Gravity Waves

[Steve Dedman]

In Shane's thread about strong violent tornadoes with low prob fcst, Dean mentioned gravity waves effecting the strength of the Parkersbug EF5.

Could some of you fine folks expand on that? How do gravity waves go about enhancing (or inhibiting) the strength of a tornado? Maybe explain exactly what they are, and what their general effect is atmospherically as well?

Are these waves forecastable events? Can we look at something like a CAPE chart to see probabilities? Or is the effect just something you realize is there during or after the event?

Thanks!

 

[Chris Lott]

I don't know if this will help, but here is a study put together by Lon Curtis and Al Moeller of the Jarrell,TX tornado that formed along a gravity wave. Pretty interesting.

http://homepages.vvm.com/~curtis/Jarrell/Jarrell.htm

 

[Dean Baron]

Hey Steve.

Here is the PARKERSBURG NWS ASSESSMENT that talks about the storm and how they think the gravity waves played a role in the storm/tornado development and their intensity. Its a long read, about 50 pages, but it is well worth it (not all of the pages talk about gravity waves and their roll with the storm).

HERE is the thread from here at Storm Track with a lot of commentary from members about this topic which has some good info too.

From what I remember gravity waves cant be predicted, but they can be seen on visible satellite or (I think) even some times on radar. But I'll leave it at that, the links I posted should fill you in on what you want to know.

 

[Wes Carter]

Here is a short paper on gravity waves: http://mcwar.org/library.html. I read a paper a while back that went in depth about the Jarrell, TX F-5 and the suspected effect of gravity waves but I can't find it. I bookmarked the one posted earlier by Chris Lott and look forward to reading it.

 

[mikegeukes]

Iowa State University has a Real Time Gravity Waves Page
http://www.mesoscale.iastate.edu/jimmyc/rtgrav.html

Mike

 

[Steve Dedman]

The discussion in the advanced forum about the "strange cloud formations" some describe as ship trails led me to this page:

http://www.spc.noaa.gov/coolimg/gwavecb.htm

The explanation set off the lightbulb for me. Makes all kind of sense now.

Thanks for the input!

 

[Paul Knightley]

I tried the Parkersburg link above but it failed - this one works though http://www.crh.noaa.gov/images/dmx/ParkersburgServiceAssessmentFinal_Jan29.pdf

 

[Chad Cowan]

In Shane's thread about strong violent tornadoes with low prob fcst, Dean mentioned gravity waves effecting the strength of the Parkersbug EF5.

Could some of you fine folks expand on that? How do gravity waves go about enhancing (or inhibiting) the strength of a tornado? Maybe explain exactly what they are, and what their general effect is atmospherically as well?

Are these waves forecastable events? Can we look at something like a CAPE chart to see probabilities? Or is the effect just something you realize is there during or after the event?

Thanks!

Gravity waves are relatively common in the wake of thunderstorm complexes (MCSs, MCVs, derechos, etc). The stable cloud bearing layer in these cases is prime for showing the 'ripples' spreading out from the updrafts as they act like a pebble thrown into a pond. Depending on a number of factors, if a supercell moves into a gravity wave and ingests the turbulent air, its vorticity may be enhanced.

Gravity wave on August 23, 2007 in Chicago: