March 8, 2009

Statistics:

Initial Target: Springfield, IL
Departure: Westchester, IL 9:00 am
Arrival: Westchester, IL 3:30 pm
Intercepts: Springfield, IL
Tornadoes: 0
Hail: None
Wind: Non-Severe (not measured)
Features: RFB
Miles: 395

Summary:

Targeted break in fast moving line of embedded supercells near Springfield, IL.  Intercepted tornado warned cell in Springfield before noon, but precipitation obscured structure.  Fell behind storm while routing to follow and was unable to catch up with 60 mph storm motions.  Dropped to unwarned cell noting RFB.  Followed storm until it pulled away as well.  Shot back end of storms in clear air behind fromt before calling it a chase at 1:30 pm.

Crew and Equipment:

Solo Chase.  Equipment: TH-F6A Tribander, and GPS/Cell Phone equipped laptop.  Photography by Skip Talbot.

Details:

The first setup of the year looked little more to me than an equipment test as I watched it approach on the models.  A surface low was to track northeast through IL bringing up near 60 dewpoints ahead of a trailing cold front. Speed shear was forecast to be very strong, but unidirectional.  The weaker directional shear and the forcing on the cold front lead me to believe this would mainly be a linear event.  With no cap the storms were forecast to fire early, so I targeted Springfield at 18z where the best of the marginal instability was forecast to be.
A line of storms went up early in the morning in Missouri.  I expected the line to be completely congealed by the time it crossed into IL, but some veering with height in the lower levels probably kept the cells semi discrete.  I headed down 55 hoping to catch a break in the line.  As I approached my initial target, a cell heading right for Springfield went tornado warned.  The cell exhibited rotation on the radar, and local firefighters reported a tornado.  I core punched the storm as it passed through Springfield.  I was unable to discern much structure as I cleared the southern end.  The winds were quite intense, however.
I exited on highway 54 in a vain attempt to keep up the storm.  The wicked speed shear was causing these cells to move northeast at 60 mph.  Even though the highway I was on nearly paralleled the storm, the tornado warned cell was pulling away from me.  A cell to the south started to overtake me and I got caught in the precip core.  Although it was unwarned, I dropped a couple miles south to see if there was any structure.  There was a rain free base and flanking line on the southwest corner of the cell:
I kept up with the cell south of the tornado warned storm on 54 as best I could.  It too eventually started to pull away.  It also seemed to be weakening, probably due to the moisture mixing out from the veered 850 mb winds.  It was clear skies behind the line and I had a nice view of the convection as it raced away to the northeast.
A few of the cells in the line went tornado warned as they crossed into Indiana.  Once behind a line of storms moving 60 mph, however, there is no catching up.  I called it a chase at 1:30 pm, which is probably the earliest time I have ended a chase.  I made it back to Westchester by 3:30.
Conclusion:

Even though this was a bust by my standards, it was still a fun chase.  After nine months without chasing, being able to core punch a tornado warned storm, see an RFB, and see some sunlit convection is a nice treat.  I also got to successfully test my new Verizon data card and Kyocera cradle router.  My forecast and timing was also pretty close.  I could have gotten on the scene a few minutes earlier to get into a better position to catch the tornado warned storm, however.

 

Lessons Learned:

  • Pick an intercept point for fast moving storms well ahead of the storm's path.