The weather WAY ahead (10 days or more) – Page 10

Hawai’i in Arizona

Yesterday, in the wake of TD Odile, it was about as Hawaiian a day in Arizona as you are ever likely to see. First, the high dewpoints, ones that replicate those in HI, mid and upper 60s (69-70 F in HNL right now), cloud base temperatures of around 60 F, and with misty, even drizzly warm rain around at times. The only thing we didn’t see was a rainbow, so common in HI they named a sports team after them.

If you thought the clouds looked especially soft-looking yesterday, I thought they were, too. That soft look that also characterizes clouds in Hawaii and other pristine oceanic areas arises from low droplet concentrations (50-100 per cc), characteristic of Hawaiian clouds.¹ Both low updraft speeds at cloud base, and clean air result in low droplet concentrations in clouds.

The result of these factors?

The droplets in the clouds are larger than they would be forming in air with more aerosols (having “cloud condensation nuclei”, or CCN) and stronger updrafts at cloud base. Yesterday, you could have remarked to your neighbors late yesterday morning, as the rain and true drizzle began to fall from that Stratocumulus deck out to the SW-W, that the droplets in those clouds, “….must’ve exceeded Hocking’s threshold” of around 38 microns diameter. Lab experiments have demonstrated that when droplets get to be that large, which isn’t that large at all, really, that they often stick together to form a larger droplet, which in turns, falls faster and bumps into more droplets, and collects them until the original droplet is the size of a drizzle (200-500 microns in diameter) or raindrop (greater than 500 microns in diameter) and can fall out the bottom of the cloud.²

6:10 AM. Light drizzle or rain due to collisions with coalescence rather than due to the ice process falls from yesterday morning’s Stratocumulus deck (fuzzy, misty stuff in the center and right; eyeball assessment). Quite exciting to eyeball.

9:46 AM. So clean and pure looking, these clouds during a brief clearing yesterday morning. These might well have been seen off the coast of Hawai’i.

10:23 AM. One of the Hawaiian like ambiance of yesterday was both the low clouds, the humid air, and the green texture on the mountains highlighted by the occasional ray of sunlight. Fantastic scenes!

11:31 AM. Being a cloud maven, I wasn’t too surprised to see drizzly rain start to fall from our Hawaiian like Stratocumulus clouds, but I was excited!

11:41 AM. Stratocumulus clouds mass upwind of the Catalinas. Hoping for a few drops at least.

12:07 PM. An especially tropical looking scene I thought, with the very low cloud bases, the humid air; the warm rain process likely the cause of the rain on Samaniego Ridge.

6:08 PM. As the day closed, this fabulous scene on Samaniego Ridge. Clouds might be labeled Stratocumulus castellanus.

6:25 PM. As the air warmed in the clearings to the southwest and west of us, King Cumulonimbus arose. Expect some today around us.

Mods still coming up with cold snap at the end of the month, even with rain as the cold front goes by. How nice would that be to finish off September? Still have a couple of days of King Cumulonimbus around as tropical air continues to hang out in SE Arizona. Hope trough now along Cal coast can generate a whopper here before that tropical air leaves us. Am expecting one, anyway, in one of the next two days, probably our last chances for summer-style rain.

Speaking of Odile….

the thought that inches of rain might fall in Tucson, something we all heard about two eveings ago WAS warranted by the gigantic amounts that occurred as Odile slimed its way across extreme southeast AZ. In modeling terms, the error in its track was pretty slight, but the predicted amounts that we COULD have gotten were pretty darn accurate. I did not see these amounts until after writing to you yesterday. Note those several four inch plus values around Bisbee, and the one in the lee of the Chiricahuas. That one 4.45 inches over there suggests to me that the Chiricahuas like got 4-6 inches. Check’em out:

24 h rainfall ending at 7 AM AST yesterday for SE AZ (courtesy of the U of AZ rainlog.org site).

The End

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¹Except those affected by Kilauea’s “VOG” which have much higher concentrations, and look a little “dirty.”

²A thousand microns is a millimeter, in case you’ve forgotten, and that’s only about 0.04 inches in diameter. Most raindrops are in the 1000 to 3000 micron diameter range, though the largest, measured in Brazil, the Marshall and Hawaiian Islands, can be about a centimeter in diameter.

O, models, disappoint

Odile passed to the S and E of Cat land, leaving only 0.13 inches here in the Heights, the Sutherland ones. Didn’t even get the half inch I hoped for. Oh, well, we can be happy for the droughty areas of New Mexico that got the brunt of that tropical system as did portions of extreme SE AZ. You may know that for many days in advance and up until 11 PM the night before last (shown here), our best models had O practically passing right over us with prodigious rains indicated.

Unfortunately, we meteorologists often “go down with the ship” when this happens due to model forecast consistency. Only in the last minutes, so to speak, did the model runs get it right (but too late to be of much use) and finally indicated that the true path of the heaviest rain was NOT going to be over us, as was already being discovered via obs. O was such a cloud mess, the mods may have been off in locating where the center was. Not sure. Will have to wait for the panel report.

Seems to be preciping on the Cat Mountains right now, though doesn’t show up on radar, so its likely a RARE “warm rain” event here in AZ where the rain forms by collisions between larger cloud drops to form rain drops and the cloud tops are low¹. Maybe that’s O’s legacy; tropical air and a warm rain day sighting.

BTW, whilst Catalina and most of Tucson didn’t get much, it has continued to rain steadily in our mountains over the past 24 h with Dan Saddle, up there in the CDO watershed, leading the way with 2.09 inches in 24 at this hour (5 AM) and its still coming down lightly, as noted. Its been a fantastic rain since it was steady and soaking up there over that whole 24 h period, much like in our winter storms. Below, some totals from the PIma County ALERT gauges. You can see more totals here.

Gauge    15         1           3          6            24         Name                        Location
    ID#      minutes    hour        hours      hours        hours
    —-     —-       —-        —-       —-         —-       —————–            ———————
Catalina Area
    1010     0.00       0.00       0.00        0.00         0.16      Golder Ranch                 Horseshoe Bend Rd in Saddlebrooke
    1020     0.00       0.04       0.04        0.04         0.20      Oracle Ranger Stati          approximately 0.5 mi SW of Oracle
    1040     0.00       0.00       0.00        0.00         0.12      Dodge Tank                   Edwin Rd 1.3 mi E of Lago Del Oro Parkway
    1050     0.00       0.00       0.00        0.00         0.16      Cherry Spring                approximately 1.5 mi W of Charouleau Gap
    1060     0.00       0.00       0.00        0.00         0.16      Pig Spring                   approximately 1.1 mi NE of Charouleau Gap
    1070     0.00       0.00       0.00        0.00         0.04      Cargodera Canyon             NE corner of Catalina State Park
    1080     0.00       0.00       0.00        0.00         0.20      CDO @ Rancho Solano          Cañada Del Oro Wash NE of Saddlebrooke
    1100     0.00       0.00       0.00        0.00         0.08      CDO @ Golder Rd              Cañada Del Oro Wash at Golder Ranch Rd

Santa Catalina Mountains
    1030     0.00       0.04       0.04        0.08         1.73      Oracle Ridge                 Oracle Ridge, approximately 1.5 mi N of Rice Peak
    1090     0.00       0.00       0.04        0.04         0.75      Mt. Lemmon                   Mount Lemmon
    1110     0.00       0.00       0.00        0.00         0.43      CDO @ Coronado Camp          Cañada Del Oro Wash 0.3 mi S of Coronado Camp
    1130     0.00       0.04       0.04        0.04         0.31      Samaniego Peak               Samaniego Peak on Samaniego Ridge
    1140     0.00       0.08       0.28        0.35         2.09      Dan Saddle                   Dan Saddle on Oracle Ridge
    2150     0.00       0.00       0.04        0.08         0.71      White Tail                   Catalina Hwy 0.8 mi W of Palisade Ranger Station
    2280     0.00       0.04       0.12        0.16         1.02      Green Mountain               Green Mountain
    2290     0.00       0.04       0.04        0.04         0.47      Marshall Gulch               Sabino Creek 0.6 mi SSE of Marshall Gulch

BTW#2, true CMJs (cloud maven juniors) will want to photograph the rain from these shallow clouds, this rare, Hawaiian-like rain event², lining the Catalinas this morning as soon as its light enough. It would be like photographing a parakeet on your bird feeder here in Catalina, one migrating from South America. I think that’s where they come from. Anyway, your cloud-centric friends from other part of the world would be quite interested in seeing your photos of this.

Is the summer rain season over?

No way! (But you already knew that, though it sounds more exciting to put it that way, in the form of a question like the TEEVEE people do)

Now we get into some interesting weather times as we go back into the scattered big thunderstorms feeding on the moist plume that accompanied O. That moist plume will be around for the next few days. These coming days, with their thunder squalls, may well be the most “productive” ones for rain here compared to the piddly output of O here in the Heights. We have upper air goings on that are likely to make storms cluster more into big systems a time or two during the next few days instead just the one over here and over there kind of days, the ones you hope you get lucky on to get truly shafted. So, “fun times at Catalina High” ahead, to paraphrase something.

Yesterday’s clouds

11:15 AM. The look of a stormy sky, Stratus fractus lining Samaniego Ridge, overcast Nimbostratus producing R-- (very light rain). — 11:15 AM. The look of a stormy sky: Stratus fractus lining Samaniego Ridge, orogrpahic Stratocumulus topping the Ridge, overcast Nimbostratus producing R– (very light rain).

4:56 PM. By afternoon the deeper clouds were gone leaving Cumulus, a couple of distant Cumulonimbus clouds with their rain shafts, and an overcast of Stratocumulus or Altocumulus, no precip coming out of them.

6:28 PM. The sunset, while OK, like O was a little disappointing since more clouds could have been lit up by the setting sun but weren’t.

The weather way ahead

Cool weather alert: based on model consistency, which I have already discredited earlier, there are cold snaps now appearing for the end of September and early October. They’ve shown up in a couple of runs now. They have some support in the NOAA spaghetti factory plots.

The End.

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¹There’s a nice description of “coalision” , the warm rain process not involving ice, in Pruppacher and Klett (1998) if you really want a nice book about cloud microphysics in your library.

²Mostof the rain that falls in Hawaii falls from relatively shallow clouds with tops at temperatures above freezing, no ice involved, contrary to the usual situation here where ice is necessary.

Unexpected ice; rain to fall in September

Like you, I did not expect to see ice-in-clouds yesterday. I could feel your surprise when I looked to the north and saw traces of it in the exhaling part of a Cumulus congestus–like you, really didn’t think I’d see clouds that large, either. But there the ice was.

Later, it was even more obvious, and a fat cell even developed up there toward Globe in mid-afternoon. Didn’t expect to see one so close.

Also, did you catch the cluster of Cumulonimbi on the north horizon at sunrise? That was an unexpected sight for you and me as well.

I wonder, too, if you were down at Steam Pump and Oracle you noticed that a few drops of rain fell? That was really unbelievable, since it was practically clear overhead when I exited the PF gym and saw them on the car I had just washed and waxed in the belief that no rain could fall for at least 10 days. Yes, it was a day of surprises for both of us.

Didn’t think I’d be bloggin’ today, either. Life has so many unexpected twists and turns.

Yesterday’s clouds

: 6:05 AM. Unexpected sighting number 1: Dawn Cumulonimbi up there toward the Mogollon Rim.

11:37 AM. Unexpected sighting number two, ice. See far right frizzy, smooth area in "exhaust" part of Cu. — 11:07 AM. Unexpected sighting number two, ice! See center right frizzy, smooth area in “exhaust” part of Cu.

11:37 AM. Unexpected sighting #3: Didn't think those turrets could extrude so far into the extremely dry air above those tops, but there it is, extruding like anything. (Center right). Also note the ice in the lower tops, left center, and the hint of a rain shaft! Unbelievable. — 11:37 AM. Unexpected sighting #3: Didn’t think those turrets could extrude so far into the extremely dry air above those tops, but there it is, extruding like anything. (Center right). Also note the ice in the lower tops, left center, and the hint of a rain shaft! Unbelievable. The dark blob at left in mid-air, obscuring a portion of the cloud, is a pipevine swallowtail butterfly that surprised me by flying into the frame as I snapped the photo. Yesterday may have been the most surprising day of my life, maybe yours, too.

2:18 PM. “USN4”: This gargantuan cell up there by Globe. Unbelievable that a cell this big was so close to our area considering all the dry air that was moving in.

2:28 PM. A surprisingly thin turret that has gone completely to ice (right side). The extruding turret on the left, certainly would have some ice in it, but also, as you can see from its texture, has a lot of liquid cloud droplets in it, too. This is a nice example of the glaciation cycle in a small cloud.

3:40 PM. Showers, and likely some thunder out there, just a few miles N of the Biosphere 2 facility. A pretty scene since the blue of the sky is darker now as the sun's elevation sinks toward the winter solstice. — 3:40 PM. Showers, and likely some thunder out there, just a few miles N of the Biosphere 2 facility. A pretty scene since the blue of the sky is darker now as the sun’s elevation sinks toward the winter solstice.

3:48 PM. Thunder beyond the Lemmon. The turret on the left has converted to all ice, while the mounding ones in the center and right, still have some liquid cloud droplets. The soft-serve look, compared to the crenellations of droplet clouds is due to the differences in concentrations. There are always few ice particle concentrations than droplet concentrations so droplet clouds look thicker, have sharper edges, more detail, but, we've been over this more than a few times. Sorry to belabor the point. — 3:48 PM. Thunder beyond the Lemmon. The turret on the left has converted to all ice, while the mounding one in the center, still has some liquid cloud droplets. The “soft-serve” look on the left, compared to the crenelations of droplet clouds, in particular, that darker turret in the center, is due to the differences in concentrations between the two phases. There are always fewer ice particle concentrations than droplet concentrations in clouds, and so droplet clouds look thicker, have sharper edges, more detail. But, we’ve been over this more than a few times. Sorry to belabor the point.

The weather way ahead

Mods continuing to show rain in our area sometime between the 6th and 12th of September, which would result in a non-rainless September. Sometimes, those mods think its due to a tropical storm remnant of a tropical storm that hasn’t formed yet. So, its quite mystical, that rain.
Still, the indications are that some rain will return after the long dry spell ahead.

Best model output for you

Been looking around at quite a number of model runs (well 2, anyway) trying to find the best one for you. Here it is. Its yesterday’s WRF-GFS run that was based on 11 AM AST global data. Has some great rains for us here in Arizona. Those rains, and that incredible hurricane that saunters up the coast of Baja in about ten days, aren’t depicted as well in later model runs, so there’s not much point in showing them. If you want a great, OBJECTIVE forecasting, you know, go to Bob, or the NWS, or wait for Mike L’s detailed one from the U of AZ later this morning! You’re not going to find “objectivity” here when it comes to forecasting rain for a desert region¹. Let’s look at two examples of weather excitement in that now-obsolete-run-but-doesn’t-mean-it won’t-happen-anyway-just-because-its-a little-older-run”¹: 1) Lotta rain in Arizona (that’s a different near-hurricane over there in the SW corner of the map, one that in one model run from Canada, formerly went over Yuma! Sorry Yuma, and all of Arizona, both of which would have gotten, in that event, a bigger dent in the drought than shown below. Oh, well.

2014081818_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_072 — Valid on Thursday at 11 AM AST. Green pixels denote those areas where the model thinks rain has occurred during the prior 6 hours. Most of AZ covered in green pixies! Sweet.

2) Fascinating near-hurricane just off San Diego on the 29th of August, likely surviving so well due to the California Niño mentioned here lately. BTW, this particular hurricane is predicted to be exceptionally large and intense out there when it revs up in a few days, maybe a Category 4 at its peak, looking at some of the model runs. “Let’s go surfin’ now, everybody’s learnin’ how….” The Beach Boys, 1962, sayin’ it like it was for us near-beach bums way back then when the summer hurricanes in the Mexican Pacific sent huge waves poleward on to our southern California beaches, as the one below will².

Valid in ten days. — Valid in ten days, Friday, August 29th at 11 AM AST. Near hurricane brings rain to San Diego. Colored regions now denote where the model thinks it has rained in the prior TWELVE hours (coarser resolution because its not going to be that accurate in the placement of highs and lows anyway, so why waste time over-calculating stuff?

Yesterday’s clouds

What an outstanding, if surprising day it was! After it appeared, in later model runs available late yesterday morning, that the late afternoon/evening bash from the high country wasn’t going to happen after all (producing local glumness), we had a remarkable in situ explosion of cloud tops. Those clouds just erupted from an innocuous, patchy group of Stratocumulus that invaded the sky around 5 PM. Still, even with the early turrets jutting up there, it didn’t seem possible, at 7 PM, there would be much more growth into showers, let alone, thunderstorms with frequent lightning lasting several hours that happened. Eventually rain even got into Sutherland Heights/Catalina, with 0.17 inches here, and 0.12 inches at the Golder Bridge, and that didn’t seem possible since the rain shafts were so locked onto the Catalinas, and east side for so long. Dan Saddle, about 5 mi S of Oracel, counting the mid-afternoon thunderstorms that locked in upthere, got a 2.68 inches over the past 24 h! That should have sent a little water down the CDO. BTW, a location in the Rincons is reporting 4.09 inches in the past 24!

5:50 AM. Day started with "colorful castellanus." Hope you saw this. — 5:50 AM. Day started with “colorful castellanus.” Hope you saw this.

Update ann DSC_0239 — 12:26 PM. After a late morning start, the Cumulus congestus tops were streaming away from the origin zone of Mt. Lemmon to over the north part of Saddlebrooke and the Charouleau Gap. No ice evident yet, but it was just about to show itself.
BTW, the “51ers” have a nice baseball team in Vegas (of course), this brought to my attention by neighbors recently, showing that a degree of strangeness permeates American life, as also shown in these blogs.

12:44 PM. Ice virga now seen in the right hand side falling out as I passed the budding wildlife overpass now being constructed on Oracle Road. I guess scents and signage will be used to direct wildlife to the overpass.

1:49 PM. Took about an hour more of rain and development for the thunder to start from these locked in turrets that kept springing on The Lemmon.

4:54 PM. Long before this, it was "all over', the rains no doubt up there had helped to put the fire out, so-to-speak, and with no anvils advancing toward us, there was even hardly any point to remain conscious. It is done. — 4:54 PM. Long before this, it was “all over’, the rains no doubt up there had helped to put the fire out, so-to-speak, and with no anvils advancing toward us, there was even hardly any point to remain conscious. It is finished.

6:54 PM. Shallow grouping of Stratocumulus provided a nice, if boring, backdrop to the setting sun's light on Samaniego Ridge. — 6:54 PM, 2 h later. Shallow grouping of Stratocumulus provided a nice, if boring, backdrop to the setting sun’s light on Samaniego Ridge.

7:04 PM. Only ten minutes later, and I'm out wondering around in the backyard looking for a nice sunset shot, when I see this shocking site, a protruding turret far above the other tops. Still, I pooh-poohed anything but a ragged collapse in the minutes ahead. It was too late in the day for heating or anything else to generate rain in situ from these lower clouds (now topping Mt. Lemmon). — 7:04 PM. Only ten minutes later, and I’m out wondering around in the backyard looking for a nice sunset shot, when I see this shocking sight for the time of day, a protruding turret far above the other tops. Still, I pooh-poohed anything happening but a ragged collapse in the minutes ahead. It was too late in the day for heating or anything else to generate rain in situ from these lower clouds (now topping Mt. Lemmon). Nice pastel colors, though.

7:32 PM. Though "pinkie" in the prior photo did fade, new turrets kept bubbling upward, and in disbelief, this one reached up beyond the ice-forming temperature threshhold (is probably topping out between 25-30 kft, not huge) and a strong rain shaft emerged on the Catalinas. After a little while longer, lightining began to flash to the east as the Reddington Pass area started to get hammered. Eventually in the early nighttime hours. these cells propagated to the west, giving us that bit of rain here in The Heights of Sutherland. How nice, and how mind-blowing this whole evening was! — 7:32 PM. Though “pinkie” in the prior photo did fade, new turrets kept bubbling upward, and in disbelief, this one reached up beyond the ice-forming temperature threshhold (is probably topping out between 25-30 kft, not huge) and a strong rain shaft emerged on the Catalinas. After a little while longer, lightining began to flash to the east as the Reddington Pass area started to get hammered. Eventually in the early nighttime hours. these cells propagated to the west, giving us that bit of rain here in The Heights of Sutherland. How nice, and how mind-blowing this whole evening was!

Today

Got some Stratocu (castellanus in some parts) topping Sam (Samaniego Ridge) this morning, an outstanding indication of a lot of moisture in the air, moisture that’s not just at the surface. U of AZ has thunderstorms moving toward Catalina during the late morning (!) and afternoon from the SW, not the usual direction we’re accustomed to. So, keep eyeball out toward Twin Peaks or so for exciting weather today! Oh, my, towering Cu top converted to ice, must be 25-30 kft up there right now at 7:06 AM! Also, notice nice shadow on lower Ac clouds.

The End

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¹“Truth-in-packaging” portion of web blog statement.

¹Its chaos in the models due to errors in them we don’t always know about, chaos that we try to get a handle on with plots from the NOAA spaghetti factory. But you know all that already, so my apologies for repeating myself again and again. I thought I would see what would happen if I put TWO “1” footnotes….

²Of course, in those days, we had little knowledge about how many hurricanes there were down there due to the lack of satellite data and ship reports. But when the “Weather Bureau”, as it was called in those days did know, there was always good surf on the south facing beaches, like Zuma Beach. So going to the beach, unlike now where wave forecasting is so good, was a real crap shoot. You’d come over that first viewpoint of the ocean on Malibu Canyon Road, on your way to Zuma. one that over looked the ocean a little offshore from Malibu, and either go, “Holy Crap!”, or hope for the best. It was a swell time for lightly employed youth. Below, the best “Holy Crap!” view coming around to that viewpoint, early September 1963 (never saw anything like it before or afterwards; swells were never visible so far offshore from this spot, meaning Zuma would be gigantic). Still remember those Zuma waves, so far out to sea, as the height of small telephones…

Nearly drowned that day at Zuma, me and my pal ignoring lifequard's advice not to go in. HELL, we'd been body surfing the biggest ones we could there for years by then. Fortunately, he didn't have to come and get me, which saved a lot of face. — Nearly drowned that day at Zuma, me and my pal ignoring lifequard’s advice not to go in. HELL, we’d been body surfing the biggest ones we could there for years by then. Fortunately, he didn’t have to come and get me, which saved a lot of face.

Much adieu about nothing (i.e., no rain)

There are a lot of photos here of yesterday’s clouds, considering it was a day with no rain. Oh, well, pretty normal for a cloud-centric person where the least cloud minutiae is somehow “interesting.”

8:13 AM. Very gratifying and a little surprising to see the first tiny Cu spring up so early in the morning off'n Lemmon. But, would it be only shallow moisture? — 8:13 AM. Very gratifying and a little surprising to see the first tiny Cu spring up so early in the morning off’n Lemmon. But, would it be only shallow moisture?

10:13 AM. Also a promising sign, a thin turret rising out of a blob of small Cu. Mr. Cloud Maven Person apologizes in advance if this shot is somehow offensive. — 10:13 AM. Also a promising sign, a thin turret rising out of a blob of small Cu. Mr. Cloud Maven Person apologizes in advance if this shot is somehow offensive by suggesting a middle finger.

10:52 AM. Clouds mass above Ms. Lemmon, BUT, can they reach the ice-forming level where the temperature is as low as -10 C (14 F) or lower so that they can rain? I'm thinking it'll be close, but was not real hopeful. — 10:52 AM. Clouds mass above Ms. Lemmon, BUT, can they reach the ice-forming level where the temperature is as low as -10 C (14 F) or lower so that they can rain? I’m thinking it’ll be close, but was not real hopeful.

11:19 AM. Amazing! On this expected to be dry day, Ms. Lemmon and her environs have created a Cumulonimbus cloud! Nowhere within a hundred miles was there another cloud like this!

11:19 AM. Zoom of the icy "calvus" top in the middle (its not very fibrous yet, but is clearly loaded with ice, unlike the crinkly turret at left. Sometimes that "calvus" look is compared with the look of "cotton candy." You remember, cotton candy don't you? — 11:19 AM. Zoom of the icy “calvus” top in the middle (its not very fibrous yet, but is clearly loaded with ice, unlike the crinkly turret at left. Sometimes that “calvus” look is compared with the look of “cotton candy.” Within about 10 s, there was a rumble of thunder! You remember, cotton candy don’t you?

12:56 PM. Pretty clear here that the day was done as far as Cumulonimbus clouds are concerned as the drier air moving in the from the west took it toll, and well as the cooling of the mountains by the prior thunderstorm. Or was it done? CM thought so, but maybe I shouldn't tell you that, causing you to lose confidence. — 12:56 PM. Pretty obvious here that the day was done as far as Cumulonimbus clouds over the Cat Mountains are concerned as the drier air moving in the from the west began to take its toll, as well as the cooling of the mountains by the prior thunderstorm. Or was it done? CM thought so, but maybe I shouldn’t tell you that, causing you to lose confidence.

1:50 PM. A truly shocking sight to CM. The Cumulonimbus clouds were able to start up again!

2:04 PM. Mr. Cloud Maven Person enjoys showing you how fast cloud tops can glaciate, and this was a nice case. — 2:04 PM. Mr. Cloud Maven Person enjoys showing you how fast cloud tops can glaciate, and this was a nice case (Cb calvus stage here).

5:23 PM. Well, it was all over by this time, no more Cbs, but here's a Cumulus mediocris showing crepuscular rays (ray features due to high aerosol content of the air). — 5:23 PM. Well, it was all over by this time, no more Cbs, but here’s a Cumulus mediocris showing crepuscular rays (ray features due to high aerosol loading of the air).

7:32 PM. Nice pastel colored Cirrus spissatus cumulonimbogenitus (I couldn't stop with just "Cirrus", I had to ruin it with a long unpronounceable part. Oh, well, that's what cloud-maven person does. — 7:32 PM. Nice pastel-colored Cirrus spissatus cumulonimbogenitus (I couldn’t stop with just “Cirrus”, I had to ruin it with a long unpronounceable part. Oh, well, that’s what cloud-maven person does.

Next and maybe last rain of the summer (kidding only a little) looks to be around August 3rd still. Flow aloft looking awfully grim overall for summer rain in Catalina mod longer term predictions… This may be the worst thing I have ever said to a desert people during their “wet” season. Let’s hope we have about 5 inches on August 3rd or so!

Snowbirds may head back to Arizona as low temperature records fall in the eastern US in a few days

Forgetting about yesterday’s unforecast subdued afternoon convection hereabouts after about 1 PM), lets talk about the misery of others; the little crybabies that leave Arizona in the summertime, decimating its economy, so that they can be cooler and “happy” in northern climes (while dodging hail and tornadoes, we might add).

Well, how about them birdies being really COLD before very long, due to record breaking low July temperatures? Yes, that’s right, what’s left of the “polar vortex” will once again, due to global warming, of course, spin out of control and down into the northern US in just about 5-7 days. And with it, long term July low temperature records will fall in the eastern US. Count on it.

So, once again, as some scientists alleged last winter, global warming will actually cause cooling. (Almost everything that happens is due to GW these days, as we know. (“GW”, BTW, now repackaged in the catch all, temperature-neutral phrase, “Climate Change”, during the past few years because, globally, it stopped getting warmer way back in ’98, and when the years began to pile up without global warming, scientists had to find another phrase to hang their mistaken hats on. (Where was the usual scientific “caution” back then?)

HOWEVER, continuing on with this harangue, and being a “lukewarmer”, we must watch out that the coming big El Nino doesn’t release a spring-loaded, pent up release of global heat. Might well happen, so don’t give up on “GW” quite yet; hold some cards on that question for another few years.

And, of course, if there is a step jump up in global temperatures just ahead, the phrase, “climate change” will be dumped by scientists and media for “global warming” again. Count on it, #2.

But, I digress, mightily, mainly due to yesterday’s cloud disappointments.

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Not in a great mood after yesterday’s bust, as you can tell, except for that strong thunderstorm that pummeled the north side of the Catalinas beginning about 11:30 AM, that was pretty cool; had continuous thunder for about an hour and a half, too. Dan Saddle up on Oracle Ridge got 0.63 inches, but you can bet 1-2 inches fell somewhere up there.

I was so happy then.

I thought the “Great Ones” would arise upwind of us in the direction of Pusch Ridge, but no. Those clouds got SMALLER as the afternoon wore on, it was incredible, and by sunset they were gone with only trashy debris clouds of Altocumulus and Altostratus cumulonimbogenitus from great storms in Mexico drifting over our sky. Even the sunset was disappointing.

Well, that 3:15 am to 3:30 am little shower this morning than dropped 0.15 inches here in the Heights, and 0.24 inches down there at the Bridge by Lago del Oro gave a psych boost¹ that got me here on the keyboard.

10:55 AM. Nearly invisible veil of ice crystals begin to fall from an older Cumulus congestus turret. This was about an hour and a half ealier than the prior day, indicating that the Cu tops were reaching that level sooner than the prior day, suggesting bigger things (I thought). When you see this happening this early, you also look for an "explosion" some massive turret to suddenly blast out of these developing clouds, and that did happen within about half an hour after this. — 10:55 AM. Nearly invisible veil of ice crystals begin to fall from an older Cumulus congestus turret. This was about an hour and a half ealier than the prior day, indicating that the Cu tops were reaching that level sooner than the prior day, suggesting bigger things (I thought). When you see this happening this early, you also look for an “explosion” some massive turret to suddenly blast out of these developing clouds, and that did happen within about half an hour after this.

10:55 AM. Close up, in case you don't believe me. — 10:55 AM. Close up, in case you don’t believe me.

Today? Check here. Once again, mod expects early Cumulonimbus on The Lemmon, then groups of thunderstorms move in during the evening (as was more or less predicted yesterday, but didn’t happen.) Will go with mod again, though, because I would like that to happen.

The weather way ahead

We’ve talked about cold air, now to balance things off, how about a discussion of the warm air ahead? Real hot air.

Was blown away by the spaghetti outputs from last night for the period of about two weeks from now. You can see the whole package from the NOAA spaghetti factory here. Below, our weather in 12-15 days, usually beyond confident predictions, but not here:

201407221700 spag_f288_nhbg — Valid at 5 PM AST July 22nd. Massive blob of really hot air settles in over the western half of the US. In this map, the most reliable long term predictions are over the western half of the US and over the Saharan Desert (indicated by the lack of lines in those two areas. A lot of lines means the weather pattern is pretty unpredictable.)

Valid at 5 PM July 22nd. Massive upper level blob of really hot air sits over the entire West! — Valid at 5 PM July 25th. Massive upper level blob of really hot air continues to dominate the western half of the US.

The hot blob of air should lead to record HIGH temperatures all over the place in those days beginning around the 20-25th of July. Rainfall here? Indeterminant. If the high center sits over us, it might just be hot, real hot, but dry.

But, if the configuration aloft is as shown in the second plot, it could be very wet as tropical disturbances shift northwestward from Mexico into Arizona.

Sorry, can’t do much with precip from these, I don’t think.

The End, and covering all the possibilities, CM

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¹Paraphrasing, the song for weathermen, those speaking to clouds; “Rain on me, when I’m downhearted….”

A day with Cirrocumulus, Cirrus and Cumulus; summer rain season looks to start on time

What a day, Mr. and Mrs. Catalina, except for that last second “header”:

7:57 AM. Cirrocumulus with exceptionally fine granulation (left center). You might feel a little chop if you were flying in it, but it would be hardly anything. More chop, lower right, where you have something akin to ocean waves rolling along from left to right.

8:04 AM. Pretty Cirrus fibratus (strands are pretty straight in Ci fib).

4:47 PM. Pretty scene over the S-Brooke population complex. — 4:47 PM. Pretty Cu humilis and fractus scene near the S-Brooke population complex.

5:05 PM. Nice shadow bounding the Catalinas, — 5:05 PM. Cu hum and fractus over the Catalinas, Nice shadow bounds the mountains I thought.

The weather way ahead, 10 days and beyond; dreaming green pixels

Rain showing up around these parts beginning overnight on July 3rd-4th, kind of a normal time for a summer rain season onset. This from last evening’s global model crunch. Prior model runs have been dry, so it could be bogus, of course. But, its a hopeful sign. Rains every day after that in this run. Below, the titillating start as rendered by IPS MeteoStar:

Valid at 5 AM AST July 4th. Green areas show those ones where the model has calculated some rain in the prior 12 h.

Valid at 5 PM AST July 8th. Raining all over Arizona by this time. How great would that be? Com'on model! — Valid at 5 PM AST July 8th. Raining all over Arizona by this time. How great would that be? Com’on model! Don’t let me down! A feel a really old song coming on about being let down.

Let’s look at some spaghetti and see if the “solution” above has any credibility at all:

Valid at 5 PM July 4th. Note gaps in red lines in northern Arizona and NM. Errorful mod runs are therefore pretty confident the necessary ridge of high pressure aloft WILL be centered to the north of us. So, there is a fair amount of confidence from spaghetti that the summer rain season will start pretty much on time. — Valid at 5 PM July 4th. Note gaps in red lines in Arizona and NM. Errorful mod runs (deliberately so, recall) are therefore pretty confident the necessary ridge of high pressure aloft WILL be centered just to the north of us at this time, extruding all the way from the central Atlantic. So, there is a fair amount of confidence from spaghetti that the summer rain season will start pretty much on time. What’s also supportive is the bulge in the jet stream to the north in southern Canada, as indicated by the bunching of those bluish lines. Pac NW looks cool and rainy with this pattern, BTW. You can enjoy more spaghetti here.

So, right or wrong, you heard it here first because I got up early; summer rain season looks to start on time.

The End.

The streets of Marana-Oro Valley-Catalina, the cloud ones

In case you didn’t notice, there was a prolonged street of clouds emanating from possibly as far away as Kit Peak, or maybe just the Tucson Mountains. Lasted for a few hours.Happens only on days with relatively shallow clouds (cloud-topped boundary layer) with a little wind, meaning that the thermals from the surface heating ended up being capped by an inversion or other stable layer, and those thermals form clouds in some places. In this case, a long line of intermittent clouds formed from an initial air bump caused by those mountains far to the SW of us. CTBL is more often invoked as a term by cloud folks when the sky is much cloudier in low clouds than these shots from two days ago, such as when the sky is covered in Stratocumulus clouds.

These kinds of streets occur over the same places whenever a day like this comes along. Think of it, especially here in Arizona, as a row of shady air under which you might like to live compared to those areas on either side of this cloud “street.” In Seattle, where the “cloud topped boundary layer” is almost a daily occurrence, you want to avoid being under the cloud street, where it can block the sun, and instead find the clearer slots!

3:19 PM. Barely hanging on now, but still present. Dissipated within about a half hour of this shot.

TUS rawin for June 18th, 5 PM AST (launched about an hour and a half before that).

For those sharpies that day and logged in their cloud diaries that ice formed in those shallow Cumulus clouds, they will be a little chagrined by this TUS sounding. This sounding suggests the clouds around the balloon were topping at -8 C, too warm for ice formation in shallow Cu. Let us begin to explain this puzzle by presenting evidence of ice formation in those clouds on the 18th:

4:13 PM. Virga hangs down from Cu mediocris, maybe only a km thick toward Charoleau Gap. — 4:13 PM. Virga hangs down from Cu mediocris, maybe only a km thick toward Charouleau Gap. Lots of ice visible.

4:13 PM. Overhead view of likely ice vellum between Cumulus clouds. The clouds themselves may well have a few ice crystals, but too few to provide any visual indication except in the clearings between them. Ice crystals evaporate more slowly than liquid drops when encountering sub-saturated air between clouds, and so can be visible a bit longer if present between clouds in marginal situations like this. Confidence level that this little patch is ice and not just haze is about 70-80 percent.

Simple answer to our connundrum; due to lifting of the air as it approached and went over the Catalina Mountains, the tops of the clouds reached those temperature below -10 C where is begins to form. We would guess even closer to -15 C in that cloud in the distance beyond Charouleau Gap due to the amount of ice. Ice increases with decreasing cloud top temperature, but the temperature at which ice onsets can change on a daily basis; higher onset of ice temperatures on days in which the clouds have larger drops in their tops (a phenomenon originally reported by Ludlam in 1952, then re-discovered by Rangno and Hobbs (1988) who did not, at that time, know of the Ludlam finding, and thus, did not cite it. Pretty embarrassing, really. Was cited later in an update, however.

The weather way ahead

Seasonal rains beginning to show up in southern Arizona now on models beginning around the 4th of July as a big anti-cyclone parks itself over the Four Corners area in the latest model run from 11 PM AST last night. Very excellent run.

The End

‘Manda rain

BTT you read this, rain oughta be falling or near by as the remnants of ‘Manda hurricane dribble into Arizona today. Looks like there’s just enough rain upstream right now (4 AM) to produce, hold your breath, a MEASURABLE amount here in Catalina! Likely will be just a few hundredths, though, as much as two tenths is about the top potential from this. At this point, anything measurable is a fabulous rain!

Mods have been oscillating on whether it would rain here for many days, but last night’s run ended pleasantly with a “correct” forecast of measurable rain. See green pixelation over Catalina below:

Valid for 11 AM AST today. Heart of rainband over us then, mod says. — Valid for 11 AM AST today.
Heart of rainband over us then, mod says. From IPS MeteoStar.

Your Catalina cloud day

(Also, another great cloud movie from the U of AZ here....)

5:15 AM. Cirrus, leaning toward “spissatus”, heavy dense patchy Cirrus.

7:42 AM. Cirrus fibratus/uncinus. “Cirrus” will do it.

4:35 PM. What would a day be like without Altostratus? Here, “translucidus” because the sun’s position is visible. When the sun can’t be seen, its “opacus”, like a lot of science can be.

5:27 PM. Walkin’ doggie and this seemed like a nice shot of the rustic neighborhood streets, the Catalinas, and up top, some glaciating Altocumulus, castellanus on the right side; hasn’t gone through the ice forming stage yet, or the ice hasn’t fallen out that’s in it.

7:18 PM, Crepuscular rays show up as the sun sets due to smoke and haze under the clouds. The clouds? A mix of flakes of Altocumulus and Altostratus (the solid blob), some Cirrus on top of it all.

The weather way ahead…

Not a lot showing up here for mid-June, so won't say anything about that. — Valid for June 12, 5 PM AST. Not a lot showing up here for mid-June weather, so won’t say anything about that. I suspect it will be warm, though.

Nice weather we’re having; snowbirds ejected to the north too soon

Sure, there was a little mischievous wind in the early afternoon, BUT, as a day in late May in Catalina/Sutherland Heights zone of Arizona, wherein the temperature is less than 100 F, well, it was pretty darn great. Another one is on tap today just like yesterday today, too. Feeling sad about the early, northerly ejections of “snowbirds” who thought because of the warm winter, May would be an inferno here and are missing some splendid weather. Doesn’t work that way. You just don’t know.

Lot of interesting clouds yesterday, too, real cold ones. Those Cumulus that formed in the late morning and afternoon started producing ice almost immediately. Wonder if you caught the first ones over there beyond the Charouleau Gap around 11 AM? They did not look as high-based as they were, thus, as cold overall, dad-gum, those cloud bottoms were running around -10 C (14 F)!

How high off the Catalina ground were they? Oh, about 13,000 feet, or about 16,000 feet above sea level (about 550 millibars). I woulda guessed, as you would have, about 8,000 feet off the ground when I first saw them forming (and not looking at the temperature and dewpoints, from which you can make a pretty good calculation of the cloud base height). From the Cowboys at the U of Wyoming, this sounding for TUS yesterday afternoon:

The Tucson balloon sounding for yesterday afternoon, launched around 3:30 PM, ascends at about 1,000 feet a minute.

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Weather Hints for Every Day Use by “Art”: You can calculate the height of a Cumulus cloud base by taking the difference between the temperature and the dewpoint, dividing it by 5, square that number, add the number you started with, and subtract the square root of 2.

DId I get the number you started with?

(Actually, stop at “dividing by 5”, multiply that number by 1000, and you’ll come out just about right. Yesterday, 85 F temp, 20 F dewpoint, leads to 65 F difference, divide by 5, you get 13, and times a thousand is an estimated CUMULUS cloud base of about 13,000 feet above you, not too bad).

———————-

Continuing….. Since bases were so cold, tops were exceptionally cold, too, for shallow Cumulus and started producing ice when they were only about 1,000 to 3,000 feet thick, with cloud top temperatures of -15 C to -20 C (about 4 F to -4 F). Some of the highest tops, all east of us, and mostly on the east side of the Catalina Mountains, were likely as cold as -30 C (-22 F).

You can see yesterday’s small Cu spewing ice in the great U of AZ time lapse movie here. Only plays for one day, though.

You may also have noted in your cloud diary the bifurcation in the Cumulus array of yesterday. Almost no Cumulus west of Catalina, and plenty in the east half of the sky, appearing to be largest in the distance in the east. We were literally on the edge of the moist plume from the south that was hoped to end up been west, with us deeply embedded in it, and where measurable rain might have fallen here as it did east of us yesterday. Oh, well.

Today, with a low center passing over us tonight and a blob of Pacific Ocean air in it, and while that air is cold and pretty dry aloft, it will be a little more moist and so cloud bases today should be a little lower, and warmer, than yesterday’s. That means a little more water condensing in them than in yesterday’s clouds, and a greater chance of sprinkle here. Hoping for measurable, but its probably less than a 50-50 shot at that. Likely will be some thunder in the area of SE AZ, too. And, as always with high cloud bases, gusty winds that arise due to virga and rain falling through the dry air below cloud base. (Yesterday afternoon’s gales in the Sutherland Heights, momentary blasts of 40-50 mph, were NOT due to virga, but a rather to something I didn’t see coming, maybe a smallish low center–nothing really showed up on the maps.)

You can see the forecast trajectory of that upper low coming toward us, from the University of Washington’s Huskies, whose #14 softball team plays away, really away, at #1 Florida in Gainesville this weekend–how crummy is that except for the great Cu there and its important enough to be on TEEVEE Saturday?) computer output by clicking on this informative sentence.

You will also see in the above loop that our low takes its time moving along, and will keep the skies interesting with Cumulus and weak Cumulonimbus clouds today and tomorrow, along with temperatures below seasonal norms for late May (aka, less than 100 F) ((Snowbirds left too soon; ice still melting off some areas of the Great Lakes!))

From the cloud vault; yesterday’s clouds

10:28 AM. Small Cu began forming in the lee of the Catalinas during a horseback ride with a friend, in case you didn't think someone as cloud-centric as me could have a friend. — 10:28 AM. Small Cu with lenticular type tops began forming in the lee of the Catalinas during a horseback ride with a friend, in case you didn’t think someone as cloud-centric as me could have a friend. Calm winds, then, too.

11:08 AM. First ice! Can you spot it? — 11:08 AM. First ice! Can you spot it in the distance? Horse can’t believe that ice is forming already, and is rolling around in ecstasy, thinking about what it might mean for the afternoon.

1:43 PM. Approaching low with air moving upward ahead of it, triggers a batch of Cirrus and Cirrocmulus lenticularis (really high lenticularis) upwind of Catalina and above some Cumulus fractus.

3:18 PM. One of the more remarkable sights yesterday, were the small Cumulus clouds (humiilis or mediocris) that iced out. Look at ll the ice that formed in this small cloud, exiting on the left side, but dominates the whole cloud from this viewpoint. When you see this, it tells you how COLD those clouds are. First guess should be around -20 C at top when you see this much ice in a cloud this SMALL. Clouds having warmer bottoms, can have warmer tops that look this icy because ice forms in clouds at higher temperatures when the drops in them are larger. — 3:18 PM. One of the more remarkable sights yesterday, were the small Cumulus clouds (humiilis or mediocris) that iced out. Look at ll the ice that formed in this small cloud, exiting on the left side, but dominates the whole cloud from this viewpoint. When you see this, it tells you how COLD those clouds are. First guess should be around -20 C at top when you see this much ice in a cloud this SMALL. Clouds having warmer bottoms, can have warmer tops that look this icy because ice forms in clouds at higher temperatures when the drops in them are larger (see Rangno and Hobbs 1994, Quart. J. Roy, Met, Soc.) Oh, yeah, baby, have some pubs!

6:58 PM. Iced out Cu/weak Cumulonimbus beyond the Gap, the Charouleau one, end the day. Shoot, a slight change in trajectory from the south, and they woulda been here.

7:00 PM. Meanwhile, all quiet to the NW, no Cu whatsoever demonstrating the moisture edge we were on.

The weather ahead and WAY ahead

Now what I think is really interesting, which is almost everything to do with weather, is that the models are suggesting a tropical injection again at the end of MAY into early June, with a chance of a decent rain again. As you can see in the plot below from the NOAA spaghetti factory, a trough to the west of us and over California is a virtual certainty now at the end of May. That means the air above us will be, while quite warm, originating from the deep Tropics with the likelihood of clouds and precip coming up from there. Nice. Will keep me posted on these developments, in case no one else is reading this far.

The End.