We’ve waited a LONG time for a rain day. It was so nice, so photogenic as well. I hope you enjoyed it as much as I did.
Also, you may have seen the Froude Number1 in action as Cumulus congestus and Cumulonimbus clouds developed and went around the sides of the Catalina Mountains instead of developing over them and dumping big shafts of rain on them. The heaviest rains yesterday were due to streamers of showers and with an OCNL TSTMS that were north and south of us, Oracleville, Bio2 area, and Marana, Avra Valley where over half an inch was logged in some places.
Still , we managed a third of an inch here in Sutherland Heights, the first appreciable rain since I don’t know when, though, I could look it up. Too long, though, even for Catalina.
Some regional totals, 3 AM to 3 AM: Precipitation Report for the following time periods ending at: 03:19:00 11/04/16 Data is preliminary and unedited. —- indicates missing data Gauge 24 Name Location ID# minutes hour hours hours hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.08 Golder Ranch Horseshoe Bend Rd in Saddlebrooke 1020 0.12 Oracle Ranger Stati approximately 0.5 mi SW of Oracle 1040 0.08 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway 1050 0.16 Cherry Spring approximately 1.5 mi W of Charouleau Gap 1060 0.16 Pig Spring approximately 1.1 mi NE of Charouleau Gap 1070 0.24 Cargodera Canyon NE corner of Catalina State Park 1080 0.20 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke 1100 0.16 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains 1030 0.04 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak 1090 0.16 Mt. Lemmon Mount Lemmon 1110 0.16 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp 1130 0.28 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.08 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.16 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station 2280 0.04 Green Mountain Green Mountain 2290 0.16 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Santa Catalina Foothills 2090 0.04 TV @ Guest Ranch Tanque Verde Wash at Tanque Verde Guest Ranch 2100 0.16 DEQ Swan Swan Rd at Calle del Pantera 2160 0.08 Sabino @ USFS Dam Sabino Creek at USFS Dam 2170 0.24 Ventana @ Sunrise Ventana Canyon Wash at Sunrise Rd 2190 0.16 Al-Marah near El Marah on Bear Canyon Rd 2200 0.04 AC Wash @ TV Bridge Agua Caliente Wash at Tanque Verde Rd 2210 0.00 Catalina Boosters Houghton Road 0.1 mi S of Catalina Highway 2220 0.04 Agua Caliente Park Agua Caliente Park 2230 0.04 El Camino Rinconado El Camino Rinconado 0.5 mi N of Reddington Rd 2240 0.04 Molino Canyon Mt Lemmon Highway near Mile Post 3 2390 0.24 Finger Rock @ Skyli Finger Rock Wash at Sunrise Rd
Except for a morning or afternoon sprinkle, no rain in sight, just a warm up back to above average temperatures. Dang.
1The young fluid dynamicist, Richard Penniman, fascinated by the flow around mountains, and who later became known as the rock and R&B entertainer, “Little Richard”, first brought the Froude Number to public attention in his song, “Tutti Froude-e.” The title, after an early release failed to capture the public’s imagination, was later revised for greater “accessibility”, to the song we know today as, “Tutti Frutti.”
2Who can forget “Max and the Storm Troopers” and that great song? I would submit, “everyone.” Of course, few know that after 1968 they changed their name to “Led Zeppelin.” And that, my friends, is “the rest of the story”, as Paul Harvey might say if he was lying about something anyway.
We have a monthly rain total that’s not zero! But will there be more this month? Stay tuned until November 30th! (Nothing imminent.) In the meantime, a very pretty blue sky day today pocked with residual Cumulus clouds, maybe some virga. There’ll be nice cloud shadows and sun on the Catalinas again today.
In the meantime, here are the Pima Country reports for last evening’s rain. The heaviest amount seems to be at our end of the Catalinas at Pig Spring, with 0.39 inches. Nice.
Yesterday’s clouds and why
Not exactly the way they were supposed to go, the ice cloud shield WAS on the horizon to the NW at mid-day but didn’t advance over us, but rather fizzled out. That’s OK. What was left of it enhanced a spectacular sunset through the rain.
The Cumulus clouds were the stars of yesterday, doing something in the way that the old rock band, Jethro Tull used to do. The members of JT would come out on stage as roadies, fiddle around with equipment for awhile, then suddenly turn around and began playing! Oh, who can forget Jethro Tull and that Aqualung album that roiled the rock waters back in 1971 by interrupting heavy, driving rock with acoustic interludes and flute playing (!!! )? What were they thinking?
Well, our Cumulus clouds pulled a fast one, too, after hanging around, fiddling around not doing much, then blammo, here comes the ice around 4:30 PM, followed by an eruption into an honest-to-goodness Cumulonimbus cloud with a strong rain shaft, sending forks of lightning to the ground, and pea to grape-sized hail bouncing off the roof with winds gusting to over 30 mph. This spectacular happenstance was triggered by a surge of much cooler air in conjunction with the lifting of air associated with our approaching trough just above those Cumulus tops yesterday afternoon. That steepened the lapse rate; spring-loading those Cumulus clouds as it were, allowing tops to rise and still be that bit warmer than the surrounding air and stay buoyant as they rose. Here are a couple of TUS balloon soundings rendered by the Cowboys of the U of WY:
While cloud fattening and ice was expected late in the day with sprinkles and light showers, the U of AZ mod run based on 5 AM AST data was spectacular yesterday morning in foretelling this larger eruption as that cold air moved over us. But were grape-sized hail stones and LIGHTNING expected? Not only “no”, but “HELL no”.
Here’s your day, reprised below, of which the MOST IMPORTANT part was the first detection of ice, very tough yesterday, but a precursor to the rain that began to fall a few minutes later. You can also reprise your day here thanks to the U of A time lapse films. Watch what happens around 5 PM, if you can read the tiny font in the lower left hand corner.
May take Jake Horse out to see if the Sutherland Wash is running, anyway, if the CDO is not running here in Catalina.
Thunderstorms (at least 4 separate ones yesterday), with hail, graupel, wind, rain; what a nice day for Catalinans and our environs. Lightning was still visible as of 7:52 PM last evening, and close enough that thunder could be heard, technically meaning a thunderstorm is in progress in weather parlance. Here’s some pea-sized hail for you, sent by a listener, “Dave”, in Sutherland Heights:
Was awakened by a moderate rainshower just before 3 AM. Dropped 0.03 inches in a few minutes, to bring the total to 0.40. Another shower followed within half an hour, but bucket didn’t tip for even 0.01 inch. May have to jiggle it to get that extra 0.01 inch that I KNOW fell. Hahahah.
In the meantime, exulting over the large amounts, so well foretold by the U of AZ Beowulf Cluster run from 24 h ago. Truly amazing! Our total here was also well=predicted by that model; amounts in this storm increase northward reaching 0.87 inches at Oracle State Park, 0.55 inches at the NE corner of Saddlebrooke. We SO needed a good rain. Here’s where the totals are:
Here are some mind-boggling statewide totals from the USGS, some approaching two and a half inches of water content at Sunflower near Payson! How great is that?! Really, this has been a billion dollar storm in dropped water and snow. Maybe it should have a name now.
You will can also access rainfall data from the U of AZ rainlog.org network here, and from CoCoRahs national network for Arizona here. As always, its necessary to point out that in the rainlog network, the measurements reported this morning will be assigned to yesterday’s date, while the ones in the CoCoRahs system will be assigned to today, March 9th.
Since its unlikely to rain for at least 10 days, I thought I would overdo the precipitation data for our billion dollar storm.
Sadly, as you will see in this Pima County ALERT gauge totals above, we in the north end of the County really got the nice rain; most of the county did not. We were lucky we were that bit farther north because it wasn’t the wind direction helping us out in most of the storm; that “help” is taking place now because the wind is more from the west at cloud levels. Going into yesterday yesterday evening the wind at cloud/mountain top levels was from the south-southwest rather than from the west, and normally that more southerly flow helps the south facing sides of the Catalinas, as much as us. So, it was more to do with cloud top temperatures and those clouds being a bit too warm to the south, while northward and to the northwest (perpendicular to our jet stream), the temperatures decreased rapidly at the same level in the atmosphere, and that in turn, allowed cloud tops to deepen more as they went nortward. Make any sense? Here’s a map of temperatures aloft for yesterday, two graphics to try to explain this:
First, here’s last evening’s TUS sounding, as rendered by the Cowboys of Wyoming. Its got some writing on it:
———begin tedious stream of consciousness again, probably worth skipping——–
Graupeling hard here at 3:38 AM! Third shower since getting up! Pounding roof. Very small, like rice grains. Just quit, like someone turned a light off at 3:41 AM. Tells me its a new cell that just formed with narrow strands of precip/graupel. Investigating…no echo at 3:36 AM nearby… waiting for next 6 min sweep… 2:42 AM: No echo! I have not seen this happen before. Could it have developed and died in less than 5 min? Did not tip bucket! Its just like yesterday, we had no less than four hail/graupel episodes and I was beside myself thinking of those balls of ice bouncing OUT of my rain gauge collector! I was being short-changed in the amount of precip I could report. I think I am going to have to add to my rain total, maybe 0.03 inches due hail balls that bounced out
——————–end of tedious stream———————-
OK, now up to 0.13 inches in rain that has fallen since about 3 AM. This is great, because now the total amount in the storm is 0.50 inches here!
After a few sprinkles-its-not-drizzle amid brief sunbreaks yesterday morning, the first thunderstorm rumbled across Marana and the Oro Valley at 9:30 AM.
These early morning stratiform (flat) clouds will disperse into Cumulus and Stratocumulus in clumps. They’ll be cold enough at cloud tops for ice and virga, but clouds likely will be too shallow for more than a hundredth or two in the heaviest precip areas around Catalina. Things dry out later in the day, the Cu becoming smaller, so the best chance of measurable rain is before, say, 2 PM.
Get camera out fast, too. THere was a huge dump of hail or snow on Charoleau Gap last night or this morning I suspect, and it looks spectacular even now at 6:53 AM. Its local, because its not seen at the same elevations to the south on Samaniego Ridge. But, it will just be gorgeous with those deep blue skies and white Cumulus clouds all around.
What a nice day yesterday was, ending with this fabulous, but run-of-the mill sunsets we get to see here in the Catalina area on a regular basis. Yesterday was interesting because we had two graupel (soft hail) showers, the first about noon, and the second with a blast of thunder (1) at 1605 PM. If you weren’t lucky enough to get any, measure it and report it to the National Bureau of Standards, or the NWS, here’s what it looked like on our old chaise lounge a couple of minutes after it fell (see below). Some of it was “conical graupel”, pointed on one side, though that is not visible here. Graupel, soft hail form when there aren’t many ice crystals in the cloud and the cloud is chock full of droplets at below freezing temperatures. Those droplets freeze instantly onto the ice crystal as it makes it way down to the ground, eventually losing all of its identity as it become a little snowball. Usually, where this happens in the cloud is in a very limited region, and, it usually doesn’t last for a long time. So, consider yourself especially “lucky” to see graupel/soft hail, hail. I do. If you want to relive yesterday’s clouds, as seen from the U of A, go here. “Above Catalina” is at the left, beyond Pusch Ridge.
What’s exciting now is that something akin to an atmospheric iceberg is barreling down on us (SE AZ) from the north. This “cold low” center, representing a column of extraordinarily cold air in this case, goes from the ground all the way up through the “troposphere.” IN this case, the troposphere is squashed down to less than 20,000 feet over Wy0ming right now. The stratosphere is above that, and above “cold lows”, the stratosphere dips down over them. Usually its twice that height at our latitude.
Here’s what I am talking about, shown in this morning’s 500 millibar pressure map (about 18,000 feet above the ground) or usually half way up through the troposphere (map courtesy San Francisco State U.) The winds flow along the green lines, ones that bend gently toward the west over the Great Basin. That bend in the wind represents an area where a small low center amid this giant river of wind will form in the next 24 h and that little center of circulation should pass right over us!
Now, not a single model output that I saw from last night’s runs had enough moisture in this forming upper center to have snow even fall on Mt. Sara Lemmon (e.g., the U of AZ regional model from last night).
A few days ago, the Canadian model was suggesting a signficant storm here from this center. I really believe it. Well, that’s “bye-bye” since the center is not well to the west of us as that Enviro Can model indicated it would be, but rather will end up right over us (which means much drier). The U of WA model run from this morning’s data says that a little “L” will be right over my house on Thursday morning (see reddish map below) ! Man, it will be cold over me! Might lose some plants in this one before its over.
However, I am going to stick my neck out and expect (hope) there will be just enough moisture for flurries around here (Catalina area) anyway tomorrow into tomorrow evening.
BTW, the U of A has just issued a special weather discussion here. You’ll want to check this out!
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