Category Archives: Definitions

Happy desert everyone!

I think it should be a holiday when the summer rains have crested over the inch mark, a “personal holiday” anyway, if you get one where you work.   With a second day in a row yesterday with THREE sets of thunderstorms going over Catalina, and hearing thunder from about 1 PM until 9 PM, it was a fantastic day.   And if you didn’t get goose bumps watching the sky darken over the Cat mountains around 5 PM (second shot), well, I feel sad.

Me?  I vacated dinner to make sure I didn’t miss anything as that started to happen. Its a matter of priorities.  I am a poor dinner guest in summer.   But what a dramatic sky that was in its greenish blackness rising over the Catalina mountains!

And with 0.36 inches total yesterday,  and a nice lightning show between 7 and 9 PM, the rain gauge in my gravel driveway has now received 1.09 inches over the past 48 hours.  Happy desert!

Some areas of the Canada del Oro wash watershed received over an inch in the past 24 h after having been largely bypassed by the previous day’s rain.  So, that is great news, too.  Is there anything better than seeing water in the washes here in the desert?

So, we have “inched” that bit closer to that happy happenstance, to be alliterative there for a second.  To the left, one of those intense rainshafts that did it.  Rainshafts are like tree roots in a way.  Sharp, vertical rainshafts like this one (looking toward the Charoleau Gap) are likely associated with tops right above it that are probably 40,000 feet or more above ground level.

And of course, with the outflow winds gusting to around 40 mph, there was some very local some storm damage as well along with some flooding (documented below).

Seems like another day with great clouds (like those in the last photo), rain and lightning around.  Enjoy!

0.73 inches

Bullseye thunderstorm off the Catalina’s between 12:30  and 1:30 PM really did it, dropping a miraculous 0.55 inches.  I suspect that 300 yards N and S got less than our driveway did where the gage is located.   The smells, the puddles, the water running down the road; it was all so marvelous, and seemingly it has been decades since we saw this kind of sight.  And then, after it looked like it might be “all over”. that dramatic darkening of the lower cloud bases pushing over the Catalinas from the east suddenly began to occur around 6 PM, followed by another nice rain of 0.14 inches.   While we did not get the core of that massive system, it was great to see all the rain fall in western Tucson from here, knowing how dry it is everywhere.   Finally, that little bit of rain after dark, plumped the gage another 0.04 inches to bring the total to a wondrous 0.73 inches, every drop so necessary now!

Below, a sequence of the cumulus building off the Catalinas, beginning around 10 AM, ending with the approach of the main “dump” just after 1 PM.  Sometimes seeing this happen, and being so close to it reminds me of being in an airplane meandering among the Cumulus.  The second shot is a great indicator for the rest of the day, a tall, skinny little cloud1 that shows just how ready the atmosphere is to allow huge clouds like yesterday to happen.  Seeing that type of cloud should really get you excited about what the rest of the day holds.

An even better way to view yesterday, in a cross section mode, is from the U of AZ time lapse video here.  You’ll be amazed by these “volcanic eruptions” of Cumulus and Cumulonimbus clouds over Mt. Sara Lemmon.  Better hurry though.  Movie is overwritten by today’s later on!


Finally, the “icing on the cake” to be quite unoriginal; that wonderful sunset.

The End except for the footnote.

1You might well call the cloud in the second shot,  “Cumulus castellanus”, though technically there is no “castellanus” variety for Cumulus as there is for other cloud genera like Stratocumulus.  You could just call it a “towering cumulus”, the kind of remarks seen in airport aviation weather reports, though for some reason my mind always drifts into other domains completely;  paleontology, anthropology, and I think of that early man, Homo erectus.  Perhaps it was too risqué for those naming clouds to use that modifier as a variety name.

Rainy portent in a scruff of cloud

….that scruff of cloud topping Mt. Sara Lemmon around dawn this morning, to finish the thought.   This:


Because seeing a cloud topping Mt. Lemmon instead of well above it indicates that the air is very moist and cloud bases are going to be realtively low, substantially lower than yesterday.  This in turn means even more rain will reach the ground after falling from cloud base today, more of the terrain will be involved with launching deep clouds later this morning,  with their crayola black bases and impenetrable rainshafts scattered around the area this afternoon and evening.

Will we get one of those rainshafts?

Well, no one knows exactly where they will be, but my best guess, based on a few summers here, is that Catalina will at least get measurable rain today, and a real dump of a half an inch or more is well within range.  Yesterday, two brief light showers only gave us a “trace” of rain.  Darn.  But, if you noticed, the rainshafts from the clouds yesterday were denser than the day before, and that trend will continue today.  Sometimes these dumps, just like the 4 PM shower yesterday, are invigorated and started by the gush of winds from dead showers off in the distance.  One of the patterns here is for a gush of wind to blast out of the N or NE, and suddenly, the clouds overhead start filling in in response to the gush of air.  The gush causes the air over it to be pushed up.   And, this can happen very rapidly, going from clouds that draw a yawn, to “Oh, my gosh, look how dark it is over us now!”  Better lie down now for a moment until this gush of excitement passes over.   But, this is going to be a GREAT day for Cumulus and Cumulonimbus clouds!

And what a sunrise display of lightning and a cumulonimbus clouds!

“Pyrocumulus”, an awful sight yesterday evening

There may have been some sharp eyed folks that saw a great looking Cumulus congestus in the distance off to the NNE of Catalina yesterday.   The shots below were just before 7 PM LST.  Perhaps there was a shower or thunderstorm on the Mogollon Rim.

Sadly, even I was fooled for a few microseconds until you notice that there is NOTHING even slightly resembling the size of that cloud anywhere in the sky.  Then,  it dawns on you that it must be a “pyrocumulus”, the kinds of artificial Cumulus clouds that form atop the highest, and hottest portions of fires when there is a bit of humidity in the air. Once the fire dies down some, then all you see is smoke, the last evidence of the trees and the plant life consumed below.  Likely was a new fire, too, dammitall.    It was probably 50-75 miles away;  also just visible in the satellite imagery.   The second shot is an attempt at a close up, marred a bit by some kind of large insect that happened to fly by as I was shooting.  Just above the horizon of that second photo, you can JUST make out the telltale smoke below the bottom of the pyrocu.  The last photo, from Hornepayne, Ontario, Canada, is an example of a pyrocu up close, just as it was forming.  This was due to a prescribed burn by the Canadian government.  The cloud droplets are white while the smoke is black.   The cloud droplets are about 100 to 1000 times larger than the smoke particles, and reflect (have a higher albedo) more of the sun’s light than do the smoke particles.


Rain update:  Still looks like a great onset of the rainy season after a little “hip fake” today and tomorrow, that is,  a slight insertion of tropical air ahead of an unusually strong, winter-like storm in northern California.  That weak insertion of tropical air should lead to a few weak, high-based showers and thunderstorms on the high terrain.  And with high bases, there will be the chance of exceptional winds near showers due to the virga and rain falling into otherwise pretty dry air.   After this little episode,  the normal summertime anticyclone aloft rears up from the Tropics and after a couple of dry days and plants itself to the north of us.  This allows more humid tropical air to arrive pretty much on time, around the 3rd and 4th of July.  So, get ready!  It will be so great to see all the dust washed off the cacti, the stupendous sunsets, the lightning, the rainshafts, the whole works.  I’ve waited a year for this season to roll around again!  There won’t be a living thing that is not “happy” by the middle of July I would think, unless there has been too much flooding, always a possibility here.


Thinking about ice on a HOT day

Good grief, its already 88 F at 5 AM here in Catalina!

With a whole stretch of 100 F plus days ahead, maybe it would be good if we looked at some ice and thought about it.  Below are some ice crystals, as photographed by Magono and Lee (1966), a publication that is thought of as the “bible” of ice crystal classifications.   If you did or do field work on snow, in the air or as it fell to the ground, you likely classified the ice crystals that you saw as suggested by these venerable researchers.

Ice crystals have different shapes and different temperatures and saturation levels in clouds.   Magono and Lee classified those shapes by temperatures and saturation levels at which they formed, and you can see some that in the pages shown here:   Magono and Lee When you saw an crystal with a particular shape, or if it had frozen cloud drops on it, you then knew something about the temperature and humidity at which it formed;  that crystal’s history so to speak.

“Factoid”:  Nearly 100 percent of all rain that falls on us here in Catalina is that due to snowflakes, hail, soft hail (called “graupel”) that have melted on the way down.   For example, those huge drops that first fall out of that big, dark cloud base right above you are without doubt melted hail or “graupel.”

As you examine at these natural ice crystals in detail, thoughts of cool air should come rushing over you.   This is because the air in which these crystals formed would have to be cooler than  about -4 F (24 F), the highest temperature at which a natural ice crystal can form, and even then, those only under special conditions.

I suggest meditating on each photo.

In general, the ice crystals shown below go from higher formation temperatures to lower ones.    The first ice crystals shown, for example, are “needles.”  They form at temperatures between -4 and -6 C.  These are temperatures that moderate-sized Cumulus congestus tops sometimes reach, or winter Stratocumulus clouds. An example of using this knowledge in our module of “Converstional Meteorology” would go something like this.    Lets say on a winter’s day, deep and dark in December (why does that phrase sound familiar?) that you saw some “needle” ice crystals falling on your dark jacket at the top of Mt. Sara Lemmon.   The sky is cloudy in low Stratocumulus clouds, witih higher Cirrus clouds visible through the breaks in the overcast.    I have made this a bit complicated to test your knowledge.    It would be quite embarrassing for you and everyone who knows you if you then said, looking at those needle ice crystals (or even “sheath” ice crystals,  “I think these fell from those higher  Cirrus clouds we can see through the breaks in the overcast.”   Instead, you would likely know that they must have originated within the lower, warmer shallow clouds and NOT  from the Cirrus clouds overhead since the ice crystals in Cirrus clouds are mainly short stubby columns, and pointy ones called “bullets”, and sometimes in deep Cirrus clouds,  bullet rosettes, ones that look like a “bouquet of bullets”, p55 in part 2 below.  (Part 1 is ice former at higher temperatures, and part 2 are those ones that form at lower temperatures in general.)

Copies of the original photos here:




May add a bit more later, but gotta go walk a horse now…..

The “greening” of Arizona

In the numerical weather models, that is.

IPS Meteorstar, regurgitating the National Center for Environmental Prediction’s (what happened to simple titles like,  “The Weather Bureau”?) model output from last night has come up with MORE GREEN in that run over prior runs in the State of Arizona.  This,  over the next two weeks!  Caveat:  Might mean this run’s WRONG because of having changed quite a bit, but personally I am getting pretty worked up now.  Kinda tired of the dust here in Catalina, AZ, the cloudless skies,  etc.,  so there are a lot of reasons to want to believe this last run is absolutely correct.

Take a look.  Here are a couple of panels from that run.  You can almost smell the desert after the first rains!  See the impassable roads and washes!  Feel the moss starting to grow under the mesquite trees!  It would probably be of interest for you to take some pictures of dusty plants and stuff before the rains hit, and then the same views afterwards to document the wonderful changes that are going to take place in the next week and two.

BTW, I hope you are not afraid of maps like those below with “isobars” on them, lines delineating (hmmm, is that redundant?) where the pressure is the same, circling around highs and low pressure centers.  You see, most media people and TEEVEE weather presenters think you’re afraid of “isobars” and so they don’t show them.  Too much for you.   They only show you an “H” for a “high” and an “L” for a “low.”

I think you’re better than that;  I will not dumb this down.  I will insert maps with isobars more or less “willy-nilly” as I think would be interesting for you.

Also, I like the expression, “willy-nilly.”

The End

Attention: We interrupt this drought with some (forecasted) summer rain

The numerical leprechauns that spread green (our ancient weather map code for areas of rain) have put a coupla green pixels in the State of Arizona!   The first green pixel from last night’s run appears on Monday evening, June 27th in extreme SE AZ.  Its not much, see  first map below, probably only enough rain to give an ant a drink of water, but, just think, we will have some CLOUDS!  The cloud drought will be over!  

After this itty bitty possibility, and as the jet stream buckles in the eastern Pacific, our bloatful upper level high, normally in place during the first week in July,  is in its normal place in the first week in July!  Imagine, after all the weather “discrepancies” around the country, a normal map!   This means that the tropical air will spurt northward as that ridge develops over and to the north of us and we’ll get into some real nice Cumulus and Cumulonimbus clouds for a few days!   Think of those cool breezes blasting out of the rainshafts, even if you don’t get that rain yourself!  Think how nice that will be.

So when does that little preview of the summer rain season begin after the 27th?  Two days later, on Wednesday evening of the 29th, and then we should be set for several days of clouds and scattered thundershowers.  Check it out here at IPS Meteostar.   Here are some examples below.   Now the first couple of green areas in the State of Arizona will require a magnifying glass.   The mods also suggest it will dry out again after the evening of July 8th.  Phooey!

The End.

The Myth: Climate scientists were not on the global cooling bandwagon in the 1970s

Advisory:  heavy reading ahead…have to fill time during current cloud drought

In an article published in the Bulletin of the American Meteorological Society (BAMS) in 2008, it was asserted that there was no “concensus” on global cooling in the 1970s.  Why address this now?  I was busy before now….

Overall response to this BAMS assertion:

Hogwash!  Rubbish!  Bilge!  (I’m pretty “excited” here).

In fact, perhaps the most outrageous statement I have ever seen in a peer-reviewed journal was that of the BAMS Editor, quoted below in red.  In defense of the Editor, he was only parroting the conclusions of a major article in that BAMS issue purporting this distortion.  The appearance of such an article can be seen as a failure of peer review.   Here is what the BAMS Editor wrote in summarizing that bogus claim:

“In this issue, (the authors-names omitted) show that we were indeed misled about global cooling–but not by scientists. (emphasis added by the present writer).   Rather, we are confused about the recent history of our own science.”

I wanted to gag when I read this.  I was doing decadal climate studies in the early 1970s and so I was “pretty familiar” with the literature.

First of all, what were scientists really saying about climate change back then?  I will cite two major sources from the 1970s:

Below, a quote by Wilmot N. Hess, then the Director of 11 NOAA programs,  from the preface of  Chapter F on Climatic Change in the book, Weather and Climate Modification, published by Wiley Interscience in 1974.  (The volume, a collection of essays by experts,  targeted senior-level college students in the sciences and engineering, or working scientists or engineers who don’t know much meteorology.)

“It has been suggested recently that we are near the end of an integlacial period.  Studies of climate changes are in their infancy.  We know that there have been four episodes of glaciation in the recent past covering a period of about 1,000, 000 years.  A conference at Brown University in January 1972 discussed this problem and the MAJORITY (the font can’t be big enough here!) of the participants concluded that:

Warm intervals like the present one have been short-lived and the natural end of our warm eposch is undoubtedly near when considered on a geological time scale.   Global cooling and related rapid changes of environment, substantially exceeding the fluctuations experienced by man in historical times must be expected within the next few millenia or even centuries.‘”

Here’s what those climate scientists were looking at over just the past 100, 000 years of the earth’s climate.   Their concern will be obvious.  Note the “present” is on the left, not right as per normal.  The numbers “4” and “5” represent “interglacial” warm periods, the first the present one, called the Holocene, and “5”, the Eemian interglacial period.  Look, too,  how the temperature was trending DOWNWARD over all that glacial time until our present interglacial.  Source:  National Academy of Sciences, 1975.

Now imagine you are a journalist at that Brown University Conference…and you also learn that the earth’s temperature has been falling for more than 25 years (not shown in the above graph).  Futhermore, the CO2 people also inform you that the recent decline in temperatures over that 25 years would even be GREATER if it wasn’t for the mitigating effect of CO2!

What are you going to tell your public?   It’s obvious.

So how did such a scientific distortion get published in BAMS in 2008 by supposedly knowledgeable authors? Were they themselves confused about the history of climate change?  Was it due to their methodology?  Or was it a propaganda piece all along, a revisionist history resembling something analogous to the type of pieces that came out of Pravda of the former Soviet Union, a piece written to correct an earlier error,  so that that we scientists look like we had it right all along?  Probably all of these, in this writer’s opinion.

Lets look at what the authors did.   The full article is here.  In support of their phony claim, the authors of the BAMS article used a “bean counting” approach, the results of which they display in a contingency table.   They tabulated articles on climate change and its likely causes in peer-reviewed journals, looked at the conclusions, and if the article concluded that CO2 was going to warm the world, it would be placed in the warming world column, if the conclusion was ambiguous they gave it a nul ranking, and if the article concluded we were headed for a cooling, it went into that column.  The authors then told us that because they were more articles about CO2 and warming than nul or cooling articles, that must be what everyone believed, a major fallacy in reasoning.

However, either out of ignorance of our science hierarchy,  or having an axe to grind, they counted prestigious reviews with the same as that assigned to a single publication by “Joe Blow”, somebody who might never have been heard from again.   So when they counted an 1975 assessment by the National Academy of Sciences, an organization that periodically reviews subjects of critical interest, employing dozens of experts and reviewing dozens of peer-0revied articles, the authors assigned that review the same weight as the other publications.   It was like assigning an elephant the weight of a flea.

Nor did the authors mention the 1968 American Meteorological Monograph, The Causes of Climatic Change; not ONE paper in that tome discusses CO2 and its possible effect on climate!

And, of course, they did not cite the Wiley-Interscience volume with its contents concerning climate,  quoted above.

But why were scientists in the 1970s concerned with global cooling and not paying so much attention to CO2?

By 1975, the earth’s temperature had been in DECLINE for about 30 years!   This was in spite of massive increases in CO2 during that 30 years.   The cause of that decline has not been ascertained even as of today.  That decline in temperatures was reversed in the late 1970s,  as has the cause of the leveling of the earth’s temperature during the past 10-12 years, also in spite of increasing CO2.  Furthermore, some authors attributed that reversal to changes in the Pacific Decadal Oscillation which occurred in the late 1970s, not to CO2.

Against that background of a long term decline in temperature by the mid-1970s, it was known that the current “interglacial” period we are in (also known in science-speak as the “Holocene”)  would not last forever.   In fact, it had gone on about as long as the earlier one about 100, 000 years ago, called the Eemian (number “5” in the figure above), or about 10-12,000 years.  This was of concern to paleoclimatologists in the mid-1970s against the backdrop of declining temperatures.   Recall we departed from ice age conditions in fits and starts only about 18,000 years ago, and after a few thousand years reached the current Holocene “warmth.”

Here’s what the National Academy of Sciences (Understanding Climatic Change) had to say in 1975, p188:

“One may still ask the question:  When will the present interglacial end?  Few paleoclimatologists would dispute that the prominent warm periods (or interglacials) that have followed each of the terminations of the major glaciations  have had durations of 10,000 +-2,000 years.  In each case, a period of considerably colder climate has followed immediately after the interglacial interval.  Since about 10,000 years has elapsed since the onset of the present period of prominent warmth, the question naturally arises as to whether we are indeed on the brink of a period of colder climate.   Kukla and Mathews (1972) have already called attention to such a possiblity.  There seems little doubt that the present period of unusual warmth will (emphasis in the original) eventually give way to a time of colder climate, but there is no consensus with regard to either the magnitude or the rapidity of the transition.  The onset of this climatic decline could be several thousand years in the future, although there is a finite probability that a serious worldwide cooling could befall the earth within the next hundred years.”

So, global cooling is in our future, no doubt about it.  However, the NAS pointed out that the bad for us cooling might be offset by CO2, or, if there was a further warming, that before the eventual cooling, that CO2 would exacerbate that.  To me, what was being written by the NAS was vastly different than the mere “0” assigned to that piece by the BAMS authors.

Now, when a journalist reads a statement by the prestigious National Academy of Sciences that there is a possibility of a “climatic decline” (that’s how cooling was looked at, namely, it would be worse weather for us than we have now in the Interglacial) in just a hundred years, what is he going to write?  If he wrote about that for, say,  Time magazine, that global cooling was “in the bag” and might even happen within a 100 years,  he would have gotten it  from our highest scientific organization.

In sum, there WAS widespread concern among climatologists and scientists about global cooling, particular in the early 1970s.   It was no myth.



Climate change: What they were saying, 1968

While waiting amid the smoky skies for some clouds…

In 1968, the American Meteorological Society (AMS) published a Monograph, Volume 8, No. 30, to be exact.   Monographs are special collections of papers on a particular subject representing experts in the field and their purpose is to bring the scientific community up to date on the progress in that field.  This particular monograph was entitled, The Causes of Climatic Change. The Editor of this collection was J. Murray Mitchell, a world renown climate expert.  There were 18 papers by various experts in the field of climate.  Not ONE of those papers addressed the influence of carbon dioxide!

Only in the concluding remarks, does J. Murray Mitchell mention that we have to keep an eye on CO2 because it still may rear its head in modifying climate.

Why was there not a single paper on CO2 in that 1968 AMS volume on climate change?

There were papers being published in journals about the possible influence of CO2 on climate.  However, while CO2 was increasing drastically during the 20th Century, the global temperature had begun  declining slightly for about 20-25 years (from the early 1940s) when this monograph was published.   So, while it was known that CO2 COULD warm the climate, something else was going on in those days even as CO2 increased.

Most troubling in the context of falling global temperatures, as Mitchell points out in his concluding remarks, is that the causes of ice ages were not understood.  Several theories were put forth in this volume, such as  “galactic dust” having reduced solar radiation, but none were satisfactory in those days.

SO with the earth’s temperature in decline, it is not surprising that CO2 was “off the radar”, or very distant at that time, and with a cooling underway, that theories about the causes of ice ages seemed to be more important.

That situation was not much changed into the mid-1970s where in the National Academy assessment of Climate and Weather Modification:  Problems and Progress, we find the NAS panel noting the “recent equatorward shift in ice boundaries.”

Cirrus show

Just a couple of photos of yesterday morning’s glorious display of Cirrus (OK, “uncinus”) clouds, those high, icy white ones that were so fantastic enhanncing the desert and Catalina mountain background, taken from on top of a horse.

As you know by now, those Cirrus clouds are composed of tiny ice crystals, but, as tiny as they are, they are generally far larger than droplets in clouds.  So,  when ice clouds form, they are essentially precipitating clouds.  Those ice crystals are too heavy to stay aloft and the larger ones settle out producing these extremely fine, delicate strands.  Sometimes those trails extend thousands of feet below the “head” of the cloud where they were generated, and as they fall, go into regions where the wind is slightly different in velocity and direction, and so you get interesting twists and turns.

If you could fly up there, you would find tiny snowstorms of simple ice crystals shaped like little bullets (a crystal type), triangular prisms, stubby columns,  or plates, crystals that would  sparkle as they went buy and showed their pristine faces to the sun.   Seen’em do that many times when with the U of WA and their flight research program.  They look like daytime shooting stars, or fairy dust, as they rush by the pilot’s window,  and also where I was, viewing from a dome atop the fuselage of our various aircraft.  You would not know you were in a “cloud” except for those displays.

The last photo is of a droplet cloud, Cirrocumulus, composed of extra tiny cloudlets.   It was a higher altitude one, pretty cold up there, maybe -30 C.   Went off the “screen” before it may have crystalized into a Cirrus cloud many do. I thought it was a nice view, taken on the Canyon Loop Trail near Green Rock yesterday.

The End.