Cloud-maven – Page 54 – About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno

A look at Catalina’s empty water year container so far; but spiget may be about to be turned on

While waiting for measurable rain to begin piling up in November, let’s look at no rain so far for the current water year which began October 1st:

Updated to 2013 Catalina WY rainfall averages — The observed monthly rainfall is shown by an adjacent column in yellow on the right… (hahaha, trick or treat, there isn’t any yet)

In fact, speaking of piling up, here’s some rain in this forecast from the Canadian GEM model already for the night of November 4th-5th, and, of course, windy on the 4th before the cold front with this barges in. And, I am happy to report that the USA WRF-GFS model is ALSO showing rain during this time, after being rather reluctant until the run from last night at 11 PM AST, seen here. This is lookin’ good now for our first measurable rain in over a month.

Valid at 5 AM AST November 5th. Colored regions in the lower RIGHT panel are those in which the model thinks it has rained during the prior 12 h (overnight, Nov-4-5). You might have to use binoculars to see it.

But wait, there’s more!

Amajor precip episode has shown up in the 11 PM AST WRF-GRS run from last evening! Check out these renderings from that model run from a site I like, IPS MeteoStar:

2013110206_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_288 — Valid for Thursday, November 14th at 11 PM AST. Colored regions indicate where rain should have fallen in the prior 12 h. Note heavier blob over us, indicated by darker green!

2013110206_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_300 — Valid for 11 AM November 15th. Precip for the prior 12 h ending at this time shown by colored regions. Note bull’s eye in this area (likely associated with mountains around here). So, the mod thinks it could be raining over a 12-24 h period.

In the past we have seen numerous examples of “fantasy rain” produced for us here, often involving decaying tropical storms, that turned out to be completely bogus in this time range, that beyond 8-9 days. Its pretty normal for goofy things to show up in these models beyond that time. Just too much chaos going on and using measurements with their inevitable errors, even if fairly slight ones, not to mention that we don’t really have all the answers to how the atmosphere works.

So, what do we do? We deliberately input errors into a few model runs at the very beginning and see what happens, how crazy the key contours and isobars get. “Pretty cool, huh?”, as Bill Nye the science guy might say if he were writing this. Where they remain pretty steady, that’s where a prediction, even one ten or more days out, is going to be very reliable. Here’s is a sample of one of those crazy results from NOAA:

The plot above indicates that there is a very strong signal for a big trough and storms along the West Coast 10 days out. The red lines show that there is a strong signal for the jet stream from the subtropics to be a bit south of us.

The main point here is to point out that while the DAY OF THE RAIN on those forecast maps might change in the models, there are still going to be a number of days where troughs and fronts threaten to bring rain yo Catalina over the next two weeks, and one’s likely to make it as a rainy one.

Thinking now, having a rain bias (“truth-in-packaging” note here), that November’s rain will be near or above normal.

Today’s clouds

Look for a few Cirrus and maybe Altocumulus to appear late in the day with the likelihood of a nice sunset shot.

Measurable rain to fall in November (!)

That’s it. Its a kind of news release, best released on the 1st. Its news, of course, you won’t find on other weather sites because maybe they’re chicken, or prudent. Check back on November 30th, and if its rainless again, there will be no mention of this forecast.

But, after the rainless October (we average about an inch here in Catalina), you probably won’t believe me. Check this out from the NOAA spaghetti factory. I got pretty excited when I saw it. I think, you will, too, maybe mention it to your neighbors over coffee this morning, having been pretty convinced yourself after seeing this that storms are a brewin’ for Catalina and vicinity (all of Arizona) in November:

Valid for November 10th at 5 PM AST. Originates with global data obs made at 5 PM AST last evening, and represents a few key 500 millibar height contours after DELIBERATE little errors have been put in and the computer model rerun with them in it.

Thank E. N. Lorenz, a meteorologist for Chaos Theory and maps like the above that show how little tweaks in the original data can change stuff a lot if things are fragile, but not so much if the signal is robust, and things not so fragile. Here a deep trough along and off off the West Coast on November 10th is virtually guaranteed by the blue and red lines that plunge so far to the south off the West Coast. A trough out there, as you know, gives us the best chance for rain as it progresses to the east. The bunching of lines indicates where the forecast, with baby errors, is strongest, like off Asia, and hereabouts, off Baja. Those red lines are pretty much where the south edge of the jet stream will be at this time of year. As you know, we have to be on the north side of the jet during the winter here in old Arizony to get precip, so it looks good for that to happen as we move forward in the month.

BTW, here’s your official forecast for the whole month of November from the Climate Prediction Center (CPC). As you can see, this November is a tough month for them, no real signals showing up for the month as a whole as indicated by the HUGE areas of “EC”, i.e., “equal chances” of above or below normal precip. We’re kind of on the edge of “we don’t know what’s going to happen” (in the popular lexicon, “clueless”) which is good. The signal for continued drought here is not so strong, though it is there. Poor New Mexico, though.

November precip forecast for North America made on Halloween by the CPC.

Cloud photo op coming up

A weak trough ejects from the Pacific and over us beginning tomorrow, and it should bring some great photogenic Cirrus and Altocumulus clouds tomorrow afternoon and evening, likely some “castellanus” if you care. Likely to be some virga (snow falling from the Ac) too, so could be a great sunset shot coming up. With the virga, always a slight chance of a sprinkle-its-not drizzle.

The End.

Pretty cloud day

One of the best, really, never mind all that wind yesterday. No rain, of course, in our future, not even fantasy rain these days.

See usual rehash of yesterday’s clouds, the 60s, in case you forgot, below:

SONY DSC — 8:49 AM. This Altocumulus perlucidus cloud behaved like a lenticular, holding in place for at least 2 h, but did not have the classic pancake or sliver look of lenticularis clouds. Air likely too unstable (temperature dropped with height rapidly) and allowed tiny cumuliform elements to form. Only on the very right edge where it first formed, did this cloud appear “lenticular” in any way with its smoothness

2:09 PM. One of the many examples of iridescence seen yesterday in those Cirrocumulus clouds, or on the very thin upwind edge of Altocumulus lenticularis clouds. Its due to the formation of extremely tiny droplets, a few microns in diameter, that cause the sun's light to go around them and in doing that the white light from the sun gets broken down into its colored components. Do you remember that white light has the wavelengths of all the colors in it? Here you can see some of them. — 2:09 PM. One of the many examples of iridescence seen yesterday in those Cirrocumulus clouds, or on the very thin upwind edge of Altocumulus lenticularis clouds. Its due to the formation of extremely tiny droplets, a few microns in diameter, that cause diffraction in the sun’s rays (see link for a more complete explanation and nice examples). Do you remember that white light has the wavelengths of all the colors in it? Here you can see some of them, and photograph them by performing a replication of the Black Power salute of Tommy Smith and John Carlos from my alma mater, San Jose State, one that beat the Wyoming Cowboys recently in fubball. I added a link in case you forgot and wanted to get worked up again. Yes I was at SJS when that happened down Mexico way, minding my own business doing weather forecasts with a political slant (left, of course, because that’s what made you popular during the rad lib days) for the college paper. Suddenly, I feel like going to San Francisco, putting some flowers in my hair.…

2:19 PM. Cirrocumulus and Ac lenticularis in the same layer. Recall Cc can’t have shading, not that it matters that much.

The End.

Having an effect after all; sunsets, clouds, and the weather ahead

I was driving down in Tucson yesterday, kind of moping around about all the blogs I had done with little or no interest. You may recall from a blog I did a few months ago I reported to my reader that a business site had evaluated the worth of my blog, and due to the amount of traffic it brought, it was found to be worth $25.

But then as I rounded Campbell and headed northbound from Fort Lowell, I saw this sign exhorting fellow Tucsonians to watch clouds! My mood brightened. Maybe there were a few out there that I had affected after all; a whole cloud watching movement had started! I did see, however, that since the sign maker was wondering whether there were clouds in the sky or not, and there was a lot of Cirrus overhead, I saw that I had more work to do.

This sign seen near Campbell and just north of Fort Lowell yesterday afternoon.

Yesterday’s clouds

9:03 AM. Cirrus fibratus in rolls, undulations due to waves in the atmosphere associated with the strong jet stream above us. — 9:03 AM. Cirrus fibratus in rolls, undulations, due to waves in the atmosphere associated with the strong jet stream above us.

In case you were asleep, watching Monday night fubball, and NOT watching clouds, here is yesterday’s magnificent sunset as the sun underlit those dense Altostratus clouds that developed from thinner Cirrus ones during the afternoon and evening.

Today, more mid-level clouds and with strong winds aloft, we should see some lenticular clouds in the lee of the Catalinas. Videoing them would be a good thing for you to do because you would, in fast playback, be able to see how they keep forming on the upwind side and disappearing on the downwind side while holding their overall position. If the moisture increases, they expand, and if it decreases, they shrink and dry up, something likely to happen later in the day.

While that’s going on, there’ll likely be some Cumulus and Stratocumulus off to the north, and since the air is going to be much colder aloft to the north today, some ice is likely to form in them late in the day in those northern clouds, leading to some virga. Those lower clouds, according to our models, should begin appearing around here, too, in the late afternoon and evening. Alas, measurable rain is very unlikely, and with this, last little threat, October 2013 will go out rainless here in Catalinaland.

Farther ahead…..

More middle and high clouds and great sunrises and sunsets are likely on November 3rd and 4th as a little upper level trough creeps in from the lower latitudes of the Pacific off Mexico. It was once projected by the models to bring rain to here, but now it seems only a sprinkle is possible; most of the tropical moisture shunted to the south and over northern Mexico.

In the longer term, while all “fantasy rain” has disappeared for AZ based on last evening’s 11 PM AST model run, stronger than normal storms are showing up for California later in the first week of November, and with that, we’ll always have the hope that this time, the “fantasy” in that model calculations is no rain shown for here.

The End, but enjoy those pretty clouds today!

More fantasy rain eventuates from tropical influences for SE Arizona in latest model run

My fantasy rain team (I call, “WURF-GOOFUS“) already has FIVE inches of fantasy rain in Arizona for November, and here’s more from last night’s 00 Z model run! In case you went to school lately and have trouble finding where you are, I have added an arrow on the map so that you’ll know where SE AZ is (“hey”, we’ve read those stories about HS students not being able to name states….)

Valid for Wednesday, November 6th at 5 PM.

And its not only this map, but a few after this as well. Here’s 24 h later and its STILL raining in SE AZ, with a rain center right on my house!

Valid for Thursday, November 7th at 5 PM AST. How great is this fantasy rain?

I’m thinking now that my fantasy rain team from WURF-GOOFUS has six or seven inches predicted for just November! OF COURSE, its not real rain, its fantasy rain, but, there it is again.

Losing control, the rainless October, the mostly clear skies day after day getting to brain functions, hallucinating again over model outputs of clouds and rain…. Must seek treatment.

The End.

Pretty skies; pretty Cirrus

Here are some shots:

The weather ahead

Tried to find some rain for you in the models, but only one had rain, and that was the low resolution (big grid spacing) Canadian GEM model posted here. It had the rainy panel (lower right) for SE Arizona calculated from last evening’s global data:

Valid for Wednesday morning, 5 AM, October 30th. The colored areas in the lower right panel are those ones where the model thinks it should have rained in the prior 12 h. Note heavier, red-blobs in AZ! How great would that be? Again this rain is the result of a westerly trough grabbing the moisture out of a tropical storm off Baja, a very “iffy” situation, to quote a term oft used by the much honored, late atmos sci Professor Richard Reed of the U of WA¹.

Also, I am really learning about how much the WRF-GFS model likes to bring hurricanes and tropical storms into the Southwest. Yesterday’s model run at 11 AM AST, had another doozie coming up the coast in two weeks still having tropical storm strength and its about to pounce on northern Baja, southern Cal, and maybe AZ. Here is that depiction for your amusement, valid at 11 AM, Saturday NCAA football day, November 9th.

: the stuff of dreams for Saturday, November 9th, 11 AM AST.

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¹

The late Richard Reed, a man that did not mince his words. The nicest thing he ever said to me was, "Those guys have gotta be stopped." — The late Richard Reed, a man that did not mince his words. The nicest thing he ever said to me was, “Those guys have gotta be stopped.”

Not likely to verify, but a wonderful map (but, “trending up” in twitter-speak)

This is definitely not the same title as was a few days ago for a similar map, one also valid for Nov 3rd-4th. That title was quite different: “Not likely, but a wonderful map.” The rainy Arizona map back then from our best model showed a tropical storm and moist plume being drawn northward into AZ.

Almost the exact map as that one a few days ago has shown up again out of the blue, if you can say that when you’re talking about clouds and precipitation. There’s been nothing like that former map since that first time it showed up, and, in view of how odd it was, you tend to write it off as something you’ll not see again. But there it was again, now only 10 days out.

Below, the happy, rainy AZ map churned out by last night’s model run based on global data taken around 5 PM AST yesterday ( from IPS MeteoStar):

MOdel outpur valid for 5 PM November 4th. Shows tropical storm remnant being sucked up toward Arizona with lots of rain already here. — Model output valid for 5 PM AST, Monday, November 4th. Shows tropical storm remnant being sucked up toward Arizona with lots of rain already here. Green blobs denote where the model thinks rain has fallen in the prior 12 h, which here is the entire State of AZy!

Below is the pattern aloft that steers (hahaha) all that moisture into our water-challenged State, one that has a lot of steers.

HOWEVER, this rainy situation requires a lucky conjunction of a Pacific trough coming in out of the Pacific onto the southern California coastline, while a tropical storm/former hurricane is off Mazatlån at that same moment. If these two features of interest are just about anywhere else than is shown here in these model projections, forget it.

The flow pattern in the middle of the troposphere, around 15,000 to 20,000 feet above sea level. Yep, that's right, half the air is gone by the time you get to only about 17,500 feet! — The flow pattern in the middle of the troposphere, around 15,000 to 20,000 feet above sea level. Yep, that’s right, half the air is gone by the time you get to only about 17,500 feet!

The first time this rainy map was shown for Nov. 3-4th, back about five days ago, the chances of it actually happening were probably somewhere around 0.2 percent. Just too much had to fall into place. Coming up twice, however, jacks the lucky numbers up to, oh, maybe to an 8 percent chance of actually happening as a wild guess. Not a great chance, but one that’s trending upward. You know, after the rainless October that’s about to finish up, we really deserve this storm in early November. The NOAA spaghetti factory has good support for a trough along the California coast at this time, so its likely THAT ingredient will likely be in place on November 3rd-4th.

Yesterday’s clouds; yes, there were a couple, some patchy Cirrus and a little band of Altocumulus, some of the latter trending toward lenticularis-ee ones. later on. Here they are.

2:37 PM. Patches of Cirrus drift across the southeastern sky.

The End

Expect a cloud sighting today

Probably an Altocumulus or Cirrus.

The End.

In memoriam: Pepper

Not likely but a wonderful map

Last evening’s model¹ run based on global data from 5 PM AST yesterday, gave us this, the remnant of a tropical storm barging into Arizona on November 3rd, just after our rainless October closes out:

Ann 2013101900_CON_GFS_SFC_SLP_THK_PRECIP_WINDS_384 — Valid at 5 PM AST, November 3rd two weeks from today.

As an expert “spaghetti” decipherer, you can easily see from the map below that there’s not much chance of this happening though its not completely impossible. Too much “noise” in the pattern around here (lines aren’t bunched like they are off Japan and in the western Pacific). I just posted the map above because its the first one in SO LONG that had any Arizona rain on it, that green and blue stuff on the map above.

Valid at 5 PM November 2nd, the day before the map above, but close enough.

Who knows, maybe there’ll be a cloud over us one day again, too.

Of note… unusually cold air for October is poised to rush into the eastern and central US in several waves during the next two weeks; those events have a much higher probability of occurring according our venerable NOAA plots of spaghetti like the one above. Likely will see cold air refugees beginning to bail to Arizona in their droves from eastern units of the country as October low temperature records fall.

Its great to be where other people want to be.

The End.

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¹Namely, the Global Forecast System-Weather Research and Forecasting (GFS-WRF) model, pretty much our best.

Yesterday’s drizzle

Some rare drizzle precip¹ fell yesterday. Suggests clouds were pretty “clean”, that is, didn’t have much aerosol loading and the concentrations of droplets in them was low (likely less than 100 cm^-3) Also likely, in view of the recent strong winds, some of the aerosols in those clouds might have been large dust particles² rather than those due to just “smog” and other tiny natural aerosols. Large dust particles can not only influence the development of ice at higher temperatures than normal (above -10 C), but is also known to aid the formation of rain due to cloud drops bumping into each other and sticking together; collisions and coalescence because large dust particles can accelerate this process by forming large initial drops at the bottom of the cloud where drops first condense. Here, drops are nearly always too small to bump together and join up unless clouds are deep, like our summer ones, and ice is going to form anyway.

So, yesterday, was a bit of a novelty. Some photos and story telling:

The late Jack Russell, engineer, listening to Art tell another cloud investigation story. — The late Jack Russell, flight engineer, listening to Art tell another cloud investigation story.

2:43 PM. Cumulus humilis field over Saddlebrooke.

3:06 PM. Drizzle precip just a memory. These clouds too shallow to rain. — 3:06 PM. Drizzle precip just a memory. These clouds too shallow to rain via collisions, and too warm to form ice.

Looking ahead….

Mods paint dry weather for the next 15 days, and so yesterday’s disappointing “trace” (don’t recall here that Mr. Cloud Maven person had predicted at least 0.02 inches!) may be it for October. Phooey.

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¹Drizzle: Fine (size range, 200-500 microns in diameter drops) close together, that nearly float in the air. Very difficult to bicycle in drizzle even with a cap or big hat. Fallspeeds, just a few mph. Smaller sizes can’t make it out of the cloud, or evaporate within a few feet almost if they do. Even true drizzle occurrences, you can’t be too far below the base of the clouds or those tiny drops won’t make it down to you.

²What is a “large” dust particle in a cloud? Oh, 1-10 microns in diameter, real rocks compared with the other stuff normally in them. So’s you get a drop that’s already pretty large as soon as condensation takes places. And, if the updrafts are weak at the bottom, then only them big ones might be activated, keeping the whole cloud’s droplet concentrations low! Happens even in places in the middle of huge land masses where in Riyadh, Saudi Arabia, we saw this happen on a dusty, moist day in shallow Stratocumulus clouds. They developed some drizzle drops. I was with the National Center for Atmos. Research on a field project then.

³1988: Rain from Clouds with Tops Warmer than -10 C in Israel (Quart. J. Roy. Meteor. Soc.)