The Cerulean Arc

Tag: storms

  • 19 May 2013 | Oxford-Newkirk-Maple City, Kansas-Oklahoma | Supercells

    19 May 2013 | Oxford-Newkirk-Maple City, Kansas-Oklahoma | Supercells

    The trough that led to the amazing Rozel, Kansas tornadoes on May 18th, 2013 was positioned to support another round of severe weather on the 19th. Dew points were reaching into the upper 60s into eastern Kansas and Oklahoma. With steep mid-level lapse rates, mixed layer cape levels were heading over 3000 J/KG. Ample shear was in place to support supercells. The exit region of an advancing speed max ended up giving further support to strong, widespread convection over eastern Kansas.

    An outflow boundary was positioned just south of the Oklahoma-Kansas border. With the advancing dryline, these two would help focus storm initiation and increased tornado potential along the outflow boundary.

    500 MB
    Synoptic
    Surface Obs/DP
    MLCAPE
    0-6KM Shear
    300MB

    I chose to begin my chase further north in Kansas because I anticipated Oklahoma storms along the boundary would propagate into difficult chase territory and storms further south along the dryline would enter dense urban areas along the I-35 corridor.

    Storms ended up erupting in two clumps: one area from east-central to south-central Kansas, and another pretty much right over the OKC metro area.

    21Z Visible Satellite
    21Z/Oxford Storm
    23Z/Newkirk Storm
    01Z/Maple City Storm
    Video documentary of the chase.
    Thematic spot to park and check data south of Moline, Kansas (1800Z)

    As storms matured, I made my way toward a cell approaching Oxford, Kansas. By the time I was positioned east of Oxford, the storm was HP and had a tornado warning. The look of the storm was incredibly menacing. The forward flank was lofting a ragged, low shelf that had the train-like appearance of an inflow tail as it led into the sealed notch between forward and rear flanks. Positive lightning strikes were landing just ahead of it and casting off fearsome canon-shots of thunder.

    Reflectivity and position near Oxford, Kansas (2133Z)
    Approaching forward flank (2133Z)
    Positive charge lightning strikes ahead of the Oxford HP Supercell.
    The green rear flank rolls northeastward along the heavy forward flank of the Oxford HP Supercell.

    As the green RFD curtain approached, like it was rolling along the gears of the forward flank, I repositioned three miles further east. From this new spot, I witnessed the spectacle of rapid circulation developing in the rain free base just ahead of the FFD/RFD notch as a new RFD seemed to push out, trying to get ahead of the occlusion. The established RFD was moving in quick, so I had to abandon that spot and drive east to stay ahead. So I wasn’t in position to see the tornado that was reported 6 minutes later about 6 miles northeast of that spot.

    Circulation developing in the rain free base just ahead of the Oxford HP Supercell.

    About that time, the Oxford storm started to congeal with others and form into a severe squall line. This convinced me to work my way southward to stay out of the mess and look for opportunities with any isolated storms on the tail end of the squall line. I had some pretty impressive views of the advancing line as I headed south.

    Massive gust front on a congealing squall line from Winfield, Kansas (2158Z)
    Another gaping gust front as seen from 4 miles south of Arkansas City, Kansas (2242Z)
    A brief rope tornado was reported 1 mile north of Arkansas City about 17 minutes later.

    I eventually wound up on an isolated supercell near Newkirk, Oklahoma. I was able to hang out for a half hour in that spot and watch it approach. RFD was working its way into the base and encouraging a slender wall cloud to inhale scud, but it just wasn’t strengthening. I was also concerned about the quality of roads to my east, so I let it go. It picked up a tornado warning not long after.

    Reflectivity and position near Newkirk, Oklahoma (2304Z)
    RFD cuts into the rain free base of a supercell 3 miles north of Newkirk, Oklahoma (2311Z)
    Scud rises into an anemic wall cloud on the Newkirk supercell (2313Z)
    RFD on the Newkirk supercell (2316Z)

    Since new development still seemed likely, I decided to give the farm roads to the east a try. They were a lot better than I thought–pretty rocky actually–so I spent over an hour navigating north and east as I watched a very thin line of convection do pretty much nothing exciting stormwise, but did make for an excellent sunset display.

    Tail end of a line of convection on the Kansas-Oklahoma border (2357Z)

    After finally getting back onto a paved road, back into Kansas, I noticed a severe-warned storm, moving up out of Oklahoma. I tried racing south to get ahead of it, but couldn’t manage it. After it passed, I did get to sift through its wake and picked up hail as large as 3 inches along the roadside about 7 miles east of Maple City, Kansas.

    Collection of large hail (0130Z)
    Three inch hail near Maple City, Kansas (0130Z)
    Three inch hail near Maple City, Kansas (0130Z)
    My first contribution to an SPC storm report.

    So, no tornadoes, but definitely some awesome sights on this chase. The dynamics near Oxford were unforgettable, and even though I missed seeing the tornado, I had an amazing perspective on that storm.

    May 19, 2013 Chase Map
    SPC Storm Reports – May 19, 2013

    Links to more chase accounts from May 19, 2013:

  • 18 May 2013 | Rozel & Sanford, Kansas | Tornadoes

    18 May 2013 | Rozel & Sanford, Kansas | Tornadoes

    This was the third day of a week-long trip to the plains and the first heightened possibility for strong supercells.

    The setup featured a negatively tilted upper level trough over the western US that put southwesterly flow over the plains. This led to the formation of a surface low over southwest Kansas with a dryline draping from the low down through the panhandles. Rich moisture being advected into the area on southeast surface winds brought dewpoints in the mid to upper 60s through the southern and central plains and up to 70 degrees into Kansas. All the moisture and heating coupled with steep lapse rates led to mixed layer cape values in the extreme range from 3 to 4 thousand j/kg.

    500 MB
    Synoptic
    Surface obs/Dew Point
    MLCAPE

    With these conditions in place, agitated cumulus began to develop along the dryline and north of the surface low, and by mid afternoon storms were firing in eastern Colorado and northwest Kansas.

    21Z Visible Satellite

    A shortwave ejecting over the panhandles and Kansas by mid to late afternoon along with strong heating along the dryline helped convection overcome the strong cap and develop further south along the dryline. By 7 to 8 pm, deep layer shear had reached 40 to 50 knots along a corridor from northeast Colorado to west central Kansas. Low level storm relative helicity also ramped up with the strengthening low level jet, reaching 200 m2/sec2. The combination of adequate deep layer shear and storm relative helicity combined with extreme instability led to supercells capable of producing tornadoes.

    500 MB Shortwave Trough
    23Z Satellite
    0-6 km Shear
    0-1 km SRH

    My initial target was the vicinity of Ashland in far south Kansas. After noting where development was occurring along the dryline, I moved up to southwest of Greensburg and waited for convection along this section of the dryline to take off. I followed a cell that finally started to strengthen southeast of Spearville. And it eventually produced two tornadoes near Rozel and Sanford.

    20Z Satellite
    01Z Satellite

    After car camping for the night, south of McCook Nebraska, I made my way south through Kansas, toward my initial target near the Oklahoma border.

    Overnight spot south of McCook, Nebraska — 1300Z

    Along the way, I took advantage of a few photo opportunities. As I drove down one farm road, looking for a secluded spot to brush my teeth, wash my face and do a Clark Kent clothing swap—because I’m Super that way—and I ran across this blaze of yellow flowers beneath a series of wind turbines. It’s hard to capture how striking that was in a photograph, but here you go:

    Turbines and flowers near Cimmaron, Kansas — 1700Z

    Skies were clearing the further south I went, and really priming the atmosphere for storms later in the afternoon. As I cruised along the dryline from Ashland towards Greensburg, towers started going up. And then dying…leaving behind a bunch of sad orphan anvils that were drifting away in disappointment.

    The past couple days, I had been working on being conscious of foreground elements to complement the sky in any photographs. It’s so easy to see this awesome sky and shoot with a bland, flat foreground that you don’t notice how boring it is until later when you’re processing images. So: mailboxes, wind turbines, farmsteads, any given stand of trees…I took them where I could get them. (Doesn’t mean my heat-of-the-moment tornado & funnel photos always benefited from decent composition…see down the page.)

    Convection developing along the dryline — 2052Z

    Finally a cell managed to outwit the cap near Spearville and the chase was on.

    Developing supercell near Spearville — 2205Z

    As I made my way east of Kinsley, the cell started to get rooted into the boundary layer. And now we finally had a nice looking supercell with structure that really started to beef up. It had a bit of the mothership flavor to it. The way I see it, this is a Star Trek (The Next Generation) model dropping down out of the clouds. And because after the J. J. Abrams’ reboot, Federation Starships goof around in the atmosphere these days like it weren’t nothin’ but a thing.

    Panoramas of the supercell near Offerle — 2310Z-2318Z

    I was working the dirt roads as much as possible, which turned out pretty nice as long as I was paralleling the storms. (I didn’t get too comfy with those roads though when things were more inbound.) As I was driving north on 50th Avenue, about 4 miles west of Kinsley, I was surprised to see a little shear funnel up in the vault. It was very persistent and lasted several minutes.

    Shear funnel in the vault — 2326Z

    RFD was making various attempts at nudging into the base when another cell popped up and started encroaching from the south. I wasn’t sure if it was going to wreck the leading cell or which base to focus on. So I split the difference and got a bit behind the lead cell I was originally pacing.

    Cell merger under way – 2345Z

    The lead cell ended up eating the trailing cell, and then it really took off. The RFD started making a major push and digging a deep pocket into the rain free base. Rotation started ramping up behind the clear slot and it was looking pretty imminent.

    Rotating wall cloud south of Rozel, Kansas — 0021Z

    About 5 miles southwest of Rozel, it started winding up a funnel that gradually made its way to the ground and grew into a sturdy, long-lived tornado spinning away behind a remarkably clear RFD slot.

    Developing condensation funnel — 0025Z

    Rozel tornado fully condenses — 0029Z

    Rozel tornado — 0032–0033Z

    After photographing and filming it for several minutes, it started to dissipate. So, I moved up to keep pace, and noticed a new funnel condensing and then roping back out. This was actually still the original circulation, which was apparently still on the ground, and more of a last, condensational hurrah.

    Rozel tornado rope out — 0050Z

    I made my way further east on L Road, another hefty funnel appeared to my northeast, near Sanford. Light was starting to fade and it was backed by its forward flank. So contrast was low, and camera noise was high. I sampled some frames from the video where lightning helped silhouette the tornado. It was interesting to watch the axis of the tornado move counterclockwise around the larger meso circulation. So it was drifting westward for a while before running its cycloid pattern back eastward.

    Sanford tornado — 0102-0104Z
    Video frame grabs

    It eventually started to rope out and bend back way to the west, lit by purple, turquoise and orange twilight colors. There’s so much going on—I wish I’d have popped the camera on a tripod and gotten a decent low-ISO exposure. As it is, still lots of high-ISO noise so I could go hand-held.

    Weakening tornadic funnel drifts west of Sanford, Kansas — 0110Z

    Just when I thought it was done, I called my wife to see how things were going and talk about everything I had just seen. While talking on the phone, this floating earthworm of a funnel suddenly popped into view, off to the northwest. Just this cool little disembodied funnel twisting around, way west of its parent storm. Circulation was still on the ground as it drifted westward before finally winking out.

    Detached rope out

    Unfortunately, a home and a couple farm buildings were damaged by the tornadoes; thankfully however, there were no injuries. It was an amazing spectacle. Slow storm speeds. Clear RFD. Incredible structure and an assortment of tornado morphologies. If only the next two days had worked out that way…

    Chase map for 18 May 2013

    Video of the chase and tornadoes is here:

    Storm reports

    Links to more chase accounts from May 18, 2013:

  • 19 March 2013 | Lometa, Texas | Storm Chase

    19 March 2013 | Lometa, Texas | Storm Chase

    A forecast shortwave, 1000+ J/kg of CAPE, and directional shear supportive of supercells along a northwest-southeast boundary brought us to central Texas on Tuesday. We got a late start heading out of Elk City, but arrived near Lometa just in time to watch the first convection go up to the west of us.

    Convection fires west of Lometa, Texas

    The lead cell was gaining strength, but still linear in appearance, and we positioned ourselves along US 183 thinking that it would cross the highway just to our west. The leading edge of the storm was hitting the boundary and getting demolished–pretty strikingly actually. I figured it was dying out, and we’d wait for another cell to try it’s hand. I gradually realized that the lead cell wasn’t shriveling up and dying, it was just dropping its wasted, linear, northern edge and mashing up its inflow on the boundary, taking root and gaining strength.

    Trees and precipitation were obscuring the base. So we quickly re-positioned further southeast and noted a nice, bell-shaped base had formed with good separation from the forward flank.

    Supercell gains strength southwest of Lometa, Texas

    I was also realizing that the road network was going to make positioning a struggle. We made our way to Rt. 580 and headed west to get closer, when the base started looking pretty gnarly. This was my first time intercepting a RFB along the fringe of the forward flank so I was having trouble picking apart the silhouetted structures through the precipitation. Just as I was making out the inflow tail, RFD and tattered wall cloud, a multi-vortex funnel took shape like cheese pulling off the tip of a slice of pizza.

    Tattered, complex funnel takes shape

    The upper rope section was obvious, but it was attached to a heavier lower segment that seemed to be laminar in profile, so that might have been a chunky segment of the funnel. Hard to say for sure, unless someone closer has better shots with more dimension than mine.

    Funnel sequence
    Video of funnel (Frustrated that I forgot to set the video camera focus to infinity)

    We snagged a few shots and some video before it dissipated. As we drove back to the east, a new meso was spinning up to our south. After this point, the cycling and meso hand-offs were pretty steady and extremely impressive to watch in action.

    RFD gust front and shelf form under new meso south of Lometa, Texas

    Keeping the rental car out of the hail on the sparse diagonal road network meant that we couldn’t get back ahead of the hopscotching cycle-fest. We almost raced ahead of the third new bell-shaped base, but had to turn back when the marbles started hitting. But not before getting an awesome glimpse from the vault as the inflow and condensation raced in along the leading edge of the base.

    Reflectivity of the cell as it went from linear and appearing to die on the boundary (left) to nice supercell spitting out a funnel (center) to a cycling supercell that headed me off from getting back ahead of it (right).

    It was a new positioning perspective and pretty exciting to be in that location, but also a bit frustrating with a car that I can’t afford to get pinged. This was also my first experience watching a storm get forced into intense cycling by a boundary. I’m hoping a few others got some good shots and from better locations than I had!

    New rain free base forms near the horizon, south of Lometa, Texas

  • 17 March 2013 | Texas Panhandle | Storm Chase

    17 March 2013 | Texas Panhandle | Storm Chase

    A shortwave crossing the Texas panhandle Sunday afternoon helped light up a line of elevated convection. We headed out from Elk City to hang out under the gust front and get some hopefully nice twilight photos. The line was severe-warned for a while with strong outflow gusts producing several reports in the western Panhandle. I wasn’t expecting much more than a few photo opportunities.

    Driving west on I-40 toward the advancing line

    After spending some time in the cool outflow, I noticed a rain-free base form east of us on the leading edge of the line. I figured it would look nice as the sun got further down and lit it up, so we headed east on I-40 to get ahead of it.

    About the time we were getting near the outflow interface, we were surprised to see an amputated, chaotically spinning, gray rope of condensation materialize over the highway in front of us. It winked in and out, and then got a bit more persistent as it drifted from south to north. I didn’t have perspective on the cloud base overhead to see if this might have been a fractured piece of a landspout, or if it was a gustnado. I’m interested on any thoughts about whether gustnadoes produce condensation funnels.

    Animation of condensation funnel crossing I-40 (facing east)

    I wasn’t ready with either camera, so this 5 animation is a pretty crummy attempt to show the feature drifting across the highway. (What this doesn’t show is the churning action going on–pretty much like a remnant section of a rope-out.)

    Apart from that, the dwindling convection led to some nice sunset views.

    Backlit panorama of the dissipating QLCS
  • 11 October 2012 | Northern Arizona | Storm Chase

    11 October 2012 | Northern Arizona | Storm Chase

    Today looked like it might be an exciting weather day in Arizona with a cutoff low moving inland from the California coast. Instability was modest, but bulk shear and helicity were high enough to open up the possibility of organized storms and possibly brief supercell structures. I headed out toward Ash Fork on I-40 and gradually made my way back toward Flagstaff as the lines of convection developed eastward. West I-40 laughed at me and didn’t pan out for organized storms. (There were a few rotating cells that developed between Cordes Junction and Verde Valley, and out east between Payson and Showlow later in the evening.) Still, all the shear did some nice sculpting on the cloudscapes.

    Near Parks, I was greeted by the most intense rainbow I think I’ve ever seen. I remember thinking to myself that it looked as brilliant as a fist full of light sabers. Just smashing color straight into the forest. No surprise–the photos don’t do it justice. But it was a great view to cap off what was otherwise a bust for severe storms.

    A small cell struggles to survive just east of Ash Fork, AZ
    A tendril of scud creates a false funnel east of Ash Fork, AZ
    Disorganized convection races northward just west of Williams, AZ
    A brilliant rainbow crashes into the forest at Parks, AZ
    Rain streaks through a full rainbow at Parks, AZ

    12X Time Lapse Video of the Storm and Rainbow

  • 24 July 2012 | Flagstaff, Arizona | Monsoon Storm

    24 July 2012 | Flagstaff, Arizona | Monsoon Storm

    We had some nice, strong convection develop over Flagstaff today. Instability was approaching 1000 j/kg and maybe a measly 15 kt of shear at best. Still, as I was heading back into the office after grabbing some lunch a little before noon, I noticed one of the developing cells was sporting a pretty sturdy lowering. I dropped lunch off at my desk and checked FGZ radar. The cell actually appeared to have a weak couplet associated with it. So I grabbed my camera and went out to get some photos.

    For a pop-up monsoon storm, it was actually a real beauty. The lowering I saw earlier was still in place, and based on its position in the rain free base and relative to the precipitation core, I’d hazard to call it a wall cloud. Further up along the back of the rain free base, an inflow tail was pressed up against the core.

    Monsoon thunderstorm structure southwest of Flagstaff – July 24, 2012 • 12:00 PM

    As it moved eastward, it started to gust out and the inflow lowering became shelfy–and probably looked pretty menacing to anyone closer to the base.

    Storm gusts out and produces a low hanging shelf – July 24, 2012 • 12:03 PM
  • 18 March 2012 | Southwest Oklahoma | Tornadoes

    18 March 2012 | Southwest Oklahoma | Tornadoes

    While visiting family in Elk City, I chased some storms on March 14, 16 and 18, and wound up seeing three tornadoes on the 18th.

    I made the Sunday chase after a convective shambles in the TX panhandle on March 16. This turned out to be an incredible follow-up. Deciding between better moisture south near the Red River vs. better H5 winds north by the OK panhandle was my biggest challenge as I made my way toward Shamrock, TX on I-40. Based on reliable results with NAM and HRRR forecast models on March 14 and 16, I was relying on them more heavily.

    By the time I got to Shamrock, HRRR was forecasting some convection up by the OK panhandle and southwest KS, but it was showing this to be short-lived. The more robust, sustained development was forecast along the dryline west and southwest of Childress and moving into southwest OK. When I got to Shamrock, the cumulus field was congesting along the dryline in agreement with that area proving to be a successful initiation point, so I fueled up, cleaned the windshield and headed south.

    As I approached the Red River, towers were going up, and as I moved into Childress, a really nice updraft and anvil were overshadowing the town.

    Storm initiation

    Following the storm back over the Red River meant either racing the core along Hwy 62 and glomming with an inbound stream of chasers, or taking some side roads over to Rt. 680 just NE of the OK/TX border. I chose 680, and after sledding along several miles of farm road whose last maintenance heralds from before the dust bowl days, I made it to an I-Dare-You type bridge crossing with the storm moving over the OK border just ahead.

    Bridge crossing at the Red River

    After cringing at the forbidding screeching noises as I rolled across the bridge, I parked about a mile further north and shot some time lapse video and panorama shots. The lead cell was being hugged by a trailing cell with an incredibly solid hail core. I wondered if this would be like the mess on Friday near Lubbock with each batch of convection being demolished by whatever formed behind or in its inflow. For a while, both cells sported great structure and inflow features, and I couldn’t decide what to photograph.

    Wall cloud on lead cell and structure on trailing cell

    As I followed at a hail-safe, happy-rental-car distance, the lead cell became dominant and from there, the RFD did all sorts of wonderful things to the updraft base and enclosed wall cloud. From that distance, I was having a hard time resolving details behind the nearly constant precipitation curtain, but rotation had become sustained and it was one great photo op after another with some very tantalizing wall cloud structures emerging periodically through the hazy mists.

    RFD with obscured wall cloud/circulation
    Mothership structure

    I travelled the smaller county roads as much as possible, which lowered the convergence factor with chaser hordes. I still encountered smaller groups at key intersections and vantage points. This small group was enjoying a perfect RFD donut hole backed by a shaggy wall cloud and tail.

    Chaser audience, RFD donut hole and alligator’s mouth tail cloud

    About the time the tornado warning went up for the storm, I was back on a main road headed north, trying to get in better position when I was passed by law enforcement blazing north with lights flashing. I figured they were getting ready to road block my route, so I started to detour east to find another dicey county road, when a quick check out the side window showed a funnel snaking down (7:04 PM). I squeezed off some still shots, but wasn’t in time with the video camera. The slender funnel I saw may have been a small satellite to something bigger happening behind the precipitation curtain–there appears to something ominous going on along the right edge of that rain curtain in the photo.

    Satellite Tornado and Rain Wrapped Circulation (7:04 PM)

    Anticyclonic satellite tornado near Reed, Oklahoma

    As I stepped my way north and east, I was awestruck by the incredible structure on this storm. While I wish I could have been closer to view the detail in and around the wall cloud and the tornadoes it spawned, I can’t complain in the slightest about the views I got of the entire storm from a few miles away.

    As I navigated northward near Granite, OK, I found a high vantage that gave me a view of a second tornado spinning up near Willow, OK (7:30 PM).

    Initial touchdown near Willow, Oklahoma

    My third for the day spun up a few minutes later at 7:38 PM. This one lasted a couple minutes before the slender rope dissipated.

    Ropeout a few minutes later

    I followed the storm a bit more as it approached Clinton, but lightning was too sporadic to make out any more features, so I made my way into Elk City for a big steak and fries at Western Sizzlin. Chasing solo, trying to run two cameras and experiencing this unbelievable storm gave me a case of full-blown sensory overload–I’m still having vivid flashbacks. It was a great chase and I can’t wait for my next opportunity in the northern plains in June.

    Video from the chase:

    Links to reports and photos from others chasing the storm:

  • 16 March 2012 | Lubbock, Texas | Storm Chase

    16 March 2012 | Lubbock, Texas | Storm Chase

    The beautiful, isolated Kansas LP cell a couple days earlier had me excited to witness more explosive development on March 16th. MLCAPE values from 2000-2500 j/kg were forecast along the dryline in western Texas with the cap opening up by mid afternoon. With a mid-level impulse yielding up to 50 kts of bulk shear, mid-level lapse rates approaching 8.5 c/km, and directional shear supportive of rotating updrafts, it looked like severe storms were on tap with large hail, and a slight tornado risk as the LLJ strengthened by early evening.

    HRRR suggested two areas for convection to break out–near Lubbock and south of Midland. The reflectivity forecast hinted at the southern target being choked off soon after forming, so with a bit of relief at the shorter drive, I targeted the dryline in the vicinity of Lubbock.

    As we neared Post, TX, storms were firing along the dryline, and a strong cell south of Midland had gotten the attention of the SPC as severe watch areas went up from southwest Texas to western Oklahoma. Storms near Lubbock were looking good to me, and we targeted a cell that was essentially moving over Lubbock–it soon picked up a severe warning. As we paced the storm and watched it develop while keeping the rental car out of the hail, the storm started to develop inflow bands and what looked like a bobbed beaver tail.

    Panorama of severe warned storm near Lubbock, Texas
    Rain-free base struggles to get organized while my daughter looks on

    Before long though, a flurry of developing storms west and southwest of our storm began interfering with it and with each other until the whole mess essentially disintegrated. The remains of dissolving storms still present great photo opportunities, and we made a few stops on the way back to Elk City to take in the pleasant views.

    Another storm with a sturdy inflow tail chokes off our original cell’s inflow
    Dissipating storms paint the sky for our drive back to Elk City








  • 14 March 2012 | Englewood, Kansas | Storm Chase

    14 March 2012 | Englewood, Kansas | Storm Chase

    This day didn’t promise to be much of a storm producer. Southwesterly flow aloft was weak–30-35 kts–over a solid cap. However, with instability from 1000-2000 j/kg, 35 kts of bulk shear, and low/mid level SRH around 100 m2/s2, the possibility of a photogenic storm going up had me ready to head out.

    By midday, the HRRR model was forecasting convection breaking through the cap along the dryline in the Oklahoma panhandle. Satellite was showing a patchy cumulus field developing along the dryline in the panhandles. So Giselle and I headed out from Elk City to see if something would break through.

    As we headed north on 283, we were introduced to the horrible Wireless data coverage of northwest Oklahoma. With no satellite updates to tell us how things were going along the dryline, we kept moving and hoping cloud tops would start to show above the haze. I’m used to the clear, dry air of Arizona where storm bases are visible from 50 or more miles away. So it’s frustrating at first to see how quickly visibility drops off on the plains–of course, it’s that hazy moisture that makes the storm environment so explosive here.

    By the time we approached Shattuck, Oklahoma, we were seeing hints of the dryline cumulus to the west. Some of the cloud heads popping above the haze layer looked like they might be developing cu towers, but it was impossible to tell without seeing whether there was a rising tower beneath the bubbling fringe. After some more driving with that frustrating feeling that the cap might hold everything down, we finally saw some convincing development that egged us onward.

    Growing cumulus tower in the north Texas panhandle

    While the initial tower collapsed, another congested batch further north on the Kansas-Oklahoma border was holding together.

    Congested cumulus near the Kansas-Oklahoma border

    We headed for that developing storm, and by the time we reached Englewood, Kansas, it had developed an anvil and was putting on a beautiful display northwest of town.

    Developing cell northwest of Englewood, Kansas

    As expected, the cell remained elevated for the two hours that we followed it, but the updraft displayed broad rotation and barber pole structure with some limited lightning. Colored by the setting sun, this isolated, mini-LP cell was a beautiful sight as it glided away over the lonely Kansas landscape.

    Mini LP Supercell drifts from Englewood to Ashland, Kansas

    20X Time Lapse Video of the Storm

  • 4 October 2011 | Maricopa, Arizona | Storm Chase

    4 October 2011 | Maricopa, Arizona | Storm Chase

    I chased some stunning high-based storms with brief supercell structure in southern Arizona earlier this week.

    A trough moving in from California was forecast to take on a negative tilt as it drifted into Arizona. Dynamics would be favorable for severe storms with 40-50 kts of shear, positive vorticity around the base of the trough, and some chances for winds sufficiently veering with height to support multicell and weak supercell structure. The SPC forecaster commented that the NAM was handling parameters nicely, so I gave it more attention for my initial plan than the RUC and GFS. It forecast a tongue of modest instability (500-750 j/kg MLCAPE) moving eastward from Yuma through the central deserts and then lava-lamping a blob of CAPE northward through the Phoenix area by late afternoon/evening.

    I was initially tempted to head west, toward Kingman that morning. Ongoing convection associated with another field of instability was being spurred by a streak of upper air support. It didn’t help that Flagstaff NWS was discussing the remote possibility of an isolated tornado for the northern Arizona forecast area. The Phoenix forecast for southern Arizona conceded the possibility of brief supercell structures, but didn’t go so far as to leave the tornado possibility on the table. Still, the best combination of instability and jet streak dynamics seemed poised to effect southern Arizona more favorably than elsewhere. I also wanted to play in some terrain that had better visibility. So that’s where I headed. I planned my first stop for Wickenberg to sidle closer to the front and then have a good road option to the southeast as I watched how convection developed.

    By 10:30AM as I was nearing Cordes Junction I could see storms already blossoming south of Wickenburg along the cold front. I chastised myself for getting a late start and possibly missing an early show. But better dynamics were still hours away, so I pushed the frustration aside. As I approached Wickenburg along Rt. 74, a gap in the hills allowed a brief birds-eye view of one of the early storms pushing out an arcing ring of dust–one of many I’d get to sample through the day.

    Storms erupting southwest of Wickenburg.

    As I sat at the intersection of Rt. 74 and 60 checking radar and satellite, I was dodging ongoing feelings of self-doubt. Convection in northwest Arizona was doing very well for so early in the day while storms popping up in southwest Arizona were blooming and dying in short order, shooting thin anvils eastward in spurts. I was starting to worry that the atmosphere was going to get tapped of whatever available moisture there was, and the show in the north might be the only real play for the day. Still, I decided that as long as I was part-way there, I might as well commit the rest of the way to my southern target. So I cruised the rest of the way past Laveen, and south of South Mountain. Along the way, the storms pulsing along the cold front were really starting to push the dirt around. Much of my drive south ran me right through the diffuse wall of a dusty gust front.

    Driving along the dusty gust front south of Laveen, AZ.

    I parked the car off the road in the scrubby wastes northeast of Estrella Mountain (appears to be a perfect spot for disposing of contraband and bodies) and watched the merging arcs of dust pushed westward. A strong storm peeling away from Ajo dissipated as it approached and ran into a sad capping problem that was centered pretty much over my head. I held onto hope that the cap would erode as the dust cleared out and the surface heated back up. But the surrounding environment continued to be harsh on convection. One sad little cell pushed up over the mountain, but then faded into a mist.

    Dying storm pushes another arc of dust eastward as it drifts over Estrella Mountain.
    A weak cell makes it over the ridge and manages to develop a tiny little base.
    The same cell now fades into a hazy mist.

    Another batch of convection brewed back up over Ajo and then split as it moved over Interstate 8. The right mover looked really good, and I quickly headed south toward Maricopa to intercept it. As I rounded the east side of Estrella Mountain, I could see the dark core of the storm pushing up against the ridge. I soon caught a glimpse of the rain free base and a distinct lowering. Maricopa Road was thick with 75 mph rush-hour traffic, and I had a challenge finding a place to pull off safely. Casa Blanca Rd. did the trick. Although the storm had dwindled to a fraction of its former bulk, it still had a very nice show to put on. I spent the next several minutes photographing and filming a beautiful wall cloud being sculpted out of the storm’s base.

    Persistent lowering beneath the rain free base.
    Panorama of storm and surroundings as wall cloud takes shape.
    RFD begins to sculpt the wall cloud.
    Closer view of wall cloud.

    Wall cloud tries to pull in a little bob-tail on the right edge, while beginning to recede back into the base. RFD is cascading nicely down the left/south side.

    After dropping into a nice, morphing cylinder, with a bit of RFD cascading down its south edge, it merged back into the base for a few minutes. As the storm moved further north, the base tightened up into a stunning barber pole with another, furry wall trying to form beneath.

    The base of the storm tightens back up, developing barber pole structure.

    By this time, another cell to my south started raining on me and feeding my target storm some cool, misty air. As I rushed northward to to get out of the rain, the storm base began to erode into a tattered claw, painted across a dusty, desert landscape. I hated not having a good place to pull over and capture the amazing sight to my left. To make the best of it, I rolled down the window, and snapped several uncomposed shots while concentrating on the road ahead of me, hoping one or two of them would frame it nicely. Fortunately that worked, and I came away with a couple in that series that I actually liked.

    Panorama of storm base and surroundings as another storm to the south begins to rain on the parade.
    The swirling storm base begins to tatter and erode as it chews on more stable inflow.
    Last hurrah before traffic, stop lights, and curtains of rain let it pull away into Chandler, Mesa and points beyond. Note the stubby little tail hiding in the rags.

    Before leaving that morning, I tried to sober myself with some rough odds:

    • 80% chance of seeing some storms.
    • 30% chance of getting a good look at a severe or otherwise interesting storm
    • 10% chance of intercepting a storm with supercell structure
    • 5% chance of a wall cloud
    • <1% chance of seeing a funnel or better

    Four out of five’s not bad, I figure! I was pretty happy with how things went as I spent the next 160 miles driving back up the mountain in pouring rain. Although the Maricopa storm possessed some key elements, I’m not sure I would call it a supercell–maybe a ‘marginal’ or ‘brief’ supercell. After reviewing the time lapse video, it did show rotation in the updraft, but it was not vigorous and had a very small radar signature by the time I intercepted it. In hindsight, I think that outflow from the earlier convection was what was killing the storms that I hoped would “come to me”. I should have taken the extra driving hit and headed further south to Interstate 8 to catch a more pure fetch of moist southerly air where the convection was happier.

    Taking a cue from Skip Talbot–

    Lessons Learned

    • Don’t let the early show distract you from the main play for the day.
    • Do factor in the atmospheric consequences of the early show when positioning for the main play.
    • Clean dust off my camera’s sensor–cleaning the blobs out of the images later is a pain in the rear.
    • Southern Arizona has better chase terrain and visibility than the mountains of northern Arizona…but the road network still stinks compared to the plains.
    • Invest in a swatch of black velvet for the dashboard. Positioning the video camera on a huge, dark jacket to hide dashboard-window reflections is an obnoxious balancing act.
    • Blindly shooting photos out the side window can actually work if you have no other options.
    • Even at low speed, cruise control on my car is a force of evil when it encounters flooded highway ruts.
    • September/October in Arizona is my new second-chance chase season.
  • 13 September 2011 | Flagstaff, Arizona | Rotating Storms

    13 September 2011 | Flagstaff, Arizona | Rotating Storms

    The second week of September has been a great week for organized storms in Arizona. A cutoff low developed over southern California, and has been drawing up moisture for several days and providing decent shear aloft. Lower level winds haven’t been very strong and veering with height in the first kilometer not very promising. However, bulk shear from 30-40 knots, cooling and diffluence aloft, and ample moisture led to strong storms and support for occasional supercells.

    Supercell thunderstorms are not common in Arizona, but after missing the storms that led to last year’s Arizona tornado outbreak, I’ve been keeping an eye out for California cutoff lows. Being at the right place at the right time to view and film a rare Arizona tornado is so close to being unrealistic, that I’m not too anxious about it. However, catching an Arizona supercell seemed doable and would be a very nice gem to collect.

    I’ve had my cameras ready in the car and kept an eye on radar in hopes of catching a good storm. I made a couple local chases the week before, caught some broad rotation in one storm and brief barber pole structure in another, but not much else. Then on the afternoon of September 13, I noticed weak, but sustained, rotation on a couple storms on doppler radar. I headed outside to get a look and to the north I saw a robust storm perched over the San Francisco Peaks. The rain free base sported a zone of rising scud, and I was surprised to see what appeared to be a wet RFD slot slicing into it. As the razor edged rain band pushed in, the rising scud quickly congealed into a wall cloud with a laminar profile and nice rising motion. All I had was my cell phone, so I had to suffice with a couple low-quality photos.

    RFD and brief wall cloud southwest of San Francisco Peaks about 2:30 PM
    RFD and wall cloud progressing

    Hoping it would hold together, I quickly ran to my car to grab my cameras. By the time I got back to a good clearing in the trees, the original updraft cycle had eased off and the wall cloud had broken up. I was pretty disappointed, but the storm still looked strong, so I found a new vantage point along a stairway leading to the roof of my office building. I set the video camera up for a time lapse while shooting still photos as the storm cycled two more times.

    Storm base moving over Schultz Pass
    Panorama showing storm structure 3:00 PM

    While shooting photos, I called my wife while she was running errands about a mile further north, closer to the rain free base. Besides describing a wicked looking storm and an occasional spray of hail, she mentioned the warm inflow that was feeding it.

    The videos below show a time lapse view of the storm. I suggest clicking through to Youtube and viewing in high res

    By now, a flanking line and gust front had developed along the storms southwest flank, and there appeared to be an inflow tail stretching eastward behind Mt. Elden. One area of rotation drifted eastward through Shultz Pass and dropped a broad, tattered wall cloud. This area seemed to be occluding while new circulation was trying to develop just south of it on the other side of the RFD gust front.

    This second video shows detail in the wall cloud, including an interesting, conical structure drifting through it. The structure persisted for about 40 seconds. Although I wonder if it was an embedded funnel, I can’t be sure–I can’t discern motion in the dark silhouette.

    Wall cloud drifting behind Mt. Elden.
    Suspected funnel embedded in wall cloud.
    Storm structure as new base forms.

    The new area of rotation began to pull in rising scud and even started to form a tail cloud. It was definitely exciting to see it try to tighten up as rotation got faster, but it lost cohesion, and the storm pulled away to the northeast and out of view over the mountain.

    RFD gust front makes a strong push.
    Tail cloud begins to feed into new lowering.
    RFD Slot.

    This cycling supercell was a real treat to view. While I imagine it would be a disappointment by plains standards, it was pretty awesome as Arizona storms go. Unfortunately, the core was planted right over the Schultz Fire burn area and led to another round of serious flooding for neighborhoods downstream.

    The station that recorded the radar images below is located to the southeast.

    Base velocity at 2:30 PM showing 15 kt gate-to-gate shear during first wall cloud photos.
    Base velocity at 3:00 PM showing 20 kt gate-to-gate shear in two locations during next sequence of photos.
    Base reflectivity at 3:00 PM.

  • 11 May 2011 | Oberlin, Kansas | Storm Chase

    11 May 2011 | Oberlin, Kansas | Storm Chase

    I woke up on day 4 ready for an awesome day chasing some powerful storms across Kansas. Hopes dashed: a quick check of satellite showed something had gone wrong. A huge MCS was moving northeast out of the panhandles and raining all over everything. The forecast for an explosive day took a nosedive and the south-Kansas target was getting washed away with cool, cloud-covered stability. There was a chance that all the elevated convection would move out in time for the sun to warm it back up and try for a recovery, but it was looking pretty slim. I bailed out of the grunge hotel and hung out at a gas station refreshing satellite, forecast models and SPC analysis. Some chasers were hoping for an earlier recovery in southwest Oklahoma while others were hanging tight for renewed hopes in southern Kansas.

    Just across the street from the grunge hotel, the TIV team scavenges for parts.

    Gradually, the MCS moved out and clear skies started to edge in from the west. At the same time, I noticed that new convection in north Texas was sending huge, dense anvils racing northward just in time to block out the sun again. That was all I needed to see. My forecast area was toast. I headed west toward Dodge City to look for a opportunities closer to the surface low and in clear air. By the time I reached Dodge CIty, the SPC had posted a tornado watch discussion for northwest Kansas. The dryline was sticking out like a sore thumb from my position and on northward, but the cirrus canopy was hugging right along its eastern edge. So I got on Route 23 and took off for northwest Kansas. As I made my way north, a check of the rear view mirror showed new convection popping up right over Dodge City and looked like it was reaching for the ground and trying to get surface based. I almost turned around to give it a shot, but that cirrus deck was heavy and I figured the storm was going to have a horrible fetch of inflow. So I kept hauling north.

    As I got closer to I-70, I could see storms to the north along the stationary/warm front beginning to go up. And here I was approaching from the south again. One of these days, I figure I’ll position myself to not be playing catch up. Spending 15 minutes with stop-sign guy on a one lane stretch of road construction, waiting for the pilot car was a time of great sadness and anxiety. Somehow I still managed to catch up with a decent severe-warned storm on Highway 83 south of Oberlin. I was on the wrong side, and it was outflow dominant, but it was still the best thing I had intercepted the entire trip. I caught sight of an interesting lowering behind the rain curtains, but it didn’t go any further than that before gusting out in a spectacular torrent of ragged scud and spindled shear vortices. I followed its remains past Oberlin where I caught the beautifully lit sight of another cell to the southeast. Radar show it to be weakening, so I decided to head north then east and sample its core.

    Panorama of convection looking north along Highway 83 in NW Kansas.
    Very wide panorama of severe-warned cell south of Oberlin, Kansas.
    Rain free base with tantalizing lowering.
    Enhanced reflectivity view of the Oberlin storm.
    Velocity scan showing broad rotation
    Tattered scud and shear vortices twist and fray as the Oberlin storm gusts out.
    Nicely sculpted pillar of scud flows along the gust front.
    Dwindling light reveals another dying cell to the southeast.
    Time lapse video of the day’s chase. Click through to YouTube to view in HD.

    As I drove through the blinding rain, I noticed a car riding my tail. If they want to go play Hydroplane-on-the-Highway, I figured that’s their business. So I pulled off the side and motioned them to pass. Instead they pulled alongside and told me I better hurry since the worst was headed this way. I hollered over the pounding rain, that yes, thank you, I know, but that I wasn’t willing to drive as fast as them. So off they went. A couple more miles got me out of the core, and a great view of another nice lightning display on a dark Nebraska road with the frogs and crickets jamming away into the night.

    The last of the convection moves north, flickering with lightning as night descends.

    I eventually made my way back down to Highway 36 and west to just beyond the Colorado border. I pulled off on a dirt road and caught bursts of sleep while the surface low spun overhead entertaining and distracting me with bursts of rain and lightning all night long.

    Lessons Learned:

    • Even the best setups can be demolished by situations that the forecast models didn’t anticipate.
    • I made a good call abandoning the southern target when I did. The early convection and continued cloud cover destroyed all hope for that area. I’m also happy with making the decision to not go after the Dodge City cell. The cirrus canopy strangled it and it died out soon after.
    • There’s always next year…
  • 10 May 2011 | Pratt, Kansas | Storm Chase

    10 May 2011 | Pratt, Kansas | Storm Chase

    My third day on the plains was a travel and practice day, in anticipation of the big Kansas outbreak day on Wednesday. South Dakota, Nebraska and northern Kansas fell away behind me as I made my way to Pratt, Kansas by late afternoon. A chance for a few elevated storms was forecast, and I took the opportunity to practice navigating around one of them on the awesome Kansas road network. As my sample storm drifted north-northeast, I gave the sandy, dusty farm roads a try, and got a good feel for how some of the dodgier ones were mingled in with the better-maintained roads. The consistency was a lot sloppier than the South Dakota experience the day before–definitely not something I want to be on when it’s wet. I gradually let the storm slip by to my north as it put on a nice lightning display for me.

    An elevated storm drifts along north of Pratt, Kansas, providing a nice opportunity to practice pacing and positioning along the local farm roads.
    Radar view of my little practice storm.
    Appreciating the sights along the way. This patched up old farm building was loaded with personality.

    This was the one night I set aside for a motel to rest up for the big day on Wednesday. Money was tight, so I picked a low cost option on the east side of Pratt. The various long-term motel residents on the south wing were tailgate-partying and I probably would have been a little more unsettled if I wasn’t so tired. There were no bedbugs that I could see, but I kept everything off the floor anyway. I asked for replacement sheets that didn’t have hair on them. The new set of sheets had holes in them too, but thankfully no spare hair. I layered bath towels along my sleep area, maintained posture and had zero contact with the rest of the bed. Not ideal, but it was a great relief compared to the car seat sleeping position. It was so nice to have a shower too–don’t touch the walls, or shower curtains of course.

    Lessons Learned:

    • Less maintained Kansas roads can be dicey for a Honda Civic even when dry–stay away when wet.
    • Budget $60 for a less grungy motel experience. Bring a sleeping bag just in case.
    • Set video camera to 1/30 sec. exposure to keep lightning from being chopped up by rolling shutter effect.
  • 9 May 2011 | South Dakota | Storm Chase

    9 May 2011 | South Dakota | Storm Chase

    My second chase day started with the sun’s warm rays piercing broken clouds above a nearby farm. I slept a little later than I wanted, but had plenty of time jump on I-90 and head west toward Murdo where I waited for signs of initiation along points further west. This setup was difficult to forecast. The best moisture/instability/shear was wrapping north and northeast of the surface low, north of the warm front. I had a hard time picking the best spot for storm initiation and was really hoping visual cues and satellite would point me toward development with enough time to adjust and intercept.

    I wasn’t the only one in Murdo watching the sky and refreshing satellite views and SPC observations. The Dominator crew and about a hundred other chasers were parked in various hotel and gas station parking lots hanging out, scarfing convenience store food, throwing frisbees, scrubbing windshields, jaywalking, and checking out each other’s chase vehicles. I was concerned that the best, first storm would collect an instant caravan and I wanted to get out before that happened. Turns out this wouldn’t be the problem. As I headed further west, the sky grew heavy with fast moving stratocumulus. It was frustrating to realize that I was going to have a terrible time visually spotting points of storm initiation.

    Eventually, northbound radar returns started to pop up along I-90, east of Rapid City as well as a nice, tornado-warned cell far to the south near Crawford Nebraska. I started to drive south, thinking I could intercept the Nebraska storm somewhere near Wounded Knee. But then I second guessed myself and figured that I’d probably make this long drive through the badlands with difficult terrain and bad road options and the storm would be past its prime by the time I intercepted. So I headed back north of I-90 and traded one set of bad road options for another. I was positioned right at the southern end of several developing radar returns and finally caught a glimpse of one of the new towers to my east. To my north: wet gravel roads. I thought, ok, let’s try these roads out and see if I can get ahead of the development and intercept around from the northwest.

    Developing radar returns just before I began my long drive north to try and intercept the pick of the litter. (My location is shown by the blue target.)
    Rough Kelvin-Helmholtz clouds forming in a nicely sheared environment.
    A sunlit anvil blossoms to the east of my position.

    My Honda Civic and the wet South Dakota dirt roads played nicely with each other. However, what with the Belle Fourche River Valley, majorly broken road grid, and wet dirt-gravel surface, I was no match for the storm motions. It didn’t take long to realize that I wasn’t going to intercept any of the storms I thought I would. So I plotted a path to hit Route 34, then Route 73 and work my way back toward I-90 and see if any new development would head my way.

    Stunning overlook of the Belle Fourche River Valley.

    It took forever to get back to a paved road, and night had fallen by the time I hit asphalt again. As I made my way back east, then south, severe and tornado-warned storms lit up the sky to the north and east. I was frustrated that I had failed so miserably at positioning myself, but the non-stop lightning show was a beautiful parting gift as I drifted along the lonely South Dakota highways.

    Severe and tornado warned cells avoid my chosen route.

    I parked for a few hours of sleep near Kadoka, SD, where the drizzling remains of the tornado-producing Crawford storm finally passed overhead and drifted off into the flickering night.

    Lessons Learned:

    • If dirt roads are the only way to intercept a target already to my north, and there is a good possibility of a southern target, opt for the southern target.
    • Committing to a long, unpaved route in an area that is not fully gridded is probably a one-shot deal.
    • The Honda is compatible with at least some of the wet, unpaved roads in southwest South Dakota–although copiously wet would probably be a different story.
    • Setups where the target area is north of the surface low are a serious weakness for me to anticipate development.
    • South Dakota is a beautiful place to chase.
  • 8 May 2011 | Mitchell, South Dakota | Storm Chase

    8 May 2011 | Mitchell, South Dakota | Storm Chase

    I got on the road Saturday afternoon, left Flagstaff, drove most of the night, and made it to eastern Nebraska by Sunday late afternoon.

    I’ll try to do a more detailed summary later with more photos. (I’m extremely worn out.)

    After checking models and spc discussion each time I stopped to fuel up, I decided I would head to the warm front. Unfortunately, eastern Nebraska turned out to be a wasteland of uncooperative cloud streets. The cap wasn’t budging there at all. I figured I was going to have a complete bust on my first day out. But then inhibition started to part in South Dakota, a few storms started to blossom. Most were too far to consider, but a small, fresh one was within reach, so I raced north. As I got closer, I realized the cap had clamped down and nothing was left but an orphan anvil.

    I kept going north, just in case, and was suprised by a view of a new tower going up on the other side of the Missouri river, half-lit by the coppery light of the setting sun.

    Satellite view showing my target storm as a bright blip in the far south-southeast corner of South Dakota. (Note the only tornado-producing cell in the south-central part of the state–too far out of reach.)

    The new tower was farther north than I thought, and was moving north at about 25 knots. I decided not to keep chasing it in the dark, so I broke off, satisfied to see it sputter with lightning as it drifted away. At least I got a distant storm and some lightning for day 1.

    I fueled up again and did some supply shopping. Afterward, as I drove to a section of gravel roads south of Mitchell, SD to park for the night, I was overwhelmed by nonstop lightning behind me. I pulled over to figure out where it was coming from. Sprawled out to my west was a huge, sculpted shelf cloud, gaping with rain, wind and lightning–and it was visibly expanding in my direction. I didn’t want to get the car golf-balled, so I raced down the dirt roads, going after a good north-south paved road. Along the way, I made some brief stops to photograph this majestic thing.

    At one stop alongside a small lake, the sound of katydids, frogs and other nocturnal creatures blended in with the non-stop thunder of the approaching storm. It was wonderful. As I continued south and east, I realized the entire gust front was going to chase me into Missouri if I let it. So I hunkered down in a farm field access and embraced the drenching rain and unceasing lightning. It was an amazing way to end the day.

    Radar showing my position with the approaching gust front.

    Lessons Learned

    • Argh. Just play closer to the triple point–don’t get creative with points further out along the warm front.
    • The cap likes to be stronger further south.
    • A shorter focal length lens would be nice for capturing massive gust fronts and shelf clouds.
    • After night fall, shut off the car, get outside and enjoy the sights and sounds of lightning, thunder, and wildlife.