Improbable Twister

 Posted by at 9:48 pm on July 21, 2013  Storm Review  Add comments
Jul 212013
 

Taken from Video Posted on Dan Difranco's Facebook Page

Taken from Video Posted on Dan Difranco’s Facebook Page

Much to the surprise of *everyone*, a small tornado touched down in Springfield this Sunday evening, July 21st!

I first noticed a storm report of wind damage plot on my radar software earlier this evening. The National Weather Service said they would investigate.

Turns out that the damage had a track.  This was verified by video posted on Dan Difranco’s Facebook Page, showing a condensation funnel.

Here’s a link to that video:

https://www.facebook.com/dan.difranco.3/media_set?set=vb.511714911&type=2

Here’s another showing a lowering (trees block lowest portion) on the Instagram page of Joshackworth:

http://instagram.com/p/cDGxZOTKnS/

Estimated Tornado Track From Sunday, July 21st, 2013

Estimated Tornado Track From Sunday, July 21st, 2013

Here’ s the report from the Springfield National Weather Service:

“NWS storm survey indicated that an EF-0 tornado touched down near the intersection of east Cairo Street and south Pickwick Avenue. the tornado traveled east along east  Cairo street and lifted at the intersection of east Cairo street and Glenstone Avenue. Estimated wind speeds with this tornado were around 60 mph. this tornado damaged multiple trees and caused minor damage to roofs.”

Susan Jurgensmeyer, who lives 2 blocks east of Glenstone and Cairo describes it: “I heard the wind, the walnut tree in the neighbors yard was really swaying, and the wind sounded really loud and just came on real fast. It was over in a few seconds, it seemed like.”

This tornado was undetectable on radar.  It  occurred under the updraft of a developing storm.  Radar shows no evidence of rotation that can be distinguished from “background noise”   The echo itself does have a sort of broad “hook” on it which is visible post-storm but would have defied detection in real-time.

Hires radar at About the Time of the Twister

Hires radar at About the Time of the Twister

Here’s my radar review. I’ll have more detail on Monday when I receive the high-resolution data:

 

 

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