May 6, 2010

Triple Tornado Thursday

Thursday, May 6:
SHORT: I will be leaving Lawrence here soon for Ottawa, KS where I expect initiation in the next couple hours. Very large hail will be likely here in eastern KS, and there is an outside chance at tornadoes. If I do see one, it will be the third Thursday in a row. I will try to get the live stream up, but I've been having difficulties with that since switching to Blackberry and can't guarantee it will be without hiccups. My video of the tornado near Washington, KS and other fun stuff from last Thursday is on the Videos page.

LONG:Well the new Day 1 outted my favorite lesser-known forecast reflectivity model so I don't mind talking about it now... the HRRR has been absolutely stellar this season with predicting initiation (timing AND location). For each of the last 6 hourly runs (up to 18z) it has been initiating convection between 23z and 01z along the nose of the strengthening LLJ in essentially the same location in eastern KS. With +60kts of effective shear, supercells will be the dominant storm mode. The question is whether or not the storms will be able to form south of the warm front and root in the boundary layer, not atop the stable layer north of the warm front. If they do become surface based and then interact with the boundary, there is a good chance of tornadoes in the 7-9pm time frame, given the strong low-level turning. That's a big if, though. As of right now, I don't think the dynamic ascent and surface heating will be enough to break the cap, I think isentropic lift will be needed for that. Regardless, I'm expecting to see a few significant hail reports to the south and southwest of the KC metro area this evening.

Below is a composite map I threw together of the 17z HRRR's output for 7pm. The fcst composite reflectivity shows a nice blob southwest of Lawrence, right on the WF, and other updrafts further south, into the warm sector. The underlay is the sfc CAPE chart, showing +2000 j/kg south of the front. The white line is the 1500 j/kg isoline from the MUCAPE chart (not shown), which indicates ample elevated instability north of the warm front. LINK:

1 comment:

  1. Dear chadcowan blog author,

    I am hereby contacting you, following a visit of your blog, which I find very appropriate for a publication.

    I am an employee of Bloggingbooks publishing house, which is the new publishing brand of the well-established scientific publishing house, known as SVH Verlag. We are currently actively looking for new authors.

    Bloggingbooks would like to broaden its publication's portfolio and in this respect, comes my question: would you have any interest in publishing your blog posts into book format?

    You will find information about bloggingbooks on our homepage ( The best way to get in touch with me will be per e-mail.

    I am looking forward to hearing from you.
    contact email: m [dot] gorbulea [at] bloggingbooks [dot] de