Landspout Tornado Forecasting and Detection

[Bill Tabor]

I thought it would be good to start a thread on landspout tornadoes since April 17th we apparently had a number of them.

What is the state of the art in regards to forecasting them and detecting them?

What features were in place April 17th that indicated a number of these might pop up?

How easy is it to detect them by radar? Can they be detected by radar?

I might note that the 17th these were expected to be low topped storms, but not low topped supercells.

Also I find it interesting that the SPC log for that day lists a number of the tornadoes as 'landspouts' or 'cold core tornado'. Is the public and spotters now sophisticated enough to know the difference and report them accordingly?
http://www.spc.noaa.gov/climo/reports/070417_rpts.html

 

[Mikey Gribble]

Davies has a good paper on this topic. They can be detected by radar, but since there isn't mid-level rotation (mesocyclone) it often doesn't show up until the landspout has already formed.
I don't know much about forecasting them. They typically form from misocyclones along boundaries through vortex stretching when they are ingested into an updraft. Boundary intersections are a good location. Geography tends to favor wind shift lines in certain locations that also focus landspouts (Colorado). Steep low-level lapse rates can also help with stretching, so that is something to look for when forecasting landspouts.
I haven't looked at the setup for the 17th yet and I don't have time tonight, but if nobody else comments on it tonight I will take a look tomorrow morning. I don't know much about this topic, but hopefully this helps.

 

[David Drummond]

April 17th tornadoes around the Lubbock area were cold core tornadoes.

http://www.srh.noaa.gov/lub/climate/Local_interest_events/2007/20070417_landspouts/

 

[Justin Turcotte]

Wakimoto has written some very informative papers on the subject. Look his name up in a journal search. One of his earlier papers was titled along the lines "Non-supercell Tornadoes".