Art Rangno – Page 26

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?

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.

: 1:56 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.

6:26 AM. Early portent: Cu congestus, aka, “heavy Cumulus) piling up this early.

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.

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.

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.

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.

Nice weather we’re having….

Has added up to more than an inch here in Sutherland Heights/Catalina after last night’s MCS went by (Mesoxcale Convective System), aka, “doozie”. Looks like almost three inches has fallen on top of Ms. Lemmon, too!

This MCS blew up out there late yesterday afternoon to the southwest and west of us, and then the blast of wind, estimated here to over 40 mph in the strongest puffs, roared in about 8 PM last night.

Would have seen a nice “arcus” or line cloud with that wind, too had it been daylight.

Squall lines in the Plains States are often like that, the wind, the pounding rain/hail, then a few hours of “stratiform rain”, after the wind dies down and the arcus cloud and heavy rain have ended. Even looked like an eastern Plains State evening in July, if you’ve ever been there with the leading heavy ice cloud ejecting toward us as the sun went down.

4:49 PM. Classic appearance of an incoming squall line, as so often seen in the summer months in the EASTERN portions of ND, SD, NE, KS, OKC, etc, where nighttime rain and thunder occurrences rule at that time of year. In the higher western portions of those states, the storms occur earlier in the afternoon, often starting out there, then merging into lines as the late afternoon progresses. Nice if you like lightning at night, and you’re in Sioux Falls, SD, or OKC.

5:27 PM. Getting closer. Local tragedy was occurring as a home off Lago del Oro was burning up, left foreground. — 5:27 PM. Getting closer. A local tragedy was in progress as a home off Lago del Oro was burning up, left foreground.

We interrupt this presentation for a public service reminder concerning some drops that fell yesterday afternoon:

“Its not drizzle, dammitall!”

3:32 PM. As the drops began to fall in a 5-minute shower, I thought about those wrongful people out there that might have called this "drizzle" as the first few drops fell. — 3:32 PM. As the drops began to fall in a 5-minute shower, I thought about those wrongful people out there that might have called this “drizzle.”.

OK, something like the above is probably a little too adult for children to say, but, of course, we adult cloud mavens we like to say it whenever we can to educate people in an emphatic way.

Drizzle drops, which have to be very close together unlike these, would not even be large enough to cause visible spotting on pavement, and barely, or don’t make a splash at all in a puddle of water. Too, drizzle falls from SHALLOW, low-based clouds with a broad droplet spectrum. It doesn’t fall from Cumulonimbus clouds, or Altocumulus castellanus virgae, Altostratus, etc.

This oft repeated message here is repeated again because a meteorologist friend of mine repeatedly called the “sprinkles” we had here two days ago, “drizzle.” As a result, our friendship is on “hold” for time being. You really have to clamp down on the errant things that people say about weather phenomenon. I try not to say too many myself.

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Had a nice rainbow after that afternoon period drizzle (hahah) went by that dropped 0.03 inches:

5:48 PM. Nice shaft and rainbow toward the Gap. Was hoping to get a LTG bolt infused with the rainbow, make thousands of dollars on it, but, it didn't happen. — 5:48 PM. Nice shaft and rainbow toward the Gap. Was hoping to get a LTG bolt infused with the rainbow, make thousands of dollars on it, but, it didn’t happen. But, a terrific scene anyway.

See some LTG off to the NW now. Should be more of that around this afternoon.

The End.

Traces of rain and a Lemmon rainbow

DSC_0612-1 — 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.

DSC_0617-1 — 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.

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:

Finally, dessert:

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

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.

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, 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:

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.

Bye-bye Joe low, see you in a week or so; remembering the 1962 Columbus Day storm

Joe is pretty dried out after dumping so much rain on AZ and NM, and will be spinning around northern Mexico before heading back out to sea off Baja to re-hydrate before coming back with another round of rain for AZ and Catalina in a week or so, maybe as much as 10 days before he gets back.

In the meantime, let us remember the Columbus Day storm, whose anniversary is coming up. The remnant of Typhoon Freda (not Olga!), infused the westerlies with extra energy, to produce one of the greatest tempests of all time when it struck the West Coast and passed inland over the Willamette Valley on its way to Seattle. It kept an extremely intense center having winds well over 100 mph, some estimates to over 150 mph; in essence equivalent to a Category 4 or 5 hurricane passage sans the torrential rains.

Below, the National Weather Service Remembers, in a reminder that it can, and will, happen again.

Recently, the jet stream has swept up the remains of Typhoon Oho and that triggered a strong “extratropical” cyclone in the Pacific, though far from shore. More tropical cyclones are forecast to form and be swept up by the westerlies in the next two weeks…..

NOUS46 KSEW 091729
PNSSEW

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE SEATTLE WA
1030 AM PDT FRI OCT 9 2015

..COLUMBUS DAY STORM ANNIVERSARY IS MONDAY OCTOBER 12TH…

MONDAY OCTOBER 12TH IS THE 53RD ANNIVERSARY OF THE 1962 COLUMBUS DAY STORM…THE STRONGEST NON-TROPICAL WIND STORM EVER TO HIT THE LOWER 48 IN AMERICAN HISTORY. AS THE GRANDDADDY OF ALL WIND STORMS…ALL OTHER WIND STORMS ARE COMPARED TO IT.

THIS STORM WAS EXTRAORDINARY. WIND SPEEDS EXCEEDED 150 MPH ALONG THE OREGON AND WASHINGTON COASTS AND TOPPED 100 MPH IN THE WESTERN INTERIOR VALLEYS FROM EUGENE TO BELLINGHAM. SINCE EITHER MANY WIND INSTRUMENTS LOST POWER OR WERE DESTROYED BY THE STRONG WINDS…THE ACTUAL HIGHEST WIND SPEEDS WERE NOT MEASURED OR KNOWN.

THE STORM KILLED 46 PEOPLE FROM NORTHERN CALIFORNIA TO WASHINGTON AND INJURED HUNDREDS OF OTHERS. IT BLEW DOWN OR DESTROYED THOUSANDS OF BUILDINGS AND KNOCKED OUT POWER TO MILLIONS OF PEOPLE FROM SAN FRANCISCO TO SOUTHERN BRITISH COLUMBIA. THE WIND STORM BLEW DOWN 15
BILLION BOARD FEET OF TIMBER FROM THE COAST TO AS FAR EAST AS
WESTERN MONTANA…ENOUGH LUMBER TO BUILD A MILLION HOMES.

COULD ANOTHER STORM LIKE THIS ONE OCCUR AGAIN? THE ANSWER IS YES. AND NOW MANY MORE PEOPLE LIVE IN THE REGION THAN BACK IN 1962 ALONG WITH ALL THE ACCOMPANYING INFRASTRUCTURE SUPPORT. FOR INSTANCE…THE 1962 POPULATION OF WESTERN WASHINGTON WAS ABOUT 1.5 MILLION. TODAY IT IS OVER 6 MILLION.

IMAGINE WHAT WOULD HAPPEN IF THAT STORM STRUCK
AGAIN TODAY?

WIND STORMS OCCUR ALMOST EVERY YEAR IN THE PACIFIC NORTHWEST. SOME OF OUR REGIONS STRONGER ONES OCCUR ABOUT EVERY 10 YEARS SUCH AS THE HANUKKAH EVE WIND STORM OF DECEMBER 2006 THAT KNOCKED OUT POWER TO ABOUT 1.5 MILLION PEOPLE IN WESTERN WASHINGTON.

SO IT IS PRUDENT TO PREPARE NOW FOR WIND STORMS OR ANY OTHER
HAZARDOUS WEATHER OR OTHER EVENTS THAT CAN OCCUR SUCH AS
EARTHQUAKES…TSUNAMIS AND VOLCANIC ERUPTIONS. HERE ARE A FEW KEY RESOURCES TO HELP YOU GET READY AT HOME…AT WORK OR SCHOOL…OR IN YOUR VEHICLE. WHEN YOU ARE PREPARED…YOU ARE NOT SCARED.

I was a small child, but 21 years old, when the infamous Columbus Day storm of 1962 hit the upper West Coast. I hoped it would come down my way, there in Reseda, California. It didn’t, only got as far as ‘Frisco.

I wrote out the weather reports for this storm from Short Wave Radio (SWR) with my best fountain pen. Here they are, because I never throw anything out. These transcribed weather reports were broadcaset twice an hour, five after.

Weather text, in ink, for the October 12, 1962, "Columbus Day" storm as compiled from Oakland Radio via SWR. — Weather text, in ink, for the October 12, 1962, “Columbus Day” storm as compiled from Oakland Radio via SWR. SFO-Frisco, S-T, SEattle Tacoma AP; POR=Portland, OR; STK=Stockton, CA; LAX=LAX; RSA=Reseda, CA. The last three digits is the altimeter setting, with the first digit missing. Note that at 6 PM PST October 12th, SFO is having near hurricane force gusts, and at 8 PM PST, Portland is reporting gusts to over 90 mph. The 9 PM PST ob for Portland was missing!

12:23 PM. Cumulus mass over the Catalinas.

1:47 PM. When I wasn’t watching, this broke out!

1:48 PM. Looking SSW. Looked awesome, but only heard one rumble of thunder.

1:48 PM also, looking SW. “Spin move” used to get sky shots from all quads pretty much all at once. Those shown are the best. It was clear to the NW-N.

1:55 PM. Dark base to right begins to unload on some lucky person.

2:06 PM. Told ya! Nice addition to the prior day's storm. — 2:06 PM. Told ya! Nice addition to the prior day’s storm. Raining here now, too.

2:32 PM. Nice line of Cumulus humilis or mediocris trailing off the Tortolita Mountains W-NW of Catalina.

: 2:35 PM. A well-known, de facto livestock pond was enhanced by that afternoon’s rain on our country access road. “Do not enter when flooded”, but everyone does anyway.; The End.

Pre-dawn thunderama raises rain total to 0.49 inches

in Sutherland Heights, that is. but 1.58 inches (!) over there by Tangerine and Oracle Road:

Personal weather station rainfall totals as of 7 AM AST this morning. All of these totals are for the period after midnight last night! The green and yellow regions are rain areas from the TUS radar.

Yesterday’s clouds; pretty spectacular stuff

2:42 PM. Out of focus hailstone. Thought you’d like to see that first.

The remainder of the photos were taken at various times during the day, except as noted:

2:49 PM. Dwarf rainbow due to the high altitude of the sun.

2:49 PM. Dwarf rainbow with a larger view of backyard letting go to HELL, not doing anything with it, or, as we would say, is a “restoration of habitat combined with erosion control project in progress (Letting nettle grass takeover, too.) Its great being environmental and lazy at the same time! Hahahaha, sort of. Originally this recovering area was scrapped off for a new septic system. Is in recovery now. Yay!

Twofer

Rarely do passing lows get a two chances to produce rain, but the low passing overhead today and tomorrow, does. Ten days from now, its overhead again! How funny izzat? And precipful, too.

Measurable rain will fall today in Catalina CDP (“Census Designated Place”, i.e., its not a city), and in about 10 days when the SAME low returns after a boomerang trip down Texico way, thence to Baja, thence to so Cal, and back over Arizona on the 10th-11th after picking up some juice over the east Pac.

Thinking, as you are now, of a minimum of 0.05 inches and top of 0.50 inches, the latter larger amount if projected afternoon thunderstorms land on us. Thus, best estimate, average of those two extremes, thinking Gaussian conceptual model modal value here, about 0.275 inches.

BTW, should be something in the way of an arcus cloud, or a batch of low scudding clouds underneath Cumulus and Cumulonimbus bases this afternoon as a windshift to the NW comes through in the afternoon or early evening hours, well in the next 18 h or so. That could be a dramatic sight, and with that windshift, the temperature will drop 5-10° F.

When the low trudges over us the second time around in mid-October, the estimated extreme amounts are a trace minimum, and 1.00 inch max, in other words, pretty clueless here about how much could fall the second time around ten days from now.

If you don’t believe me about all this, here are is the WRF-GFS prediction for this afternoon, followed by the WRF-GFS model prediction 10 days from now, today being October 6th, in case you don’t know what the date is today, maybe you’re retired and lose track of the days and dates because you don’t have a lot to do everyday, just kind of sit there:

5 PM AST, today, October 6th. Joe low goes by, heads toward Texas.

5 AM AST, Friday, October 16th, the day before football day. Joe returns after visiting NM, TX, MEX, Baja, east Pac, then SC. Full cycle here, from IPS MeteoStar. Pretty humorous to watch this happen.

Yesterday’s clouds, punctuated by a large worm

6:57 AM. If you thought the clouds were fatter to the north most of the day yesterday, you were right. Many modest Cumulus passed overhead of Catalina and then fattened up to the north because the lifting mechanism aloft was stronger to the north of us. Quite a few moiuntainstations registered over an inch to the north of us.

However for a moment, we did have a shower threat move toward us from the south, this:

11:52 AM. Whilst on a hike up the Baby Jesus Trail, this appeared. Looked promising! But, vaporized into mere sprinkles. If you saw this, you almost immediately were thinking of ice forms like needles and sheaths, since the cloud was relatively shallow, and its still warm aloft. Needles and sheath (hollow columns) only form at temperatures above -10° C. Such an occurrence is rare in Arizona, so, quite an interesting bit of hand-waving here.

10:57 AM. Hike up the Baby Jesus Trail was punctuated by seeing a very colorful worm of some kind. Not much else happened in weather or wildlife the rest of the way, Morning glory coverage was a little disappointing.

4:17 PM. I am sure when you saw this Cumulus congestus that you, as I was, thinking you'd see a little ice emit out the right, aging and descending side. No ice was visible. However, it was kind of neat to think how close we are now in our cloud assessments, right or wrong. — 4:17 PM. I am sure when you saw this Cumulus congestus that you, as I was, thinking you’d see a little ice emit out the right, aging and descending side of this cloud. In fact, no ice was visible. However, it was kind of neat to think how close we are now days in our cloud assessments, right or wrong.

The End

Some recent Catalina water year data

The last data point is for 2014-15. These data are an amalgam of the Our Garden site on Pinto and Columbus, from the top of Wilds Road, and the last two years from Sutherland Heights.

OOPS. I was listening to a Southwest CLIMAS podcast, originating at the U of AZ, and realized I missed in the above graph what can only be termed an “ineffectual Niño” that which occurred in 1986-88 and did not produce a precipitation “signal” here. How lame was that?

So, while we are excited about the prospects of extra rain this winter due to the current, supersized El Niño, like all things weather, some doubt must be in place.

Rather than hiding the omission of the “ineffectual El Niño” period, I am inserting the corrected water year history plot here with slightly revised annotation so you can compare them both.

These data are mostly from Our Garden, 1977-78 through 2011-12, located at Columbus and Stallion. The data after that are from Sutherland Heights, Catalina, some 2 mi or so to the SE of that site, and about 300 feet higher in elevation. So there is a bit of what we would call a “heterogeneity” in the data.

The downward trend is misleading, since the Our Garden record began with extremely wet water years, due to a combination of a shift in the Pacific Decadal Oscillation that occurred in 1977-78 (a shift that squelched the then record West Coast drought) and a Niño or two.

That kind of downward trend shown for Catalina in cool season precip does not show up in the Statewide averages for the whole year, anyway, shown below.

Those annual data show the usual oscillations between drier and wetter epochs in Arizona. In the plot below, you can see that had the Catalina record started in 1950 or so, there would likely be little in the way of a trend since so many of those years were drier than average. You can also see the effect of the PDO change in the late 1970s where year after year was above for the State of Arizona as a whole.

The annual (Jan-Dec) state averaged rainfall for Arizona through 2014.

The weather ahead

Rain, tropical skywater, still appears headed our way around the 4-6th of October.

The End

Filling up the portent jar…

With these model outputs¹ for early October. First, a tropical system barges into Arizona bringing copious rains:

Valid in 264 h, only 11 days from now! — Valid in only 10 days from now, sometime in October. Forget any rain chances in the rest of September. Temperature plummeting here now after hot night of foehn like wind from the north.

The exact same map above with annotation. — The exact same map shown above with annotation for helpless little weather babies that can’t see what’s going on.

But its gets even BETTER! In only two weeks, this tropical rampage:

A near hurricane strength tropical storm is about to smash into southern California bringing widespread rains to Cal and the whole SW, which once again, includes Arizony. — A near hurricane strength tropical storm is about to smash into
southern California/northern Baja bringing widespread rains to Cal and the whole SW, which once again, includes Arizony. Wow, wouldn’t that be something!

The End

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¹These outputs, rendered by IPS MeteoStar, a great weather provider, are from the WRF-GFS model. You can’t find a better model than the WRF-GFS, unless you can access the European one (ECMWF), thought to have better “skill scores”.

So, combined with the giant El Niño in progress, which will spin off stronger tropical storms than usual (definitely), and the results of trillions of calculations from our best model that shows a lot of rain headed this way in TWO episodes in 10-15 days. The chances of this actually happening are way over 10%!

Spaghetti actually has a “weakness” in the upper level pattern that will allow that first system to creep toward us; not so much support for Hurricane “Giganta” that comes toward SC, or system number two.

Will get back to you when the drops start falling…

Your updated Catalina Water Year data

Might was well, since no rain will fall here through the end of September (ugh). Here it is:

But lets look at a wider set of data to see what’s going on with the whole State of Arizona precip, through 2014, anyway. The plot below is the ANNUAL statewide average, January through December, the worst possible way to display 12 mos. of precip data. This is because it slices the cool season (October through May) in half, and whole cool seasons in particular can be impacted La Niñas and El Niños that usually only last one cool season. So those kinds of effects are muted in the presentation of annual averages in the plot below (from NOAA NCDC). Sure wish they would issue water year averages (October through September) or even the West Coast, July through June annual average; both of the latter two methods capture El Niños and La Niñas well.

The End