Category Archives: The desert

Arizona: the Emerald State

Now THAT was a monsoon-like day yesterday, one right out of the western state of Kerala, India; the thick rain of mid-morning, seemingly thicker than most here, the clothes-gripping humidity outside, the strip of fog on the side of the western Ghats, oops, Catalina Mountains, the relatively gentle breezes in the rain, the subdued green hues under the overcast of light rain at the end of the unusual morning drencher, aspects that, en toto,  made the morining seem so India-like to me (and I’ve been there in those Kerala rains).  Take a look at our green state and State.

10:37 AM, after 0.76 inches of thick rain with occasional thunder. Nimbostratus up top, Stratus fractus along the Samaniego Ridge.
10:53 AM. Looking toward Charoleau Gap.







In the Ghats, India, 1975,  in case you didn’t believe that I have been in ACTUAL monsoon rains.



And while the rest of the day was sunny, humid and cool for us, the rain wasn’t over with another thunderbludgeoning last night after 9 PM that brought 0.25 inches and the day’s Catalina rain total to 1.02 inches.  Drink up, desert!

Here are the rain reports from around Pima County.  Looks like the “Catalina” foothills has the 24 h total winner at 1.38 inches.  Here are other rain reports from around the State from the USGS.  One of these stations, Chrysotile,  NE of Globe, had 4.21 inches in the 24 h ending yesterday afternoon, also a total that is VERY Indian monsoon-like.

We also had a nice Altocumulus lenticularis at sunset, suggesting some wind aloft.  Seemed almost fall-like seeing this because they are more common with our winter troughs.


6:53 PM.

Another Big Day ahead

3 AM, Arizona obs. Several stations have dewpoints in the low 70s, with TUS reporting, along with light rain, a shockingly high dewpoint of 72 F, really extraordinary.

Get ready! A disturbance over southern California will help organize our storms into ones like those that occur in central Florida today, grouping them into large clusters, with some eye-popping rain amounts likely somewhere in the State (“eye-popping”, 3 plus inches).  Don’t be too surprised if you hear about a “tube” somewhere as well.  Tubes happen in conditions like these.

After today, its “mostly” dry through the end of September, with the best chance of rain on the 27th-28th.

The End.

Rainy days and Saturdays

Nice sunset yesterday….as some Stratocumulus spread over the sky underneath a pesky Cirrus cloud cover, clouds that announced the beginning of our next rain spell, now underway.

Light rain is falling this morning at 4:07 AM, and has been for hours, amounting to 0.01 inches.  However, some places in Pima Land have gotten much nicer rains, around a third of an inch in the Cat Mountains overnight, for example; check here.

Progress of the real monsoon, since June 1st, can be checked back there at the beginning of this sentence.  The coastal state of Karnataka has an average rainfall of about 70 inches since June 1st, a below normal amount, believe it or not.  However, being a statewide average, that 70 inches doesn’t reflect the hill stations in the western Ghats, surely to have about twice that amount.

Now, as a further aside, Karnataka, Kerala, two Indian west coastal states  would be a great place to go for a vacation now!  There you could REALLY absorb a REAL monsoon, where passing rains, heavy, pounding, thick with drops, visibility down to less than a mile, go on hour after hour with brief interruptions.  Its really pretty amazing and worth experiencing, at least once.

But, not much lightning there, like we have, because the rain develops mainly through a process not requiring ice, much like the rains in Hawaii where lightning is also rare.  The rain develops largely through the collisions of drops, ones that stick together after they collide, and get bigger on the way down through the cloud, sometimes called the “warm rain process” because ice is not involved, and that causes most of the rain in that Indian coastal region.  Cloud bases are right on the deck, and are typically 20-25 deg C, very, very warm.

In contrast, to continue a pedantic stream, “warm rain” is rare here in Arizony because cloud bases are relatively cool (less than 10 deg C in the summer as a rule), and droplet concentration are moderate to high (hundreds per cc).  Higher cloud droplet concentrations make it harder to grow cloud droplets big enough to collide and stick together inside our clouds.

But, we do get that kind of rain, “warm rain” here once in a great while in Arizona as part of the rain that forms in our Cumulonimbus clouds when their bottoms are especially warm, higher than 10 deg C.  Seems to happen about once or twice a summer in my experience so far.

What’s ahead?

Now that afternoon and evening rains around the area are back for the foreseeable future (5 days), what’s way ahead, beyond the foreseeable future?

There, as you know, when we start thinking about beyond the foreseeable future we start thinking about spaghetti! What do those crazy northern hemisphere-wide plots produced by NOAA with their dizzying numbers of lines mean for us here in Arizona?

First, I present a map of the 500 millibar contours as produced in the Haight-Asbury hippie district by San Francisco State–I mention this because the lines on this 500 mb map look a little nervous and maybe it has something to do with that map origin, being from a cultural area whose norms are “anomalous.”  I have pointed out  on this map, “Our Big Fat Anticyclone”, one whose position is critical for decent summer rains here.  In this map, as you can see, its not really OUR “BFA”, but rather belongs to Amarillo, TX, as of last evening.

Nevertheless, it is well positioned to fan humid air from the southeast into Arizona, as is happening now.  Remember, the circulation around a big fat anticyclone is clockwise.  When it sits on top of us, things are not so good; upper level temperatures are high, humidities are low up there, stifling convection and preventing tall Cumulus clouds.

But when the high is away on holiday, temperatures are lower above us, its more humid up there, and those factors allow for deep convection; huge Cumulonimbus clouds.  It only takes a few degrees difference to go from those dry days we just had with their Cumulus pancakus, to the kinds of days ahead for us now, where clouds stand tall!

Continuing, finally, Here’s is today’s plot for 15 days from now, the afternoon of August 11th, based on global data taken at 5 PM AST yesterday.  What do you see?  You see an arrow pointing to something of a void in all the “spaghetti.”  That void represents the most likely position of our BFA some two weeks from now, and that position is pretty darn good for summer rains here.  And it is in that region, to the north of us, almost the whole time from now!

So, based on this “most likely” position, one would venture that the rich summer rain season we have had thus far, will continue to be active.  Of course, this doesn’t mean rain everyday, but that breaks will likely be short through almost the first two weeks of August.

Can you imagine how tall those desert grasses and weeds will be by then if this is the case?

The last couple of photos document our fabulous re-greening now in progress.  If you haven’t been out in the desert, you should get out there and experience this wonderful event.  Doesn’t happen every year, as we know!

On a clear day you can see Flagstaff

Of course, you can’t see the TOWN of Flagstaff, you silly person, the title was just a hook to get you here to read about clouds!  The earth curves too much for you to see Flagstaff, for Pete’s Sake. How could you even imagine that such a title could be true?

But, you CAN see the tops of Cumulonimbus clouds boiling upward OVER Flagstaff, maybe there is someone you know there and you could call them about it, find out how much it has rained.  Those Cumulonimbus tops stick up above the horizon in that direction about a quarter of an inch if you were to take a ruler out and hold it out in front of you.  Thought you’d like to know this.

Here’s the scene I am describing from yesterday afternoon.  In case you wouldn’t know what to say to your Flagstaff friend, I’ve tried to help you out in the caption for the second photo.  Maybe its your mom you haven’t called in a while….  Who knows who it might be that you know up there?

1:27 PM. The scene. Cumulonimbus tops, likely above 40,000 feet above sea level, lined the higher terrain of the Rim to the NW-NE from Catalina yesterday afternoon.  BTW, I really like Catalina.  Who would have dreamed I would end up HERE coming from Seattle!
1:27 PM. Arrow points to a top right by Flagstaff!  If you have a friend or a relative up there because its too hot here, you could have called from Catalina yesterday and said, “Hi, I see its raining up there.  Are you getting much?  Friend:  “How do you know its raining? Did you look at some radar?”  You reply, “No, I can see the cloud over you from here, I really didn’t need to look at the radar.”

Finishing off today’s lesson: The tops you see are ALMOST always completely composed of ICE crystals and snowflakes because they too damn cold at 40,000 feet or so (temperature less than -40 C, less than -40 F; they are the same numeric at that temperature, yet another piece of knowledge for you) for anything but ice we think.

Some embarrassed people have reported liquid water at temperatures below -50 C such as Robert H. Simpson, former head of the National Hurricane Center and also husband of the late Joanne Simpson, famed Cumulus researcher and FIRST WOMAN TO EVER RECEIVE A PH. D. in meteorology1.  Must’ve have been an especially great marriage because they both loved weather and clouds and hurricanes and probably talked about ’em all day.

Continuing with something relevant, once when Bob (Simpson) was in Seattle giving a talk, after the talk I said to him, smiling, “You must be pretty embarrassed about reporting liquid water at -62 C”, as he did in 1962 in a conference paper, and again in 1963 in the peer-reviewed journal, the Monthly Weather Review.

He smiled and said, “The theoreticians don’t think its there, but its there.”


The weather today and the next few days into August?

Scattered rains, lightning thunder EVERY day into August! I am so happy. More rain is on the doorstep.  Take a look below at what this extra rain we’ve had so far in July has already done to our desert as of three days ago, July 25th.  Its incredible, isn’t it?  I call it, the “re-jungle-ation” of Arizona accompanied by the appearance of new life forms; see last photo.

1Joanne Simpson, after reviewing my grades, advised me to give up meteorology. She was a professor at UCLA then (1963), and I wanted to “walk on” as a met student in their program. In effect, though I didn’t realize it then, she saved me from myself since UCLA was WAY too theoretical for me in the approach to weather. Later I attended San Jose State2, a program much more suited to me with my weak math skills.  (Can you put a footnote in a footnote?)”

2While at SJS in the later 1960s, I was forecasting weather for the college paper, forecasts that devolved into silly, juvenile, lame topical humor, much like the “humor” here.  To drop another name in this blog, I loved what KRLA-AM, a top 40 station in Los Angeles, where I grew up,  was doing in those turbulent days of the late 1960s. They had dared to start a news parody program, recreating news events that they would first report in a serious manner.  It was bold and courageous for a mainstream media station; they dared to offend. I wanted to be a part of it, and went down to apply for summer work there in 1968.

My interviewer?  A young Harry Shearer.  The “Credibility Gap“,  the KRLA news parody team in those days, consisted mainly of Harry, Richard Beebe, and David L. Lander.  An example of their work, “Dawn of New Era for Man”,  KRLA’s 1969 Apollo 11 counter coverage to the major networks; its 8 min long, Arizona’s Papago Indians mentioned.  You can’t find this on the internet!

Back to the interview:  Harry briefly examined my topical forecasts for the SJS paper, ones I presented to him pasted on a blank sheet of paper.  After just a minute or two, he said, “I don’t think they’re that funny.”   It was painful to hear, but upon later reflection, oh, so true!  I left immediately.

I had some low moments in the 1960s, but here I am!