Definitions – Page 58

Thundering and thundering but no raining and raining

Not here, anyway…

We live in interesting times. As with so many days since June 30th, thunder almost rules the day, going on intermittently for hours, as it did yesterday. And yet, only a little rain, just a few drops from an anvil overhang just after 2 PM, can find its way here to my house here in Sutherland Heights, Catalina. I know areas down toward Golder Ranch Drive and just south of there have gotten brief hard rains this July, but not here. What is going on?

Or what is NOT going on? Not enough heating I guess, only the very highest terrain participated in Cumulus and Cumulonimbus production yesterday; those cloud bottoms just could not work their way off the mountain tops, and so only the middle and higher dissipating portions dribbled over Catalina land. No disturbances to group them either, regardless of temperature, like two mornings ago when the line-cluster of thunderstorms came through.

Lets just hope that upper low that used to be over Virginia a coupla days ago can get here and be that needed “disturbance.” You probably didn’t know that weather moves from Virginia, or even Ohio, to Arizona…..well, its happened, and no doubt due to climate change where weather is backward from what it usually is, this low is , now over MO, continues moving west and south, reaching AZ by Wednesday the 17th.

It is a little unusual to see that and here’s what real convective-severe storm weather guru Bob (lives in Tucson, BTW) is saying to a weather folk group in Albany, NY:

“Ed and Greg – the current forecasts looked familiar to me. Check out the 500 mb analysis
series from 00Z 9 August 2003 through 12z 16 August 2003. Short wave in westerlies
over Ohio morphs into an inverted trough in the easterlies. The IT moves SW across the
southern Plains and ends up near the Four Corners on the 16th. It was associated with
a widespread thunderstorm outbreak across Arizona on the 14th. Bob Maddox”

“On 7/12/2013 11:25 AM, Edward Szoke – NOAA Affiliate wrote:
Greg – we remarked about this up at the CIRA weather briefing yesterday in Fort Collins. We see westward moving systems in the sub-tropics, but this far north and heading so far west does seem rather unusual. It looks like quite an outbreak of convection in OK come Sunday presumably as the cold pocket aloft moves over that area. Maybe it will keep moving west, close off and deepen over the 4- corners and bring us the seldom-seen but often talked about July snow! (OK – heat has made me go goofy – hope all is well at the Wx Channel). ed”

End of filler material from experts to get you a little excited, as we all will be if this comes to fruition as now foretold in models.

Yesterday’s pretty castellanus:

5:57 AM. Altocumulus castellanus spire under a higher layer of Altocumulus. — 5:57 AM. Altocumulus castellanus spire under a higher layer of Altocumulus perlucidus.

5:57 AM. Looking west toward the Tortolita Mountains at a large grouping of those lower castellanus clouds. This, I thought, was one of the best shots I've taken of those clouds. — 5:57 AM. Looking west toward the Tortolita Mountains at a large grouping of those lower castellanus clouds. This, I thought, was one of the best shots I’ve taken of those clouds.

6:28 AM. As sometimes happens with these clouds, they can group together and morph into true Cumulonimbus clouds based at high levels, and not caused by heating at the ground. This is a common situation in the Plains States during winter when moist Gulf of Mexico air overrides cool winter air masses. — 6:28 AM. As sometimes happens with these clouds, they can group together and morph into true Cumulonimbus clouds based at high levels capable, as yesterday, producing lightning and brief heavy rain; they’re not caused by heating at the ground like our afternoon and evening storms. This is a common situation in the Plains States during winter when moist Gulf of Mexico air overrides cool winter air masses at the ground.

Our afternoon clouds, ones springing off the heating slopes of the Catalinas, dribbling overhang with sprinkles on Catalina once or twice:

1:30 PM. Cumulonimbus over Ms. Lemmon, middle and upper portions hanging out over Catalina.

4:06 PM. Got pretty excited when this behemoth sprung out over the Cats. But, faded quickly after a lot thunder.

Oh, well. Day ended up with a nice multi-cloud layer sunset, always the best ones:

7:38 PM. Why we love the summer rain season. — 7:38 PM. Why we love the summer rain season and would never go to places like Michigan to avoid it.

Today is supposed to be about like yesterday, but hopeful that more rain can dribble off the Cat Mountains.

The End.

A morning surprise; 0.22 inches here doubles the July total

At least it wasn’t predicted the day before, but how nice to see a “mesoscale convective complex¹” (a bunch Cumulonimbus clouds clustered together) come roaring over the Cat Mountains yesterday morning. Here it is, in case you missed it and want to see it again, from the beginning when what was going to happen was in doubt:

11:00 AM. Major rainshaft, and accompanying dark base where updraft is forming new precip approaches Catalina area.

11:47 AM. THe dramatic backside of this cluster, resembling those seen in the Plains States, good mammatus, too. — 11:47 AM. The dramatic backside of this cluster, resembling those seen in the Plains States; good mammatus, too.

It was great, too, to see some evidence of water on the ground, and several natural livestock ponds form due to the storm. Its been too long since puddles formed. I like puddles, BTW².

11:18. Evidence of significant rain; a puddle has formed.

4:38 PM. Calves inspect new livestock pond on Equestrian Trail Road. — 4:38 PM. Calves inspect newly formed livestock pond on Equestrian Trail Road. Mom not impressed.

Go here to see some regional rainfall totals from the Pima County network and here for the U of AZ network.

What was best was the clarity of the air after the rains washed all that smog, and we had our brilliantly white clouds against that deep blue sky back:

4:10 PM Cumulus mediocris over the Catalinas.

Today:

First, right now (6 AM) we have some of the best Altocumulus castellanus around I have ever seen. So pretty!

U of AZ 11 PM mod run expecting afternoon showers/TSTMS over Cat Mountains today, trailing off to the NW and near Catalina proper. Showers and lightning now to the S-SW, expected to die out before reaching us. So, happens, look for bases launched in the late morning and early afternoon to drift overhead–often a street of clouds forms over the southern portions of the Cat mountains about where that dark base in the first photo is, and if we’re lucky, will dump in this area. Look toward Table Mountain and a stream of clouds from around there headed this way.

————

¹It would be great if you used this term with your neighbors when talking about yesterday’s rain: “That was a great MCS that came through yesterday morning! Hope we get another one today, though rain in the morning here is rare, but anyway…..” Neighbor “A what went through?” You: “Oh, sorry, I meant a nice cluster of thunderstorms. ” You continue: “As a cloud-maven junior, I’m learning a lot incomprehensible jargon that I can use to impress neighbors. Hey, have you heard of the ‘diffusion domain’? That’s when you’re flying in clouds and you can’t see either the ground or the sun! The next time you fly and that happens, tell the passenger next to you…..”Hey, I think we’re in the diffusion domain.”

²Photographed a lot of puddles on a trip to Death Valley in 2005 (wettest rain season there in 75 years). It was a lot of fun for me.

Water, water everywhere in the sky, but not much fell on the ground

Yesterday was a disappointment. Oodles of water up there above us, as represented by cloud bases somewhere around 15 Celsius (59 F) yesterday morning, early Cumulonimbus activity–one was up toward Oracle by 10:37 AM–Oracle got 1.06 inches yesterday, but while the skies darkened over Catalina several times, they didn’t “unload.” Maybe only once or twice before in six summers have I seen this darkening to the level we had yesterday, without a rain shaft soon falling out of it. A couple of examples from yesterday:

1:29 PM. A Cumulus congestus takes shape over Cat State Park, and heads toward Catalina. Only sprinkles fell.

2:40 PM, looking toward Charoleau Gap. It doesn't get more "portenful" than this. I was SURE a shaft would crash down, and with it, the WIND from the north, the clouds then building over ME to the south, as happens so often when heavy rains pour down on the Gap. Didn't happen, at least not until too late, long after it had moved farther north. — 2:40 PM, looking toward Charoleau Gap. It doesn’t get more “portenful” than this. I was SURE a shaft would crash down, and with it, the WIND from the north, the clouds then building over ME to the south, as happens so often when heavy rains pour down on the Gap. Didn’t happen, at least not until too late, long after it had moved farther north. Got pretty dejected.

So, what went wrong? Why were the clouds SO DARK, even shallow ones like Stratocumulus, let alone the Cumulus congestus, but with so little “emitting power”?

The darkness of these clouds was surely due to the high smoky aerosol content of the air that led to unusually high droplet concentrations in these clouds. The higher the droplet concentrations, the darker the bottom of the cloud, say holding cloud depth constant. So, a moderately deep cloud, but one too shallow to rain, can look like these, like the normal darkness on the bottom from which blinding shafts of rain fall. So, most likely we were looking at smog-laden clouds, the kinds of ones in our future around the world because that’s what we do, produce smog and smoke, well, us and lightning.

And, as we recall from Squires and Twomey (1967), smoke inhibits the formation of rain in clouds. I am sure most of you remember that article about smoke and sugar cane fires in Australia, and how those smoked up clouds did not rain like the ones around them that were “clean.” This phenomenon has been reported on numerous occasions since, like how in LA it helps reduce drizzle (mist rain) occurrences.

However, as we know, even smoked up clouds can rain IF they get high enough to reach the -10 C level here because then copious amounts of ice, soft hail and snow will form aloft, and down it will come! That only happened in isolated places, like over Oracle where they got that inch of rain (at least around here). So another cause of dark clouds lacking in downspouts was that they were not QUITE deep enough for the tops to reach -10 C. up around 20,000 feet above the ground yesterday–those tops were SURELY so close, though!

Back to smoke effects. With bases as warm as 10-15 C yesterday, there should have been rain formed without ice, and almost certainly a little did (these eyeballs detected some yesterday afternoon on the Catalinas). However, this is the type of rain that smoke inhibits most. This is because with so many cloud droplets competing for a given amount of condensation, they all stay too small to collide and stick together (requires drops bigger than 30 micrometers in diameter (let us not forget Hocking and Jonas (1970)…. So, we lost some rain due to smoky skies there, too,

Next, it can be relatively cool with tremendous amounts of rain IF there is a good disturbance to cluster the clouds together, forcing converging air near the ground, taking it away at Cirrus levels. We didn’t have a “disturbance”, a trough or a low to help out.

Finally, without the help aloft, we needed, as you can all guess by now, that bit more heating at the ground, maybe just a few degrees was all to launch some really large but isolated storms.

Today?

U of AZ 11 PM mod run has Cbs developing over the Catalinas by noon, and during the afternoon some of those showers trail to the northwest over Catalina. I think one will. So, once again we have a day with rain around, and maybe today a little cell will bombard us with a quarter of an inch. Should be warmer, today and that will help since again we have no trough help. Still smoky, as you can see here at sunrise by that orange-brown layer below this morning’s Cirrus. So, once again, the clouds may look a bit darker than they “should” when we have clean air.

The End except for this nice morning shot of Ac perlucidus undulatus I would call it. Very nice!

6:54 AM. Altocumulus perlucidus undulatus, if you care.

Sign of a good rain day today after some disappointment yesterday (only 0.17 inches here)

Stratus fractus on the sides of the Catalina Mountains:

This tells you how wet it is out there, if per chance you haven’t walked around in it, and also tells you that moist air has some depth. These are the lowest clouds yet of our summer rain season. CUmulus cloud bases later this morning and this afternoon should also be lower than any prior day, and that means more rain gets to the ground, and likely the cloud clusters are large.

Fingers crossed for half an inch or more today here in Sutherland Heights-Catalina area.

BTW, some points in the Catalinas, such as White Tail, got 1-2 inches yesterday. Douglas way in the corner is already over 4.6 inches or about 160 % of their whole July normal. Excellent.

The End.

Catalina summer rain climo (again)

Running out of material, which is quite interesting because I haven’t been doing much, so am reprising these….

We had a little uptick in rainfall last year mostly due to that four and half inches in July. Very nice. No trend is evident in the summer rainfall here, global warming aside.

When it falls in summer….

Hmmm. Just noticed a discrepancy in the years of record. Huh. Must investigate later.

Some of yesterday’s clouds

One of my specialties is cloud bottoms, and there were several opportunities to photograph them. Here’s a quite nice one, hoping one day it might appear in a gallery, it’s that good I think. It was just starting to unload its watery burden onto the unsuspecting folks in south Catalina and Oro Valley (see next shot):

4:03 PM. From Sutherland Heights looking SW toward Oro Valley, just 19 min later.

Models chock full of moist days for at least a week ahead, so “let the games begin”. Certainly we Catalinans will get nailed one of those days. Extreme SE AZ has been pretty wet so far, with Douglas having almost 2.5 inches already. Will be green down there soon! Might be worth a trip to see how things are coming along.

The End, except for this shot of the prior day’s really dramatic sunset:

Jackpot

“If its 110 degrees, can thunder be far behind?”

Nope.

Here from IPS Meteostar, a favorite place to look at weather, this.

Only 13 days from now. Heavy rain shown for SE Arizona! — Valid only 12-13 days from now, July 9th at 5 AM Local. Heavy rain (blue region) shown for SE Arizona during the preceding 12 h ending at 5 AM! (More simply: “overnight.”

Sure, could be illusory as we know, but it does demonstrate that we are deep into the summer rain season by July 9th, as predicted by the seasonal outlook from the U of AZ. After the past desiccating months, fingers crossed.

Also, let us consume some spaghetti to see if there is any truth to this rain at all:

Yes! I love spaghetti! Upper high in correct position for good rains here, around the Four Corners area (area lacking lines), so that heavy rain COULD actually happen!

BTW, hope TV Weatherman George comes back. He is very, very good. I know I tease about TEEVEE weathermen, but maybe its only jealously, and also I don’t think I could do their job, too much (non-atmospheric) pressure! I might say something awful, in a happy talk context:

“Too bad about those people in that plane crash, but, ‘hey’, how about those Wildcats!”

No, it really does take some real explanatory and graphics skills to do TV weather these days, plus be likeable on top of those. George has those skills and attributes.

In case you missed them…these stunning skies

Cirrus uncinus. Started out looking like radiating lines of Cirrus, but this look is due to perpspective:

1:10 PM. Much later.... — 1:10 PM. Much later…. Well, in cloud time its much later because these guys will gone in a just a few minutes jetting along at 25,000 feet or so. Note those tufts at the top suggest momentary liquid water followed by ice formation and fall out (in LONG strands).

Cis fib and Cis spis lead to nice sunset; big trough, big wind ahead

Cirrus fibratus and Cirrus spissatus, of course. Here they are from yesterday.

2:56 PM. Cirrus fibratus, straight or gently curved elements.

7:28 PM. CIrrus spissatus (thick, patchy Cirrus) with other varieties.

The weather ahead

Troughulent weather is ahead as you can plainly see here from the NOAA spaghetti factory:

Here’s what it looks like on a regular 500 millybar map (IPS MeteoStar):

No rain in it for us, but if you missed having wind yesterday the 21st, well this situation will make up for it. Likely to be gusts over 40 mph in these here parts when it actually peaks out in about a week. In the meantime, a West Coast trough ahead of this violent jet streamer from the Pacific will keep the air moving long before this unusual event slams into Cal.

The End for now.

Pretty castellanus

5:29 AM. Ac floccus and castellanus with virga. Cloud bases (sans virga) were at -10 C (14 F) yesterday.

Along with Altocumulus “floccus¹” as well, many with ice virga. Some clumps got so enthusiastic that they went into sizes that we really can’t name, too large to be Altocumulus elements, and too small to be what we normally would call Cumulus or Cumulonimbus. Here are some more examples of yesterday’s clouds:

5:49 AM. ????? Mostly glaciated, though little virga shows out the bottom. — 5:49 AM. ????? Mostly glaciated, though little virga is coming out the bottom.

6:14 AM. "Micro-cumulonimbus"??? Its got all the ingredients, little anvil. fully glaciated here, and a few drops fell all the way from 13,000 feet about the ground. — 6:14 AM. “Micro-cumulonimbus”??? Its got all the ingredients, little anvil. fully glaciated here, and a few drops fell all the way from 13,000 feet above the ground, but there is no real shaft something you like to see when you call a cloud a Cumulonimbus, Highest tops above 30,000 feet, colder than -40 C (-40 F).

6:22 AM. Off to the south, this classic example of regular Altocumulus castellanus and floccus. So pretty. Note ice plumage beyond Pusch Ridge.

6:53 AM. Lesson. Some liquid water drops reach the highest, coldest point in this buildup. On the right, they're all gone, only ice remains. The droplet part is brighter because the droplets are smaller and reflect more of the sun's light than do the larger ice crystals. — 6:53 AM. Some liquid water drops reach the highest, coldest point in this buildup; that brighter part peaking out on the left. On the right, and at the top, the droplets that were present earlier in this part of the cloud have all evaporated; only ice remains (except in those partly shaded cloud rags). The droplet part is brighter because the droplets are smaller, they’re are more of them, and reflect more of the sun’s light than do the larger ice crystals at the top.

Taking a bite out of drought in the Plains States

Here the Drought Monitor for May 7th. Looks pretty bad in the central and southern Plains States and the central and southern Rockies.

But here’s what’s happened according to WSI’s radar-derived rain totals over the 7 days ending since this map. Makes you fell that bit better for our drought-stricken brothers even if we didn’t get anything. And it looks like rains will continue off and on in droughty Plains areas now for another two weeks. Excellent. Nothing in sight here, sadly.

The 7-day rainfall totals ending on May 14, 2013.

The End (still putting life together after moving; posts will be a bit sparse).

—————-

¹“Floccus” has a ragged or lofted base, one higher than the other ones around.

Dawdling low to bring scattered showers for a couple of days in 10-13 days

We’re not into streamlined titles here.

In the meantime, before taking a hopeful look way ahead; wind and dust. Today begins the well-forecast model trough and low event from more than 10 days ago for the 17th, except its happening on the 15th and 16th. It means afternoon dust and wind, wind and dust, followed by unusually cool air on the 17th. No rain likely in this one, though, like the last dust event; just some scattered Cumulus on late on the 16th and 17th.

The weather way ahead: After the dust, idle speculations of distant rain

There’s a tiny low now east of Hawaiian Islands, that, models say, will dawdle around out there for awhile, but also be drifting eastward eventually, not being picked by the jet stream and Nike swooshed to the northeast as most such lows would be. Just continues along at low latitudes until reaching us late on Thursday, April 25th. Here it is in the NOAA spaghetti plots. It would be astonishing if this itty-bitty low gets here, but, here’s the hopeful sequence in “spaghetti.” This is only brought up because its the first model rain that has shown up for southern AZ in a long, LONG time.

Valid at 5 PM AST. Friday, APril 225th. — Valid at 5 PM AST. Thursday, April 25th (00 Z 26th in Central Universal Time). Note the green CLIM line, bulging toward the Equator where it crosses northern Baja. This means over the decades, there is a tendency for a trough to be in our area. This MIGHT explain why the chance of rain here in Catalina, while small at the end of April, does not decline during the last week or so.

In case you don’t still don’t believe me, here’s a colorful model loop showing that this is supposed to happen to that low east of Hawaii. Further support can be seen in some green pixelation over Arizona from IPS MeteoStar’s rendering of our WRF-GFS model, our best, for the amounts of rain in the 12 h ending on the morning of the 26th.

I hope you’re happy now.

The End.

PS: Pretty happy myself, after learning through a bz website that this blog has value! How much? TWENTY-FIVE US dollars! Thanks tremendously to both readers!