TWISTEX project has been fairly quiet the past couple of weeks due to a summertime pattern across the Midwest.  It seems like the incredible tornado season of April and May ground to a halt when the calendar flipped to June.

Past couple of days:

We did manage to have two final days of chasing last Sunday (June 19) and Monday (June 20).

June 19:

Target for this day was in northeast Colorado.  We initially targeted Joes, Colorado when a storm initiated in the Pawnee National Grasslands south of Kimball, NE.  Storm was tornado warned much of its life, but failed to produce a tornado.  We finally gave up on the storm early evening when three storms initiated in southwest Nebraska near a Benkelman-Trenton line.   We decided to target the center storm as it seem to have the best rotation based on RADAR.  Upon our arrival the storm began to weaken.  Right at dusk, the storm strengthened once again and became tornado warned.  Followed an area of strong rotation until it got too dark, thus terminated the mission for the evening.  There were reports of power lines down and numerous power outages, and even some reports of tornadoes after dark, but we were not able to confirm this.

We stayed in Grand Island, NE for the evening.

June 20:

This was a big day for tornado production!  A tight surface low centered in northcentral Kansas moved slowly to the Nebraska border.  Very powerful upper level winds and low level turning provided a good atmosphere for tornadic supercells.  The surface low actually wrapped the warm unstable airmass over the top of the low, and even to the northwest where a tornado producing thunderstorm initiated near Quinter, Kansas.  There is some debate if this storm actually started as a ‘cold core low’ or not.  We eventually targeted these storms crossing into Nebraska heading for Elm Creek, Nebraska.

As it seems to be a continuing theme, TWISTEX caused the first storm to dissipate upon our arrival.  Fortunately, a second storm to the north initiated, and produced several tornadoes that TWISTEX observed. Perhaps the strongest tornado of the day was an EF3 tornado that was reported to be 1/4 mile wide was sampled at very close range southwest of Amherst.  This was a rain-wrapped tornado that was impossible to deploy on, however we managed to collect some MM data fairly close to the tornado.

Other storms initiated south of York, NE where several tornadoes were reported.  We tried to intercept the final storm of the season, but it was moving too fast, and tornado production dropped off significantly upon our arrival.  Mission was terminated by late evening, and stayed in Columbus, NE for the evening.

Future:

Based on model forecast guidance and remaining budget, it was decided to terminate TWISTEX missions for the year.  Overall, we intercepted over 35 tornadoes including several violent tornadoes during the super outbreak in Alabama on April 27.  We managed to capture the entire life cycle of the Canton tornado on May 24th with RADAR, along with mobile mesonet readings from all team members.

We wish to thank the following for their support for our TWISTEX mission this year(no particular order):

Discovery Channel/Original Media        (Discovery.com)
EWR Radar                               (EWRadar.com)
LINE-X                                  (linex.com)
Hyperion Technology Group               (hyperiontechgroup.com)
National Instruments                    (NI.com)
Mastercraft                             (mastercrafttruck.com)
Classic Soft Trim, Inc.                 (classicsoftrim.com)
Tommy Gate                              (tommygate.com)
ATS Diesel                              (ATSdiesel.com
PCB Piezotronics, Inc.                  (pcb.com)
Rigid Industries                        (rigidindustries.com)
FLIR Systems                            (flir.com)
GoPro                                   (gopro.com)
Iowa State University                   (iastate.edu)

Without all of your support, TWISTEX would not have been possible.  I’ve tried my best to include all of the supporters–if I forgot somebody–please let me know, and I’ll resend with corrections!

Thanks to Dr. Howie Bluestein for keeping me on his discussion list–wished we would have crossed paths this year!

I personally wish to thank all of our TWISTEX team members for their dedication, hard work, and persistence as we moved through this very challenging year.  Although this was a record year for tornadoes, most of these days were very challenging to conduct good science missions due to fast moving tornadoes and poor road networks.  We also had our share of vehicle issues (had to get towed once during a chase!).

For me, I move on to my next field program to study lightning.  This is in conjunction with a DARPA funded program called PhOCAL (Physical Origins of Coupling to the Upper Atmosphere from Lightning) working with Dr. Walt Lyons with FMA Research.  I’m also working with National Geographic Magazine to capture a naturally produced lightning strike with our ultra high-speed camera capable of 1 Million frames per second.  We’ll get it done this year!

These multiple programs will start after a week (or so) of rest from being on the road for 2.5 months.  These programs will run intermittently from middle of July through the middle of September.

Past couple of days:

Group had several down days due to the lack of good parameters for severe storms.

Today:

Making a quick call to head out to eastern Nebraska this morning.  Good backed surface flow with strong low-mid level winds with excellent looking hodographs in the Topeka, KS-Lincoln, NE-Red Oak, IA triangle. Preliminary target:  Nebraska City, NE.  We plan to depart around 8 AM, Denver crews are scrambling to meet us for a timely departure.

Tomorrow:

Frontal boundary pushes south into Missouri.  Surface dynamics weakens considerably, and pushes well south of the good mid level flow.  Likely down day, but will evaluate in the morning.

Future:

Future is very uncertain.  Only hope the next several days are ‘pockets’ of reasonable flow at the mid levels, as there are not any significant systems that will move through the midwest until the 17th or so–if one believes these long-range forecasts..

Past couple of days:

Chased a broken line of storms across northern Nebraska on May 30 (Monday).  Several storms were tornado warned, and noted two cloud/ground circulations near O’neill. The first circulation we watched had a brief multi-vortex structure near the ground, but pretty broad circulation overall.  This persisted for a minute.  The second circulation was related to outflow/inflow couplets along the gust front that persisted for several minutes where dust swirl was brought up to the rotating cloud base.  Certainly had the appearance of a Haboob afterwards.

Today:

Tough forecast today.  Looks like we may have storms in Southwest Nebraska, although the model data is sending mixed signals as to convection breaking out.  Some models show no thunderstorms over Nebraska, while others show storm initiation.  Moisture is creeping northwards with a developing strong 850 flow by early evening over western Kansas and Nebraska.  Due to the uncertainty of convection, we plan to hold in O’neill until there is some clarification on storm initiation

Tomorrow:

Another tough forecast call.  Strong mid level trough pushing through the northern plains late tonight with a developing, northward moving surface low with eastward trailing warm front would set the stage for supercell thuderstorms with possible strong tornadoes over North Dakota, possibly northern South Dakota.  The huge fly in the ointment is the very strong cap that is currently forecasted by most of the model runs.  This would render the strong possibility of a blue-sky bust tomorrow.  Otherwise, all other parameters seem to be in place for a big day. The big question is–do we go after this setup with the investment of expenses getting crews to ND?  Tough call.

Currently our plans are to have M3 and Probe hold somewhere in Northern Nebraska tonight after the chase(??) today, and make the call in the morning.  Interesting comparisons to the forecast struggle we had with the big Bowdle tornado day.  Some of the forecast parameters are similar to that big day on May 22nd (Trop flow, similar 500 flow, under a ridge, big worries about cap, etc..) of last year.

Future:

Or lack thereof…  Upper flow dissolves, surface flow weakens–looks like an extended down time that could last a week or longer!  Who knows–the long-term forecast solutions have been terrible so far–so we’ll keep the hope alive.

Yesterday:

Tough chase across Arkansas yesterday.  Targeted northeast Arkansas in in an area where the terrain was reasonable to run ops.  Isolated storms initiated just west of Little Rock around 3:30 PM, and quickly became supercells.  For some reason, most of these storms in Arkansas struggled to produce tornadoes most of the afternoon (although most were tornado warned most of their life span).

Finally, one storm did produce a tornado in West Memphis, AR just before sunset.  Tornado had a condensation funnel half way to the ground and a debris cloud was visible much of its life.  As we crossed the Mississippi river into Tennessee, the tornado actually became a waterspout in the MS river moving east at 60 MPH.  This rotation on the river basically ‘chased’ us into TN!  A very interesting sight.

Tornado was too unpredictable for any deployment attempts.

A few minutes later, the weak tornado dissipated.  Stayed in Memphis, TN for the evening.

Today:

Storm system moved into the Atlantic states with tornado watch boxes in Pennsylvania and New York state.  Too far for us to chase.

Tomorrow:

Zonal/NW flow over Oklahoma is adequate or supercells, however the cap is pretty strong, thus will continue our return to Colorado.  No chase tomorrow.

Future:

Pattern sets up for good shear across Colorado and Nebraska for possible upslope chasing across the front range early next week–if we get enough moisture.

At this point, it appears that Sunday might be our first opportunity in Colorado.

Last couple of days:

On Sunday, TWISTEX intercepted a long-live tornado producing supercell that produced multiple tornadoes in the hills of northeast Oklahoma near Dripping Springs, OK.  Although the local terrain provided significant challenges, the group was able to observe multiple touchdowns along the path were we terminated the chase at Dripping Springs.

This Supercell was located south of the storm that generated the devastating Joplin, MO tornado.

On Monday, the group observed (and collected MM readings) a tornado that was located just south of Fairview, OK.  Tornado lasted about 4-5 minutes with the debris cloud displaced several miles to the west of the funnel.  A few other spin-ups were noted as well.

Tuesday was a big tornado day for Oklahoma and Kansas.  SPC has issued a high risk for tornadoes as the forecast parameters were similar to the big tornado outbreak day on April 27.  Our group intercepted 3 tornadoes, one of which was quite strong near Canton, OK.  We had RADAR running throughout the tornado life cycle, but ground clutter blocked some of the signal early in its life. We went through one velocity fold due to the measured velocity couplet using a high PRF setting.

The ‘wedge-type’ tornado paralleled highway 51a coming within 1.5 km of us, but never crossing our road for a deployment.

We observed 2 more tornadoes with the same supercell storm before a storm merger happened–which weakened the storm.  At one point we had two tornadoes in progress on either side of the road (51a) only a few Km apart.

Today:

Another active day is ahead for tornadoes–with another tornado outbreak expected for the Ozarks including eastern Arkansas/Missouri and parts of western Tennessee and Mississippi and southern Illinois.

We almost didn’t chase today due to crew exhaustion, however the setup does look decent for strong tornadoes in northeast Arkansas/southeast Missouri.  This terrain isn’t bad to chase in *if* storms initiate in this flat terrain.  At the moment, the plan is to target the cold front between Little Rock and Stuttgart, Arkansas by mid afternoon.  Excellent CAPE and great turning of the winds in the lower levels should be sufficient for tornadoes.

Tomorrow:

Down day as the storm system pushes off the east coast. Will return to Colorado for a few days.

Future:

Looks like a few down days as northwest flow prevails over the Midwest.

Yesterday:

Intercepted tornado producing supercell that crossed over Topeka last night.  Watched in disbelief as the strong rotation crossed right over downtown Topeka.  Fortunately, it did not produce any tornadoes until the storm moved northeast of Topeka.  Partially blocked by trees, team members witnessed the tornado as it crossed Perry Lake.  Deployed the EWR radar several times and was able to watch the velocity couplet on radar as the storm moved northeast.  Limited visibility and trying to cross the Kansas river prevented us from getting close enough for deployment.

Today:

An active day is ahead for several areas of the country today.  The best 500 flow seems to be over Iowa and Illinois by late afternoon, but it appears that the best combination of CAPE and Helicity is over the Oklahoma area.  EHI values over 12 are suggested by the RUC just east of the Oklahoma City area.  500 winds are only 40 knots, but jet stream flow (200 mb) will be pushing 100+ knots.  Huge moisture pool across Oklahoma with southerly winds should provide a good combination for supercells and tornadoes today.  Our initial target is Oklahoma City.

Tomorrow:

The active pattern continues tomorrow for western Oklahoma as the next wave slowly ejects out into the southern plains.  0z models suggest that the wave is slow to eject out, but enough shear should be in place for supercells across western Oklahoma and southwestern Kansas.  The dryline will retreat west overnight tonight as a new surface cyclone develops over the Texas panhandle by tomorrow afternoon.  At the moment, we’re targeting the area around the Gage to the Woodward area.

Future:

Tuesday looks like a very active day for tornadoes across Oklahoma.  Too far out to nail anything specific right now.

Past couple of days:

While enroute to St. Louis on Thursday, we intercepted four tornadoes north of York, NE.  Since we were in a loaner vehicle (TWISTEX truck broke down again in southern MN during a chase).

We drove to St. Louis Thursday evening/Friday morning for RADAR installation.

We’re pleased to announce that we now have RADAR aboard!  EWR has provided us a EWR700 Doppler RADAR system to use during our TWISTEX missions for this year.  This is a huge upgrade for us as RADAR is something that TWISTEX lacked for several years.  The folks at EWR in St. Louis, MO worked tireless last Friday to get this RADAR installed on the truck.

We returned to Denver on Saturday with the new RADAR system aboard, and began work on getting the new probe instrument prepared for our departure on Thursday.  Through the tireless efforts of our crew, we now have the new 500 pound tornado in-situ instrument aboard and ready. Hopefully, the instrumentation will continue to work pending the long ride to our target.

Huge maiden voyage on many fronts for TWISTEX today.

Today:

Somewhat of a complicated forecast today as a low deepens in southeast Colorado (per morning RUC analysis).  Strong backed flow across the warm front on I-70 and points south suggest good tornado potential from Wakeenny to Russell to Ness City triangle.  Storm initiation should happen by mid afternoon.  At the moment, we’ll target Hays for crew meet-up by early afternoon.

Tomorrow:

Problems with tomorrow’s forecast with overnight precip.  Model data suggests storms will be in place all day, limiting any instability for afternoon.  At this point, chances are pretty slim for operations, as the wave weakens a bit–but will evaluate later.

Future:

Future uncertain through the weekend–looks like the best day after today could be on Tuesday with the next wave emerging.  0z GFS suggests that next Thursday could be back in the Mississippi area again.

If the forecast suggest that no opportunities exist after today, we may decide to head back to Denver.

Past couple of days:

Near total cap bust for TWISTEX on Sunday and Monday.  Sunday, we targeted the eastern Nebraska area, and storms developed near Presho, SD, where a weak, very short-lived tornado developed.

Monday, we targeted an area near Murdo, where storms actually developed about 60 miles to the west (around Kadoka) after sunset.  Although it would have been great to see these storms initiate, we terminated operations at sunset.

Today:

A reasonable setup exists today in west central Minnesota today.  0-1 KM shear and cape are huge, although some of the latest RUC model runs suggest weakening surface flow.  Most forecast models break out precip west of the Minneapolis/St. Paul area, thus the TWISTEX group plans to give it a try.

The big challenge is to get to the Kansas target in time for tomorrow. We stand the chance of the target being capped off for the third time in a row today–but its a chance the crew wishes to take given the grim long-term forecast.

At the moment, it looks like the best combination of cape, shear and lift appears to be west of the Minneapolis/St. Paul area.  Hopefully, initiation will happen a bit further west and south..

Tomorrow:

Looks like a big day for Kansas and Oklahoma tomorrow.  Strong upper level flow and reasonable hodographs suggests that tornadoes are possible both in Kansas and Oklahoma.  The big trick is to get to the best area in time for tomorrow from Minnesota.

Future:

Thursday may have one last fragment of opportunity before the huge omega block pattern settles in over the midwest.  Haven’t looked at Thursday to make a determination-we MUST get to St. Louis for RADAR installation before the end of the week.

Blocking pattern may persist for a week or even longer.  Although painful to endure, this will give us time to finalize our instrumentation for the balance of May and June.

Assisted with the relief effort in Tuscaloosa and Birmingham, Alabama clearing trees and assisting with the search effort.  Amazing damage with homes totally destroyed, and trees completely stripped.

One of the amazing facts we’ve heard is that collectively there are roughly 1,000 miles of tornado tracks that were generated across Dixie Alley last week-most with devastating damage.

Truck blew a turbocharger during the super outbreak chase, and was in the shop for a week afterwards getting the work done.  Unfortunately, it disrupted the radar installation plans last week, and now the next round of severe weather begins today(perhaps).

Today:

Huge thermal ridge across most of Kansas, Oklahoma, and Texas.  Perhaps a few high-based storms would initiate near the Rio Grande under the southern branch of the subtropical jet stream.

12z model data suggests that storm initiation may occur on a convergence/wind shift line from Lincoln, NE to Sioux City, SD line. Impressive low level shear and storm relative flow suggest a narrow window for tornadoes within an hour or so of storm initiation.  Meager jet stream flow is a problem, but should be sufficient-for a while before the storms become rain wrapped.  Storm system will evolve to an MCS after dark, and will drift into Iowa through the evening.

Our target is a Lincoln to Fremont, NE line.  Storms should initiate by late afternoon.  Hopefully, storms do initiate.

Tomorrow:

Model data very inconsistent from day to day, but the general feeling is somewhere in South Dakota with the wave slowly nudging its way out. Won’t speculate, as it will change tomorrow.

Future:

Very uncertain–current thinking is this wave will push through the midwest by Thursday allowing time for RADAR installation in St. Louis on Thursday or Friday (depending on timing).

Yesterday:

Historic tornado outbreak in Dixie Alley yesterday with a reported 162 tornadoes (as of SPC this morning).  All of the severe weather parameters were textbook perfect, with sickle-shaped hodographs everywhere in Mississippi and Alabama, and with incredible low level shear, provided the perfect environment for destructive tornadoes. Almost every storm that initiated in Dixie Ally created tornadoes sometime during their lifespan.

Intercepted numerous violent tornadoes including the long-track tornado that moved through the Tuscaloosa and Birmingham area claiming numerous lives.  These tornadoes were moving at 50 MPH making any kind of instrument deployment extremely dangerous.  We witnessed the Tuscaloosa tornado about 30 miles to the southwest of Tuscaloosa, and immediately called emergency personnel warning them of the tornado in progress.

All of these tornadoes were only intercepted once as they passed the highway in front of the team.  One interesting item of note–these tornadoes were passing through trees that were 40-80′ high, and noted that due to the surface roughness(created by the trees themselves), the tornado vortex was very disorganized near the ground, and by visual observations-the collective wind speed was considerably less.   Even these violent tornadoes were not simply a ‘buzz saw’ moving through the trees maintaining good vortex structure.  As the vortex crossed the road in front of us, it briefly ‘organized’ into a continuous ‘cone’, then broke apart as it progressed to the east back into the vegetation.

Kudos to the entire team yesterday.

Today:

Today begins a multiple drive day back to Colorado.  There is a small opportunity for a chase in SE OK on Saturday, but this will be carefully monitored and weighted on delegating time to fully prepare for full TWISTEX operations in a week.

RADAR installation will likely commence sometime next week if all the hardware is ready.

Beyond:

After a brief return of severe weather in OK on Saturday, we might get a long needed break for the crew to continue final preparations.