching machine at the University of Arizona, courtesy of IPS Meteostar:
The weather way ahead
Still looking for that chance of rain before July…. haha
Troughy conditions will actually recur aloft over us over the next few weeks it seems, which means slight chances of rain, but periodic cold fronts passing by, mostly dry ones. Best chance for rain still seems to be around the 20th, plus or minus a day or two, even though mod outputs have backed off that scene. But, we have our spaghetti that tells us the models will likely bring back that threat around the 20th, even if some individual runs show nothing at all or only close calls. We shall see if this interpretation has any credibility at all, won’t we?
Of note, Cal having big April in rain and snow after the gigantic January and February accumulations! Looks like they’ll continue to get slugged by unusually strong storms, off and on, for another couple of weeks. Water year totals are going to be truly gigantic.