19 June 2014 lightning show

   The 15th International Conference on Atmospheric Electricity is taking place in Norman this week.  There is also actual lightning.  I left Norman Thursday evening after helping out with the conference and met an ongoing cluster of strong to marginally severe thunderstorms near Binger, OK.  The easternmost cell began propagating slowly eastward, developing a couple transient areas of low-level rotation and producing quite a bit of CG lightning.  I set up just off Route 81 south of El Reno as the sun finally dropped far enough to allow lightning shots.  Outflow winds sustained at 40+ mph made it nearly impossible to keep the camera steady on the tripod.

At least one flash connected with the ground between me and the horizon:

I missed quite a few close CGs.  The storms slowly began to slide east and with several flashes reaching ground less than a mile away, it was time to reposition east down Reno.

   I dropped south and east into Mustang, then headed for the hill on Highway 9 west of Norman.  The storms had almost stalled again and were too far away.  After some maneuvering around Blanchard, I gave up and made for the OU parking garage.  There wasn't much to the storms at that point, but a small cell to the west fought off nocturnal cooling long enough to spit out several more CGs.

Three tornadic supercells in West Texas, 5/26/14

   Monday (Memorial Day) was an epic chase of about 600 miles round-trip.  It was also my mom's first storm chase.  We left Arlington just after 1 p.m. and raced toward supercells developing in West Texas, from Midland/Odessa northward.  We closed on the first storm, a tornado-warned supercell turning southeastward near Big Spring, a little after 5 p.m.  It was an aquamarine-glowing beast of a storm that was becoming HP as precip fell between it and a new supercell to its west-southwest.

County Road 262/371 just south of I-20

Intersection of County Roads 371 and 270, 5:33 p.m.

   The storm exhibited a more defined base as it approached I-20.  At 5:38 p.m., a spotter reported a rain-wrapped tornado crossing I-20 near Coahoma.  The tornado was not clearly visible from our location nearly 10 miles to the east.

Rain-free base at 5:35 p.m.

5:38 p.m.

As the gust front hit, we retreated to FM 670 to escape southward, stopping for a few last shots of the blue-green storm.  It wouldn't regain serious tornado potential but was photogenic.

   With the first storm weakening and cutting off northward and eastward road options, we targeted the new supercell behind it, which was diving southeastward toward Sterling City.  In Sterling City, we watched storm #2 attempt to get its act together.  A few minutes after the following photo was taken,  a tornado was reported 14 miles to the west-southwest.  The new updraft trying to get going on the southern flank was interesting, but never seemed particularly organized, so any tornado was probably in the rain-obscured lowering farther north.  Scud from the edge of the precip core was continuously being pulled up into that region of rain wrap, looking like a tornado I saw on 4/17/13 near (coincidentally) Sterling, OK.

West side of Sterling City, 5:40 p.m.

   While in Sterling City, I was approached by a local resident in an SUV who introduced herself as the editor of the newspaper.  She asked what was coming and when I told her the storm was tornado-warned, she asked why the sirens weren't sounding.  That was a good question.  In fact, even as the storm closed in, I never heard a siren in Sterling City.  After that, another local hollered out of her car window and warned us not to go west.  "There's five tornaduhs in there!"  Even in the age of Twitter, real-time severe weather information remains a game of telephone; an iffy multi-vortex report becomes five tornadoes.  We dropped south of town on Highway 163 and the logjam commenced.  Chasers, Skywarn spotters, tour buses, locals with kids in tow--you name it.  Everybody in Sterling County, Texas seemed to be on 163.

   A bizarre low-level feature appeared as the storm came closer.  It didn't even seem to be attached to the cloud base and was displaced from the main updraft, but was slowly rotating and ascending.  At times it became elongated and extended to the horizon.

Just south of Sterling City looking west, 7:08 p.m.

   About that time, the first hailstone either of us noticed came flying into my mom's hand.  The storm was chucking at least half dollars ahead of it; they were actually being blown from east to west in the inflow.  Not wanting to take damage just to watch a weird little gustnado, we bailed southward as hailstones shattered across the road and occasionally on the car.  Fighting hail, traffic, and rolling terrain, we didn't get a good look at the storm as it crossed Highway 163 and had to watch it from farther south.

Looking north around the time a rope tornado was reported, 7:14 p.m.

   Well clear of the storm's path, I took a couple of photos at 7:24 p.m. that show a thin, faint feature extending from the cloud base to the horizon north of the RFD gust front.  I hardly noticed it at the time, but after seeing SPC tornado reports at 7:13, 7:15, and 7:31, I went ahead and emailed the photos to NWS San Angelo in case they had additional information.

~20-30 miles south of Sterling City looking north-northwest, 7:24 p.m.

Tighter crop of tornado-like feature

Second photo of the same feature, taken about 10 seconds later

   The second storm moved off to the east and we edged north on Highway 163 to intercept a third supercell trailing behind it.  Stopping just north of a Texas Tech research radar, we watched an incredibly long inflow tail slide into the new storm's well-developed mesocyclone.  A tornado was reported, probably with this storm, at 8:05 p.m., but no tornado was evident from our position.

Looking west from Highway 163, 7:58 p.m.

8:00 p.m.

8:02 p.m.

8:03 p.m.

8:05 p.m.

8:07 p.m.

   This supercell swept across 163 with no sign of producing a tornado, and we ended our chase.  More storms continued to fire near Midland and train behind those we'd intercepted, though, making it impossible to reach I-20 without a chance of getting cored.  Even to attempt it would have required reliable radar data, something we lacked given the sparse cell service.  Instead, we raced supercell #2 to San Angelo in hopes of circling around it.  We took desolate 163 southward to FM 2469, which cut eastward through remote oil fields to a gritty little wide spot in the road called Mertzon.  From there population density slowly increased as we followed Route 67 northeastward into San Angelo.  Lightning flashed continuously in the slowly weakening supercell to our north.  We left San Angelo on 67 just before the storm moved in and dropped low-end severe hail all over town.  New convection grew overtop of us near Ballinger, filling the gaps in a spectacularly electrified MCS.  From there it was north to Abilene and east on I-20 to DFW, most of the way in trailing stratiform precip that seemed to have a lot of tiny hail in it.

   We were close to multiple tornado reports from multiple storms and saw nothing conclusive.  Cell towers and paved roads were few and far between.  The storms were messy, threw large hail well outside their cores, and rarely sustained strong low-level mesocyclones for more than a few minutes.  For as many reports as there were, there have hardly been any tornado photos making the rounds.  Some have expressed doubt about one particular report of a multi-vortex tornado early in the second supercell's life.  Even with a clear target area, it was actually a challenging day to chase.  Still, it's hard to complain about three tornadic supercells in open country.  With Oklahoma sitting at 6 tornadoes on the year--#6 hardly counts, a landspout under cold-core convection on 5/27--this is as good as it gets right now.

5/7/14 Gracemont, OK severe thunderstorm

   After dark Wednesday night, I went after developing storms in west-central Oklahoma in hopes of catching some lightning.  There was nearly continuous lightning as I closed on a storm near Binger and dropped south in front of it, but it was all in-cloud and not especially photogenic.  I got a few shots of a shelf cloud near Gracemont, my only photo stop of the night, and chased the storm back to Newcastle as it kept fighting to stay surface-based and wrap up short-lived mesocyclones.  The only excitement was some unexpected hail in RFD southwest of Tuttle.

   As I learned the next day, Gracemont took some serious straight-line wind damage about 20-25 minutes after I left it.  These photos are from a little more than a mile south of town, looking north along U.S. 281, at 10 p.m.

Cars, tornadoes, and bad decisions: 2014 edition

   A "storm chaser"--I use the term very loosely, as he seems more like a local attempting suicide--came within a football field or two of getting himself killed in the 4/28/14 Tupelo, MS tornado.  This in itself is not good.  What's ten times worse is posting a dramatic video to Youtube and encouraging other people to follow suit:

Let me be the first of pretty much everyone in the meteorological community to say:

• This guy is incredibly lucky and incredibly stupid.
• At no point was he "in the tornado."  If what he experienced looks scary, realize that he was only getting inflow jets and possibly the outermost fringe of the circulation.  Had he been fully inside the tornado, he would probably have encountered winds twice as strong.  He and a crumpled wad of metal sort of resembling his car would have been found out in that field, if not in two different fields. This, or worse, is what happens to vehicles directly impacted by strong tornadoes:

(photo from NSSL)

• Vehicles are still not safe in tornadoes!  El Reno proved that point, when several died on the roads and none died in structures.  The Arkansas tornado that threw cars off I-40 the day before this storm proved that point again.  Drivers will keep becoming examples until we learn this.  Thousands of people have been pulled alive from homes and businesses directly hit by violent tornadoes in the past few years.  I don't know of very many who survived direct hits in cars, except the fortunate TWC team in their huge SUV.

   As hard as it is to say, I don't think this guy did quite everything wrong.  He could have made one worse mistake by driving straight into the tornado.  Stopping and letting it pass always beats racing it to a crossing point (ask Mike Bettes).  The idea is to stop away from the tornado, not as close as possible to certain death.

4/26-27/14 severe weather

   Flow associated with a developing surface low in the High Plains in advance of an upper trough ejecting from the Southwest will result in rapid low-level moisture advection into the Southern and Central Plains on Saturday.  Dewpoints in the low to mid 60s will result in considerable instability (2000-3000 J/kg CAPE), but a stout cap will remain in place through most of the day as the upper-level forcing to weaken it will lag to the west.  Convergence and convective mixing along the dryline will be nearly enough to overcome the cap as stronger flow aloft/differential vorticity advection finally arrives in the evening.  Models differ on timing and location of convective initiation, but the most likely scenario is a storm or two in southwestern Oklahoma or western North Texas just around sunset.  Large low-level hodographs and increasing deep-layer shear will support supercells capable of producing very large hail.  LCLs will initially be too high for an appreciable tornado threat.  However, as the boundary layer cools and moistens with loss of diurnal heating, cloud bases may lower.  Model consensus is that a ~50 kt low-level jet will emerge over northwestern Texas and western/central Oklahoma in this time frame.  Extreme low-level vertical shear combined with any cloud cover that results from distant anvils/synoptic lift/moist advection in the LLJ should prevent rapid stabilization of the boundary layer in the 00-04z period.  Remaining instability up to 2000 J/kg CAPE and large values of SRH owing to the LLJ would mean a risk of a few tornadoes, possibly significant, if mature surface-based convection continues beyond sunset.  The temporal window for tornadoes will be short.  The most likely area for this tornado threat, if it materializes, would be southwestern to west-central Oklahoma.  Given modest storm motion, storms do not appear likely to reach the OKC metro before boundary layer decoupling ends tornado chances for the night.

   Sunday's primary severe weather setup will be to the east of I-35 after the dryline surges through in the morning hours, with southeastern Oklahoma into the Arklatex seeing the highest risk.  Current trends in the NAM suggest against ruling out morning convection in the I-35 corridor, though, and will need to be monitored.

4/23/14 lightning show

   After an awards ceremony for the College of Atmospheric and Geographic Sciences, I headed southwest to just east of Chickasha to catch the one surviving thunderstorm from the evening's low-end severe event out west.  There were quite a few CGs over Chickasha, but activity dropped off a little once I headed back to Norman and met up with a dozen or so met students on the OU parking garage roof.

4/13/14 Oklahoma storms

   This all started as a trip back to Norman from a weekend with my family in Texas, just south of Dallas/Fort Worth.  Wind profiles were highly supportive of severe weather ahead of a dryline across central and southwestern Oklahoma, but a crashing cold front turned out to be the only adequate source of lift given some mixed-layer inhibition in place.  The trip north began in light rain after church services and lunch.  Skies quickly cleared to the north and west.  I stopped briefly in Sanger, TX and south of Thackerville, OK to investigate radar echoes that popped up near the Red River, but the showers appeared both shallow and elevated.  The low-level jet was evident by then in low cumulus fragments shooting north-northwestward.  Meanwhile, the OKC metro was catching the southern end of the QLCS resulting from the cold front overtaking the dryline.  As the QLCS expanded rapidly southward, it became obvious there would be no pure dryline supercells.

   I was about to venture northward on I-35 and aim for Norman through a gap in the line when the southern end of the QLCS began firing off short-lived supercell structures.  At I-35 and U.S. 70 near Ardmore, indecision set in.  I wanted the "tail-end Charlie," which would have been best intercepted along U.S. 77/I-35 to my north, but expected another cell to take over farther south on the front, making a westward play necessary.  After a couple false starts, I hedged my bet and scooted north on I-35 to head west on Highway 53.  Flying west through rolling hills in the middle of nowhere, I came up to the first sight of interest--a rainy lowering far to the northwest, close to where a brief tornado had been sighted earlier, with a little shelf cloud to its south.  At that distance in that terrain, there was no way to see what was happening near the ground.

   At first the plan was to get west to Highway 76 near Healdton and then position north or south, but the storms had other ideas, barreling southeastward and cutting off that route.  I met the gust front along Highway 53 northeast of Healdton.

   I stayed a little too long.  With a solid wall of precip maybe a mile out and closing, and winds whipping dust off the backroads, I got a new radar update and saw quite a bit of low-level shear on top of my location.  Visually, nothing was too threatening, but a tornado had been confirmed with the next cell up the line and I didn't want to find out what might be in the rain.  I zigzagged generally southward on backroads to Lone Grove.  (Thank you, AT&T, for somehow getting me maps and radar out there.)  This completed a loop, back to the earlier decision point near Ardmore.  The new tail-end cell exhibited very strong mid-level rotation, with low levels invisible so far from the NWS radars, and was tornado-warned.  Ultimately, if I'd stuck with my original thought of going west on U.S. 70 toward the newer cell an hour or more prior, I'd have missed the marginal structure shots on Highway 53 but probably could've had better down south near Ringling.  Lesson learned.

   As it was, the storm was all over U.S. 70 near Wilson at that time.  The number of chasers and locals alike driving into the teeth of a tornado-warned HP supercell on NWS Norman's first tornado day since El Reno was disappointing.  There was a feature of interest partially wrapped in rain, but it looked disorganized and was just a ragged gap between precip cores by the time I pulled over for a picture.

   Turning around, I planned to return to I-35 and go south to intercept the southeastward-moving storm near Marietta.  The cell to the north was passing close to Ardmore with a bit of rotation, but south was the better and easier play.  Rolling south on I-35, I began to see the huge bell shape of what I was chasing.  The structure was spectacular--so much so that many chasers, including a crew from KOCO, were stopping along I-35.  As a rule, I won't stop on a limited-access road unless I'm about to die or the tornado of the century is scouring a field by the highway.  Pointing the camera in the storm's general direction while still watching the road for chasers weaving on and off, I did manage to get some of the structure.

   I jumped off I-35 at Overbrook and cut over to U.S. 77 so that I'd be able to pull over and stop.  What looked like a funnel, in a similar shape to the tornado that had touched down earlier, appeared on the north side of the heaviest precip.  By the time I got clear of trees and stopped on the shoulder, it had all but vanished.  What was left of it is above and just to the right of the bare tree in this view:

In this photo from a few seconds later, contortions in the edge of the precip might be a small gustnado:

As everything on the other side of I-35 suddenly disappeared into rain and hail...

...I bailed southward to Marietta.  Though any possible circulation was embedded deep in heavy precip, the storm was still tornado-warned and sirens were wailing in town.  Daylight was nearly gone, and road options and suitable terrain both looked hard to come by east of Marietta.  I stopped to watch the core blast through.

Finding a gap in the line behind that cell, I squeezed through and finally finished the trip to Norman.