Art Rangno – Page 96

On schedule for major AZ storm beginning Monday

Now that the models have reconciled, “come together”, to show a large storm affecting Arizona and us here in Catland beginning later Monday, it seemed interesting to ME to show you how this one gets here. This is where our numerical models do things that in the olden days before them we could never anticipate.

Here is a loop from last night’s global data on how a large, vigorous low center forms over San Diego within about 84 from right now. This loop of the high and low pressures in the middle troposphere (around 15,000-20,000 feet above sea level) from the University of Washington’s “WRF-GFS” model for the West Coast and environs:

Watch what happens in the Gulf of Alaska. Everything is rolling along FAR to our north, going toward the east, looks like it’ll stay up there with those waves moving one after the other into Canada. There is no hint of anything moving this way. Then suddenly, the wave rippling along in the Gulf turns south bound as it hits the West Coast, part of it ripped off and becoming a spinning center just off California and the rest continuing on into central Canada! Really, its amazing to see such a drastic change like that shown in this sequence.

This type of sequence has been very much like this winter’s past storms have gone through, rippling along in the northern Pacific Ocean, and then suddenly part of those waves shearing off from the main jet, making a right turn toward the SW US, becoming an isolated, spinning, wobbling center away from the steady strong westerlies of the jet stream. Some years have had lots of these “cut off” lows, and it seems we are headed in that direction this winter, at least through the first 6-7 weeks.

One of the keys to this happening is how vigorous is the storm immediately upwind of the one that plunges south, oddly. This influence of upwind storms in perturbing the jet stream downwind was discovered WAY back in the 1950s. In the current situation, an extremely intense low developing in the central western Pacific sends huge amounts of heat and clouds northeastward behind, upwind, of “our storm” and that heat and moisture (see here protruding into the Aleutians in this loop) helps amplify the jet stream downwind where our storm wave is by causing the winds shift more to the north downwind of the warm air plume at the backside of our wave).

What it is doing is building, for a time, a high pressure ridge aloft within and just ahead of it. In response to that “ridge building” plume of heat and moisture caused by that intense storm upwind of “our wave”, the jet stream downwind begins to head more to the south, IN our wave. The intense storm behind our wave is building “amplitude” in the jet stream. Amplitude in “synoptic” meteorology generally means the jet stream winds go more to the north and south rather than just east and west. And that’s what you see happen for a time in this loop, and its this greater amplitude that causes a part of the once steadily progressing wave across the Gulf of Alaska to go, “Oops, must go south now” as the winds from the north increase tremendously on its backside.

The assymetry of the winds in these waves tell you where its going next. If they are stronger on the backside, it will go south or southeast. If the winds are strongest on the front side, or east side, it will go north or northeast. If you can see the winds in the above loop, you’ll see that they reach 120 mph from the north on the backside as it plunges S, but the winds on the east side are only about half or less of that.

Hope this is somewhat intelligible. Still rewriting…!

Personal predictions? I think we’ll get at least 0.50 inches, probably see some more snow mixed in with the rain by Tuesday morning. Think about a great wildflower bloom this spring. In the meantime, enjoy the warmth and cirrus of the next couple of days. One thing that might help is that disturbance SE of the Hawaiian Islands feeding moisture into the jet stream (seen here in this loop again). I thought at first that bunch of clouds might be related to the MJO (not a coffee brand, but the “Madden Julian Oscillation” which can have a profound effect on US weather). But it wasn’t. The MJO is in the area of the Maritime Continent now. Go here for the latest NOAA details on this subtle wind regime that travels around the globe toward the east.

Last evening’s “cirrus-ee”, (ice crystal clouds), sunset.

The End.

“Come together, right now, over me” in Arizona with some rain

This song and refrain by Lennon and McCartney, amended a bit in the title for local interest¹ was actually a reference by them to a striking “divergence” in weather model predictions of that day during a droughty time in England; the models did “come together” eventually to predict the same thing, and that was for a lot of rain in droughty England in the days ahead. By the way, you won’t find this kind of historical background information in Wikipedia or in some biography.

As we saw yesterday, one model can show a lot of rain in AZ a few days, and another not. So, we, too, as did Lennon and McCartney, wanted those models to “come together” and show the needed rain over us; not one model doing this and another one doing that, as they can do. I know a lot of you were fretting all day about which one was going to be right, the dry one or the wet one for Arizona? Well, we have seen them “come together” over the past 24h.

Expect rain and snow!

And a goodly amount of it, in AZ, including Catalina, beginning late on Monday and then continuing off and on for a couple of days! Wildflowers, here you come! Maybe you should get that better camera before the spring bloom, and also help the economy along while doing so.

And as you might have speculated, the Canadian wet model run for Arizona, the one one showing a storm pattern similar to the ones we have had intermittently in November and early December, was the one that won out over yesterday’s model “diffugulty.” This is great news unless you’re chauvenistic and just that bit peeved that the Canadian model won this event in the “weather model Olympics.” Oh, well. The US model, while now predicting storminess for us is a bit drier than shown here. Still, its all good.

Here’s last night’s juiciest Enviro Canada panel for AZ, that for Tuesday morning at 5 AM PST showing the storm barging well into AZ (lower right panel). Exult! The entire sequence can be seen here.

On a cloud note, we had for a time yesterday, some of the rarely seen Cirrus castellanus, icy clouds with turrets. Usually its too cold and too “stable” for turrets at heights above about 30,000 feet above the ground, but there they were. See below.

___________

¹In the early original drafts of this song, the reference was to “England”, not Arizona. As you can see, those part of the lyrics referring to location and rain were a bit awkward and were eventually dropped.

Sunny malaise

2clr4me. I’ve never texted before, but there it is.

Unfortunately 4me, but fortunately for those “bird people” that come here to avoid real weather, it is going to be sunny except for some passing cirriform clouds over the next few days, a real weather malaise. However, the good part is that the temperatures are rebounding pretty fast.

However, we can take solace in the fact that clouds and rain are again on the model horizon, not the real one. Those friendly Canadians up north in their version of the ECMWF model have indicated it will be a whopper, whilst the USA “WRF-GFS” is indicating just a mild event, one that occurs much later than the Canadian “solution.” (“Solution”, hah! Nothing is solved here!) So, once again, we are stuck with a lot of uncertainty partly because it originates with another low that has/will drift away from the main jet stream. Here is the Canadian view of a whopper for this next Monday. Note that AZ is as green as a leprichaun below, lower right panel, indicating widespread rain. Note big upper low center circulation centered over Kingman, AZ (upper left panel). This would be a very wet scenario for Catalinans.

Next the US model for the same storm and time (Monday afternoon at 5 PM LST) from IPS MEteostar. Note that a low center is nowhere to be seen in AZ, but INSTEAD two low centers are seen, one over Crescent City-Eureka-I-Found-It, California, and one west of Ensenada, MX. This is so funny! Yet annoying. But no rain has yet appeared anywhere in AZ in the US model at this time! In fact, as seen in the last map for the exact same time as the Canadian model with all that rain in AZ, the nearest rain to us is sill about 300-500 miles off the California coast! Amazing! Yet, annoying. These are calculations based on physics. (Well, the “physics” are implemented differently.) Imagine if your hand calculator said that 2 and 2 was 4 on one day, and the 7 the next. The world would be discombobulated because no one can do math in their heads anymore.

It takes a coupla more days for the US model rain to get here to AZ, late next week, and then, its marginal at that. Well at least the US model has some rain in it someday. I guess we should be thankful for that.

But what would be a “tilter” in this scenario when you have such “model divergence”? Persistence might do it. Look how the Canadian model result below so strongly resembles the kinds of storms we’ve had since the start of November, the isolated low that drifts down into the SW. This seems to be, at least, our early winter pattern that we have seen several times now, and when IN a pattern, it may be best in forecasting to “stay the course”, lean toward the model solution that shows the kinds of storms that have already been happening when the models outputs are so different. It will be fun seeing how this turns out!

The End.

An icy 0.06 inches Catalina dessert

Like most people, I like dessert, especially if its precip in the desert. Yesterday’s “graupelly” fall of little ice ball showers weren’t expected, a surprise entree. Even the local model run by the U of AZ weather department on their “Beowulf Cluster” of computers had the showers staying to the north. So as a weatherperson, you would go with those models; “hey”, they’re the best we can do. That’s what the TEEVEE weather guys do, too, unless they are really great and can tweak and improve them by knowing the kinds of errors the models make.

A side light: A professor of weather at the University of Washington recently gave a big lecture about how it is useless for the National Weather Service to try and beat the computer models for tomorrow’s and beyond weather. As in the humorous take on that old spoken word, how-to-live song, Desiderata, “Deteriorata”, by the Fire Sign Theatre back in the 70s, this professor told the NWS to, “Give up”; devote your time to getting the first day right, among other things. The computers have a tough time in the first 6-12 h, as we saw yesterday.

Yesterday, you could see the “errors” developing right off the bat. All of the billions and billions and billions of calculations by the models, to say something Carl Sagan, the astronomer-cosmologist might say if he had been a weatherman, were unraveling; going wrong, incorrect, getting an “F” for rain/snow prediction. It was going to be a bad day for the computers, who, as we know, generally know more than we do, especially about us and the things we do and buy.

Yesterday, the first exciting hint for me that the showers might reach here rather than just be a little to the north as the models said, was this scene whilst out with the dogs around first light, 7:30 AM. Look at that shower going by the Charleau Gap! I thought I might see lightning! But then I usually think I am going to see more in weather, and in other areas of life, that I want to have happen than actually happens. I thought, for example, that the Washington Huskies would beat the woeful Oregon State Beavers in football. Actually fairly confident there. But, “no”, it didn’t happen.

Back to weather: the proper weather person would have exclaimed when seeing showers to the left and to the right early yesterday morning (and popping out on the TUS radar) as I did, “Wow”, these clouds have ice in’em! And that wasn’t supposed to happen!”

So this was the first sign that we had a good chance of showers/snow yesterday. It was a truly great moment because the computers are so often correct.

But yesterday, they were going down! Cumulus congestus/weak Cumulonimbus clouds everywhere!

I felt great. When weather computers fail on the dry side, it makes me feel better as a human. And of course, seeing these shafts of precip, you could opine knowledgeably to you friends that the cloud tops are likely colder than -10 C (4 F) (since ice formation in clouds before that temperature is reached would be unlikely here in AZ).

Here are some additional shots from that glorious day yesterday, including, for Oregon State fans (“hey”, the former company team is going to a bowl game!) a closeup of “graupel” for your viewing pleasure. The last shot is when subsiding air arrived and squashed the Cumulus down over the beautiful Catalina Mountains into “humilis” versions late in the afternoon.

The weather ahead? A strong storm still shows up in about a week.

The End, except for trying to get this layout right!

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!