Thursday, December 9, 2010

Part I: 50+ Years of Hail Data

As 2010 comes to an end, I though it would be interesting to investigate the past 50+ years of the severe weather climatological record. While there are plenty examples of the problems with severe weather reports (e.g., Doswell and Burgess 1988;Grazulis 1993; Brooks and Doswell 2001; Brooks and Doswell 2002; etc.), they are the only "ground truth" data available to researchers. For part 1 of this series I will be examining hail data; however, I plan to examine tornado, wind, and all reports. It should be noted that all data presented in this series is courtesy of the Storm Prediction Center's (SPC) SVRGIS dataset.

Quick hail facts from 1955-2009
  1. 6.6% of hail all reports can be considered significant (+2" in diameter).
  2. May exhibited the highest frequency of severe reports per year at ~1,080.
  3. An average year will see 4,654 severe and 308 significant severe hail reports.

Below, you will find a potpourri of climatological maps/graphs regarding hail data. Enjoy!

(Click for animation)

Watch closely and you will be able to see urban areas and CWA boundaries...


Brooks, H. E., and C. A. Doswell III, 2001: Normalized damage from major tornadoes in the United States: 1890–1999. Wea. Forecasting, 16, 168–176.

Brooks, H. E., and C. A. Doswell III, 2002: Deaths in the 3 May 1999 Oklahoma City tornado from a historical perspective. Wea. Forecasting, 17, 354–361.

Doswell, C. A., III, and D. W. Burgess, 1988: On some issues of United States tornado climatology. Mon. Wea. Rev., 116, 495–501.

Grazulis, T. P., 1993: Significant Tornadoes: 1680–1991. Environmental Films, 1326 pp.

(EDIT 12/09/10: Added normalized county map)

Sunday, June 6, 2010

Damage and Comments on 6-5 Tornadoes

Damage pictures from the tornado that passed through Streator, IL can be found here.

A copy of the NWS PNS statement can be found here.

National Weather Service lead forecaster Gino Izzi and I covered the Magnolia to Streator damage and came up with high-end EF2. There were a few arguments for EF3 at a location in Streator where a 8" cinder block (with steel reinforcements) garage was partially destroyed. Given that all of the surrounding damage was indicative of EF2, Gino and I did not feel comfortable assigning EF3 in that location. East of Streator, there were 6 high tension power lines down. DOD/DI for these lines is low end EF3, but there were no structures to confirm any of this damage so I'm not sure if Gino is counting it. According to everything we can piece together (including reports from Paul Sirvatka) the low-level rotation was phenomenal with intermittent touchdowns. Maybe the velocities just off the surface were EF3 allowing the high elevation/tension wires to become susceptible.

Things to note:

1) There is no special recipe for tornadoes :)

2) LLJ is *very* important

3) WFs in IL are magic

4) WFs in IL are very magic

I've archived a bunch of data from the setup and hope to analyze it in the coming months after I finish working on my thesis.

6-5 Western IL Tornadoes

Quick update:

What a day. Don't really care about the tornado count, but it was somewhere near 5. Doing a damage survey with WFO LOT tomorrow morning early, so will be brief:

Witnessed the Elmwood tornado, although not from the vantage point that Walker did. I'm sure some are going to have some amazing pics/video. Thing was beautiful! Didn't get too close...instead stayed back and enjoyed the structure as storms were moving 40+ mph.

Will have much more (including video) soon so check back...

Quick picture from our vantage point:

Wednesday, June 2, 2010

Weak Evening Convection

Click here for a time lapse of some slow-moving weak convection just NW of McNabb, IL during the evening of 6/2/2010. Nothing too spectacular as it was weakening while approaching. I hope to do more night time lapse like this in the near future.

More CG's

Another trip west of Ladd, IL to shoot lightning out ahead of an approaching MCS.

Radar loop of the approaching MCS

Wednesday, May 26, 2010

5-24 Lightning

Another venture out west of Ladd, IL to shoot some lightning on 5-24.

Radar capture from the "Radarscope" app

Tuesday, May 25, 2010

5/17-5-24 Chasing with CoD

Since I've been lazy blogging, I figured I should probably make one big post to get back on track. This post contains the rest of the College of DuPage storm chasing trip (trip #2) that ran from 5-14 to 5-24.
Waiting for storms to initiate in a park (Iraan, TX)

Roll/Leedy storm. Best picture of the trip IMO.

This storm eventually went on to produce the Bowdle tornado (EF 4 rating).

Funnel cloud!

Quarter hail with the culprit supercell in the background

Dumas, TX supercell

Dumas take two

Mothership NE of Dumas

Brandon takes a picture shortly before the storm hits Dumas

Ahhh! Sometimes you don't need a tornado to make a great photo!


Roll/Leedy take two.

Sunday, May 16, 2010

5/16 Crapvection

Yesterday (5/15) was a complete bust with no ‘cool’ images worth showing. We ended the day in Sonora, TX with beers and great stories after another long day of driving. This morning, we again targeted the Fort Stockton, TX area and actually got convection to develop via the Del Norte Mountains to our Southwest. It was apparent during morning analysis that anything convection was going to have a hard time becoming sustained in the weak atmospheric wind shear and lack of mesoscale convergence. We drifted south to catch up to these storms, but they could not sustain themselves without the aid of the mountains. After grabbing some dinner, a nice storm formed to our northwest and began moving toward our location. Unfortunately, as daylight began to wane, so did the storm. Below are a few images despite a rather unexciting day in the beautiful country of southwest TX. Off to Odessa, TX for a good dinner and beers. Tomorrow looks to be the best day of the trip to this point...

Storm forming on the Del Norte Mts.

Storm NW of Midland before sunset. I believe Dr. Walker Ashley was in very good position for this storm, so keep an eye on his blog for a post.

Wednesday, May 12, 2010

Saved by the Bell

Targeted the Clinton, OK area like most and got a pretty decent sunburn. Drifted north closer to the warm front as many convective towers failed to sustain any sort of deep convection. Right as we were about to call of the chase, a couple back to back strengthening radar scans from the storm SW of Woodward caught my attention. As we closed in, the storm became tornado warned. While we were not able to witness any sort of low-level rotation, we were treated to some great structure right before sundown. A saving grace for a disappointing day...

Sunset LP supercell near Woodward, OK

Nice ending to an otherwise disappointing day

Time lapse of LP supercell

A higher resolution video can be found here.

Tuesday, May 11, 2010

2010 Chase Season Starts with a Bang


The 2010 chase season started with a bang for me on Monday. After starting the day in Springfield, MO, it was quite evident that all of the ingredients necessary for tornadic thunderstorms were coming together along the dryline in western OK. After stopping near Wellington for a quick sandwich and data crunching, a storm began to fire just east of the dryline near Chester. The storm quickly induced tornado warning and we were able to intercept it near Lambert. Its appearance was 'elevated' at best during a time when the inflow region of the storm sat nearly stationary for ~15 min. on a day when storm motions were over 40 kts. to the northeast! Due to poor road options, we were forced back east on highway 11 which presented a major chaser convergence issue. By this time, the RFD had kicked and a very strong low-level circulation was present on radar. Since we were chasing the storm east as it was crossing Highway 11 from the southwest, we inevitably crossed the damage path. While some of the damage appeared tornadic in nature, very strong (I can verify :]) RFD winds were likely the culprit to many shredded trees and downed power lines. We were able to witness a rare anti-cyclonic tornado just east of Cherokee. While it was only a brief spin-up on what turned out to be a very big day for tornadoes further to the South, it was a good way to dive right back into chasing after a very long winter.

Walnut size hail. Some was as large as tennis balls!

Briefly tornadic anticyclonic rotation on Highway 11 near Cherokee

Golfballs covering the ground

2 1/2" hail with the culprit supercell in the background
As for today...

I honestly think that today's setup is much more chaser-friendly. The environment down along the Red-River near 00Z is progged to be pretty favorable for supercells with at least an outside shot of bagging a tube before the storms turn to HP bombs. Also, storm motions will be much more manageable. If there is just enough lift along the retreating boundary, this could turn out to be a sleeper day that many have written off...

I will be adding some videos later today/tomorrow...