Christmas Day Severe Weather and Tornadoes in Dixie Alley

I hadn’t planned to post today, but with the severe weather that the NWS has been forecasting for several days now already underway in east Texas and conditions ripening across southern Dixie Alley from lower Louisiana into Alabama, I thought I’d pin a few of today’s 12Z NAM forecast soundings to the wall to let you see what the squawk is about. I’m focusing on Louisiana because it seems to me that, from a storm chasing perspective, that’s where the best chances are for daylight viewing–not that I think there will be a whole lot of people chasing down in the woods and swamps on Christmas, but I need some kind of focus for this large and rapidly evolving event. Remember, the sun sets early this time of year.

To summarize the situation, a vigorous trough is digging through the South, overlaying the moist sector ahead of an advancing cold front with diffluence across Louisiana, Mississippi, and Alabama. Shear and helicity are more than adequate for supercells and strong tornadoes, with forecast winds in excess of 100 knots at 300 millibars, 80 at 500, and 45-50 at 850, ramping up to 60 at night per the Baton Rouge NAM.

I’ll start with three soundings in southwest Louisiana at Lake Charles. It’s obviously a potent-looking skew-T and hodograph, with over 1,600 J/kg SBCAPE and more-than-ample helicity. No need for me to go into detail as I’ve displayed parameters that should be self-explanatory; just click on the image and look at the table beneath the hodograph.

What I do find noteworthy is the very moist nature of this sounding, suggestive of overall cloudy conditions and HP storms. This changes quickly around 20Z (second image), with much drier air intruding into the mid-levels.

From there on, temperatures at around 700 mbs begin to warm up until by 23Z (third image) they’ve risen from 1.5 degrees C (18Z) to 5.9–a gain of nearly 4.5 degrees–and a slight cap has formed and becomes strong by the 00Z sounding (not shown). Note how the surface winds have veered, killing helicity as the cold front moves in. End of show for Lake Charles.

Farther east in the Louisiana panhandle, you get much the same story at Baton Rouge, except the more potent dynamics appear later and more dramatically, with 1 km helicity getting downright crazy. I’ve shown two soundings here. The first, at 18Z, has a dry bulge at the mid-levels but moistens above 650 mbs, and by 20Z (not shown) it has become even moister than its Lake Charles counterpart, to the point of 100 percent saturation between 600 and 800 mbs. Helicities are serviceable but less impressive than to the west.

There’s a big change in the second sounding, this one for 00Z. The dewpoint line sweeps way out, and look at that wind profile! With a 60 kt low-level jet, helicities are no longer also-rans to the Lake Charles sounding; at over 500 m2/s2, they’re hulkingly tornadic, and the sigtor is approaching 13.

Mississippi is obviously also under fire, and I hope the folks in Alabama have taken the 2011 season to heart and purchased weather radios that can sound the alert at night.

To those of you who chase today’s setup–and I know there are a few of you who are down there–I wish you safe chasing. But my greater concern is for

the residents of Dixie Alley who live in harm’s way and aren’t as weather-savvy, and some of who–despite the NWS’s best efforts–may not be aware of what is heading their way this Christmas Day.

Having just glanced at the radar, I see that the squall line is now fully in play. I’ll leave you with a screen grab of the reflectivity taken at 1725Z.

Have a blessed and safe Christmas.

ADDENDUM: In watching the radar, it’s obvious that the 12Z NAM was slow by an hour or so. Can’t have perfection, I guess.

Mini-Tornadoes: Defining a Microscale Mystery

In Europe they have mini-tornadoes. There was a time in my callow, formative years as a storm chaser when I was unaware that there was such a thing, but one learns. Besides, even veteran American chasers could make the same mistake as I, and probably have done so many times. From the reports, photos, and videos I’ve seen, a mini-tornado so closely resembles a standard-issue tornado in appearance and effect that here in the United States, most chasers would find it impossible to tell the difference.

However, Europeans–newscasters and reporters in particular, who are largely responsible for disseminating the mini-terminology–are more discriminating and not easily impressed. In Europe, it seems that anything less than a Great Plains-style wedge isn’t considered a full-fledged tornado.

Not that wedges are a common occurrence across the pond. The perspective I’ve described appears to be based not on great familiarity with tornadoes, but rather, on a paucity of experience with them other than what is gleaned through viewing videos of the mile-wide monsters that stalk the American prairies. Now those are tornadoes! Compared to them, a trifling, block-wide vortex is … eh. Small change.

Plenty of U.S. chasers would take exception. The problem is, no mini-tornado criteria have been established that could provide a basis for arguing that probably 99.9 percent of mini-tornadoes are simply tornadoes. Not that at least one attempt hasn’t been made to provide such criteria. Back in 2006, in a thread on Stormtrack, I myself presented a plausible set of determinants for mini-tornadoes, complete with a damage-rating scale, and I’m surprised that the NWS never adopted it. Follow my logic and you’ll see for yourself that true mini-tornadoes are a phenomenon few Europeans, let alone Americans, ever encounter.

Mini-Tornado Criteria

A true mini-tornado must meet the following standards:
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•  It is five feet tall or less. Of course, this implies an extremely low cloud base. You’d have to squat in order to get a decent photo.
•  Width: Two feet or less.
•  Human response: You feel a strong urge to say, “Awww, ain’t that cute!” You want to pet it and maybe even take it home with you and give it a nice bowl of debris.
•  The synoptic conditions can be contained within five city blocks.
•  Overshooting tops can be viewed from above by taking an elevator to the ninth floor.
•  Damage (introducing the M Scale):

  • M0: Damage?
  • M1: No noticeable damage.
  • M2: No, there’s no stinking damage. Now go away.
  • M3: Okay, some damage now. Card houses knocked over unless securely glued together. Hair ruffled. That sort of thing.
  • M4: Now we’re talking damage. Well-built card houses scattered into a lawn-size version of 52-Card Pickup. Ill-fitting toupes snatched away. Nasty things happen when you spit into the wind.
  • M5: Inconceivable inconvenience. Securely glued card houses swept entirely away and lofted across the lawn. Well-gelled hair twisted into impressive new designs. You want to get out of the way of this baby.

I hope this helps. Of course, according to these criteria, I suppose the UK has yet to experience a true mini-tornado. Someone should probably inform the press. And none of us should hold our breaths waiting for such an occurrence, because, truth be told, mini-tornadoes are extremely rare.

But not utterly non-existent. The late, talented storm chaser Andy Gabrielson managed to capture on video his personal encounter with a good mini-tornado candidate on May 24, 2010, in South Dakota.* Check out his YouTube video at 1:56, and like me, you too can say to yourself, “What the heck was that?”
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* The footage up to 1:56 is not a mini-tornado.

Building a Baseline of Ability: Revisiting an Oldie-But-Goodie Music Post

The problem with blogging is that old material tends to get buried beneath new posts. Jewels are lurking down there in the sedimentary layers, and they deserve to be brought back to the surface from time to time. Some of them surprise me. I think, Did I write that? It seems like someone else sharing wisdom and encouragement with me that I can benefit from today.

Such is a post from back in May 2010, two-and-a-half years ago, which I titled “Mastering the Sax: Building a Baseline of Ability.” I hope you will find it helpful and encouraging, as did I in rereading it.

Waterspouts on Lake Michigan

Saturday, September 22, was the first day of autumn 2012. It was also my first-ever time seeing waterspouts. I’ve chased them a few times (if chased is the right word) previously within the past two years, but not successfully. This time made up in spades for those occasions. I don’t know how many waterspouts I saw, but “lots” ought to cover them, including one that made landfall about a hundred yards north of me at Tunnel Park. I managed to capture that one on video. But I’m getting ahead of myself.

I woke up at 5:15 a.m., showered up, and headed for the lakeshore. The ICWR waterspout forecast indicated a high probability of waterspouts all along the eastern shore of Lake Michigan, and the main concern seemed to be simply finding adequate near-shore convection. That didn’t seem to be a problem, since a line of thunderstorms was moving across the lake from Wisconsin and heading east almost straight at me. Based on the line’s slightly southern component, I decided to head for Holland Beach.

A nice cumulus field had overspread West Michigan as I pulled into the state park. At the entrance, a ranger informed me of restricted parking due to a marathon that was being routed through the park by the beach. The racers hadn’t yet arrived; in fact, very few people were present, and having the parking lot mostly to myself, I chose an optimal spot where I had an unimpeded view of Lake Michigan.

The stiff lake breeze concerned me. Westerly surface winds–and strong ones at that–didn’t seem to me to bode well for waterspouts. How would the convergence necessary for spout formation occur over the water with unidirectional winds? Still, the waterspout index was maxed out, and here I was, so I guessed I would find out.

After a while, the western sky began to darken. The storms were moving in, but they would take a while to arrive. Meanwhile, a green blob of convection on GR3 corresponded with a cloud bank stretching perpendicularly from the waters to the shore about ten miles to my south. It seemed worth checking out, so I grabbed my camera and headed across the beach toward the pier near the lighthouse. From that vantage point, I finally got a good, complete view of the convective band.

A slim, well-defined gray tube hung from the distant cloud base. Bingo! My first waterspout! I began snapping pictures.

The salmon run was on, and all along the channel, fishermen were having a heyday. Focused on fish, they seemed oblivious to the elegant spectacle unfolding over the water. How could they not see it? I pointed it out to one fisherman. “Wow! A waterspout!” he said. Then he went back to his fishing. To each his own, though I suppose he could fish and watch the spout at the same time.

I don’t know how much time passed–fifteen minutes, maybe twenty. By and by, the spout dissipated, and I returned to my car. I didn’t need to look at my radar to know that the storm was closing in. I could see the lowering clouds and rain shafts over the water.

What the radar did tell me, however, was that heavier convection was heading toward the Saugatuck/South Haven area. So, as the first of the marathoners began to trickle into the park, I decided to drop south toward where chasers Skip Talbot, Jennifer Ubyl, and Jonathan Williamston were located.

I got as far as US 31 before realizing that I had made a tactical error. Heavier convection was beginning to fire in a line that promised to train in directly over Holland Beach. Nuts. I had just compromised myself by fifteen minutes, and in the meantime, a marathon had gotten underway. I turned around and headed back toward my old location, but now the road was filled with runners and closed to traffic.

I decided to head for Tunnel Park just a few mile north of Holland Beach. But Lakeshore Drive was also clogged with marathoners. Thus began a frustrating quarter-hour of driving down sideroads and through neighborhoods, trying to gain access to the lakeshore. Ultimately, I wound up pulling over kitty-corner across the road from the park entrance, watching morosely as runners ran by. But there was a cop standing next to his car, shepherding the crowd, and … what the heck. I walked up to him and asked him if I could cross into the park. Sure, he said. The race ended officially right at this point. Just look for an opening, the cop told me, and then I could nudge my car across the road.

Free!

The storm was arriving as I pulled into the park, and rain had begun to fall. I grabbed my cameras and raced toward the tunnel. The other end opened out onto the beach, affording a sheltered location where I could watch for spouts without getting wet. It was a perfect setup.

The only other people there at the park were a young ethnic couple with a baby and a small child. I greeted them and talked with them about waterspouts as we watched a shelf cloud advance over the storm-driven surf. After a few minutes, the guy pointed toward the lake and said, “Is that one?” I looked, figuring it was a false alarm, some turbulent scrap of scud ascending along the shelf cloud. But no, he was pointing at the water, where a rotating patch of spray was clearly visible. It was only a couple hundred yards away, small but unmistakable. Waterspout!

And now another, larger one was organizing to my northwest. I could see no funnel, but then, the shelf cloud was now almost directly overhead, and features that might have been obvious at a distance were lost in the jumble of clouds. Regardless, the rotating cascade looked intense. I grabbed my camcorder. There was no time to set up the tripod; I would have to manage the best I could with hand-held. I hit “record” and began shooting the waterspout as it progressed toward the shoreline.

At first, it appeared to be heading toward us, which didn’t concern me. The waterspout was non-tornadic, and while it obviously packed some strong winds, I felt that the greatest threat it posed was a nasty sand-blasting. We could retreat into the tunnel if necessary.

But the spout made landfall about one hundred yards to my north. I ran out onto the beach to try to capture more of it as it progressed up over the foredune, but I was too late, and that section of my footage turned out pretty wobbly. Still, I had about forty-five seconds of shaky but ultra-cool footage of a Lake Michigan waterspout hitting the shore at close range. The first thirty seconds is the best, but I’ve chosen to show the whole shebang because I think there are some points of interest in the latter part, flawed though it is.

Back at my car, the radar indicated more intense convection headed toward Grand Haven. After sending a report to Spotter Network, I got onto Lakeshore Drive and began heading north. The stream of runners had thinned out, and the road was open, though still patrolled by the police. A little ways north of the park entrance, I noticed a “damage path” of tree trash–clusters of leaves and large twigs–scattered across the pavement. The road was only a quarter-mile from the shore, and I have no idea how far inland the waterspout made it before dissipating, but I suspected that a few runners had gotten quite a surprise.

Up at Grand Haven, a cloud bank to my northwest put down a series of spouts. These were much farther offshore and not particularly impressive at the time I viewed them, though I’ve seen some stunning photos by another spout chaser from the same location. After a while, the waterspout activity dwindled off, but I’d gotten my fill and was glad to head back east.

Back in Grand Rapids, I processed my video of the spout at Tunnel Park and attempted to send it to WOOD TV8. But the ftp upload failed, so rather than waste more time, I stopped by the station and let their tech handle things. The footage got aired on the evening news.

After that, I somehow wound up in Lowell. It was a lovely, moody day, perfect for the first day of fall, and I guess I just felt like a drive. Anyway, I found myself on the waterfront, watching ragged cumulus clouds drift over the broad, windblown face of the Flat River. To the north, a small, low-top storm billowed up above its less successful convective comrades and spread its cirrus anvil eastward. It was a beautiful sight, as was the entire sky, and I couldn’t resist taking a few more pictures. The last view on this page looks to the south, where the Lowell Showboat rests at its dock just upstream from the Flat River Grill and the dam beneath the startlingly blue September sky.

And that is that. Two days later, the same intensely azure sky prevails and this chill wind testifies that autumn is indeed at hand. The trees are still mostly green, but change is in the air. My hunch is, we won’t be getting a “second season” for storm chasing. If not, Saturday was wonderful compensation and will see me through to next spring.

Two Giant Steps Licks

Lately, my book The Giant Steps Scratch Pad has enjoyed a modest spate of sales. I appreciate that musicians take an interest in it. On my part, it was a labor of love, and it’s gratifying when you, my readers, find it worthwhile enough to shell out your hard-earned cash to obtain a copy. Every purchase is a shot of morale for me, not to mention a nice dent in my electric bill.

As a way of saying thanks, I thought I’d share with you a couple of favorite new Giant Steps licks that I’ve been practicing. They correspond to the A section of Giant Steps’ A-B form and have a bebop flavor to them.

Since I’m an Eb alto saxophonist, I’ve written the licks out for my instrument. C, Bb, F, and bass clef instruments will need to transpose accordingly. ‘Nuff said. Without further ado, here are the licks. Click on the image to open and enlarge it.

My First North Dakota Chase This Saturday

I’ve never chased storms in North Dakota, but that’s about to change. Tomorrow Rob Forry and I are hitting the road for the severe weather event that’s shaping up for Saturday along the Canadian border.

This has been a puzzling scenario to forecast, with the models gradually aligning after painting some radically different scenarios. The NAM has wanted to move the system eastward faster and place the better  tornado action across the Canadian border, while the GFS and Euro have been more  optimistic and, I believe–I hope–more accurate. What the heck–Canada may get more shear, but North Dakota has the big CAPE.

We’ll find out Saturday. Lacking an extended driver’s license that would grant me access to Canada, I’m counting on North Dakota to deliver. I feel confident

enough that it will that I’m taking the chance. I keep eyeballing the region from Minot east toward Rugby and Devil’s Lake, and north, and a bit south. Skew-Ts have looked consistently good in those parts, and there’s plenty of CAPE to get the job done–around 4,500  J/kg MLCAPE per the GFS. My hope is that all that luscious, pent-up energy will produce something like what the NAM 4km nested CONUS radar shows at the top of this post.

Come on! Big tubes and gorgeous storms drifting across the wide sublimity of the North Dakota landscape, and then steak and beer later on.

How to Solo on “Confirmation”: Guide Tones

In recent months I set myself to tackling a project that I had put off far, far too long: getting my arms around Bird changes. In one way or another, the Charlie Parker tune “Confirmation” has been a regular part of my practice sessions these days. Recently I finished transcribing a Richie Cole solo on “Confirmation,” and of course that was enlightening. I’m currently in the process of memorizing both it and a Parker solo on the changes. It has all been profitable in unlocking the logical but nevertheless challenging harmonies.

Developing a set of guide tones is immensely helpful in mastering Bird changes, particularly in the first four bars. The exercises on this page will help you do so. Click on the image to enlarge it. Note that the exercises are written for Eb instruments. If your instrument is pitched differently–eg. Bb tenor sax or C flute–you’ll need to transpose accordingly.

In exercises one and two, I’ve stripped the guide tones down to a whole note for every bar. You can modify them as you wish, but I find it helpful to start by keeping things as simple as possible.

Exercises three and four take the form of boppish etudes that utilize the guide tones.

I highly recommend that you practice these exercises with some form of harmonic accompaniment so you can hear how the pitches sound in context with the actual chord progression.

That’s it–gotta scoot. I hope you find these little nuggets profitable. If you enjoy them, you’ll find plenty more on my jazz improv page.

Memorial Day 2012: A West Michigan Lightning Extravaganza

I have yet to take some truly razor-sharp images of lightning, but each time I go out, I learn a little more about how to improve my lightning photography. Last night afforded me a great opportunity. Storms forming ahead of a cold front moved across Lake Michigan and began to increase in coverage as the night progressed, and I roamed with them across West Michigan from the shoreline at Whitehall and Muskegon State Park to inland northeast of Lake Odessa.

My expedition was marred by the fact that I left the adapter plate for my tripod at home. I compensated by setting my camera on top of my dashboard and shooting through the windshield, an arrangement that works okay but

which considerably limited what I was able to do at the lakeshore. Using the hood of my car to steady myself, I managed to capture a few shots of a beautiful, moody sunset, with the red semicircle of the the sun gazing sullenly through rain curtains of the advancing storms. However, parking by the side of a busy road where everybody had the same idea–to pull over and watch the storms roll in over the waters–just didn’t work very well. After too many time-lapse images marred by tail lights (see photo in gallery below) I decided to hightail it and try my luck inland.

It was a good choice. The storms multiplied as I headed back toward Caledonia, and with lightning detonating to my north and closing in from the west, I decided to continue eastward till I found an ideal location–a place far from city lights and with a good view in all directions. I never expected to drive as far as northeast of Lake Odessa, but I’m glad I did.

Note to self: STOP USING THE ULTRA-WIDE-ANGLE SETTING WHEN SHOOTING LIGHTNING. Zooming out all the way to 18 mm is just too far, and cropping the shots doesn’t work well. The crispness goes downhill.

For all that, the images below aren’t all that bad, and a few turned out really well. After Sunday’s busted chase in Nebraska, it was nice to enjoy a few mugfulls of convective homebrew right here in West Michigan. I finally arrived home at the scandalous hour of 4:15 a.m., far later than I ever anticipated. I was tired but pleased. This Memorial Day lightning display did not disappoint.

An Active Weather Pattern Moving In

These next few days look interesting severe-weatherwise from the northern Plains into the Great Lakes. Today holds the potential for a significant blow near the Missouri River in South Dakota, Minnesota, Nebraska, and Iowa. Here is a RAP forecast sounding for Sioux Falls, SD, for 00z tonight.

I’ve been eyeballing that area via the NAM for a number of runs. Capping has been an issue for a while now, but NAM has consistently wanted to break the cap in the area I’ve mentioned. If I could have found a partner to split costs, I’d have left last night, but the thought of going it alone and blowing a wad of cash on a cap bust–a distinct possibility, with 700 mb temps hovering AOA 12 degrees C–spooked me.

Now I think I should have taken the risk. Today could be another Bowdle day, and I wish I was in Sioux Falls right now. Some of the  indices there for this afternoon look pretty compelling, at least if the RAP is on the money. The cap could break between 22-23z, and if that happens, then walloping instability (mean-layer nearly 3,900 J/kg CAPE and -10 LI) and mid-70-degree F surface dewpoints will surge upward into explosive development, and ample helicity will do the rest.

However, the SPC is not nearly so bullish as the above sounding, citing the complexity of the forecast due to capping and the lack of dynamic forcing. That’s been a repeated theme. Today looks like one of those all-or-nothing scenarios where chasers will either broil in a wet sauna under merciless blue skies or have one heck of an evening.

Boom or bust for those  who are out there. As for me, this evening I will either be watching the radar and beating my head against the wall or else congratulating myself on my good fortune for not going.

But I’ll also be packing my gear in preparation for tomorrow, and later tonight I’ll be hitting the road with Bill and Tom. I’m uncertain what Sunday holds, but last I looked, the dryline by the Kansas-Nebraska border looked like a possibility on both the NAM and GFS. The weak link seems to be the dewpoint depression; it’s wider than one could hope for, suggesting, as the SPC mentions in its Day 2 Outlook, higher LCLs. I haven’t gone more in depth. We’ll look at the model runs again tonight and pick a preliminary target for tomorrow.

Confirmation: A Richie Cole Alto Sax Solo Transcription

I am not the world’s most accomplished jazz solo transcriber, but every time I tackle a project, I discover anew just how beneficial the discipline of transcribing jazz solos is. This latest transcription has kicked my butt. Richie Cole is–to put it in words you’ll rarely hear from a sedate, late-middle-aged Germanic male–one bad mofo on the alto sax. He has carved his niche as a bastion of bebop, and as such, his language is largely accessible. However, Richie has a way of interpolating material that requires serious effort to figure out exactly what the heck he’s doing.

So it is with his rendition here of the Charlie Parker standard “Confirmation.” Some of Richie’s rhythms and trills caused me to sweat blood for hours trying to at least approximate in a measure or two ideas that flew glibly from the man’s horn in the matter of a second.

The solo is transcribed from Richie’s 2007 CD The Man with the Horn. A quintessential bebop tune, “Confirmation” rips along at 246 beats per minute, providing Richie with a perfect vehicle to demonstrate his formidable chops and his broad bop vocabulary. Anyone who wants to gain mastery of Bird changes will profit from working on this one.

Note: I transcribed Richie’s solo for Eb instruments, specifically the alto sax. I haven’t attempted to show all of Richie’s slurs and nuances, just a few that I felt needed to be indicated. To get a real feel for his articulation, you’ll need to listen to the recording.