Mike Z
EF1
Does anyone know why/how the El Reno tornado changed direction from SE to NE? Also, how rare is a change of direction like that?
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- Weather and Chasing
- Historical weather events
- 2010s
2011-05-24 El Reno OK EF-5
- Thread starter Brian McKibben
- Start date
Alex Elmore
EF2
I believe the tornado you are referring to isn't the tornado discussed here, but the May 31, 2013 El Reno tornado. While many maps that display tornado tracks have them moving in a straight line, it's fairly common for tornadoes to deviate from a straight path. This is essentially because tornadoes are formed by interactions between the outflow and inflow of the parent storm. Changes in intensity in either the outflow or inflow could cause a change in a tornado's path. The May 31, 2013 El Reno tornado is an exceptional case, but I believe the change in its path was due to the strong rear flank downdraft that was present in this storm, pushing it more to the NE. It's fairly common for tornadoes to curve to the left (relative to the motion of the storm) near the end of their life span. This tornado just happened to be a pretty dramatic example of that.
Trochoidal/cycloidal motion also probably explains a significant portion of any tornado's track. Imagine a tornado as a single point embedded within a circular mesocyclone that is both rotating and translating. The tornado's path would be defined by tracing the path of the point along the (mesocyclonic) circle as it rolls along in the environment. I believe that explains a lot of sudden and hard right turns such as the one the May 20 2013 Moore tornado took. Such a path also implies an overall leftward curve over the life cycle of any tornado.
I think that environmental influences such as rear-flank outflow or ambient inflow generally only impact a tornado's path during the dissipating or rope stages of a tornado. During the development and mature stages, the parent mesocyclone strongly controls the path of the tornado.
Ethan Lang
EF2
I would really like to see more ratings given due to Mobile Radar. One thing I haven't understood was that if we scan the tornado and see that it obviously is reaching EF-5 wind speeds but only does EF-3 damage (El Reno 2.6 mile wide) then why not actually rate it EF-5. Had the El Reno tornado struck more buildings and residential areas I truly believe we would have seen more significant damage.rdale
EF5
That's called reviving a dead thread
The EF scale is based on damage. ONLY. I'm part of a group that is revising the EF-scale and mobile radar data will most likely be a part of the future process. But for now - rules is rules.
Ethan Lang
EF2
One thing I have taken great interest in is the variation in wind speed between the main circulation and any subvortices. For instance will the 2.6 mile wide El Reno tornado five days after this we saw doppler scans over 300 in some of the subvortices. Whereas the tornado only got rated an ef3 based on the damage.
Warren Faidley
Supporter
The ratings are based on engineering damage reports correlating to specific wind velocities. An EF5 might only produce EF3 or lower ratings depending on what it strikes for the survey. Radar is not official. I disagree with this, if a calibrated radar can provide an accurate wind speed. I witnessed the Red Rock, OK tornado on April 26, 1991 and it was only rated an F4. However, Dr. Howard Bluestein's Doppler crew measured a 270 mph (+) wind speed. For my own satisfaction, I rate the tornado as an F5.
Andy Wehrle
EF5
I think some people are confusing the El Reno EF5 of 2011 with the El Reno EF3 (officially) of 2013.
Ethan Lang
EF2
I am certainly not confusing these two, I have studied the El Reno 2.6 mile wide extensively because it interested me so greatly. That one in particular bothers me with the rating. There is no reason that tornado shouldn't be an EF5Similar threads
