Thunderstorms, rain, hail, pummel Catalina finally!

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

Yesterday’s Clouds

6:50 AM. "Shape of things to come."
6:50 AM. “Shape of things to come1.”  “Nothing could change the Cumulus shapes of things to come” yesterday, to paraphrase here, as evident in this Cumulus shedding ice in the downwind decaying end on the left.
DSC_9096
7:35 AM. Look at this little guy, so full of ice. Another harbinger of the ice-filled clouds about to arise, and with ice, precipitation, snow aloft, graupel (tiny soft snowballs), and even some hail (solid ice). You could guess here from how shallow this Cumulus cloud is that the bases must be at near the freezing level, and tops must be at least as cold as -10° to -15° C, cold for such a small cloud. But what would we call such a small cloud? Cumulus congestus praecipitatio or virgae (since the present of ice absolutely means some precip up there, not likely reaching the ground though. Shoot from the hip estimated depth 2 km, or around six thousand feet.
11:37 AM. Sure enough, as it got warmer, Cumulus congestus/small Cumulonimbus clouds arose trailing ice northwestward in huge plumes of ice. Note to airborne researchers: be sure to sample the older parts of the turrets that have trailed downwind and turned completely to ice even though that trailing portion doesn't look much like a Cumulus cloud. It you only sample the newly risen portions, you will cheat the cloud out of how much ice it can produce since it takes a little time for all the ice to form. Lotta early airborne researchers made this error, reporting too little ice, but, of course, if they were in the cloud seeding business, they wouldn't mind at all since they could report that clouds needed more ice, that from their seeding activities!
11:37 AM. Sure enough, as it got warmer, Cumulus congestus/small Cumulonimbus clouds arose trailing ice northwestward in huge plumes of ice. Note to airborne researchers: be sure to sample the older parts of the turrets that have trailed downwind and turned completely to ice even though that trailing portion doesn’t look much like a Cumulus cloud. It you only sample the newly risen portions, you will cheat the cloud out of how much ice it can produce since it takes a little time for all the ice to form. Lotta early airborne researchers made this error, reporting too little ice, but, of course, if they were in the cloud seeding business, they wouldn’t mind at all since they could report that clouds needed more ice, that from their seeding activities!
11:37 AM. Oh, so pretty, those dark blue skies punctuated by a little muffin Cumulus cloud. Aren't you glad you live here?
11:37 AM. Oh, so pretty, those dark blue skies punctuated by a little muffin Cumulus cloud. Aren’t you glad you live here?
1:25 PM. Showers and small Cumulonimbus clouds trail off the Catalinas north of Bio2.
1:25 PM. Showers and weak Cumulonimbus clouds trail off the Catalinas north of Bio2.
1:25 PM. Showers track westward south of Catalina while the clouds over the Catalinas dissipate or remain disorganized while heading toward us.
1:25 PM. In the meantime, stronger Cumulonimbus clouds and showers track westward south of Catalina  toward Avra Valley while the clouds over the Catalinas dissipate or remain disorganized while heading toward us.
2:33 PM. A voluptous Cumulus congestus in the process of transitioning to a Cumulonimbus calvus (ice is visible but top stil pretty firm and round looking), then Cumulonimbus capillatus (fibrous top)
2:33 PM. A voluptous Cumulus congestus in the process of transitioning to a Cumulonimbus calvus (ice is visible but top stil pretty firm and round looking), then Cumulonimbus capillatus (fibrous top)  AN older turret, looking all ice, leans to the left.  Precip was already dropping out the bottom of this fat cloud.  What kind would it be?  Grauple, without doubt since so much supercooled liquid water  would remain in this cloud amid the ice crystals forming inside.  Those ice crystals, nice and pristine when they first form, would have their pretty forms obliterated by droplets that would freeze instantly on them, making them little snowballs, falling faster and faster, collecting more droplets.
2:46 PM. Moving rapidly away from Catalina, of course, that cloud has now become a Cumulonimbus capillatus (hairy, fibrous top a,most completely composed of ice--some liquid)
2:46 PM. Moving rapidly away from Catalina, of course, that cloud has now become a Cumulonimbus capillatus (hairy, fibrous top a,most completely composed of ice–some liquid may still arrive at cloud top in new turrets before quickly converting to ice.)  A portion of a rainbow can be seen at almost ground level.
2:48 PM. In the meantime, pretty strong storms, now having thunder, rage S through W of Catalina.
2:48 PM. In the meantime, pretty strong storms, now having thunder, rage S through W of Catalina.
3:14 PM. While we didn't have any great clouds near us, at least we had some nice lighting (not LTG) on the mountains from time to time.
3:14 PM. While we didn’t have any great clouds near us, at least we had some nice lighting (not LTG) on the mountains from time to time.
3:41 PM. Finally, the dramatic skies were shifting northward and measurable rain was on the doorstep. Looking SW toward Pusch Ridge and the Tucson Mountains.
3:41 PM. Finally, the dramatic skies were shifting northward and measurable rain was on the doorstep. Looking SW toward Pusch Ridge and the Tucson Mountains.
4:43 PM. Took awhile, but a decent Cumulus with a nice base now transitioning into a Cumulonimbus plopped some big drops and hail down. Streak at right is a hail particle with its fall distance in about 1/400 of a second.
4:43 PM. Took awhile, but a decent Cumulus with a nice base now transitioning into a Cumulonimbus plopped some big drops and hail down. Streak at right is a hail particle with its fall distance in about 1/400 of a second.
DSC_9220
4:47 PM. The hail got a little bigger and I took a picture of one of the stones, a little smaller than pea-sized in case you don’t believe me that some hail fell, too. Sometimes I think people don’t believe what I write, especially in footnotes….
5:02 PM. While the sunset was dramatic, it didn't bring the color hoped for, but this line of dark clouds presaged another bit of rain for Catalina.
5:02 PM. While the sunset was dramatic, it didn’t bring the color hoped for, but this line of dark clouds presaged another bit of rain for Catalina.

Except for a morning or afternoon sprinkle, no rain in sight, just a warm up back to above average temperatures.  Dang.

The End

———————-

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.

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.