Ginx snewx Posted March 14, 2012 Share Posted March 14, 2012 Yeah, I tried to dismiss it as a water drop on the lens but there are a few other shots that have water droplets on it and you can definitely tell the difference. Plus, you can tell it's in the background and not foreground. I'm thinking since we have never really seen much data and footage from inside tornadoes that over the next couple years more footage like this and from TIV like vehicles will begin to pop up. Just a guess but I was thinking maybe it is an area where extremely low pressure develops for some unknown reason yet and causes water to condense creating a cloud/contrail like entity. Maybe even a combo of expansion cooling bring the parcel down to it's DP producing condensing...possibly related to lower pressures. Edit: Watched it more closely, it appears to happen around trees and obstacles etc. You see this on an aircraft wing when you're taking off if there is enough moisture in the air. It's called wing tip vortices. There is speed shear around the trees so vortices develop spinning at a very high speed producing a region of very low pressure.Then the local temperature in the low-pressure regions drops due to expansional cooling. When the local temp drops below the local dewpoint, condensation of water vapor results in the core of the vortex, making it visible. It's most obvious at 531 Yea that seems plausible, definitively not on the camera face, the pharmacy vid shows a similar vapor like trail. Very cool stuff going on just before the huge increase in wind speeds. Link to comment Share on other sites More sharing options...
AbsolutZero Posted March 14, 2012 Share Posted March 14, 2012 You would be correct. However, the point of my question was that Mie scatterers (which can be large raindrops at higher radar frequencies) will impact CC at C-band differently than at S-band. For example, in pure rain, CC is .98+ at S-band and .93 at C-band. If there's a quantitative algorithm being developed, then the actual numbers may be impacted. Bluestein et al. (2007b) discussed CC numbers in debris (below 0.5 generally), but those weren't intended for quantitative operational use at S-band, obviously. For instance, Ryzhkov et al. (2005) found CC below 0.8 in tornadoes at S-band compared to the .5 found by Bluestein et al. (2007b) at X-band. Thank you for that nice summary. Looks like the NWS invested wisely in 10cm radars. Continues to pay off today with dual pol. If you had asked me 4 months ago if S-band radars would detect EF0 tornado debris, I would have told you no. However, just since December, we've seen TDSs with 3 EF1's and 1 EF0. These were seen very close to our radar (< 12nm) but CC was quite low (~0.50-0.60). See image below of the EF1 which hit near Moreland on 1/21/12. Here's the story in the local paper which shows a photo or two from the event. If you have GR2 and can retrieve the data from 12/22/11 (2230-2330Z) and 1/21/12 (1710-1730Z), would appreciate your thoughts on them. Link to comment Share on other sites More sharing options...
BeauDodson Posted March 15, 2012 Share Posted March 15, 2012 Hey all, this is SNELSON@FFC. That track was surveyed on the ground twice and also by air. Cobb county was also surveyed and found a weak/brief EF1. Very interesting event. I have been studying the TDS in depth since we upgraded KFFC. *Amazing* dataset that surpassed my expectations. I was in Starkville at the SE Severe Storms Symposium (presenting on the Coweta/Fayette county December and January TDSs of all things) on Friday night and watched the event unfold on TWC and nwschat. I returned home and studied the data. Without going into details, there were indeed false detections by forecasters as well as the media once a well defined inflow notch developed in Cobb, Fulton and other counties to the east. Our warnings and statements continued the mention of debris until the last warning on that storm. That said, it was *very* impressive that the forecasters correctly identified the TDS back in Haralson county so quickly and incorporated into the warnings and statements. I'd rather have this rapid detection and incorporation into warnings along with an hour of false positives, than no detection at all! Kudos to the forecasters on deck that night. Based on research from UAH and the ARMOR dual-pol radar, you really do not have a TDS without cc < 0.8, a velocity couplet, AND reflectivity values > 30dbZ. Once the storm entered Cobb county, the low correlation coefficient values were not occurring in the reflectivity hook where the tornado should be but in the inflow notch VERY close (~1/2 mi northeast) to where it should be (at the tip of the hook). The low cc values were indeed superimposed on the velocity couplet but not in an area of higher reflectivity. A very easy mistake to make, particularly when there are NO experts at interpreting real-time dual-pol anywhere! Anyways, we'll keep learning as we go. For now, I'm leading training in the NWS to include reflectivity > 30dbZ *and* knowledge of storm structure to better interpret the TDS. I will be posting some of this data to our web page on the event and/or our facebook page. Steve I think we all look forward to hearing more information on this topic - any PowerPoint presentations would be a plus. I tracked the cells that night and saw much of what you guys have been talking about above. I was impressed with the different radars and their capabilities. I am among the group that believes these new radar features hold a lot of promise when it comes to tracking tornadic cells - and giving more confidence to those issuing the warnings. Link to comment Share on other sites More sharing options...
Hoosier Posted March 15, 2012 Author Share Posted March 15, 2012 NWS Louisville posted this picture of hail damage. Nasty. Link to comment Share on other sites More sharing options...
tornadotony Posted March 15, 2012 Share Posted March 15, 2012 NWS Louisville posted this picture of hail damage. Nasty. Side tangent...some houses in my neighborhood looked kinda like that after 7/17/03 (maybe not quite as bad but close). Ours had a lot of the siding holes but miraculously we didn't lose windows. Most were not as fortunate. Link to comment Share on other sites More sharing options...
Jonbo Posted March 15, 2012 Share Posted March 15, 2012 Like someone took a shotgun to the house. I can't remember the town but it was in Iowa a year or 2 back that had significant hail and high winds that affected basically the entire town. Looked like a warzone. Link to comment Share on other sites More sharing options...
OceanStWx Posted March 17, 2012 Share Posted March 17, 2012 Like someone took a shotgun to the house. I can't remember the town but it was in Iowa a year or 2 back that had significant hail and high winds that affected basically the entire town. Looked like a warzone. Eldora. The monetary damage there far surpassed that from the Parkersburg EF5. Link to comment Share on other sites More sharing options...
*IndyMeso* Posted March 17, 2012 Share Posted March 17, 2012 West Clark Community Schools have released surveillance video of the tornado ripping through the schools in Henryville. The last shot of the gym is pretty incredible. http://www.theindychannel.com/weather/30700293/detail.html There may be better video on another news channel but this is the only one I could find that would work with running off of satellite. Link to comment Share on other sites More sharing options...
Hoosier Posted March 18, 2012 Author Share Posted March 18, 2012 I made this map of the southern Indiana EF4, color coded according to EF scale rating. blue: EF0 green: EF1 purple: EF2 orange: EF3 red: EF4 A few points. The rating for each swath is the maximum rating given in the storm survey and does not mean that every structure experienced that level of damage. In some cases, the exact start/end point of a particular level of damage was a bit unclear (an example is the area near the Clark State Forest -- exactly where did the EF4 damage end?). Ratings were not given in the survey for some rural/forested areas especially for the latter part of the track, so I assigned my own ratings based on damage descriptions given in the survey. Since no extreme tree damage (i.e. debarking) was mentioned, I assigned EF1 for the stretch to the northwest of New Washington and EF1 for the stretch from Paynesville into western Trimble county Kentucky. EF0 was given for a stretch in Trimble county where the survey indicated no observable damage in an area with inaccessible terrain. Link to comment Share on other sites More sharing options...
MN Transplant Posted March 20, 2012 Share Posted March 20, 2012 Holy crap that was close for those guys, wonder how the dogs fared. Man that went from calm to unreal in seconds. I hope those dogs are ok If you go to the Youtube site the person who posted the video says that the dogs and other animals were ok. Link to comment Share on other sites More sharing options...
yoda Posted March 21, 2012 Share Posted March 21, 2012 West Clark Community Schools have released surveillance video of the tornado ripping through the schools in Henryville. The last shot of the gym is pretty incredible. http://www.theindych...293/detail.html There may be better video on another news channel but this is the only one I could find that would work with running off of satellite. I did find this http://news.yahoo.com/video/us-15749625/raw-video-tornado-rips-through-indiana-school-28666373.html#crsl=%252Fvideo%252Fus-15749625%252Fnh-lawmakers-reject-bill-to-repeal-gay-marriage-law-28688396.html Link to comment Share on other sites More sharing options...
Hoosier Posted July 1, 2012 Author Share Posted July 1, 2012 Bump. Here is my tornado count for this event: KY: 20 (1 from IN) TN: 14 (1 from AL) AL: 12 OH: 7 (1 from KY) GA: 5 IN: 5 NC: 3 WV: 3 (2 from KY) MS: 2 VA: 2 (1 from TN) FL: 1 IL: 1 SC: 1 Total: 70 The overall total is different than the sum of the state totals due to some border crossers. Hopefully no mistakes but can't guarantee it. Link to comment Share on other sites More sharing options...
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