Cumulus with Stratocumulus; hold the ice

Mr. Cloud-maven person hasn’t said much about clouds lately, which is kind of ironic since he deems himself a “cloud maven” and not much more.  Rather, he has been obsessing about POSSIBLE storms in AZ 15 days away which is kind of futile anyway.

So, as an excuse to show more cloud photos from that gorgeous day of snow and cloud shadows on the Catalinas yesterday, will go into a cloud lecture, a post-mortem so to speak.   Here are some cloud shots from yesterday, most below the one at left.  Note, not one cloud shows any virga yesterday, and some of them got, at least moderately humped up.  A promiscuous cloud maven person might have called one or two of the cumulus clouds, a “Cumulus congestus” (though they would be WRONG).  Well, maybe not that wrong–see the 1987 World Meteorological Organization International Cloud Atlas that I can’t stand because they goofed up on their cloud designations as you will see if you could only find one of those yourself.  Still kind of bummed out by that atlas, but one member of that cloud selecting panel told me they were too busy in their Paris meeting going to the Eiffel Tower and such rather than paying attention to getting the cloud photos they had properly named.   Now, where was I?

Right, I was talking about yesterday’s clouds….   Well, here are some cloud shots, ones that I was going to post 15 minutes ago before getting upset again over the 1987 WMO cloud atlas.  (Really, I could have done a better job than the WMO all by myself; it was a real boondoggle, that meeting of “cloud experts”, yeah right.)   OK, photos!

Now looking at ALL of these, you see no fibrous material falling out, even though some of the clouds look pretty dark in these perty scenes.   I was so happy to be alive and live here yesterday, feeling very, very lucky.  So, remembering the University that Bullwinkle Moose went to play football as the “Frostbite Flash”, “Whatsamatta U.”, we might say the same thing to these clouds, “Whatsamatta U?”   How’s come there no precip falling out, and those who read this silly site will answer immediately, “Them clouds ain’t got no ice in’em”, which would be correct.

But why?  It was awfully cold yesterday, and even Mr. Cloud-maven person, who does not even have the Master’s Degree, was wondering.  So, off to the TUS “99 Luftballoons” sounding data for yesterday afternoon, posted by our great U of A Weather Department below (where the lines come together are where the clouds were located).  Didn’t seem possible to me, but those cloud tops were hardly as cold as -5 C (23 F).  Ice does not form in clouds, even though they are below freezing, at this temperature in the natural state except in very special circumstances.  Ice formation in clouds, still not WELL understood, is known to be a function of drop sizes AND temperatures.   Over the oceans where cloud drop sizes are large,  it happens.  Usually, someone can get a whole scientific paper out of a cloud that formed natural ice when the top has never been colder than -4 C!

Here in Arizona, what we would call a continental cloud forming environment.   Cloud drops “is” smaller because there are so many more particles for the drops to condense on, and so the concentration of drops is higher, meaning the drops have to be smaller to condense out the same amount of water as over the oceans where the air has fewer particles for clouds to form on.   In a nice cumulus off the Washington coast of the sizes we had here yesterday, the cloud drops would be as large as half the diameter of a human hair (“wow”, huge, he sez, 30-50 microns in diameter, for the sake of a number) here in AZ in those clouds yesterday would be lucky to have drops in them as big as 20-25 microns, too small to activate ice forming processes, known to be related to drop sizes.   Oddly, the bigger the cloud drops, the HIGHER the temperature at which ice forms, especially if drizzle drops have formed.  The drops in our clouds yesterday were too small to have an appreciable fall speed, so they don’t fall out either.

Since I have published a lot of critical work on cloud seeding, one might ask if these clouds could have been made to snow by artificial means?   Even as a long time critic, the answer is an unambiguous “yes.”   With a small plane, and a little dry ice, you could have made a little snow fall out of these clouds because the tops were cold enough for that.  Dry ice, the substance you would have used,  has a temperature of -78 C, and when pellets falling, they leave a jillion ice crystals in their path as they cool the air momentarily to -40 C and below, the spontaneous nucleation temperature.  And, with ice in these clouds, the drops would be evaporating and the water molecules depositing themselves on the ice crystals.   Ice crystals in clouds of water drops are like little low pressure centers; the water molecules leave the drops and goes to ice, and ice crystal gets big enough to fall out.  Our natural precip here is like this most of the time.

So, summing up this little cloud-ice lesson, our clouds did not get cold enough, and at the temperature the tops DID get to, the drops weren’t big enough to trigger natural freezing.  Tell your friends.

The End.

“…goin’ down in the first round”

As Muhammad Ali might say, referring to the Climate Prediction Center’s three month outlook that was for dry conditions in Arizona from November to January.  So, the first round, November into early December, has delivered quite a punch against drought with another 0.40 inches here in Catalina last night.  Our December total is already 0.82 inches!  Rains have been bountiful, too, during this period in some parts of NM and Texas, horribly stricken with drought, so its been great run of drought smashing weather.   Check the latest 30 day US precip totals here (does not include the heavy rains of yesterday in TX, however).   And from WSI Intellicast, this 7 day total precip map.   Excellent.    In Catalina we now have had 2.63 inches since the beginning of November.

Below, the CPC forecast for November through January for the US issued last October 20th.  These predictions are weighted by the “moderate” La Nina event now going on in the central and eastern Pacific.  A La Nina leads to greater chances of dry conditions throughout most of the southern US.  Hence,  this forecast.  However, the correlations between a La Nina and the map shown below leave plenty of wiggle room, especially early in the winter.  Later in the winter is when the great southern US storm deflecting property of a La Nina has its greatest power, so it’s really good that we’re getting slammed early by decent rains; it might be a very dry late winter and spring.

Remember 1971-72?  And how wet it was in November and December in the SW, and then poof, almost nothing in the way of precip after January 1st?  It was awful. (I was weather forecasting in Durango, CO, then.  ((Hay! Not for TEEVEE, but for a randomized cloud seeding experiment!))


Had some pretty Cumulus clouds yesterday before the gray Nimbostratus layer moved in.  Here are a couple of shots around the Catalina area.  Always nice to see snow on the Catalina Mountains.

The last one is from today showing the gorgeous scenes, changing by the minute as the cloud shadows roll by, of the low level on the snow on the Catalinas.   Even here at just under 3200 feet elevation, last night’s rain ended with light snow for a few minutes.

Mods (from U of AZ Wildcats) don’t see precip from this next cold trough, one that lands on us tomorrow.  Darn.

Suddenly, it occurred to me that I want you to look at these forecast maps from IPS Meteostar for the next 15 days.  Just changed this to the intermediate model run, updated at 06 Z, 11 PM LST.  Much more “interesting”–means this writer saw MUCH more precip in AZ on the updated model run just now.  Check out the massive trough 12-15 days out and cross fingers.  Man, this is an exciting new change!

The End.

Seattle-like temperature day; U of A cloud machine; 2 more hundredths in exciting tiny hail/graupel shower yesterday around 3:40 PM here in Catalina though I was hoping for more yesterday but the Cumulus clouds didn’t get as deep as I thought they might in the afternoon.

I guess that title is a little long…

Yesterday’s lack of much temperature change during daylight hours here in Catalina reminded those of us from the Wet Life in Seattle and other locales west of the Cascade Mountains of our fall and winter and early spring days.   Its not unusual in those locales for the temperature to stay about the same all day due to the weak sun.  Here  temperature as Cat mtn profile is our Catalina temperature record for yesterday, one that resembles a west to east cross section of the Catalina Mountains.

However, and only about 10% of the size of the shower line I expected later in the day yesterday, clusters of “mild” showers,  not really having good shafts,  moved across that had a tiny pellets bouncing off the hard surfaces.   Nice.  When they’re as small as they were at my house (about 1/8 inch in diameter is all) they’re generally referred to as graupel, or soft hail.  These originate as ice crystals or snowflakes that collect a lot of cloud droplets on the way down and end up being little snowballs.   The process is the same as opaque rime icing on aircraft, or when clouds are below freezing on mountain tops and the trees collect ice from the impacting cloud drops.   You can usually crush soft hail/graupel in your hand.  On the other hand, if they originate from much larger drops, the icing is clear.   Won’t go into drop size differences here.  Some nice examples of rime ice can be found here from a “Romantic Asheville” (NC) website that popped up under a “rime icing” search.  Hmmm, “romantic”….

Next, while viewing the time lapse movie of clouds over the Catalinas and over us from the  U of A campus, I noticed a nefarious cloud making machine that I did not know about before this morning.  Take a look at this movie here and see this little plume on the far left of the picture tooting little clouds up into the lowest layer of clouds yesterday,  beginning about 40% into the movie.  At that time ther is an eruption of much lower clouds from the southeast.   What kind of weather making experiment are they doing to us now?   (hahahha, just kidding)

Looks like a steam plant plume ejecting a moist and heated plume right into those lowest clouds, adding some density to them.  Kind of neat to see that.  Also, you can see how the wind changes during the day yesterday.

BTW, some of the tallest buildings in Seattle (We calls’em, “cloudscrapers”) also put out little cloud forming plumes, adding to the body of clouds already in place.  “Great!”-sarcastically spoken.

The End.

Thirty-five (six, seven, eight, nine…) and counting….

Nice rainshower starting right this second at 4:03 AM which will likely add to this total.  Just did add 0.01 inches.  I was hoping for an inch or more from this situation, and it can still happen before its over by late today.   But,  in the desert,  you always have to prepare to be disappointed when it comes to rain.  However, that 0.38 inches (now at 5:18 AM) is significant and will keep prospects for a great spring wildflower bloom going.   Local 24 h amounts can be found here, FYI.  BTW, when you see in this list that Mt. Sara Lemmon has a ludicrous “zero” precip, as in this list today,  its because its snow, not rain, and isn’t melting into the gage.

BTW, a great way to observe what’s going on around here is via the Wunderground maps here where you can animate the radar.  Also, if you pay them a very small fee, you can get these maps advertising-free.  These guys do a great job I think.

First, when you open this map, you will be surprised at the number of “personal” weather stations being displayed around SE AZ, especially if you drill down.  Almost certainly you will begin wondering whether YOU should have one as the herd instinct begins to activate.  That would be great if you got one!   It is pretty remarkable how folks get all wound up about weather and decide that the number of official reports aren’t good enough for them; they must have a station next to the BBQ grill in the backyard to REALLY know what happened, and what is happening while the grill is heating up.  I have one, if that helps in your decision process.  Its here.  You have to drill down on the Wunderground map, linked above, for it to show up, though.

Cold Dead Ahead

A second atmospheric “iceberg” is shooting down out of the north at us and winds up just to the northwest of us.  The USA NWS “WRF-GFS”  (I pronounce it, “WURF-GOOFUS”)  model (whose output is shown below) had that second low too far to the east for much of any precip here in prior runs.  But last night, that model has produced a forecast that raises our chance of precip from this second blast of cold air.  Eerily, these maps eventually resemble that horrible cold spell of last early February, though fortunately it will not nearly as cold this time.  Still, you get goose bumps looking at that historic pattern recurring again.

Here is a color-coded temperature forecast from the WRF-GFS at the 500 millibar level, around 18,000 feet.  Below, a couple of snapshots from that model run based on last night’s data.   The first map below is what this morning was supposed to look like over us.   This first map is just a 12 h prediction so its likely that there are few errors and it will look pretty much exactly like this.  (Remember though that the little errors that ARE there at the outset grow into mighty oaks in errors in a few to ten days out making those forecasts unreliable in details.)

Note on the first map, that “incoming”, namely, that purple blob of low temperatures approaching the USA border from Canada.  It will be extruding southward right to AZ while our present, overhead cold low spinner drifts off to the east, passing overhead of my house about 7 PM tonight.  I will be looking up then to see what it looks like.

The second map, valid for Saturday afternoon at 5 PM LST,  shows how that blob of purple approaching the US now, has spun off an “iceberg” that is shown sitting over Kingman, AZ, pretty much where the current cold low shown on the first map is sitting.  That means we have a very slight chance of more showers, some mixed with snow here as that one goes overhead on Monday.  The chances of precip are down because this blob of upper cold air has such a long overland trajectory.

Finally, its the last map that is eerily similar to the awful cold wave situation we had last February.  It brings shudders just looking at it, reminding one of all the damage that February cold snap caused.

You can see on this last map how the very lowest temperatures (purple areas) have extruded (I love that word!) all the way down into Colorado, while another vortex has formed in AZ.  Probably too dry for anything but a tiny chance of snow flurries here on Monday morning, maybe a couple of shallow glaciating Cumulus clouds in the afternoon is all we’ll see.

The following Tuesday morning will be awful cold.  Check NWS forecast for Catalina here.  You’ll see some temps below freezing are expected, and if you live in a gully, it will be much colder than those shown here on the clear nights ahead!  Check out the minimum temperatures some time as measured at the Catalina State Park (here, pluck the morning reports for Cat SP) in the CDO wash on clear nights.  Unbelievably low sometimes, as much as 10-15 deg colder than here at my site on a hill side.

Enjoy some more rain today!

The End

Great weather map day

Check this map out below from the University of Washington Huskies Weather Department.  The whole 24 h series of sea level pressure maps is here and watch how things change in the SW and western Arizona just in that time.  You rarely see lows of this magnitude in our area as we have right now, and this much change in just 24 h in a sea level pressure map.  As you can see from the low center  centered over Ajo, AZ, (below) the air is going in counterclockwise circles in our State.  Well, of course, friction caused by cactus and mountains turns the air toward that low center, trying to get rid of it.  But, the forces producing it so far are stronger so far and so it has a very low pressure (less than 1004 millibars) for this time of year over AZ.

Note, too, that all the clouds and precip (shown here) and by those white areas on the map below, are to the west and north of the center.  But that will change as the upper air low center (second map) spins back to the southwest a bit and the air over us changes in direction from the southwest, as it is now on this upper level map, to a more southerly direction in the hours ahead.

In the meantime, Pacific air should be gaining a presence over the interior of Baja and begin circulating from there up toward us.   Clouds should literally start appearing out of the clear skies to the southwest of us in satellite imagery today (such as here) and then those clouds will work their way up this way, likely increasing in depth and coverage as they do.

Another exciting prospect is that this same process, clouds appearing out of the blue, will likely start happening over us as the day progresses, and maybe, in view of the strong winds aloft, some nice “flying saucer” clouds, namely, Altocumulus lenticularis, flat, lens shaped clouds that hover over mountains will show up over the Catalinas.

These are great days ahead for weather folk, and I hope in spite of any inconveniences caused by quite wonderful inclement weather, you will enjoy this dynamo of a weather day.  Of course, you wanna go here, to the NWS, for all the great details.

Rain?  Supposed to begin in these parts between around 4 PM and 6 PM today (you can see this here from the U of WA model).   Interestingly, this model has a rather thin band of precip sitting over us for more than 12 h.   Good grief!  Too good to be true I suppose, since we might get well over half an inch, and would certainly, if it happens, push our wildflower prospects for this spring up in view of our 1.83 inches here in Catalina in November.

Also this;  a nice satellite view of the US where you can see the night lights of the cities, if you’re up early enough and haven’t seen it before.

The End for now.

Timing of rain–go here

Hi, again,

Go here for as good as the timing on the incoming rain gets, graciously provided by the University of Arizona Department of Atmospheric Meteorology.  This model run, now in progress says that rain begins to move into the Cat Mountains by 3 PM tomorrow.  Exciting.   Also you will notice in this “total accumulation of precip” presentation, that we’re expected to get a very nice rain, looks like half inch to an inch by Friday, 2 PM, and even then it ain’t over.   Also you’ll see that by that time, areas to the north of us get SEVERAL INCHES according to this model.   However, those indicated amounts have to be used with caution since they originate with imperfectly known cloud and precip processes that we try our best to represent in models, but still come up short most of the time.  In this case, there is a “tendency” in this model to over-predict the precip.   And the onset timing could be off some as well.

Also, if you like to see time lapse of the clouds you might have missed yesterday, they have this U of A campus site with the roof cam pointed at the appropriately named Cat Mountains.  Us in Catalinaland are just behind Table Mountain, Pusch Ridge in that time lapse.  This time lapse will REALLY be interesting in the next few days.

You will also see, if you look closely, why we think of Cirrus clouds as “precipitating” clouds.  In the time lapse you will see trails of ice crystals falling out.  They are virtually dust like in size (well, they run 100-300 microns in diameter, those ones falling out), but if in it, you would hardly notice that kind of precip.   You would only see glints of crystals going by, and a dust like coating on the ground (if you were on Mt. Everest or K2).  So, once out of the body of the cloud they start to evaporate, fall even less slowly, and the trail becomes almost horizontal.   Sometime horizontal (flat) layers have precipitating Cirrus above them constantly dropping new crystals into the flat, constantly thinning layer in kind of a quasi-equilibrium.

Oops, enough of that.  Here’s is yesterday’s Cirrus-induced sunset, definitely more interesting than the above.

 

The End and waiting for the RAIN!

 

Double Vision

Who can forget rock band, Foreigner?   Remember that other hit song from that album about desert people like us, “Hot Blooded”?  I do.  But I was in Seattle then (1980s) at the U of WA, never dreaming I was going to be in hot blooded in Catalina, AZ, especially in the summers.

Today’s amazing progs with such wonderful sights maybe think of that song title because two of the same kind of upper cutoff lows are forecast to sit and spin over the Southwest in the next few days, with noticeable weather happenings,  like the wind picking up as early as Windsday (hahhaha).   What’s weather website without juvenile humor now and then?  But seeing this model output has made me quite happy, feeling good about myself and the world around me.

Again, I start with the Canadian’s (whom I sometimes tease since my relatives there might be reading this blog) model output (in totality here) from last night’s 5 PM LST global data.  The first panel is last night’s initial weather maps just to show you how drastic the change in the weather is going to be.  Look at how there is nothing but “high pressure” all over the West.

Then here’s what we see in just 60 and 132 h from that map, that is,  just this Friday morning at 5 AM LST, and Sunday morning at 5 AM (second and third maps).  Look in the upper left panels and note how similar Friday and Sunday are!  Amazing!  And the positions predicted are great for huge dumps of snow in the north parts of AZ and good rains here.  The aspect of this that really helps us is that the rains/snow won’t just come in ONE several hour spell, but should recur after they start because cut offs by their nature don’t move much but kind of wobble around like they look like on the upper maps, spinning tops, ones that initiate new bands and blobs of rain while they sit and spin.  And we will be dealing with TWO of those! Fantastic.

Now, for fun, the thing to do is NOT look at any more model runs, they could hardly be better than these, so why look?) and just watch the sky change over the next five days or so, dreaming about what will be, what COULD be.  Enjoy it all.  No matter what, the clouds will be great, the rain treasured, as will those sunrises and sunsets from time to time.

What a life we have here!

Starts with the starting model map since that seemed to be a good place to start, then Friday and Sunday maps follow, respectively:

“Who you gonna call?”

Droughtbusters! (When you have a drought)

Kind of exciting today as another complex, hard-to-predict upper low center breaks off from the main jet stream and circulates down into the Southwest on Thursday and then sits and spins for a couple of days.  What so exciting to trigger a blog in the afternoon?

One of the enigmas has been that the Canadian model, often shown here because most of my relatives are Canadian, and the USA ! model have had large differences in where this upper low center will end up once in the Southwest and cut off from the main flow.   Once in place, it sits and spins for a while, which means that if you are in the right place, it might rain off and on for a couple of days. A cut off low in the SW is one of my favorites patterns of all time, not that you care.   Remember that low of December 1967 in Arizona?   The one that nearly buried the State in snow when it sat around for a couple of days in almost the same spot?

Well, this incoming one is not as gigantic as that 1967 one, but, it has potential to produce a lot of rain in the State for the same reason: sitting and spinning like a record player somewhere in the SW for a couple of days before moving on.

Today’s model runs were exciting because now the USA and Canadian models are in sync.   Previously the USA model had the low in a spot in which most of the rain would miss us, while the Canadian one had a pretty wet scenario for us.

Now, from this morning’s global data, they BOTH see the low ending up over southern California, drifting very slowly eastward, and BOTH have good rains predicted for the State!   Imagine a couple of days of good rains.  Wow.  Droughtbusters!  (in the plural because two models have this scenario now.)

Well, of course, it doesn’t guarantee it will happen just because both models are showing the same thing over several days, but it is very encouraging.  Fingers crossed.

Below, an example of this cut off low, well away from the main jet, sitting over about San Diego.  This depeiction is valid for Friday morning at 5 AM LST.  The whole loop can be seen here.  Enjoy.

The End.

 

Thankful for the 23 hundredths

Gorgeous day yesterday with lots of…Altocumulus opacus with castellanus clouds here and there.   But you knew what kind of cloud those were already.  And our upper trough and clouds situation closed out overnight with a decent 0.23 inches of rain here in Catalina.   “Nice”,  since it wasn’t a sure thing that we’d even get rain when the tropical plume from former hurricane Kenneth (R.I.P.) was slipping by to our SE across Douglas, AZ and into NM.  Dang.  So, it WAS a 24 h to be thankful for.

There was also, ever so briefly yesterday, the “flying saucer” cloud, an Altocumulus lenticularis, apparently hovering above but really a bit downwind of the Catalina Mountains.  This photo is one of the better of that cloud variety I have taken.  Also, while it may LOOK like its hovering over Samaniego Peak, its really quite a ways downwind from there. You’ll see that in the U of A time lapse movie for yesterday here.  It appears about one minute into the movie, or just after 9AM if you can read the time signature in the lower right hand corner.   Lenticular clouds usually form when the winds aloft are quite strong, and the air at the level of the cloud is “stable”, resists moving up and down so you get laminar flow instead of turrets and bumps on the top.  Below a couple of other shots characterizing the day.

Ahead?  A LONG dry spell.  Dang#2.

The End.



THREE times in a row, Canadian model wetting it up for us

This is great!  I thought sure that the Canadian model, which has been a bit of an outlier, would take that jet of moisture and rain emanating from the remains of Kenneth the Hurricane away.  But no, yesterday morning’s Canadian run had it cruising into us with a bountiful rain, and now overnight, once again as it first did on the night before last.  So, for three consecutive model runs, this torrent of moisture from Ken, ejects rapidly over us.  Stupefying!  Today we might call this small-in-length ejection of water vapor and clouds an “atmospheric flash flood” (too short in length to be called an “atmospheric river“, the new buzz phrase for West Coast flooding scenarios when long fetches of tropical air thousands of miles long in narrow bands ahead of fronts cause deluges).

Here, with gratitude to the Canadians, most of whom live with two miles of the US because they want to be as far south as they can get and are practically Americans anyway,  is last night’s model run, showing that fine, fine looking low pressure center encroaching on southern California in 24 h.  Its that low that starts to eject the body parts from  “Kenneth” at us.  I am just beside myself with joy!

They made me happy today with this sequence (extracted from here).  You’ll want to concentrate on the LOWER RIGHT HAND PANELS and those green to yellow and red regions where RAIN is expected in the 12 h PRECEDING the map VALID time.  Unless you click on these images you will have to have a microscope to see what I am talking about.

The valid times are, from left to right, Thanksgiving Day at 5 AM AST, Thanksgiving Day when eating turkey (5 PM AST), and 5 AM AST Friday morning.  What is remarkable is how fast the rain develops after just appearing on that first panel off southern Baja.  By nightfall, the model thinks rain will have started here!  Wow!  That would mean an awful lot of, probably middle and high clouds, are already in place streaming toward us ahead of the nub of that rain area shown in the first panel.

 

 

 

 

 

 

 

 

 

If we go to the University of Washington Huskies’ Atmospheric Sci Dept web site and this loop, you can see that it’s already happening, high clouds (shown as white regions in this loop) are already being torn from poor Kenneth down there.  Keep an eye (Kenneth’s is pretty much gone) on that bulge on the NNE side in the last couple of frames.  That’s likely where our  jet of moisture will originate.

Will be cleaning out rain gauge of dust and debris;  maybe will wax collector funnel so that those raindrops really accelerate into that inner measuring tube.  Hope you do, too.  You don’t want to leave anything out there, on the sports field, or on the funnel.

The End.