Cyclone Road

CHASE BLOG

Friday, April 29, 2005


Scott Currens and I buzzed around east central and eastern Arkansas looking for the warm sector, the outflow boundary, the warm front, or anything that could help us lift some parcels in our cool, cloud-covered Arkansas target area east and southeast of Little Rock. We're still not sure why storms fired where they did around Pine Bluff, but we suspect that the earliest returns were associated with the cloud deck. They took off after that but were never very impressive, little more than semi-organized showers with a surprising amount of lightning. We saw no features of interest and I never touched a camera.

We broke off around 0z and had dinner in Helena, on the Mississippi.

I considered beginning a longer chase trip with today, but since I'm having some a vehicle issue and the pattern looks weak at best for next week, I'm heading back to Indiana until the Great Canadian Pinwheel buys a calendar and gets out of our lives.

In Scott's defense, he was headed for Ohio to visit family and was chasing on the way.


I think we have instability questions in Arkansas this morning. Obviously there's lots of clouds between the blowoff from the convection north of I-40 and the lighter coverage in the southern half of the state which does not appear to be dissolving and might be increasing ahead of the lead shortwave. Warm front is still well south which isn't unexpected, but so are the dewpoints, as a result of the upper energy being weaker and slower, and 850 mb being very lackluster and veered for the last several hours. All that can change in a hurry of course, but the boundary is sagging south and I'm thinking it will gain speed from the cold pool generated by the extensive convection up there.

All this serves to push our warm sector further and further south, so that now I'm hoping we can develop something in the area from LIT to Helena to Arkansas City. I don't know jack about that terrain, but I have heard there are pine forests somewhere down there in southern Arkansas.

Hopefully this surface low will get moving--it's been in north Texas now long enough to have taken on the scent of the Mighty Curse. We need it to put some vigor in our southerly flow, move the front, and make some kind of stand against the sagging cold air.

It's very early in the day, obviously, so a lot can change, but I feel like the tornado potential has decreased and the possibility of the cap holding for anywhere other than directly on the boundary is higher. With such a sharp temperature gradient, I'm less certain how beneficial that front will be if storms move immediately north into significantly cooler air. Hopefully it will stall and we'll see more diffusion there.

I'm still in Forrest City and will remain here a little while, conserving gas and making the most of a high speed connection. By 10:00 AM or so, I might cruise down 40 towards LIT and maybe drop south to Stuttgart, which looks to have some fair road options.


Chasers are insane, as you can tell from the last several days blogs. If you don't believe it, try this on for size: I'm in Forrest City, Arkansas (do they mispell it intentionally?) preparing to chase tomorrow in the eastern strip of the state where there are allegedly pastoral stretches of chaseable farmland and pristine tornado hunting grounds. I'm luck to have the chance to chase with a few folks who know the place.

Since I have to go to sleep right now, I'll copy what I posted to Stormtrack moments ago:

"I still have hopes for this setup and believe it will produce a few tornado reports and a large number of wind and hail reports as well.

I agree with Rich that the slower, weaker shortwave is a great help in our case, allowing more time for the warm sector to juice up and destabilize (though the part that counts is really only the swath of chaseable turf on the eastern side of the state), and reducing the massive forcing we saw in earlier runs that had us all guessing about how quickly we'd transition to linear. I think that because of the less vigorous kinematics, stronger cap, and some indication of subsidence aloft (sometimes a bad thing, sometimes just what you need!), that we have a much higher chance of discrete convection for more than the two hours I was hoping for earlier. On top of that, our storm motions have slowed a little, which means the storms could potentially fire, mature, and produce tornadoes before they leave the eastern seaboard of the CONUS. :-)

I like the I-40 corridor from Little Rock to West Memphis, and fifty miles either side of that line.

Anyway, the warm front tomorrow is progged further south, and winds in and around it remain backed longer than on previous runs yielding 0-1k ambient SRH values over 300 m2/s2 in areas where one could reasonably argue storms might reach. 3k SRH is even higher, around 350 m2/s2, a nice signal that supercells could be the favored mode for longer than expected. We weren't looking at those sort of values before because of the speed and strength of the various features aloft and surface.

There's all sorts of downside potential, too, like cloud cover associated with an advancing 850mb warm front that outpaces the surface boundary, as pointed out by a friend of mine, the Mexican smoke Rich mentioned, or the simple unraveling of the whole show if the shortwave comes out even slower and weaker than the 0z NAM depicts. Who knows?

But it seems that tornadoes aren't always about bombogenesis and negative tilt crashing shortwaves with MDT risks and dancing bears. I think there' s a chance again early next week that we could see more setups where a subtle balance of ingredients yields chaser joy in small doses."

Wednesday, April 27, 2005


Friday looks pretty good in marginal terrain. I know eastern Arkansas is fair, and people are saying the Missouri bootheel is quite flat, too.

Storm motions transition from ~30 knots around 18z to over 50 knots by 0z as the sfc low zips off to the Ohio River Valley, courtesy of the Great Canadian Pinwheel that has brought winter back like some bad 70's retro tie-die t-shirt.

I think the mode will transition to linear around 22z, depending on the true speed of the system. With this system, because of the overall pattern, I don't think the model is too fast as I normally would. However between 18-21z, as the warm front is lifting into N Arkansas and the MO bootheel, co-located with ~2000 j/kg and 250 m2/s2 0-1k SRH and 60 knots of deep layer shear, I think supercells and tornadoes appear likely.

The warm front provides some basis on which to choose a target. It's conceivable to position such that you observe storms as they approach and cross the front, so that in a way you're not chasing storms as much as the boundary.

The Missouri bootheel is 300 miles from me, which means a one day chase if I wanted. It doesn't have to be the start of my vacation, so it makes more sense--if any of this makes sense at all. Since I'm already ready to chase for a month, I'm pretty well ready to chase one day, too. I'll see what it looks like tomorrow.

Tuesday, April 26, 2005


DECLARATION OF INDEPENDENCE FROM COMPUTER FORECAST MODELS

Since my last school-related function on Saturday night, I've spent a ridiculous amount of time scrutinizing computer forecast models and I have to reign it in. I composed some guidelines for myself that should help alleviate SDS at its very worst--right before a big chasing trip--and help me reclaim my life between now and whenever I actually begin the journey into Tornado Alley.

1. No more GFS. One of my favorite things about the 2003 and especially 2004 chase seasons was that there was no time or cause to scan the medium-range progs. You had a chase right in front of you daily, and tomorrow would take care of itself, not to mention next week. It's a great stress reducer to limit the number of setups you're analyzing simultaneously. To ease the transition, I'll look a little more at the UKMET and ECMWF.

2. Check the NAM at specific times only. I plan to spend thirty to forty-five minutes looking over things between 11:00 PM and midnight, then write something up after that. Probably the same routine in the mornings, though I'd like to eliminate that entirely. I suppose I could look at the GFS only as far as its available between these times, but I won't keep myself awake until 1:30 AM waiting on the magical 264 hour solution.

3. Wait for my pitch. I'll go chasing when the NAM shows a system that has a 5% to 7.5% chance of producing tornadoes along or west of the I-35 corridor. Until then, I'm going to live a normal life.


Friday shows some signs of life on the new NAM runs this morning with a newly revitalized shortwave moving from the plains into the lower Mississippi Valley during the day.



Strong instability and favorable low level shear is forecast ahead of a deep surface low moving through Missouri and near western Illinois by 0Z. Northeast Arkansas, southeastern Missouri, and perhaps even southern Illinois (where 0-1k SRH is off the chart) become areas of interest, but these places suck for chasing. When you start a long chase trip in this sort of wooded terrain, it's a sign of desperation. I'm trying to keep my cool since this is April and a favorable pattern is in the cards for later in May.


After tonight's NAM and GFS, I'm as pessimistic about chasing for next weekend as ever. The problem is that as the "Great Lakes Cyclone" retrogrades north and then west, into east-central Canada and then central Canada, a vigorous shortwave separates from the main circulation and slings out over New England between 72 and 84 hours. This is such a powerful feature that it actually veers the low level wind fields (850 and below) all the way down to Texas, exhibiting a powerful influence on weather patterns across the eastern CONUS.

The perfect display is at 48 hours, when 850 winds in the plains back to a southerly orientation temporarily, only to fall back under the northeastern influence immediately afterwards and veer like mad. This has dire results for the orientation of the instability progged to work into the plains, and, on the best looking setup--Thursday--a double-barrel surface low forms, caught between the competition of a strong jet nosing into the plains on zonal flow aloft, and that damn New England storm.

My feeling is that I should wait until we work out from under that feature, since the longer range output is still positive, with persistent height falls associated with a southwestern US trough in the 180-224 hour range. This has shown up for so many runs now that I've lost count.

I'm not thrilled about this as I've made all the arrangements to leave for chasing sooner rather than later, and now it looks like I'll be standing down for a few days at least.

Monday, April 25, 2005


I have serious concerns about the weekend system I had projected for the kickoff of my chase trip. In the last few GFS runs, timing became an issue, with the main shortwave energy moving through the plains overnight on Friday and the backside of the system crossing I-35 on Saturday with terrible shear profiles and what looked more like an Illinois setup than Texas. Now the timing is still off and the orientation of the system is in doubt as well. At 132 hours on today's 12z run, the GFS shows a positive tilt axis to the shortwave, with wind fields below that level extremely veered, and a cold front sweeping through the warm sector.

Like I've said before, you can't take GFS solutions too literally, but as they grow closer--particularly when they cross what seems to be a "magic" line of around 144 hours--you can begin to think about the details, and the details here are troubling. Since there isn't much behind this system for a few days, I have to admit the possibilty of delaying a few days or even a week, though I continue to prepare for chasing this weekend.

Friday, April 22, 2005


Since my last post I nearly went chasing, then went back to bed instead. Ha! I nearly left extremely early Thursday morning for the action in eastern Kansas, but after my alarm went off at 4:30 AM, I thought about the long drive and the marginal setup, plus my extended chase trip coming up very soon, and went back to sleep. Turned out well since I was offered a quick opportunity to sell tornado video, and would not have been home to assemble the package otherwise.

As for the chase itself, my friends Shane Adams and JR Henley scored near Chanute in southeast Kansas. A few of their initial photos are here.

My days are relaxed right now, reading a little, cleaning up around the apartment, and trying to spend time with people who I won't see again once I leave for chasing in May and they leave Bloomington for good while I'm gone. The third-year readings are a fine ritual of closure for the group and I'm glad that the weather isn't interfering with my attendance. I have very few chase-related tasks outstanding. I need to learn to adjust the white balance on my new camcorder and learn (for the third year in a row) how to scan certain frequency ranges on my 2 meter to help find spotters on the radio.

As for the big chase trip, I'm watching the long range models like a hawk, including the operational GFS, the NMC ensembles, and any applicable European models. They continue to show a potentially active pattern in the first week of May with generally southwesterly flow aloft in a strong southern branch of the jet stream over the southern plains. So I expect to head out sometime in the next ten days, as the short-term situation clarifies.

I also added a few new images to the April 11th page, some video grabs of the large meso Mike Hollingshead and I pursued in eastern Washington County, KS on Monday.

Wednesday, April 20, 2005


I've been glued to my seat since 10:00 AM watching the setup on the western high plains, which is a lazy and pathetic thing to do when the weather outside is so nice. So after this brief entry, I'm headed out to run errands and enjoy the day.

Some practice forecasting in Stormtrack today was fun, re-familiarizing myself with some sites and incorporating new ones via newly well-connected friends. I'm anxious to get out and chase, but there's a lot of questions about when that will happen.

The GFS continues to trend favorably for early May, but the patterns are inconsistent, with sweeping upper lows that drive fronts through the plains and wipe out moisture. I'd like to see a stable pattern of westerlies aloft with strong flow over the southern plains before I head out. At the moment I don't have a projected departure date, since gas is high and I don't want to leave for the sake of leaving. I think chasing June will pay rich dividends this year and I want to be patient.

I posted a report page for April 11th, though there's no new imagery that wasn't on the blog entry for that chase. I'll capture the video tonight or tomorrow and post some grabs.

Monday, April 18, 2005


My pal Tony Laubach makes a fine argument for Colorado on Wednesday which I buy into completely. If I was already out on my vacation, I'd be all over the Front Range and DCVZ, my second favorite chase turf behind the panhandle. Eastern Colorado has the upper level support other areas are missing, and it has the golden touch of elevation and orographic lifting. I suspect Tony will have some great looking photos come Thursday morning.

But with only 12 days (12 days!!) before my May-cation, it's hard to plan another out-and-back excursion into the plains. They are exhausting, expensive, and mileage-intensive trips. If this were April 26th or later, I would be tempted to start my vacation early, though that could jeapordize June. What a weird liminal space--caught so close to my chase trip that I can't justify chasing.

Some will argue for the central plains where CAPE is impressive and I don't discount them because it is not impossible for tornadic storms to occur in weak shear environments when high CAPE is present. But I'm always suspicious of what I call "exception-based forecasting," where the argument begins with, "Well, remember that one time there was a wedge with only 100 j/kg SBCAPE and 500mb winds of 4 knots??!!" Obviously I'm making a silly example, but as a disciple of climatology, this kind of logic is like nails on a chalkboard to me, since the irresistible rejoinder is, "Yeah, and remember the 1000000 times that NOTHING happened under those conditions?"

I'm so suspicious of this kind of wishcast that as soon as somebody asks me to recall a specific event, I begin to question the setup. In atmospheric science, it seems to me, anecdotal evidence is particularly unimpressive, since in such a wildly complicated system so many variations and outcomes are possible. In other words, you can find an anecdote to support almost anything, and if that's what you're doing then there must be some major flaws with the setup you're trying to promote.

A studied and analytical approach to forecasting remains vigilant against outlier histories and does not give them more than their due, in my opinion. So I say things such as 'yes it's certainly possible,' and nod and smile politely. And there could be an angry unicorn on the dark side of the moon, too.

All that is to say I think tornadoes are possible where the CAPE max is both Tuesday and Wednesday, but I can't drive 1000 miles in hopes that another exception to baseline tornado climatology will occur, or that the models are wrong (more likely). I have to wait, only another handful of days.

Sunday, April 17, 2005


Jon Davies has just posted a brilliant case study on the April 10th cold core event. This is essential reading.


I surived last night's reading, post-reading boozefest, and the hangover this morning and afternoon well enough to complete the first of the chase reports for last weekend. Here's April 10, 2005.

I don't know what I think about chasing next week. I feel like I've been out of touch for a few days but I ran a GFS loop earlier and can't say I was overly impressed. I like to see anvil level storm relative winds at or above thirty knots, and the setups next week have weakeness at h5. I believe this could be underforecast as some have mentioned, but I'd like to see the system come ashore so we can sample the real thing before I make a decision. At this point I don't have plans to chase this week.

Saturday, April 16, 2005


Tonight is the MFA third-year student formal reading, and I'm practicing an excerpt from my novel over and over, taking breaks to examine the new GFS for next week's potential.

I don't like the trend on the last two runs, taking the system much more north and weakening it considerably. Low level wind fields become very weak and messy, and messy isn't attractive right now with my full chase vacation about two weeks away. I would much prefer not to chase, in fact, until I leave for May, since these long drives to and from the plains are expensive and inefficient.

Unless we have a real powerhouse setup move ashore, or next week's setup shapes up more promisingly, I'll likely stay put.

Friday, April 15, 2005


I bullrushed my thesis approval process, staked out various professors of English and secured all three signatures in 24 hours. I printed three copies of my thesis on the 100% cotton rag bond paper they require, then brought it to the bindery along with an extra $20 bill so they would deliver copies to the Graduate School and the English Department on my behalf. What all this means is that after Saturday's formal reading, I'm done here. And from the looks of the medium range forecast models, it'll be in just the nick of time.

The 12z NAM and last night's GFS both forecast the split flow pattern over the CONUS to merge beginning early next week in a pattern that could make for several days of highly productive chasing. The key to this pattern is the lack of a single, high-amplitude system that crashes through and drags a front across the boundary layer; instead we have a progressive series of smaller waves that kick off storms but leave moisture fields intact so that we can wake up the next day and do it all over again. Some of us call this the "rinse and repeat" pattern, and one of the best places on Planet Earth to experience this is the Texas Caprock, which looks like a prime candidate for serious supercell action next week.

You may remember the caprock is an elevated section of very flat land, also known as the Llano Estacado, that stretches across Texas and New Mexico and acts as an orographic lifting mechanism for storm initiation. Because of the elevation--some areas of the caprock are above 4000 feet!--you don't require the 70F isodrosotherm to hug the eastern boundary of the dryline. This is similar to how eastern Colorado can see supercells and tornadoes with dewpoints in the lower 60s. Also, some forecasters believe that the canyons east of the escarpment may channel inflow and increase values of storm relative helicity to storms moving out over the plains, but this is highly theoretical.

For next week, the GFS shows a dryline making camp on the Texas/New Mexico border and daily mixing east into increasingly deeper moisture. This pattern begins on Monday and lasts through the week. With consistent southeasterly flow up onto the caprock, and westerly midlevel support for storm ventilation, this is the best setup for supercells in the Texas Panhandle that I have seen since mid-May 2003. Of course it's several days away and subject to radical change or complete disappearance, as we have seen so often before. But I'm not as interested in the details (what happens on which day) as I am in the trend and the pattern suggestion.

The NAM this morning begins reflecting the GFS with fair agreement, placing the first strong wave over eastern Oregon and preparing to swing it down across the Rockies. Since I was able to expedite my school obligations, I should have the chance to chase this system.

Wednesday, April 13, 2005


I should have both chase reports completed by the end of the weekend. For the next few days, I'll be scrambling to collect signatures from my thesis committee members, and generating the materials to deliver my thesis to the bindery by Friday. The bureaucracy in my path is as thick as the Mexican smoke in 1998, so chasing and chase-related activity drops to the bottom of the priority list and right off the chart for two weeks. My blog updates will be short and infrequent until then, picking back up as I finish here.

I still don't know for certain what day in May I'll leave to chase, sometime between the 1st and 9th, probably closer to the 9th. GFS shows nothing of interest for the next week, thank God.

My pal Tony Laubach has a cool picture of my truck on his blog, taken from the ABC-Denver clip that ran featuring his video. Tony had a great chase day on Sunday as well.

I'll update when I post those new reports.

Tuesday, April 12, 2005


I was minding my own business on the way home to Indiana when all of a sudden.... No, not really. I had all the gear running and ready and was happy to see a field of vertical three o’clock cu in east central Kansas along Interstate 70 by 17z. Today’s setup looked like a slimmed-down and trimmed-back version of yesterday, a little less instability, a little less shear, weaker and backed midlevel flow, but with the same steep lapse rates and enough low-level shear and sufficient LCLs to make it another interesting day. I found a great long-lived storm, the Washington County supercell, which produced an ominous, vacuum-cleaner style rotating updraft base and later unleashed the single most bizarre and unexpected thing that has ever happened to me while chasing.

I’ve included some rough images processed in fifteen minutes—some of the best stuff, including the carousel meso, will have to wait for video capture and grabs.


East of Washington, Kansas April 11, 2005

Early in the day, I spotted an area of persistent towers northwest of Manhattan, and this became the Washington County storm. It produced several sustained wall clouds with varying degrees of rotation and finally organized itself dramatically between Greenleaf and Washington, Kansas, just south of state highway 36. Mike Hollingshead and I observed this storm as it snagged a boundary—either outflow or what I analyzed as a pseudo warm front in this approximate area—and anchored itself stubbornly, with an aborted split (with precip blowing northwest onto the newborn updraft, it didn’t have much of a chance), and propagation both to the south and the southeast. The southeast updraft grew dominant and Mike and I flanked it east, and observed the very low, carousel style updraft. The feature was composed of white condensation with tendrils that articulated the circulation. We were convinced it would tornado immediately. We perched on a hill and watched the storm wrap up again—the circulation tightened to an extremely rapid motion. I was stunned that there was nothing beneath. I haven’t seen that kind of rotation from such a low feature without a tornado beneath it. This was almost due east of Washington, but I’m uncertain about the time and will have to verify with my video. Perhaps around 21z.



We chased this storm and its various moving parts across the Nebraska border toward Odell, where we met up with Jonathan Garner and his chase partner. For some time, our storm had served as the intersection for a line of convection stretching to the northeast along the cold front, and to the southeast along the not-so-dryline advancing from the southwest. As this angle closed, convection approached from all sides. Our storm had no hope of uncontaminated inflow and we determined as well that we were nearly in the center of the surface low. XM streamlines confirmed this.

We stood outside our vehicles on a muddy dirt road, heads moving in all directions as the cloud motions were turbulent and quick areas of rotation appeared and disappeared. Our winds were light and northerly, then they calmed. Then they swung around out of the east, and then from the south, a little warmer than before. The next moment, in field of tall and bright green vegetation about thirty yards away, a flattened circle appeared that reminded me instantly of the crop circle hoax in the UK. The only difference was that this circle was rotating vigorously and racing toward us. I pointed and yelled “What the hell is that?” But it was on us before anybody could take a guess.

Mike turned and held his open car door, both to keep it from ripping off and to keep his feet on the ground. I crouched and turned away, gripping the side of my 4Runner with one hand and shielding my face with the other, as the winds blasted us with gravel and sand and tried to take us off our feet. It was amazing! When the circulation passed, a hard driving burst of precipitation came straight down on us for about fifteen seconds. We estimated the wind speeds in the circulation at between seventy and eighty knots. Mike reported a sense of weightlessness during the event. I’m convinced that if the vegetation in the field had been dead, it would have remained flattened.

Nobody mentioned having seen circulation in the cloud base overhead preceding the event. However, I don’t know that I was looking up there anymore than I was looking elsewhere—it was a ragged, cold air storm base the likes of which we’ve all seen. It was so benign in appearance that none of us even had our cameras out, let alone recording at the time. However, the sequence of the wind shift and the immediate precip is fascinating to consider. Was this a very weak tornado? I don’t know; I’m not trying to begin a debate. It was a vigorous circulation on the ground, that much I can say with confidence.

Soon the storms congealed into a large mess and we broke off the chase. It was great to see Mike again and I was glad to meet Jon and his chase partner. I thought I was in Nebraska too early last year—wow. It’s April and there I was again. A fun and unusual chase to cap off a happy three-day plains trip, starting with the cool get-together at the Vista in Norman, followed by one of the best chases of my life in Kansas on Sunday, and ending with a close encounter of the rotational kind in a south Nebraska field. 2005 is off to a great start.


South of St. Joseph, MO on my way home

Sunday, April 10, 2005



Tornado south of Ogallah, Kansas April 10, 2005

We observed five tornadoes this afternoon and early evening on several supercells of different types, from an early cold-core, low-topped cell to more classic supercells firing along the dryline bulge. All times and locations are approximate until I can review footage and GPS logs, probably a day or two from now. Things were hectic and I shot more video than stills, but will take a few minutes to put up an unpolished still image, albeit with some hail streaks in the shot. I’ll post video grabs in a few days.

Our first tornado of the day was very small on a cell in extreme northwest Scott County around 1:30 or 2:00 PM. These storms fired as instability wrapped around the surface low and the dryline bulge began to impinge on the marginally unstable air. Easterly surface flow most likely contributed to steep low level shear as our Wx-Worx did not indicate any shear at the time of the first tornado. We observed a very small, but identifiable supercell on regular reflectivity (via GRLevel 3) about twenty minutes prior to that initial tornado.

We hurried east as storms fired along the dryline sloping back to the southeast and south, continuing to pursue cells in Lane and Ness counties. Our next tornado was remarkable in that the circulation first became evident over water. We were crossing the dam on the eastern edge of the Cedar Bluff Reservoir in southeast Trego County when a low-hanging wall cloud produced a visible and violent rotation on the surface of the small lake. This was amazing as we had just joked about how the turnoff from the dam would be a perfect location for our storm to produce a picturesque tornado. Unfortunately, the entire funnel did not fill in, but the storm was only getting started. We observed another tornado shortly thereafter, a tall white cone that swirled tumbleweeds on ground and kicked up black dirt. This was south of Ogallah, Kansas by about six miles, but I will have to check video for the timestamp.

At this point we realized that many of these storms were advancing north and interacting with some boundary draped west to east---perhaps an outflow boundary from earlier convection, and dropping tornadoes while simultaneously slowing down. Surface winds along this feature were due east into the storms. Even storms which ingested inflow coming through the downstream precipitation of the storms to the south or southeast seemed to strengthen and rotate much more violently when interacting with this boundary. Once they moved north and into the cooler air, they weakened.

Our fourth tornado was a dark, tall stovepipe, the best-looking and longest-lived tornado of the day, which stayed on the ground for probably five to seven minutes and went through several graceful mutations, with a sleek funnel to the ground and a roiling debris curtain at the base. This was about three miles south of Ogallah on State Road 147. Again, I may have to correct some of the locations in later updates to this report. I’m basing this off a GPS logfile I’m running quickly and trying to match tornadoes with location where we’re stopped.

By now we understood the magic of the boundary and hurried to get south for the supercell then entering Hays, Kansas. There was another storm to the southeast of that, and a third even, which we called the “Great Bend” storm. Eventually, the second storm in this train would produce another tornado, which we did not see, near Interstate 70 about one mile west of Russell. At last we reached Russell and raced north on 281 in time to see our final tornado, another tall stovepipe, about six miles north of Russell. That would be the last productive storm of the day for us, and we retired to Salina and dinner at Spangler’s along I-135.

I want to thank Eric Nguyen and Scott Currens for a remarkable forecast that included playing extremely close to the low early in the setup and assuming there would be enough time to move out ahead of the dryline for the more conventional, classic supercells. There was, and both areas produced for us. I want to thank the outflow boundary without which I don’t know that anything but that first low-topped storm would have produced. As well, there is no question that chasing a day like this without some form of uninterrupted data would be very difficult or impossible. Many things came together perfectly for the best April chase of my life. It was fun as hell.

Saturday, April 09, 2005


Barring a drastic change in conditions tomorrow, I'll likely join Eric and Scott in the playing the low and then the dryline bulge in Kansas. I have worries about both targets north and south, but north is closer to the next day and finally Indiana. I like the vorticity and backed surface flow, and I think moisture is going to be fine in Kansas. Dewpoints have been sneaking up through Missouri and into Kansas all day. I don't like southerly midlevel flow and I don't trust instability to accompany the later supercells up the boundary into the central sections of the state.

I think the Texas target is a good one, too, but it has some worries with the potential for veered surface flow and late initiation waiting until the strongest forcing arrives and increasing the chance for a quick squall line.

I was headed for Enid but turned around and came to Woodward instead. Makes sense if I'm headed toward Liberal tomorrow.

Good luck, everybody!


If there was ever a setup that can't afford for
anything to go wrong, it's today--and things are
already going wrong.

The low in Colorado has divided, sort of, with a
secondary low further east than projected which is
backing the winds around Woodward. Too bad, because
the dewpoints were getting interesting up there. SPC
Meso site showed Alva at 59F dp last hour, though the
mesonet never showed that.

However, the new surface trough structure creates kink
currently in southwest Oklahoma that should move north
as these lows consolidate (with hopefully the
westernmost sfc low in colorado ingesting the
secondary low), and so I expect a new area of moisture
pooling to develop along this bend in the pressure
fields.

I'm stopped at the intersection of I-40 and 270
waiting for a while to see how this plays out. I'm
very conscious of not wasting gas, since I want to
chase both of the next two days also. Still, when I
made it west of El Reno, where the landscape really
opens up, I had a chill. There's no place like the
plains and that sensation alone was worth the small
amount of gas I expect to use for the rest of today.


I found myself in Norman, Oklahoma last night in time to make the Vista Sports Bar where several chasers had already planned a get-together. I'd never seen the famed hangout on the sixth floor downtown and called Eric to meet me there with Shane, Jo, Chad, Gabe Garfield, JR Henley and his wife, Aaron and his wife, and a several other folks I hadn't met before. Sorry if I'm leaving anyone out--didn't get all the names.

Today I find myself in an unusual situation where tomorrow's target is influenced by possibilities both on Monday and even today. Normally I like to chase one day at a time and "chase the storm you're on," which is our way of saying sufficient unto the day is the evil thereof. However, if you chase in Seymour, Texas on Sunday, you're not going to make the surface low setup in northern Kansas on Monday unless you huff it all night, as we did the night before May 4, 2003--and I doubt the journey is anymore fun now than it was then. Not to mention that none of these setups are worth breaking one's neck over. But let me put tomorrow and Monday aside for a moment and talk about today.

Today is a bust waiting to happen. Today is dry, capped, with only modest convergence along the dryline and nothing spectacular aloft. However, there is the smallest chance that a single storm could fire on the dryline, and evidence already this morning that the models are underforecasting dewpoints in a developing area of moisture convergence in the northwestern areas of the state, between Woodward and Enid, for example. There is also a persistent band of high level cloudiness up there which is casting a relatively stable shadow in that same area, creating the possibility of a thermal gradient of some sort along the surface. This is all highly speculative. The cap, again, is very strong, and not likely to break.

However, if it did, the storm would almost instantly be supercellular and isolated, albeit high-based. Therefore the SPC dedicated a full paragraph to the area they didn't even outlook for slight, and the Norman Hazardous Weather Outlook describes the setup extensively. This is what we mean by a highly conditional chance of storms. Storms are unlikely--very unlikely--but if one formed, it would certainly be severe. Seeing the pooling moisture, the possible baroclinicity at the surface underneath the cloud band, combined with northwest Oklahoma's proximity to a favored target region for tomorrow near the low, compels me to amble up toward Taloga and Woodward, and work on my tan.

I'm in Moore, Oklahoma currently and plan to leave within an hour for higher dewpoints.

Thursday, April 07, 2005


Tonight's ETA shows a stronger system more negatively tilted and reflecting much more defined wind fields and improved moisture parameters for Sunday. Even Saturday looks better though it still appears to be far too capped and dry for serious consideration.

Anyway, it's enough for me to see a trend like this, so I'll leave bright and early for Oklahoma to have position for chasing Saturday or to visit friends in north Texas (probably the latter), then for the big show Sunday, and what may be quite a followup in the Midwest on Monday. We'll see how it plays out.

Probably no morning update from me as I'll hope to be on the road by 8:00 AM.


AFD from Tulsa released a short while ago: "LOOKING AHEAD INTO SUNDAY...SEVERE WEATHER APPEARS MORE LIKELY AS MODELS REMAIN CONSISTENT IN SHIFTING STRONG UPPER LOW INTO THE TEXAS PANHANDLE BY SUNDAY AFTERNOON. SYSTEM LOOKS VERY SIMILAR TO LAST SEVERE EVENT WITH PLACEMENT OF UPPER LOW AND JET DYNAMICS. WILL DISCUSS FURTHER IN HWO EXTENDED CONCERNING TIMING...ETC."


I got nuthin'. This morning's NAM and GFS bode poorly for Saturday's already-dim prospects of elevated storms out west, though at least the SPC Day 3 showed a 5% chance of something out on the high plains after 0Z perhaps. I suspect they will drop that entirely if the evening runs confirm the meager moisture and lack of low-level definition. Saturday looks completely benign.

Sunday's solutions just posted for 12z GFS and it looks like a carbon copy of the last system which resulted in a squall line ahead of the boundary and some cold-core tornadoes behind the low. Very frustrating to once again find myself again having to make a decision sooner than would be optimal given the character of this system and the moisture questions. I don't feel good about this morning's runs as a justification for spending $200 in three days. On the bright side, the system is only now coming ashore and tonight's runs (and the morning's) should have a superior handle on the nature of the storm.

I'll go about my day and wait for the local offices to post their afternoon AFDs. I'm reading Herzog by the great American novelist Saul Bellow, who passed away a few days ago and whose death was overshadowed somewhat by coverage of Pope John Paul II.

Wednesday, April 06, 2005


I feel like a kid with chicken pox looking out the window while my friends play baseball in the empty lot next door. Several chasers I know had fun times yesterday with storms in Kansas, Oklahoma, and Texas, several of which were tornado-warned in all three states, though only a few seemed to produce and most of those were the cold core storms well west of the dryline beneath the upper level low. This is an interesting phenomena that Jon Davies has written about extensively and his work is well worth your time to examine.

Interestingly enough, many experts believed that yesterday was not a classic cold-core tornado day, yet there were multiple reports and the Dodge City National Weather Service office did an excellent job anticipating this and warning their area.

My target region nearly verified as the tornado report from Bartlesville in Washington County, Oklahoma is about thirty minutes north of Tulsa. Several storms within the Tulsa to McAlester axis earned tornado warnings, but as far as I know this was the only visual confirmation. According to the LSR, the tornado crossed highway 75 south of Bartlesville.

As I write this, a tornado event is underway in the southern tier of the United States with reports of deaths, injuries, and major damage from multiple tornadoes currently rampaging through Louisiana, Mississippi, and Alabama. Those areas are so heavily-forested and generally unaccustomed to significant tornadoes that violence such as they're witnessing today is always devastating. Let's hope they have some relief very soon.

My chase plans are coming together for the weekend. Saturday looks very dry, but if Sunday shows strong potential, then I'll leave Friday for a possible "event before the event" chase with a slim prospect of sculpted LPs perhaps in Kansas. This is similar to March 26 of last year when I enjoyed small storms on the caprock in relative isolation. Could be quite a contrast this year since if Sunday is an obvious event, most Alley chasers will make their first excursion of the season. Standing room only, I would expect. Once again, we'll see how it plays out on the models.

Tuesday, April 05, 2005


My friend Tony Laubach suffered some engine problems in Kansas very early this morning preparing for today's chase, so here's sending out some positive engine vibes to Tony and his chase partner Verne Carlson today. Since its an alternator, the guys should have no trouble recovering from the setback in time for today's storms in Kansas.

While I still prefer areas of eastern Oklahoma, from Tulsa to McAlester, for tornado chances, I think there are tornado possibilities under the upper low as well--and strong chances for some amazingly photogenic updrafts and supercells. I'm looking forward to their imagery.

My sights have turned to the weekend in Texas. The GFS has shown chase opportunities for Saturday, Sunday, and even Monday for several runs in a row--and this sounds like exactly what I'm looking for, multiple chase days in favorable terrain, so I am planning as if I'm headed for the lone star state either Thursday or Friday.

Monday, April 04, 2005


Okay, new Day 2 was slow of course, and I'm starving! Anyway, the latest outlook confirms my thinking about the minimal tornado threat in the area I was examining, and I'll now stand-down and start the process all over again for....SATURDAY! LOL.

Yes, that's right, another system coming up this weekend looks much more westerly than anything we've dealt with so far, and the last three GFS runs in a row have shown some potential for storms in or near the Texas Panhandle region.

Back to the drawing board.


Very briefly: the ETA this morning and last night's GFS have finally drank the Kool-Aid regarding a slower, more southerly track for the system. This is good news for chasers, keeping the surface low in the southern plains and offering at least initiation in chaseable terrain from southeast to south central Kansas into north central and northeast Oklahoma, and trailing along the dryline into northeast Texas. From the modest moisture progs and strong wind fields, severe storms appear likely with the tornado threat mitigated by the modified Gulf air. From 36 hours away, it does not appear to be a big tornado day and indeed all offices are pointing to large hail as the primary threat.

I've decided to sit this one out, yet I am packing my things in case the next Day 2 outlook somehow changes my mind. This is not likely. While I think there's a good chance for supercells, I think they will move very rapidly in the area I most prefer--northeast OK around Tulsa--and will grow linear very rapidly. While this would be a blast if I lived in Texas and only had one afternoon to lose, I don't see this storm system worth my three day investment from Indiana.


Despite having their honor impugned by the plains NWS offices conspiring with HPC to prefer the European models today, the US numerical progs refuse to get with the program and continue to show a system a little too fast for my taste. I remember well that on March 21st, the system was also forecast to move too quickly and did not, but the runs we have are all I can go by when I'm this far away and have to decide in the morning.

Best thing to do, I guess, is grab seven hours of sleep and decide by 10:00 AM. I suppose I could be on the road by around noon and make Tulsa by 10:00 PM. I have not made up my mind.

Sunday, April 03, 2005


I mentioned this morning that European models favored a slower and more southerly track. The newest versions of the UKMET and EC continue this trend, and NWSFOs in the plains are preferring this output to our own, homegrown NAM and GFS. See ICT's and OUN's most recent discussions here.

According to the ICT discussion, the NAM initialized poorly this morning, which is interesting although it doesn't explain how the last few runs were similar to the 12z's unless they all got off to a rocky start. But then we remember that it wasn't long ago this looked very much like a west-of-35 show. It may not be west of the interstate, but it might be much further west that it looked on the NAM. It is significant that the FO's are adopting the slower, southerly track and chasers should maintain vigilance.


The NAM and GFS are moving into closer agreement now and their solutions look similar. I can't find the newest runs of the Euro-models but I looked at last night's, both of which look more southerly and somewhat slower. I think it's entirely possible that convection will initiate in eastern Kansas and eastern Oklahoma, but it's impossible to disagree with the SPC SWODY3 that the likely mode would be linear with the strong forcing, very unidirectional wind profiles, and vigorous midlevel cold air advection. So it looks like a squall line at the moment.

Wednesday in Illinois looks like a weaker version of last Wednesday and is of no interest currently.


Reading the models is like eating various kinds of sushi: you have to clean your palette between fish to get the full flavor. With mystical model-reading, you have to purge your mind of what you thought was going to happen and especially what you wanted to happen with the forecast.

In this upcoming system particularly, each run is a new world. Things seem muddled to me--hints and rumors and innuendo abound in this morning's ETA: Iowa might be a player now, or north central Missouri or eastern Arkansas. The dryline is still in eastern Oklahoma at 18z according to the model; who are we to say it won't initiate with plenty of time to chase fair turf in east central sections of the Sooner State? The dryline lags to the southwest in Texas and could remain very near the I-35 corridor until late in the day, with excellent deep layer shear. Or the entire show could slow at the last minute and look exactly like it did 48 hours ago, with the target in western Oklahoma again. Nothing would be too surprising at this point.

I'm going to wait for the GFS (and maybe UKMET and ECMWF, too) before I draw conclusions. So look for another post in a few hours, but the variation has all but shut me down for chasing this one. As I said a few days ago, I have a lot of work this week and needed iron-clad solutions with excellent agreement. This has been anything but.




For the first time ever, I found my website stats module and discovered how many people are reading this blog. I'm amazed--approximately 50% increase in visits each week for the last three weeks. You desperate chasers. Go read a novel!

Saturday, April 02, 2005


Tonight's ETA took the middle ground between its earlier and slower solution and the faster track of the other models including the 18z ETA. But the plot thickens! This run shows the system taking a distinctly negative tilt, which would ordinarily make chasers very happy, but the closed nature of the low and the stacked profile still creates veered flow just above the surface. The fast moving dryline sweeps rapidly across Oklahoma in this run, leaving moisture in its wake. I'm not sure why this happens, really--perhaps it mixes east too quickly? Or it could even be a "double-dryline" structure where an elevated dryline moves across the region first, but that would not sufficiently explain the strange sfc dewpoints in the wake of the boundary.

I don't know. But the weirdness of the model makes me think this is looking more like a sucker trap all the time. At the moment I am undecided--you can't take models too literally, and when we step back and see what we have, it's still a potent shortwave sweeping over a moist and unstable airmass. The details become more important as we get closer. I guess by this time tomorrow night, I will have made up my mind.


There's a lot of disagreement between the models over the timing of Tuesday's storm system. The GFS and ECMWF were much faster than this morning's ETA, although the UKMET agreed with the latter's solution. On the 18z run of ETA, however (I just can't get used to calling it "NAM"), it speeds the system too and looks more like the GFS, which maintains more or less the same pace on its own 18z run as the 12z version. The bottom line is that as of the 18z runs, all the models had hurried the system and put it in what I consider unchaseable areas.

So we can effectively throw out the timing on Tuesday and say that we have to wait for another batch of runs. This makes all the difference in the world because it determines if the most likely area for severe storms is the chaseable regions west of I-35 or the Ozark Mountains and forests of Missouri, two places I have no interest in visiting no matter how appealing the setup. Other chasers feel differently and are willing to try their hands in a variety of terrain.

We'll know a lot more tonight and tomorrow.


There is no longer any question that Tuesday is our next potential chase day in Texas, Oklahoma, or even southern Kansas. Everybody thought the GOM would be too hosed for Tuesday but it looks like three days of high pressure over the basin and a steady fetch are at least going to return modified gulf air in time for this next wave on Tuesday.

I'm not thrilled about what the models do with the orientation of the trough axis during the afternoon, but at 12z Tuesday it looks vigorous enough to do some damage with about 60 knots of deep layer shear above a fairly aggressive dryline mixing east into around 2000 j/kg MLCAPE. This is a dryline even Neal Rasmussen can love (he thinks what we all call dl's are mostly surface troughs), a genuine, west-wind-behind, gradient-from-hell mixin' dryline. No convergence issues here.

My concerns are the nature of the moist layer (too thin given recent GOM FROPA? gets mixed out by veering low-level winds as trough axis goes positive?) and the shear structure evolution given the projected axis reorientation during the day. If this happens even six hours earlier than expected, the setup is probably ruined. On the other hand, if the trough should find additional jet energy to its south and go more negative tilt than progged, it could be an impressive day.

I have to decide Sunday night, essentially, what I'm doing, then leave Monday morning for Tulsa. I have more work this week than last, and the southern plains is a three-day proposal for me. So this setup has got to look iron-clad on the runs tonight, tomorrow morning, and tomorrow night. We'll see!

Friday, April 01, 2005


I removed the link to Brian Stertz's blog and added Ben Prusia's. Brian's blog was not active.

The wave I described for next week amplified and dug much further south on last night's GFS, making it a formidable weather-maker possibility on Tuesday in the southern plains. However, because the change was so sudden and drastic, it has to be viewed with great skepticism until it appears consistently on several runs in a row.

The synoptically-evident tornadofest that had appeared at 276 hours yesterday disappeared, too, so I'm glad I saved the output. Tuesday's chances are much closer--120 hours as of last night--so we can take that a little more seriously. A southern Kansas chase would suit me nicely, though I would have to prepare in advance since I'd leave on Monday. Unfortunately the run last night closes the upper low and tracks it through the southern tier of the CONUS, making this a one-day chase event.

I prefer the two-day shows since I have to invest three days to chase in the plains: one for the drive out, one to chase, and a third on the drive home. I don't pull all-nighters on the road anymore; your ability to do that suddenly ends in your late 20's (unless you find the right crack dealer I guess), as hard as it will be for some of my friends to believe. From age 17 to about 28, I used to ONLY drive overnight when going from Texas to New Orleans to see my parents. I would leave around 10:00 PM and arrive about 7:00 AM the next morning. It was fun. I couldn't do that now if I had to. I wouldn't want to, that's for sure--it's a guaranteed way, at age 35, to feel like hell for about three days.

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