Category Archives: The weather ahead

Colorful evening ends day with a colorful morning; a note on the great Cal rains of October 2016

Not much else to talk about, no rain of course;  what is that?

But with so many colorful scenes yesterday, we can be partially sated by the  lives we lead here sans rain here.  October ended with a puny 0.01 inches in Sutherland Heights.

Now, because I grew up in California and remain a little Cal-centric, this brief diversion from AZ:

But droughty Cal got nailed though, from about San Luis Obispo, so we can be happy about that I guess.  One station, Gasquet RS,  near the Duck border,  got just under 28 inches in October; stations in the Santa Cruz Mountains, way down by Monterrey, got between 14-17 inches!  From the California-Nevada River Forecast Center, this nice map of October rainfall anomalies in that domain.  Red is real dry, and that’s the color we would be in if it was the California-Nevada-Arizona River Forecast Center:

Many departures are far over the map color-coding limit of 350%, but are over 1000% of average!
Many departures are far over the map color-coding limit of 350%, but are over 1000% of average!  Note red below normal swath.  This tells you that the mean area of low pressure at the surface and aloft was just off the West Coast.  Pac NW set maximum October rainfall records, too.

But let us not dwell any more of generous rains that others got, but celebrate the color and clouds of Arizona.   Here are yesterday’s glorious scenes, beginning with a spectacular Altocumulus lenticularis under some Cirrus at dawn:

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6:37 AM.
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6:47 AM. Ac len stack.
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10:51 AM. Tiny patch of Cirrocumulus tried to hide in front of some Cirrus. Hope you weren’t fooled and logged this sighting in your cloud diary. Cloud maven person almost missed it himself.
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12:50 PM. There were lenticulars aplenty yesterday. Here’s another one in a location a little different from normal, beyond the Catalinas. Upwind edge is the smoothest one at right. No ice streamers coming out the downwind end, so must have been pretty “warm”. Lenticulars, due to their tiny droplets and those droplets having short life times, have been known to resist ice formation to temperatures well below -30°C -22° F). Pretty amazing.
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2:42 PM. Kind of clouded up in the afternoon, and with breezes, made it seem like something was up. It was, but far to the NW of us. We have been under a streamer of high to middle clouds originating deep in the Tropics for a couple of days. Here some lower level moisture has crept in on cat’s feet, to be poetic for a second, and has resulted in small Cumulus and Stratocumulus clouds underneath the Cirrus and lenticulars standing around. All in all, though the temperature here reached 87° F, a very pleasant day.

Now, just some nice lighting and color:

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5:32 PM. The almost flourescent plant in the foreground is what is known as a “cholla.” The end elements fall off quite easily and attach to things like your pant leg if you brush by them on a horse, or if back into them while walking and correcting your horse for something when he’s acting a little “wild.”  I can report that when seven or eight of them are stuck to the back of your shirt, its really hard to get that shirt off.  In fact, it just about won’t come off without a major scream.
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5:35 PM. The higher Cirrus are shaded by clouds to the west, but the lower remnants of Stratocumulus/Cumulus and a few Altocumulus are highlighted as though they were meant to be for this photo. So pretty.  Notice, too, how there seems to be more than one layer of Cirrus.
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5:44 PM. Cirrus and Altocumulus, the latter with some turreting making those the species, “castellanus”, if you care.
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5:47 PM. A nice flame-out of Cirrus occurred as those pesky clouds blocking the fading sunlight from striking them opened up below the horizon. A few Altocumulus castellanus can be seen, too, but relegated to shadow status.

In a further celebration of dryness here, let us examine the rainfall cumulative rainfall predictions calculated by the University of Arizona’s Dept Hydro and Atmos Sci computer the period ending at Midnight on November 5th.  Says the coming rain in the State misses us here in SE AZ while falling just about everywhere else, of course.  Dang.  Let’s hope it one of the worst model predictions ever!

This really poor forecast is based on the global data from last evening at 5 PM AST.
This really poor forecast is based on the global data from last evening at 5 PM AST.

 

The End.

Rainbows and sunsets; also, fall weather coming in October!

Should be some good rain today in Catalina, FINALLY!  Thinking maybe half an inch or so over the next 24 h, something decent,  as tropical air drains o northward and over us out of tropical storm remnant, Roslyn (“Rozzi”).

Clouds and weather interruption:

Due to the name of our weather-affecting tropical storm, Roslyn, I am now reminded of a profound, life-altering “Hallmarky” chapter of life when I was in HS, involving another Roslyn  (aka, “Rozzi”).    In an another attempt to increase blog readers, those really not interested in clouds and weather anyway,  I have inserted this story about a 15-year old, shy boy and his incapacitating crush on a Rozzi R as a junior in HS I suspect it is a fairly common one in some ways, although this one leads to the formation of other people with a different classmate.    The Story of Rozzi R

This story was passed to Rozzi, who had no idea who I was,  only in 2009, btw.  She seemed to like it, and told me about her life, family and three kids.  I think its OK to share it.

——————————

Back to weather, at 7:11 AM, one pulse of rain is within a half an hour or so.  (Later, we only got sprinkles out of that first pulse).

Yesterday’s clouds

Nice rainbow last evening; nice sunset, too:

6:26 PM. Altocumulus and
6:26 PM. Altocumulus and patches of a higher mostly ice cloud (Cirrus spissatus or Alstratus?) provided quite a nice sunset yesterday evening.  Back the other way, were rainbows galore.
6:11 PM. Rainbow under a more or less stratiform remnant of a Cumulonimbus cloud.
6:11 PM. Rainbow under a more or less stratiform remnant of a Cumulonimbus cloud.
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6:17 PM.

The Prodigal Storm yesterday afternoon

Yesterday afternoon had quite the dump and something of a little ‘boob from the outflow winds, so much rain came down initially around Oro Valley/Marana, west Tucson, south of Pusch Ridge.  Was heading this way, too, with nice big, black, solid-looking base.  Started a video of it, thinking about the gush was to strike Sutherland Heights/Catalina.

Here it is, in all of its glory and subsequent dissipation:

3:09 PM. Outflow from TUS storm builds ledge of Cumulus base S-SW of Pusch Ridge.
3:09 PM. Outflow from TUS storm builds ledge of Cumulus base S-SW of Pusch Ridge.
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3:20 PM. Only 11 minutes later that new base has unloaded its load on Oro Valley. ).59 inches at the CDO and Ina Road intersection yesterday, but likely an inch fell out of this in the peak rain area. Note how the winds are pushing rain and dust west and northwest.
3:25 PM. She'll be comin' around the mountain when she comes. This was looking so good for us. Why? Look at that great SOLID base coming at us ahead of the rain!
3:25 PM. She’ll be comin’ around the mountain when she comes. This was looking so good for us. Why? Look at that great SOLID base coming at us ahead of the rain!  The lower scruffs of cloud are called “pannus” and in this case they are created by the nose of the outlfowing winds from this storm.  What you want is for those outlfowing winds to keep generating new, fresh Cumulus bases, ones that explode upward into Cumulonimbus clouds.  Without the new, good base and the updraft that goes with it, all of the rain can fallout in less than half an hour from the ones already raining.  Its a supply thing, you have to keep it going.  What if there were no new people born?  Well, after awhile the supply of people would run out.
3:31 PM. By this time, you're getting worried about this incoming system. Look what's happening to the formerly solid base. Its beginning to get "lumpy" looking with dark and lighter spots telling you the updraft is getting broken up, fallling apart, maybe due to the blockage presented by Pusch Ridge.
3:31 PM. By this time, you’re getting worried about this incoming system. Look what’s happening to the formerly solid base. Its beginning to get “lumpy” looking with dark and lighter spots telling you the updraft is getting broken up, fallling apart, maybe due to the blockage presented by Pusch Ridge.  But there’s still hope, the updraft MIGHT reassemble itself….and there are still a couple of pretty good base “hot spots” where the updraft is still good.
3:37 PM. "Its is finished."
3:37 PM. “Its is finished.”  What;s heading toward Catalina is that transparent veil of rain on the left of the shaft.  We now have no chance for a major dump.  Maybe it will measure though, a few hundredths…
3:44 PM. Need more be said? Sprinkles occurred here, did not measure. Warning: A sprinkle isn't drizzle, a continuing theme here.
3:44 PM. Need more be said? Sprinkles occurred here, it did not measure. Warning: A sprinkle isn’t drizzle, a continuing theme here.  Look at the “crapulent” bases now!  Oh, me.  I wanted to go in the house and never come out again, it was SO DEPRESSING to see this happen.  Lots of storms make it past Pusch Ridge, too, but not this faker.
3:44 PM. As usual, major shafting occurred AROUND Catalina, and not on it, pretty much like this whole summer has been.
3:44 PM. As usual, major shafting occurred AROUND Catalina, and not on it, pretty much like this whole summer has been.  This is looking north toward Bio2
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5:16 PM. Nice interplay of rain and sun.

Models, with spaghetti support, show a strong, but dry,  cold front coming through next week, and fall will be in the air as nighttime lows drop into the 40s in our colder, lower spots, like at the bottom of Catalina State Park, in the CDO wash, etc.

The End.

Rain follows the jet

0.02 inches of it, anyway, as the core of the jet stream at 18,000 feet or so passed by Catalina yesterday afternoon.  Keep your eye on the orange and reddish streak in these progs from IPS MeteoStar yesterday morning beginning at 5 AM AST and how it slides over us as the clouds began to ice up:2016042812_CON_GFS_500_HGT_WINDS_0005 AM yesterday.  Jet at this level races across central AZ.
2016042812_CON_GFS_500_HGT_WINDS_00611 AM yesterday.  Maximum winds getting closer!  Tiny Cumulus clouds begin to appear over the Catalinas and on the west to north horizon.

11:40 AM.
11:40 AM.

The jet separates deep cold air on the left side, looking downwind, and deep warm air on the south side.  The deep warm air prevents Cumulus clouds from getting very deep due to inversions and stable layers where the temperature does not change much with increasing height, or even rises.  The temperature at 500 millibars or 18,000 feet above sea level dropped from -17.7 °C to -21.1° C over TUS yesterday between 5 AM and 5 PM, while the temperature about which ice begins to form in our clouds dropped about 400 meters during that time.  With the temperatures at the ground rising into the mid-70s as the colder air moved over us, Cumulus clouds deepened, reaching the ice-forming level between 1 and 2 PM.

Also with patterns like this, the cyclonic rotation (vorticity) in the air above us is increasing like mad, and that leads to a gentle upglide motion in the atmosphere, one that also helps cool the air aloft and usually produces sheets of clouds like Cirrus, Altostratus, Altocumulus and NImbostratus.  But yesterday the air was too dry for sheet clouds to form.

First ice was noted just after 1 PM.  Can you find it?

1:11 PM. Looking N toward the Charouleau Gap.
1:11 PM. Looking N toward the Charouleau Gap.  Tiny puff of ice ejects from a Cumulus humilis cloud based at about 8 thousand feet above ground level.  Bases were running about -5 °C

Keep you eye on the brown and yellow streak.

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2:31 PM. Cumulus and Stratocumulus clouds launched off Pusch Ridge and the Tucson Mountains stream toward Catalina. The sky begins to fill in rapidly.
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3:44 PM.
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3:49 PM.
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3:57 PM. A horse eating as it clouds up.
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4:33 PM.
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5:09 PM. Light rain falls in Catalina/Sutherland Heights.
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6:04 PM. RW- (light rain showers) continue in Oro Valley.

5 PM yesterday.  Just passed!  B y this time, Sutherland Heights had 0.02 inches as  the tops of Cumulus and Stratocumulus complexes continued to cool and ascend.   The sounding from TUS at 5 PM AST (launched about 3:30 PM AST) indicated the coldest tops had reached -20 °C or so, plenty cold enough for ice, virga, and light rain showers.  Too bad the bases were so high since we could have had some real rain if they had been lower.

But, we were “lucky” to get that.  Even the great U of AZ model had no rain anywhere near us late yesterday afternoon when it fell!  THAT does not happen very often.

Looking ahead….today:

Nice Cu, ice, too.

Farther out:

Substantial rains, maybe half an inch or so,  still on tap between May 6th-8th as previously foretold here.  Yay!  May averages 0.38 inches here in Catalina.  More rain likely after that episode, too.  So an above normal May in rain is pretty much in the bag now.   Could be an especially great May, too.

The End.

April to have measurable rain in Catalina!

In the meantime, step aside;  a cold front is upon us, a dry one, unfortunately.  Should arrive by noon, bringing some small Cu here and there, some Stratocu piling up against the Catalinas, and maybe some lingering Altocumulus lenticular clouds which we got right now (4 AM) downwind of the Catalinas.

From Intellicast, this nice map:

As of 4 AM AST, the 24 h temperature change. The blue blob shows the encroaching cold air.
As of 4 AM AST, the 24 h temperature change. The blue blob shows the encroaching cold air.

Barometer will rise, too, as the cooler, denser air piles on top of it.  There’ll likely be a brief windshift to the NW, followed by backing to the SW again.

Over the next couple of days, the deep cold air in the  interior of a lingering, massive trough will settle over us, dry up top, but enough moisture in the lower layers below to produce eventually deeper Cumulus, though not today, ones likely to reach up to the “glaciation” level, which will be close to -12° C to -15° C in this situation beginning later tomorrow through the April 1st.   The bases of the clouds will be near the freezing level.

Glaciation means that ice will form in those Cumulus clouds, and some (snow) virga will drop out the bottom.  So, some snow showers or just light rain showers are likely on the Catalinas, maybe a trace or hundredth here, too,  beginning later tomorrow  through April 1st.

Should be some really pretty deep blue skies, too, cloud shadows producing quilt-like patterns on the mountains, that sort of thing we are so lucky to enjoy here.

As you know, this end of month March “lion” (at least in wind, anyway) was long foretold in the NOAA spaghetti.  Remember how we could laugh at model outputs that didn’t have a big trough here at the end of the month?

But now we wait and see if we can drain a cloud or two of a hundredth.  Overall rain chances not looking so “strong” now out of this whole several day situation.  Dang.

Clouds will be around today, especially after the cold front goes by, but its unlikely they’ll have anything drop out the bottom.

Why?

“2warm4ice”,  to be that bit textual.

Model says today’s cloud tops won’t reach -10° Ç, our magic temperature where we can usually start to thinking about ice forming in AZ clouds, those with our usual cool  bottoms.

Of course, if you’re really sophisticated, you know that the temperature at which onsets in “continental” Cumulus clouds like we have here in old Arizony,  is related to cloud base temperature:

The warmer the cloud bottom, the higher the onset temperature for ice1, “strangely believe it”, as we like to say here after Jimmy Hatlo the cartooonist thought of it first when he was making fun of RIpley’s “Believe It Or Not.”

Now onto the forecasting frontier, forecasting weather patterns way ahead, to far in advance and too specific to be truly professional

Let’s start with something easy.  Its gonna warm up real good after this big trough goes by– see spaghetti below, where a big ridge moves over us for a couple of days.  It won’t last.

Valid at 5 PM AST, April 3rd.
Valid at 5 PM AST, April 3rd.  Notice, too, that unlike most of the spaghetti pe degree of chaos introduced by the deliberate errors input at the start, have little effect (as usual).  The  blue and red contours are bunched really well.  So the positions of the ridges and troughs are normally well predicted out to this time.

Then,  uh-oh, as Robert Ellis Orrall used to sing, in 192 h, predictability begins to fall apart, but not real bad, and it shows a trough is moving in over us.

Valid at 5 PM AST, April 5th. Red contours are bunched enough so that a nice sized trough in the SW is pretty guaranteed.
Valid at 5 PM AST, April 5th. Red contours are bunched enough so that a nice sized trough in the SW is pretty guaranteed.

Finally, at the extreme end of the medium range forecasting frontier, this:

Valid at 5 PM AST, April 12th. Stormfest Southwest!
Valid at 5 PM AST, April 12th. Stormfest Southwest!

 

Hence, the conclusion that we share that April, will in fact, have measurable rain.  Of course, we only average about half an inch in April, as the overall climatology begins a serious a battle against rain heading into the ovenly days of May and June.

The End

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1The old English cloud scientist, Frank Ludlow (1952, Quart J. Roy. (haha, “Royal”, oh my) Meteor. Soc.) noticed this first, then that great Soviet Communist cloud scientist, A. M. Borovikov and his companions did (1961, Israeli Translations).  Finally, Rangno and Hobbs woke up and noticed this tendency in 1988, (Atmos. Res.) and then again in 1995 (J. Appl. Meteor.–you’ll have to go quite a ways to find the relevant diagram)  in their cloud studies and in comparisons with other ice onset reports.

 

 

 

Measurable rain to fall in March 2016

…in case you were wondering at this point.

Looks like it will be on March 7th.  Pretty sure thing at this point, maybe 75%-99% chance of rain here in Catalina, combining “spaghetti1” with other forms of forecasting.

7 AM AST Addendum:  Hell, why not go for some amounts due to extra confidence:

Min in The Heights: 0.20 inches (10% chance of less); max, 1.00 inches (10% chance of more). The average of these “mental ensemble2” extrema, 0.60 inches, which is usually closer to the actual value.

This best guess estimate for the total between midnight March 7th and the evening of the 8th, or over about a 42 h period.  Weather gaming is fun.

What’s your prediction?

—————-T. I. P.————————————

Remember, too, as a “truth in packaging” disclosure statement, that this forecast is being made by the SAME person who forecast about 12 days ago or so,  rain here in the last week of February which didn’t happen, along with large Cal and AZ blasting storms in early March.

In fact, here and in southern Cal, we had “anti-rain” in the last week of February!  This in the form of high temperatures, dry air,  and that combination resulting in unusually high  evapotranspiration rates with those high temperatures (anti-rain, since whatever surface water, soil moisture, plant moisture is disappearing into the air).  In other words, that forecast could hardly have been more incorrect.

Hell, to cuss some more, almost as bad as those forecasts for a drier than normal winter (DJF) for the Pac NW by big forecasting authorities like the Oregon State Climatologist among many others.

In fact, when they were making those forecasts, they were staring at record wetness in the Pac NW!  Incredible!  Both SEA and PDX have set DJF records for the amount of rain this winter!  Wow.  It doesn’t get much worse than that, except maybe here sometimes.

People are mad, too, in southern Cal where they were advised to buy sandbags due to the excessive flooding and rains foretold for their winter.   Well, we’ll see if March can bring back some of the lost credibility, though, frankly, its hard to do.

Think of all those global warming forecasts of a steady rise in global temps made back in the early part of this century which didn’t happen.  Wow.   Lost some credibility there, and those forecasters had to move to a new expression, “climate change” to cover up the bad forecast.

Temps on  the rise now, so watch out!  “Global warming” rising from the ashes more and more now, too.

Changing the subject quickly, the Washington Huskies softball team had a pretty great weekend at the Mary Nutter Classic Tournament in Cathedral City, CA, where it was real hot (90 F), too.  The University of Washington was the writer’s former employer.

Whistling here:  where are you Niño?  Com’ere!  Hmmmph,   nice name for a dog I think, which is what it has been so far for the Southwest.

The End

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1 Formally, called “Lorenz plots” by yours truly, and should be by others.

Valid on March 7th. All the red lines are WAY down there in Baja California central. Means a pretty sure thing the jet stream will be south of us when this incoming trough goes by and as you know well by now, when the jet at THIS level is south of us, you almost always get rain. Some 95% of the rain that falls in Tucson falls with the jet at this circumscribing us.
Valid at 5 PM AST on March 7th. All the red lines are WAY down there in Baja California central. Means a pretty sure thing that the jet stream will be south of us when this incoming trough goes by and as you know well by now, when the jet at THIS level is south of us, you almost always get rain. Some 95% of the Nov-Apr rain that falls in Tucson falls with the jet at this level to the south of us.

 

2No way is this from some big computer somewhere!

Tired of winter

Winter began, meteorological speaking, yesterday with mid-afternoon temperatures in the upper 50s to low 60s with the wind driving the wind chill down to, I don’t know what, something really low .  In other words,  winter  began here in Catalina about 18 h ago.

Enough already!  Retired to AZ for warm air and low house prices. Pretty bad, too, out there this morning, with the temp at 44° F right now here in Sutherland Heights; colder yet in low spots of course.  Only 36° F now in Black Horse Ranch.

More worse cold expected in about nine-ten days.  Precip somewhat doubtful in that a more better cold slam that hits around the 20th1.   Pretty strong support in the Lorenz plots (aka, “spaghetti plots”), too, for that cold slam, so get ready.  Those crazy plots help us to discern whether a predicted pattern in the model output is an outlier or likely to occur.

In the meantime, going out of chronological order here, THIS coming week end’s lesser cold slam  is DRY in Catalina in USA WRF-GFS model run from last evening’s run.

The Canadian GEM, however, based on the SAME global data as the US model,  has rain a plenty here in Catalina and all of AZ, Sunday and Monday!  The Canadians see a lot of tropical air feeding in from the sub-tropics over much of AZ ahead of the cold front that hits us later Monday, and that’s the reason for all the rain in that model.  The US model doesn’t see the moist sub-tropical stream getting much out of Mexico.

Note the large separation between rain in Cal and rain in AZ in the panel below.

Valid Sunday afternoon, 5 PM AST.  Lower right hand panel has rain amounts that have accrued over the prior 12 h in the model.  As you can see, quite a bit is predicted over SE AZ.  Yay!
Valid Sunday afternoon, 5 PM AST. Lower right hand panel has rain amounts that have accrued over the prior 12 h in the model. As you can see, quite a bit is predicted over SE AZ associated with the system coming out of the sub-tropics ahead of the cold front going across Cal.

So, what’s a weather forecaster to do?

Lean on the Canadians! Their model was ahead of the game on our half-incher rains early in the month compared with the US mod, so they deserve that bit more credibility here, too, I think.

BTW, the two models were identical in not predicting  rain in the  passage of the cold front yesterday.

The End.

PS:  Would post photos of yesterday’s gray, non-precipitating Stratocumulus, lacking ice in it2, of course,  for you to review, but in transitioning to a new OS in the past two days, some things have gotten wrecked, don’t work anymore.   SOS, as they say.

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1Let’s see if any english teachers are reading this blog….

2Cloud lesson/pop quiz  for cloud maven juniors:  What cloud top temperature range would you guess for those non-preciping Stratocu.  Recall it was a cold day, so you know they were at below freezing temperatures…..

Answer:  Guess that tops must have been warmer than -10° C (14° F, in plain speak)!

In fact, the TUS afternoon sounding suggests they were about – 5 ° C (or only 23 ° F),  way to warm for natural ice to form, hereabouts, anyway3.

3In really clean conditions, ice does form in clouds with tops as warm as -5° C4.

4These would really be a great factoids to pass along to your neighbors, ones that would enhance your weather esteem in their eyes.  Memorization is recommended.

“Tweener” era begins today after pre-dawn sprinkles; one photo has birds in it

We’ll have to suffer through  a few days for the next storm, i. e., experience sunny weather with pleasant temperatures.  Its amazing that people all over America come to Tucson to experience sunny days with pleasant temperatures!

0.45 inches total in The Heights of Catalina in this latest round of rain, sounds of rain.    Actually, there was also some tiny graupel/soft hail in the rain yesterday, too.

Graupel indicates a lot of cloud droplet water overhead, and that ice crystals were colliding with them until they lost their identity and became little snowballs.  In regions where there are very few ice crystals,  graupel and the harder version,  hail often form.   Its likely that nearly all those rain drops that came down with the little baby graupel were melted graupels.

Graupels…..   Makes me think of that rock group, Led Graupelin, didn’t have the impact of Led Zepelin.  But I have LG’s one and only album entitled, “Compare to Led Zepelin.”   Was only $2.99, too!  Where’s my guitar?  I think I will play, “Stairwell to Heaven” now…

When graupel or hail occur,  there’s a pretty good electric charge up there in those Cumulonimbus clouds.  Its best to be indoors when its hailing until you know if a strike might occur (if there hasn’t been one already).  Besides, its not comfortable being out in hail.   And if you were listening to the rain, you heard a few blasts of thunder toward Lemmon around 2 PM that came out of one of the more enthusiastic Cumulonimbus clouds that went by.  Got 0.12 inches total to add to the night before’s rain of 0.33 inches.

Yesterday in clouds; a sojourn in clouds from morning to evening, in that order with no times noted

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I know how much you like to see pictures of rain, so here’s one. You’re not like the “others” are you those people around you every day?

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DSC_1569Then the piston of atmospheric subsidence slammed down to squash our Cumulus cloud tops to levels and temperatures where ice could not form….

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Two picures in a row of a NWS-style rain gauge. Probably has never been done before. Has been getting a workout lately.  Everyone should have one.

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The weather ahead

Kind of funny to see the Canadian GEM model internally plagiarize itself.  Compare last night’s panel at 500 millibars (below) with that same level’s panel  foretold for six days from now.

Yep, its the same thing over again in six days, though with less rain IMO:ann yesterday at 5 PM AST

ann 6 days from now
Valid on Tuesday, November 10th at 5 PM AST.  From the Canadians.

In another interesting model development, the best USA model, the WRF-GFS is having an internal CONFLICT of major proportions.  Check these progs out generated by data only six hours apart.  The first one, showing a big trough coming into Cal, was generated by global data taken at 5 PM AST last evening.  The panel below it was generated by the same model based on global data taken just six hours later, at 11 PM AST (so it the most recent WRF output available) and has a big ridge along the California coast.

2015110500_WST_GFS_500_HGT_WINDS_384
Valid at 5 PM AST November 20th.

“Which one will the fountain choose?”, to quote old song lyrics1:

2015110506_WST_GFS_500_HGT_WINDS_384
Valid at 11 PM AST November 20th.  From IPS MeteoStar.

Of course, spaghetti tells us which one is right, mostly.

 

The End

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1Except that here we present only two “coins” not three.

Augustober weather continues on October 18th

Truly LATE breaking news,  untimely really,  but Augustober 18th was too special a day to ignore:

Giant clouds, dense rain shafts,  frequent lightning in the area throughout the afternoon,  dewpoints in the high 50s to 60 F; can it really be after the middle of October?  Or, is this some kind of preview of climate change we can look forward to in the decades ahead, that is, if you’re thunderphilic?

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5:05 PM. An amazing scene, and thunderstorm with such powerful updrafts that when those updrafts are blocked by the inversion at the base of the Stratosphere, they force the winds at that level to slow or backup and the anvil protrudes upwind (center left), something that is common with severe thunderstorms. This was significant here because the winds at 40,000 feet were around 50 kts, far stronger than anything we have here during a typical summer rain season.  Summer  Cumulonimbus  cloud anvils  can splash outward easily against weak winds up there in summer when they hit that barrier at the top of the tropopause.  This just in from Mark A:  severe thunderstorms, I have just learned here on the 20th , were observed in the PHX, and the NWS has a great link going describing all the mayhem it produced.  I did not know this until just now in the middle of writing this first caption when I read Mark’s e-mail.
1:40 PM.
1:40 PM.
1:56 PM.  Anvil of the Cumulonimbus over west Tucson, drifts overhead of Catalina, and in three minutes, rain drops started to hit the ground.  This is amazing because those drop had to fall from at around 20, 000 feet above the ground (estimated bottom of this thick anvil) and could only have happened if those isolated drops had been hailstones ejected out the anvil, something that also only occurs with severe storms with very strong updrafts in them.
1:56 PM. Anvil of the Cumulonimbus over west Tucson, drifts overhead of Catalina, and in three minutes, rain drops started to hit the ground. This is amazing because those drops had to fall from at around 20, 000 feet above the ground (estimated as bottom  height of this thick anvil) and could only have happened if those isolated drops had been hailstones ejected out the anvil, something that also only occurs with severe storms with very strong updrafts in them.  So, if you saw those few drops fall between 2 and 2:05 PM you saw something pretty special.

 

 

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6:26 AM. Early portent: Cu congestus, aka, “heavy Cumulus) piling up this early.
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6:29 AM. Mammatus of the morning., an extraordinary scene for mid-October, pointing to the possibility of an  unusual day ahead with strong storms. as was the scientific basis for giant clouds on the 18th  in the amount of CAPE predicted, over 1,000 units of Convective Available Potential Energy, later that day from computer models.   That is a lot for mid-October, take my word for it.
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3:45 PM. Strong storms did not form over or near the Catalinas yesterday, but they did get something. As you can see the top of this guy (Cumulonimbus calvus) is very subdued compared to the giants that formed elsewhere.
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5:53 PM. Peakaboo Cumulonimbus calvus top east of Mt. Lemmon provided a nice highlight after sunset. And to have convection like this going on this late was remarkable. Some heavy showers and a thunderstorm formed downwind of the Catalinas about this time,, too.
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5:51 PM. Pretty nice, summer-looking sunset that day, too.

 

 The weather just ahead, and this might be it for precip for the rest of October

A nice-looking upper level trough is ejecting over us from the SW this morning but the computer model says its going to be a dry event.  A second low center  forms just about over us in the next day.  AZ model doesn’t see much rain for us throughout these events, and rain doesn’t begin here until after dark today.

I think that is WRONG; bad model.  Watch for some light showers this morning, then a break and rain overnight (which the models do predict).   Due this quite bad model forecast,  as seen from this keyboard, I feel must interject for the blog reader I have,  an improved rain prediction for Catalina over that rendered by a computer model.

Feel like guesstimating a minimum of 0.25 inches between now and Thursday evening, max possible, 0.60 inches, so the median of those two, and maybe the best guestimate being the average of those two, or 0.425 inches here in Catalina.   When you see a prediction of a rainfall total down to thousandths of an inch, you really know that the person predicting it knows what he is doing…..

Below, your U of AZ disappointing, but objective, take on the amount of rain based on last evening’s data and one that is the result of billions of calculations.  One must remember that cloud maven person’s calculation of the rainfall amount for Catalina is only based on three.

From the 5 PM AST run executed by the U of AZ Beowulf Cluster.  Billions of calculations were involved with this model prediction; it should be kept in mind that cloud maven person's prediction is only based on three when he opines that this is not enough for us here in Catalinaland.
From the 5 PM AST run executed by the U of AZ Beowulf Cluster.

The End.

Traces of rain and a Lemmon rainbow

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6:25 AM. Altocumulus perlucidus. According to my cloud chart, informally known as “America’s Cloud Chart”, it could rain within 6 to 196 hours. Its quite useful.
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10:24 AM. Altocumulus opacus. Note the rumpled look of the sky. Indicates that the clouds are rather shallow and composed of droplets rather than a mix of ice crystals and droplets. However, if you strain your eyeballs and look to the horizon, you can see a smoothing and a little virga showing that the cloud tops are rising and they’ve gotten cold enough to produce ice. According to my cloud chart, when you see “Ac opacus” it could rain within 6 to 196 hours.
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1:44 PM. While the clouds are pretty much the same gray color as in the prior photo, they’re much thicker here and are “Altostratus opacus”. “opacus” because the sun’s position is not visible, though it wouldn’t be in this direction anyway, but to the right. The bottom of this is smooth due to widespread, light falling snow, though it not in a localized area enough to be called virga in this shot. The lack of bunched or heavy virga somewhere tells you that the cloud tops are pretty smooth, too, not a lot of variation in height.  The base is really determined by the point that you descend out of this precip, in this case up around 10 kft above the ground over Catalina.
4:12 PM.  Altostratus opacus praecipitatio or Nimbostratus, either name will do.  Recall the quirk in our cloud naming system that makes, "Nimbostratus" a middle-level cloud.  The base of these clouds is the general level where the snow falling out has evaporated.  Due to bulging tops, and stronger updrafts, a little of the precip was able to fall out because the snowflakes coming out the bottom had grown larger and were able to survive the dry air below cloud base.
4:12 PM. Altostratus opacus praecipitatio or Nimbostratus, either name will do. Recall the quirk in our cloud naming system that makes, “Nimbostratus” a middle-level cloud. The base of these clouds is the general level where the snow falling out has evaporated. Due to bulging tops, and stronger updrafts, a little of the precip was able to fall out because the snowflakes coming out the bottom had grown larger and were able to survive the dry air below cloud base.

Some rain fell about this time in Catalina.  Not enough to darken the pavement completely at any time.  The main thing to take away from that hour of very light rain is that it was not “drizzle” as even some errant meteorologists call such sprinkles.

You will be permanently banned from attending any future meetings of the cloud maven club if you refer to such rain as we had yesterday afternoon as “drizzle.”  Drizzle is fine (200-500 micron in diameter drops that are very close together and practically float in the air.  Because they fall so slowly, and are so small to begin with, you can’t have drizzle at the ground from clouds that are much more than a 1000 feet or so above the ground because as soon as they pop out the bottom, those drops start evaporating and fall slower and slower by the second, and in no time they can be gone even in moist conditions.  That’ s why its somewhat hilarious and sad at the same time,  when, in particular, military sites for some unknown reason, report ersatz “drizzle: (coded as L, or L-) in our hourly aviation reports from clouds that are based at 5000 feet or something CRAZY like that.

This band of Nimbostratus/Altostratus had a backside that approached as the sun went down, and as you know, that clearing let some sunlight enrich and dramatize the views of our beloved Catalina Mountains:

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5:39 PM.
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5:41 PM.

Finally, dessert:

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5:47 PM. Rainbow lands on the University of Arizona Wildcat’s Skycenter atop Ms. Mt. Sara Lemmon.
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5:48 PM.

The amazing rains ahead

Nothing that you don’t already know about, so no use me blabbing about it too much.  But in case you haven’t seen it, The Return of Joe Low (after over-hydrating over the warm waters of the eastern Pacific), is expected over the next couple of days, with a little help from another disturbance, to bring colossal rains to eastern Arizona and especially New Mexico.

Below, from our friendly U of  A Wildcat Weather Department a model run from yesterday’s 5 PM global data (the Wildcat’s downsize the US WRF-GFS model in this awesome depiction).

Check out the totals expected by the evening of October 23 rd.  Stupendous.  Usually these totals are a bit overdone, but even so…… Will take a nice bite out of drought.

Precipitation totals expected by 5 PM AST October 23rd.  Looks something like a tie-dyed Tee.
Precipitation totals expected by 5 PM AST October 23rd. Looks something like a tie-dyed Tee.

The End

Jumbo package

Through deliberate deception, the title is likely to bring in quite a few football-centric  people, since “jumbo package” is a term used when an offensive team bring in all the “Sumo wrestlers” they have, usually in attempts to score a touchdown from 6 inches outside the goal line.

The “jumbo package”,   however,  is about some weather, essentially at “mid-field” rather than on the goal line (i.e., just ahead):

A large and very strong upper low center is forecast to arrive on  Sunday, October 25th, football day, the last reference to football in this blog.  As it passes over Arizona, the first snow of the year would likely fall on the ‘Frisco Peaks by Flagstaff.

Tremendous rains, too, would  occur here in AZ with this low,   espepcially2 here the SE corner, should it happen.  See WRF-GFS model outputs below, as rendered by IPS MeteoStar:

Valid on Sunday, October 25th at 5 PM AST.
Valid on Sunday, October 25th at 5 PM AST.
Valid on Sunday, football day, October 25th at 5 PM AST.
Valid on Sunday, football day, October 25th at 5 PM AST.  The bluish regions denote especially heavu rains having fallen in the prior 12 h.

But does it happen?

Let’s check the spaghetti from NOAA for a hint about whether this weather happenstance has much chance of occurring:

Valid on Sunday, October 25th, at 5 PM AST.
Valid on Sunday, October 25th, at 5 PM AST.
Same map as above, except annotated for those who find the map geographically challenging.
Same map as above, except annotated for those who found the first  map geographically challenging.

You, too, as an expert on spaghetti now,  are as crestfallen as I was to see this spag output from last night, showing that the espepcially strong low is, in fact, an outlier;  a not impossible situation, but an unlikely one since we don’t have the bunched blue contours where the jet stream is strong,  down thisaway.  Rather, those blue lines are grouped over the Pac NW, and only one or two bluish contours are down here, ones that would be associated with that upper low on the 500 mb map above for Oct. 25th

Still, even when you know its an outlier, it brings hope for a bountiful rain, which is good.  Will monitor this as the days go by, in case the outlier spaghetti output is an outlier.

The weather just ahead

Of course, as all weatherman know, we still have our boomerang friend Joe Low returning with rain; that’s in the bag, and  has a little “friend” following behind him.  These, combined,  should  bring substantial rains overall in AZ and in the Catalina area,  in the form of scattered showers and TSTMs that persist over several days beginning later Thursday through Monday.  Joe et al. are slowpokes, which is good.

Haze and smoke are up, if you’ve noticed that our skies have been not so blue, but whitish.  Stuff is coming up from Mexico it appears; (Smoky) Joe will bring more of that before it gets here.  So, look for a hazy patches of Altocu and/or Cirrus in the next couple of days.  Maybe a small Cu off in the distance.

2:06 PM, October 11th.  Shows the kind of hazy, smoky conditions we've been having lately.  There is also some delicate Cirrus up there contributing to the whiteness.
2:06 PM, October 11th. Shows the kind of hazy, smoky conditions we’ve been having lately. There is also some delicate Cirrus up there contributing to the whiteness.

The End

 

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2“Espepcially” is a word I made up via some inadvertent key strokes, but I kind of like it:   “In particular, but with some energy.”     BTW, Coke tastes better than Pepsi, if that new, unexpected word made you think of a soft drink.