April 25, 2009

Statistics:

Initial Target: Elk City, OK
Departure: Naperville, IL 9:00 pm, April 24
Arrival: Weatherford, OK 11:00 pm, April 25
Intercepts: Elk City, OK 5:30 pm
Tornadoes: 0
Hail: Significant Severe (2.25 inches)
Wind: Non-Severe (not measured)
Features: RFB,  Funnel
Miles: 1117

Summary:

First in two day run to Oklahoma.  Targeted dryline/cold front triple point for initiation of early evening supercells, expecting nocturnal tornado chase.  Rendezvoused with Illinois chasers in Sayre, OK before intercepting severe warned storm near Elk City.  Witnessed small funnel over Floss Lake and encountered 2.25 inch hail core with minor damage to vehicle.  Left storm for tornado warned storm over near Leedey.  Noted gusting out RFB.  Intercepted final storm after dark south of Weatherford noting backlit supercell structure before storms fizzled. 

Crew and Equipment:

Solo Chase.  Equipment: TH-F6A Tribander, and GPS/mobile data card equipped laptop.  Pictures by Skip Talbot

Details:

Saturday and Sunday looked like big days out on the plains with a dryline and stationary cold front setting up in northwest Oklahoma with moderate instability and ample shear.  The cap was a bit of an issue on Saturday, but was forecast to break in the early evening.  With moisture continuing to advect overnight and the dryline retreating with helicity increasing, a nocturnal tornado event was expected.  I targeted Elk City, OK where the triple point was forecast to be.  I left after work on Friday night, and spent the night in the van in central Missouri.
I made it to the target area Saturday afternoon and met up with Brandon Sullivan, Mike Brady, Adam Lucio, Matt Fischer, and co. in Sayre, OK.  The cap started to break on the cold front by mid afternoon well north of us, but we waited for initiation further down the dryline.  A cell finally went up south of us and we broke up for the intercept.  I intercepted the cell just outside of Elk City, OK where I bumped into Darin Brunin and Dick McGowan.  The storm was rather high based but looked to be organizing.  We got some marginally severe hail as it passed overhead.
I moved north out of town towards Foss Lake to keep up with the storm.  A lowering appeared under the base along with a developing rear flanking downdraft notch behind it.
The north end of the horeshoe base had some rapidly rising scud that looked like a developing funnel.  It was a little difficult to discern rotation from this distance while driving, however. 

There is one road around Foss Lake, and there is no room to turn around on it or pull over.  As I drove north I started to get into some large hail.

Mike and Adam were driving right behind me.  Brandon called to alert me of a funnel cloud.  I thought he was talking about the scud condensing on the north end of the base.  Instead there was a small but well defined funnel in the middle of the base.  I admit I was fixating on the other feature and missed actually spotting it, but I did manage to snag it in my photos I shot of the base.
The funnel starts to rope out as the base moves overhead.  The hail started to get massively large at this point.  When I pulled over just north of the lake the hail was about quarter sized, but now golfballs were coming down smacking the windshield and banging loudly on the roof.
The condensation under the base changes shapes.  You can see the funnel on the left side of the image.
The condensation takes on a more convincing funnel shape before it starts to fade.  The funnel starts to rope out on the left side of the image:
The hail continued to increase in size to over 2 inches!  I was seriously worried about losing all the glass in the van so I turned south to retreat.  Mike and Brandon had already fled as Mike got a crack in his windshield.  Adam's crew stuck it out though.  The hail striking the van was incredibly loud.  It sounded like someone beating the roof with a hammer.  It made a loud wrapping noise as it hit the windshield and a dull thud as it hit the ground.  The sound of the hail hitting the guard rails next to the lake was the best though, a loud reverberating clanging.  Miraculously I made it out of the hail with all of my windows intact.  I do have at least a dozen one to two inch dents on the roof and hood now though.
After the hail passed we moved to keep up with the cell, but it was rapidly detoriating.  Mike, Brandon, and I finally made the call to bail on the cell and head on to another on to our northwest that was tornado warned.  The road options prevented us from getting too close, but we saw an RFB with some condensing scud from about 10 miles back.  A long line of chasers went past us bailing for new convection to the south as the storm lost its warnings.  We got in line too eventually, following the O'Keefe's.  We targeted a new cell near Cordell that held a tornado warning and looked promising on the radar.  We wound up intercepting after dark.  The storm had a nice barrel base with an inflow band that was backlit by lightning occasionally.  We watched it as it slowly started to fizzle.  The storms did not ramp up after dark like they were forecast to due probably to the loss of daytime instability. 
After getting some lightning pictures and chatting with the locals we called it a night and headed for the Days Inn in Weatherford, getting in at about 11 pm.
Conclusion:

Saturday was a fun chase and a good teaser for the next day.  The hail we intercepted was the largest I had ever seen and I was thankful the van didn't take more damage than it did.  Tornado reports were really sparse with only a few coming in from KS and Enid, OK well after dark.  The funnel was a decent catch although I missed actually seeing it at the time because I was fixed on another feature.

 

Lessons Learned:

  • Continue to scan the rest of the storm base even if there is a dominant feature as there maybe new developments.