A 35 year record of Catalina rainfall and what it reveals

Thanks to our friends at Our Garden just off Columbus Blvd. here in Catalina, about 1 mi northwest of my location, we have a rainfall record that goes back to the later 1970s.   This is fantastic because there are no official reporting stations nearby that reflect our rainfall climate, one this close to the Catalina Mountains.   The closest to us in rainfall is Oracle Ranger Station, but that’s at 4400 feet elevation.    We’re about 3000 to 3200 feet here in Catalina.  The long term climate stations, ones under the aegis of the government, are also at lower elevations, and more importantly are farther away from the Catalinas than we are.  Those lower, farther away stations have annual or “water year” (October 1st through September 30th) totals of only around 12 inches.   So, they don’t reflect our wetter Catalina climate.

Our Catalina average rainfall since the 1977-78 water year?  17.04 inches!  Median, 16.59 inches.  Oracle, at 4400 feet elevation for comparison, 21 inches; Mt Sara Lemmon, 30 inches. Too, you could have guessed that we receive much greater rainfall than stations farther away from the Catalinas by our more “lush”, and, being from Washington State,  I use that word advisedly, vegetation hereabouts.  Here is a chart with the water year rainfall values from Our Garden plotted on it:    (Discussion continues below)

Most of the two of you who read this blog will find this 1) quite interesting, and 2) upsetting since there is a clear downward trend in water year rainfall since the folks at Our Garden started maintaining records. Perhaps, you will wonder,  “will it become too dry to sustain life here? Maybe we should sell now and move to a wetter locale like Mobile, AL, before the bottom drops out of the real estate market in the dessicated conditions ahead.”  (Oops, the bottom has already has dropped out of the real estate market.)

But, following the words of Douglas Adams’ in Hitchhiker’s Guide to the Galaxy, “Don’t Panic” .

Let’s look at this a little more closely, shall we?  First, let’s see where this godawful decline in rainfall is located in the records.   Summer?  Winter?  Or both?

Here is our summer rainfall in Catalina (June through September) that will be VERY illustrative of where the decline is taking place because….its not here!

(Discussion continues below)

Yay! As you will plainly see, our summers are the same as ever over the past 35 years or so!  FANTASTIC!   The same number of great storms, lightning, molasses-like dense rainshafts and colorful summer skies are likely still ahead for us between June and September.  No indication here of any “climate change” over the very period in which the earth’s temperature began a noticeable rise following the coolness of the late 1940s through mid-1970s.  As we all know, that rise in temperature since the mid-1970s has been attributed to CO2.  Until recently, global temperatures and the rise in the atmospheric CO2 fraction have been in lockstep.  (Not so over the past 10 or so years for reasons that are “not well understood.”)

But our summer graph is foreboding.  Panic now!

No change in summer rainfall means that ALL of the decline in rainfall over the past 35 years is going to be contained in the “cool” season rainfall records for October through May.  Those cool season rains are due to disturbances in the jet stream; “troughs” that pass over us.  They must be decreasing in frequency over this period.   Furthermore, such a “trough” in the westerlies must have its maximum wind (i.e.,  at the 500 mb level) sag to the south of us to get rain1.

Here is the awful graph which you have now anticipated from the summer rain graph; take a deep breath:

(Discussion continues below)

As you will see, this graph is so shocking I considered calling a news conference about climate change after I plotted it, even though I am not really a climatologist, but rather, a nephologist2.   So, it wouldn’t be quite right to do that.

However, my claim in such a bogus news conference would be that it will likely stop raining in the wintertime in southern AZ within 40 years, if the downturn continues.   I will assign this decline to global warming, since almost all negative-bad news trends are these days.  And, I might have widespread credibility, perhaps a headline.  “Arizona to go dry by 2040!”  The media are, as we know, primed to accept these kinds of claims today it seems without really investigating.

But it will be poor science, an outrage, really.  It should be taken to the Catalina refuse transfer station.

What’s the truth here about our downward trend?  Its certainly a REAL decline over this time span, and,  “what does a longer record show?”

The fact is, Jenny and Wayne at Our Garden happened to start their rainfall record during one of the wettest regimes of the 20th century, and even longer!  Remember how the Great Salt Lake was filling up in the early 1980s?  Remember the huge rains in Cal and AZ in the late 1970s and early 1980s?  Well, of course, IF you DON’T have a good 100 years of experience here, you can’t recall the similar big wet spell in the SW after the turn of the century (1904-05 to about 1920) and the drying that took place afterwards, too.  Those that have been here since 1945 or so are thinking, “If you think its dry now (last ten years), you shoulda been here in the 1950 and 1960s!”

So you can begin to appreciate that our shocking trend since 1977-78 is not one that will continue forever, is not associated with global warming, but is fortuitous because of the starting and end points of our available record.   Our climate in AZ is always oscillating from dry to wet regimes and back again, even in the slightly warmer years likely ahead in the coming decades due to “global warming.”

An example of this oscillation can be seen in the 30 year STATEWIDE averages for rainfall in Arizona.   Check these out from our friends at the Western Regional Climate Center (here). They are shocking and illuminating.

As you will see, the mostly droughty 1941-1970 statewide AVERAGE for Arizona is a ghastly TWO inches LESS (11.69 inches) than that for the frequently rainy era of 1971-2000 (13.59 inches).  Incredible.   That is a HUGE difference when you average over the whole state!   That change to wetter conditions would likely be attributed to the Pacific Decadal Oscillation change in 1977-78 that rolled on for the next 20 years or so.

So, without a grand picture, even 30 years of data can be misleading, produce spurious trends.

Gee, kind of lecture-ish here, boring.  Oh, well.

So, what’s really ahead for Arizona?

Of course, nobody knows for sure, and the climate models with global warming are dicey on long term regional precip changes, such as in southern AZ.

However, I’m one of those (remember, though, not really a climo) who feels that a prediction of just the opposite conditions in the winters ahead might be a “buzzer beater”, a correct one, a winning one; that we are likely to experience a phase shift into wetter winters in the decade or two ahead rather than dryer ones as a projection of the trend line would suggest.

Enough!

The End

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1 If you still have a copy of Willis and Rangno (1971–Final Report to the BurRec, Colorado River Basin Pilot Project, Durango) you of course will already suspect this because that is also the case in Colorado as we reported.

2 Nephologist:  one who studies and has reported stuff in peer-reviewed journals about clouds, but not climate).

 

 

 

 

Wobbly storm drenches Catalina with 0.62 inches of rain!

The above could be a headline in the Catalina Cryer; but that erratic storm that sent sheets of middle and high clouds over us everyday for a week it seemed, finally came through with a stupefyingly good rain.  I just could not believe how that storm kept “giving” all day and into the evening yesterday, ending with a dramatic sunset while rain still fell (see below)!  This is where a meteorologist can be in awe and excited all day, commenting over and over again to those in his presence about how amazed he is about dank and dark skies producing ANOTHER splurge of light to moderate rain!  I’m still excited.   (Very odd behavior, especially when you have visitors from Seattle.)

But recall, at times, and on some models, no rain was in the numerical crystal ball on some runs just before this happened, while on the other hand, a few days before it happened, this kind of drenching rain was predicted several times in some model runs.  All these model fluctuations due to the erratic nature of the upper level configuration, main jet stream to the north, our storm like a spinning top, wobbling around out there in the eastern Pac.  And that scenario was giving the models and us AZ  “precipophiles” headaches and hope, but ultimately, wonder.  This storm will be emblazoned in this writer’s mind forever because of how great it “came through” for us here in SE AZ.  Take a look at the map below for last evening just as the rain was concluding, where you can see a frontal rain band is about to drench Cabo San Lucas, and the upper low center is positioned off central Baja; pretty darn unusual.  (Note: the air is flowing along the greenish “height contour” lines, so it goes from the north on the west side of the low, and usually descends, while on the east side it curls around and goes NEward, with rising motion with sheets of clouds produced, as shown here.)

Combining this rain with our other two November drenchers of just under half an inch each, we have finally had a month with ABOVE normal rainfall at 1.45 inches, at least for us in Catalina where the November average is 0.97 inches.   Sometimes it seems like above normal rain can’t happen anymore here with the droughty spell we’ve had.  But more on that and climo maybe tomorrow.  In the meantime, the latest 24 h regional totals will be here when the site is back up. Before the site crashed, Mt. Sara Lemmon had already gotten over an inch of rain as of late yesterday afternoon.

 

PS:  That next rain, only yesterday predicted for Sunday, November 20th?  Its gone.  Like the endless “puddle” seen on the highway on a hot day, that  “puddle” of rain like the one on the highway that always moves farther away, has now also been moved farther away to November 22-23rd in the models.  Don’t count on it!

Below, our dramatic sunset of yesterday.  Streams of rain off the AZ room frame the sun in front of a messy backyard.  But I will straighten it up today, I promise!

The End.

A pleasant 0.03 inches

Not sure even the dust noticed, but we had a brief shower around 8:30 PM that actually measured with 0.03 inches!  After the spectacular sunset, indicating a large clearing to the WSW, it seemed doubtful we would even get that.  But, what do I know after these past few days?

Below, an example of a nice sunset due to Altostratus clouds (overhead);  “file footage” really, since I had a rare missed shot of that one last evening).

With rain still out to the west and north of us right now (go here to see this 12 h loop of clouds and radar echoes from IPS Meteostar) there is still a chance of more measurable rain later today or overnight.  Still, the configuration aloft will not be favorable for anything of consequence; likely we’ll just a few more hundredths.  But, what do I know#2?

Also, you will see something dreadful regarding that possibility of rain.  A blast of clouds riding on a high level north wind coming out of Nevada and Utah, heading straight for our little system around northern Baja, that will try to keep any rain to the south of us.  The models, such as this one from the University of Washington, have us just on the north edge of any precip.

As so often happens, our models seem to always see another rain in the future, rains that so often fail to materialize.  This time the rain “mirage” is for Sunday, November 20th.  Oh, well, something to think about.

Have some climo data for Catalina, about 35 years worth and will be posting that in the next day or two.  Past records help you dream about what could be in a winter or summer.  Can you imagine that little ol’ Catalina has had almost 30 inches of rain in a year a couple of times? Imagine how the washes ran!

The End.

Chance of rain likely

Sorry for that silliness in the title, but I’m afraid those model runs that had our storm staying too far south to give us a “significant” rain were correct.  So we are stuck with only a chance of rain, nothing “sure” about it today or tomorrow.  Surely, there will be a little here and there in SE Arizona over the next 36 hours, but that’s about it, “here and there.”  So we might even be missed by rain here in Catalina.

These are times when being a weather forecaster is tough, because some model runs (particularly those Environment Canada ones) had a tremendous storm affecting virtually all of Arizona just a few days ago in several runs.  And, because rain is such a treasure here, there is that background bias that wants those kinds of model runs to be correct.  Also, my dad was born in Winnipeg, Canada.  So I really wanted those Canadian model runs that were wetting it up in AZ to be right!

But they were seriously off the mark, bogus, producing smoke and mirrors, etc., and the chance that they might be was indicated all along in the “ensemble” model runs (or “spaghetti” plots that illustrated all the uncertainty in where this low center was going to end up as it came toward us.  The bright side, the chauvenistic side, really, is that the USA (!) models, ones that I did not want to be correct because they never had much rain, were really far superior in the handling of this low center all along.  Below, the latest Enviro Can run that is now compatible with the US NCEP runs that had the low skirting us to the south pretty much all along.  Note red splotch over the Mexican State of Sonora in the upper left hand panel.  That are is where the most active rain systems would be!  Note yellowish-red colors indicating  lot of rain in the prior 12 h along the west coast of Sonora, lower right hand panel.   This panel valid for Sunday afternoon, 5 PM LST.  Dammitall!

But, it is likely that area of Mexico could use a good winter rain and so, in being magnanimous, I will pretend to be happy to see them get a lot of rain and us maybe even none.

In sum, wave the flag over the US NCEP model’s superior performance over the Enviro Can model!  Sorry dad.

The End

Don’t like the overnight model runs; greatly reduce precip for Catalinians

So, I am just going to ignore them until the next model runs, and not say anything right now.  Feeling chastened (once again) after all the rain enthusiasm I had.

Clouds?  Look for a lot of Altostratus/Cirrostratus (ice clouds) way up there; might look dark at times, but too high to precip, namely the kind of clouds we saw yesterday afternoon around 5 PM LST (see below).   Might be some nice sunrise/sunset photo ops.

The End.

PS:  After looking at this loop from the University of Washington for the western hemisphere, it looks like the As/Cs clouds will be eventually accompanied by some Altocumulus clouds (mostly comprised of droplets clouds) because they are lower and warmer than As/Cs.  And since they are ejecting from the tropics toward us, a good bet is for some “Ac cas”  (Altocumulus with turrets -“castellanus”).  I like Ac cas.   They will help ease the pain of these latest model runs….

Potent storm still in cards for SE AZ and Catalina!

First, lots of cirrus clouds overhead.  Get ready for a great sunrise photo.

AZ incoming storm update:  Yay! (overall impression)

Now that the US and Canadian models are “converging” a bit to a similar depiction of where the highs and lows and upper level features will be come this Saturday,  a good rain seems in the bag for at least SE AZ.  Both models were having quite a headache trying to figure out where this low off the West Coast now was going to end up, and still do, as shown below.  However, both have significant rain here in SE AZ, though when it happens Sunday or Monday, is still a conundrum.

But with that next rain, and there may be some strong winds again, our November rainfall should be substantially higher than normal.  Seems like another half inch will materialize over the weekend into Monday, as this system passes by.  That should bring us (here in Catalina Land) to around a 1.50 inches total.  Average over the past 33 years here (not in Tucson!) is just under an inch.  You can go here to see how Enviro Can (the Canadians) depict this storm situation, and here for the US version.

You will see that in the Canadian version, a trough from the Pac NW and our incoming storm off Cal now “mesh” into a single trough as both combine over the interior of the West Coast.   They do this in time for a major storm in AZ in that model with lots of wind.  In the US model, the Pac NW trough bypasses our incoming low, and so they don’t combine into a larger storm system;  rather the Cal system muddles across us a day later but still brings significant rain, though mostly to southern AZ and us.  No doubt, that in the next model run or so, these discrepancies between Enviro Can and the US model with be healed.  Still, it seems we are assured of a good rain no matter what happens at this point (he sez).  Yay#2.   Below a couple of snapshots from these runs, first the less-potent-AZ storm depicted in the US “GFS” run:

Note in the first panel that you have a trough over ID and one off San Diego.  If they combine, look out!  A much more potent storm results for us.   If they bypass one another, then things ain’t quite so good.  But see what happens?  In the US prediction, the low dawdles off Baja while the ID trough is, only a day later, over the the Corn Palace in Mitchell, SD!   Not so good for us, though that Baja low DOES dribble over us on Monday bringing some rain.

The next two panels are from the Environment Canada model run, a model based on the European Center for Medium Range Forecasting model.  Here’s what that model came up with for these same two times shown above for the US GFS one.

The difference between the US and Canadian runs are pretty subtle for Saturday morning (leftmost panels).  But look at the difference for Sunday morning; they’re gigantic!

The Canadians think that the Pac NW trough will inject itself southward into our Cal-Baja trough, meshing for a stronger storm over AZ as all that Pac moisture from the system off Baja is swept into Arizona.

The Canadian model is therefore the preferred solution to our storm dilemma.  In sum, though, rain appears in the bag for SE AZ, not so much confidence elsewhere in AZ unless these troughs combine rather than bypass one another.

Hope this is comprehensible (as usual).  Local advice:  clean out your rain gauges of dust and bugs.

The End

Canadian model returns to the “good” AZ storm” prediction; spaghetti mentioned

After re-thinking the powerful storm yesterday based on the morning’s new data and making it a semi-marginal one, most of the rain to the south, the Canadian model run came back last night with a powerful AZ storm again!   Forecasters who want lots of rain here in AZ and Catalina can get manic-depressive during these fluctuating model outputs.  The fluctuations in the PREDICTED intensity of the storm tell us that all is not known well  upstream.

Below is what transpired in this, “pretty good” Canadian model beginning with yesterday’s “retraction” (first panel below) after predicting the mammoth storm over all of AZ this weekend just 12 h earlier.  Note in this panel, valid for Sunday morning, how little flow there is over AZ  (indicated by very few “lines” or as we would call them, “contours”) compared to the run the night before (which I excitedly displayed here)!  Pitiful change.  In this first panel, upper left, we’re between two jets, the one looping around the low off Baja and the one across the northern Rockies.   Not good.  You need flowmax to help squeeze winter moisture out of the clouds as they bang up against our mountains.  And with flow, you get better overall rising motions, the kind that creates vast areas of deep clouds and rain.  We don’t got that in this first map, and you can see the heavier precip (yellowish areas) are mostly S of the border.

So, a disappointing sight, but in view of the sudden appearance of a giant storm from nowhere in the models (suggesting an error), not an unexpected “retraction” as was mentioned in yesterday’s blog. But, that “giant storm model run”,  24 h ago did see SOMETHING.

Why do I know?

Because the latest global data (from last evening), has increased the strength of the storm  hitting us to something major in all of AZ. Check the areas of precip in the next two panels from last night, hot off the press, for this Saturday and Sunday.

Also the timing of the AZ precip is drastically different in these two runs just 12 h apart.  Last night’s run brings the major storm in on Saturday and continues precip into Sunday, while the run just 12 h before that has a DRY Saturday in all of AZ! Quite remarkable changes from global observations just 12 h apart. Look, too, and how the flow over us (upper left panel, and marked by more “lines” over AZ) is so much stronger in these latest predictions compared with the flow predicted just 12 h earlier (upper left panel in the first image).

So, what does a weatherman do?  Personally, since I like rain in Arizona, I go with the new model output completely. But a real weatherman, one that is a little more objective (BTW, not an objectionable one) would play down the storm and think about “spaghetti”, not food, but plots that is.  “Are the models “converging” to a better storm or not?”, he would ask himself.  Not me.  Do small tweaks still lead to huge differences in the amount jet stream over us, predicted rain, etc.?

Last, an example of a northern hemisphere “spaghetti” plot for model predictions for this Saturday, a plot that we all use that clearly shows the models are clueless (well, at least erratic) in their predictions for the West Coast and Southwest.  That “cluelessness” is indicated by the “bowl of rubber bands” appearance of the lines off the West Coast and over the Southwest.  Where the lines are on top of each other is where there is little chance the prediction will go awry.  Where there is a “bowl of rubber bands” there is tremendous uncertainty.

So, the spaghetti plot is showing that here in AZ, its possible to have either significant rain with some flooding with this storm over the weekend, or a just a little light rain.  If you like spaghetti, you can go here and see a bunch of them. Enjoy the uncertainty.  Its a little like the rest of life.  Me, I’m preparing for a lot of rain over the weekend.  I want to see the Sutherland Wash flowing!

The End.

45; nice in hundredths and a Canadian teaser prog

A second nice rain here in droughty Catalina!  Thought 25 hundredths would be great from that little rainband, but no, we milked that system, appropriate language for rural regions, for no less than 45 hundredths, both here on Wilds Road and in Sutherland Heights.   Very Seattle-like morning, too, with DARK low hanging clouds.  Now our November rainfall is almost at our Catalina average of 0.97 inches with 0.93 having fallen already!

And if you were watching closely, and I suspect you were, you might have seen a little “graupel” (tiny snowballs) fall out of some of the Cumulus congestus (second shot below)-Cumulonimbus clouds (third shot)  yesterday afternoon here.  Historical query:  wasn’t there a song decades ago by the farmer, Don Hoe,  about tiny snowballs?  Sounds familiar anyway.

Graupel,  and hail for that matter, often show up as strands, or fiber-like regions of precip falling out the bottom of clouds, and you could see those from time to time yesterday afternoon.   That last shot is a shot taken by someone while at the same time they were driving (good grief!) down Tangerine looking toward the Catalina Mountains.   If you look hard you can see “strandedness” in the shaft to the left of the short rainbow.  (The little rainbow terminates, of course, where the precip becomes ice and not rain.

Continuing about strands from cloud bases, that’s is definitely the base area of the cloud you want to be under to see things bouncing off the ground or your car or the biggest drops.  Saw some graupel (also called,  “soft hail”) yesterday myself at Golder Ranch Drive and Oracle.

Such a pretty day, too, with the mountains so white in the morning, capped by nice orographic clouds in the afternoon.  See some of this photogenic day below.

Canadian teaser

How exciting it was to wake up this morning and see that the Canadians had provided all of Arizona with a MAMMOTH, drought-denting storm in their overnight model run for November 12-14th.   Check out these model images below, valid for the mornings of November 12th and 13th, respectively.   (The entire original series can be found here.) 

In comparison for these two output times below, I reprise the Canadian model output based on the data but 12 h earlier than those just shown below them.  In yesterday morning’s model output, rain had not even gotten to San Diego by the morning of the 13th, and a pleasant, but really kind of decrepit (just a couple of isobars around it) low center is shown STILL offshore.  

But in last night’s run for November 12th, a giant low is centered in California, 994 millibars central pressure no less, with MANY isobars around it covered the whole western US practically!  The low is nowwhere near San Diego anymore, but rather over “Sacramenta”, CA!  

Those many isobars in the latest model run mean lots of wind, and with that wind,  huge amounts of cloud laden air are going to be smashed into the coasts of California and Baja California, and with that, lots of rain as that wind drives in against the mountains.  And you can see that happens in those colored regions, lower right panel of the 4-panel model output), that’s what happens on the 12th and 13th.  

This was SO EXCITING to see!  I wanted to call all my friends and let them know about this.

But alas, this very wet scenario is likely just a teaser since there was too much change from the prior model run.  In hoping it will actually happen you may just as well be hoping that your horse, last by 6 lengths in the far turn, will spurt to the front by the finish line.  Too, this drought denting scenario was not at all seen in the US models (seen here).   Rather, our NCEP model run  resembles the old Canadian model from yesterday morning, one that showed a relatively weakly precipitation system go over us.  Dang.  Still, they all do show more rain ahead, that’s the upside of this whole blog today.

So, some kind of  bad data likely got into the Canadian model.  Still, its not impossible that the Canadian model is on to something, and that’s where the final ray of hope lies, is that somehow later today, the Canadian model sees the same rain drenching result over AZ on the 12th and 13th, and also, the US models see it as well.  So, lots of anticipation today to see how things change.   A more reasonable guess, one that I would make,  is that the Canadian model is not completely goofy, and that the US models will strengthen the storm on the 12-13th when they ingest this morning’s data.

Will post likely disappointing new results (trying to be objective here)  later in day when progs come out based on data taken globally about right now (4:40 AM AZ time).

 

 

 

 

 

 

 

 

 

 

 

 

 

Rain ahoy!

Just on the horizon.  You were probably worried when you got up at 2:30 AM and saw only a big moon and no clouds.  “Where’s the rain?”, you wondered.   “She’ll be coming around the mountains when she comes” , to quote the lyrics from that old western song about Clementine (the Tortolitas and those mountains SW of us, in this case) in just an hour or so (its 4:30 AM now), certainly before daylight it should be dark and showery.  Yay!  Might get a quarter of an inch or so, which would be great!   Check this radar-satellite imagery out from IPS Meteostar for approaching cloud and precip details.

Mods continue to show a couple of more rain events in the days ahead with some sunny, cool breaks, biggest one on the 13th.  Hope these materialize into monsters, because as many of you know (“many”, hahaha, exaggerating readership again;  actually it should be, “as both of you know”)  we are in a La Nina oceanographic regime.    A La Nina regime is usually thought of as a “storm deflector” for the SW.  However, its magical powers are most pronounced in the LATE winter and spring, so we got to get us all the rain and mountain snowpacks we can NOW to avoid a really droughty year!  However, even the “best” La Nina’s  don’t positively mean this; the correlation coefficient between droughts here and a La Nina is not 1.00, that is perfectly correlated.

As we know, in semi-arid climates, too, it only takes a few good storms to make a good year, and those can slip in during La Nina regimes anyway.  Fingers crossed for mammoth rain and snowstorms this month.

The End