Category Archives: King Range

Less data, more filling

This is the best I could do, in examining the several model outputs over the past 24 h.  Below is the very wettest forecast panel that popped out for southern Arizona during the past 24 h.  The panel below is from yesterday’s 18 Z (11 AM AST) global data and is for the evening of December 15th, about two weeks.  Nothing like what is shown in this panel showed up in model outputs afterward, dang.  Doesn’t mean it couldn’t happen, but its not a good sign.  Still, I thought you should see it.

The 18 Z (11 AM AST) model run doesn’t ingest as much global data as ones at 12 Z and 00 Z, 5 AM AST and 5 PM AST, respectively.  That means that the 18 Z run is not as reliable as those other two, is more susceptible to having goofy outputs (outliers) than the other ones.  “Less data, more filling”, of rain gauges anyway.

We ARE on the brink of a major change in the flow pattern, that is, where the troughs/jet stream will be positioned.  We have been well to the south of the jet stream and all the storms carried with it.  That will change in about a week.   We will have recurring troughs here in the Southwest after that, meaning less warm days, along with occasional chances of rain. The signal for this to happen is pretty strong in the spaghetti plots.

The question is now how strong will those the persistent troughs be as they sporadically drop by in the weeks ahead.  The strong ones for now, like the one shown below that causes rain here, are outliers for the time being.  Stay tuned.  Gut feeling here is that we’re headed for a wet regime, finally.  Its due.

Valid 11 PM AST December 15th. Greens are lighter rains, blues over half an inch. These are rains foretold to fall sometime during the 12 h ending at map time.
The 500 mb pattern (about 18,000 feet above sea level) associated with all that rain in the first panel. As you can see by the yellowish and brown colored regions for wind velocity at this level, the strongest winds at this level are well to the south of AZ-Catalina, pretty much a requirement for rain here in the wintertime. This pattern is similar to the many lows that cut off last fall and winter, ones that gave us those good early rains.  So, if nothing else, this map is a prototype of what we need for some good rains here in Catalina.

The model outputs from last evening do have a little rain here on the 10th, and NOTHING on the 15th as shown above, so I am not going to show those disappointing outputs. You’ll have to go to IPS MeteoStar to see those renderings.

Today’s clouds

Cirrus moving in today, the remnants of one of those monster rainy fronts that bashed northern and central Cal for the past week or so.  Should be a great sunrise display; get camera ready.

From the U of A Wildcats Weather Department, this loop of those approaching Cirrus clouds.

How much rain in the past seven days in northern Cal?

FYI, some sites got over 20 inches.  Here’s a map of rainfall totals from the California-Nevada River Forecast Center for the past seven days.


They needed it.  The arrow shows where the author would like to have been during those seven days, filing daily reports of stupefying amounts of rain.

I mention these rains because this episode of heavy rains was pretty well indicated in the NOAA spaghetti factory plots back in mid-November.   This flooding event is a great example of those occasional situations where a forecast two weeks out can be inferred to be pretty reliable by examining those spaghetti plots.  Those likely heavy norcal rains were expeculated on here based on spaghetti in a November 14th blog.  I really think that you could’ve done this, too, by now!

The End.


A little “troughy” here on Saturday and Sunday

Best chance for rain here, and its not that great, is later Saturday and Sunday AM as an upper level trough comes by, one that includes that bit of poor Paul, who died at sea.  Here’s what that trough looks like when its about over Catalina at 8 AM Sunday morning, this map due to the U of WA Huskies Weather Department:

Now, I will be truly surprised if I don’t see some rain hitting the ground somewhere in viewing distance around Catalina between Saturday afternoon and Sunday morning as this little trough goes by with Paul’s ashes.  But mods don’t show anything, however, at least as of now (at 5:24 AM).  Certainly, we should see some nice cirriform clouds, and middle clouds like Altocumulus, Saturday and Sunday AM.

Elsewhere in the West

Since we’re all bored with our “pleasant weather” now days, I thought I would look around and see what else is going on that might get you excited…

Unusually heavy Nor Cal rains: begin on Sunday; last for about a week associated with purple monster (trough) in map above–it sags southward along the coast.  Many inches should fall in the coastal range north of SFO (aka, “Frisco”).  Maybe we should get a field trip going, some kind of “Rain Safari” to refresh ourselves on pounding rains.  I wouldn’t charge that much.  Also, during the trip, I would pack in a LOT of information, like that in the paragraph below, which provides some trip details.

We would go to Shelter Cove, CA,  and the King Range north of there to get that rain fix.  Now, I have linked to some nice photos of this area but you would not be able to see any of those because the clouds would be based at only 300-500 feet above the ground at the coast, and everywhere else would be mostly IN the clouds.  The King Range, 150 miles or so north of Frisco,  juts up from the ocean suddenly to about 4,000 feet, which causes a lot of water to be condensed in the clouds during onshore flow.  The drops get bigger in those clouds over and upwind of the King Range, bigger than 30-40 microns in diameter at which point they can collide and stick together forming a much larger drop that falls faster and collects more drops on the way down and,  before you know it, those drops have reached millimeter-sizes (real raindrop sizes) in a hurry.   This rain-forming process called the “collisions-with-coalescence” rain mechanism or “warm rain” mechanism because there is no ice involved and it is seen on radar as a situation where there is no “bright band” where level where snowflakes are melting into raindrops as is usually seen when its raining steadily.  This situation is also called, “non-bright band” rain, something that is quite common along the West Coast but you knew all this already.  That kind of rain formation rarely happens here in AZ because it takes extremely clean air in which few cloud droplets can form in the clouds and being fewer, are larger, and here we have too many sources of aerosols and “cloud condensation nuclei” to have really pristine clouds in which this can happen.  The result here is more  and smaller drops in our clouds, ones too small to bump into each other and stick together.  I will point out those days here when the warm rain process is active–our rare wintertime drizzle (tiny, close together drops that almost float in the air) occasions are due to that process.  Some periods of that heavy Cal coastal rain will certainly have a LOT of ice mixed with liquid droplets, and those liquid droplets are either collected on snowflakes as they fall, or evaporate in the presence of ice and that water vapor that evaporated from them then deposits on the ice crystal causing it to grow (the Wegner-Bergeron-Findeisen mechanism of precipitation formation), too, so it would be quite interesting for you to go there for that, too.  You would experience two of the three kinds of rain-forming mechanisms.  (The other one, often seen at higher elevations,  like in Colorado, is where precipitation, usually very light, is formed soley via ice crystals without any liquid droplet cloud being involved.  Many textbooks overlook this third one.  Its great being on the internet and having a blog where you don’t have to worry about packing in too much information and worry about where sentences/paragraphs should end and begin; just get it out there and you’re knowledge-hungry audience will dissect it eventually.

I suppose if we drove in a marathon drive, some people would want to jump out due to info overload now that I think of it.  Of course, I would not be providing “empty” info calories, but full ones.

 Yesterday’s Clouds?

Ci uncinus with moon shot; can you find them?  BTW, Ci uncinus and other forms of Cirrus clouds are good examples of the all ice precipitation mechanism.

5:43 PM.

Rain “puddles” still on model highway the continuing puddles of water we see on a hot day in the distance on the road.  So, in the model outputs of late, there have been a couple of rainy “puddles” for southern Arizona on the horizon, 10 days out and more.   Still too far out to be reliable; they might “dry up”, as our highway puddles appear to do.

But, I would have slept in if I hadn’t been “provoked” into a blogulent life this morning by CONTINUING RAIN in the model forecasts for southern AZ. Here are the key elements from last evening’s new results:  It still rains on February 12th, though the amounts have been scaled back; not the deluge suggested yesterday.  However, a soaking rain is now indicated for February 6th, a week earlier from an entirely different system (!), previously shown as a near miss or a mere wisp of rain.

Its all good, because a pattern change is taking place, and while the details and timing of rain will be erratic for awhile, its likely that the pattern change to one that provides rain here is more likely, not “in the bag”, of course, by any means.

What would be great about a February wet spell is not only the effect it will have on our spring growth and sustaining the road to a good wildflower bloom, but also just to see decent rain in the heart of the La Nina rain deflector period.   As you likely know, the power of a La Nina to deflect storms from the Southwest is greatest in late winter and spring.   Rooting for rain now into spring is definitely like rooting for a 20 point underdog in fubball.

Here are some images from last night’s model output, rendered by IPS Meteostar, my favorite for these.  The first for Monday, February 6th, “bulls eye”, and the second for the February 12th storm.  Contrast the flow shown on the jet stream maps (panels 3 and 4) with what we have today (last panel) to see why we weather folk call it a pattern change.  Look where the jet stream crosses the coast these days and where it is on the rainy forecast days ahead.

As you can see, by the 12th, Cal will also feel the impact of another round of furious weather after the January lashings that brought 10-20 inches of rain to extreme northern portions of the State and in southern Oregon.  The largest total I have found from the later January deluges was….33.56 inches in just NINE days at Red M0und, Oregon, just north of Brookings!  Time to start thinking about another trip to Shelter Cove, CA, and the King Range.  Hmmm.  Just kidding!  I would not willingly miss a drop of rain that falls here, just too beautiful a site to see rain fall in the desert.  We love rain here!

The End.

Factoid:  If you are a snow birder from Prospect Creek, Alaska, about 180 miles north of Fairbanks, I am quite sure you are happy to be here and not there; the temperature yesterday morning at Prospect Creek was -77 F!  The US record low temperature is -80 F set at Prospect Creek in 1971.  Must be like living in liquid nitrogen there in the winter.

A Stratocumulus Monday

Yesterday gave us “Catalonians” the perfect example of Stratocumulus clouds.   But why didn’t it rain from those dark clouds, save a few drops, maybe even a brief drizzle episode that mostly moved across Saddlebrooke around 9 AM?

Those Stratocumulus clouds were GENERALLY not cold enough at cloud top to have ice crystals form in them.   There were some very light showers, mostly east of us during the day, and THOSE clouds got cold enough at cloud top to have ice form in them.

How cold does a cloud top need to be in Arizona for ice to form in it?

Around 15 F (-10 C).

Here’s the TUS  5 AM AST sounding for yesterday from the Weather Cowboys at the University of Wyoming showing the tops are right around that (normal) ice-forming limit.  Where the lines split apart is close to where the cloud tops are, and the temperature lines slant downward to the left.

You may have also noticed that the clouds got markedly shallower here after about 3 PM, noticeable in the U of A movie after 3:30 PM AST.  That was also close to the time an upper level trough and the accompanying slight wind shift occurred.  To the rear of the trough, there is always a piston of downward moving, drier air that’s going to squash cloud tops.  By the evening TUS sounding, cloud tops were barely below freezing.

Some cloud shots from yesterday’s overcast:

Sharp-eye folks will detect a sprinkle over Charouleau Gap

The weather ahead

Still looking for rain here on the 22-23rd, HOWEVER, the last two model runs confined the rain to N of us! Not good.

Nor Cal rains/flooding episode begins overnight as a series of semi-tropical storms strike the coast.

Wish I could be there for surf and on the turf there, but I have my blog audience to think about. I don’t want to let both of them down by being gone for the 10 days of this great storm series, exploring the rain intensities in the coastal ranges of Cal.  Oh, well.

Still think total rains in the best coastal mountain spots over the next ten days will be 30 inches or more, actually not terribly unusual in the King Range and similarly exposed sites.