Hoosier Posted January 6, 2011 Share Posted January 6, 2011 I posted about this in another thread but I figured I'd start a separate one. When we think of the dryline, we think of the Plains because that's where it is usually found due to favorable proximity to the GOM and elevated/mountainous terrain. However, I've found at least 4 cases where this feature or a modified version of it moved much farther east and significant tornado activity occurred. They are 4/3/56, 4/11/65, 4/3/74 and 4/19/96 (I know some of these affected other areas too but my main focus is on the states listed). Cells fired on or ahead of this boundary in all cases. Here are a couple surface maps. This one is from 4/3/56. Anyone living in western Michigan should know about this day. http://www.ejssm.org/ojs/index.php/ejssm/article/viewFile/36/36/672 4/19/96 http://journals.ametsoc.org/na101/home/literatum/publisher/ams/journals/content/wefo/2006/15200434-21.4/waf944.1/production/images/medium/i1520-0434-21-4-433-f02.gif A seasonably strong to unseasonably strong surface low was present every time. Interestingly, all occurred in La Nina years that had a drought in the southern Plains to varying degrees. Perhaps there was some sort of feedback that played a role in tandem with the overall favorable storm setup? It would be fairly time consuming but it would be interesting to see how often this type of thing happens. Clearly this is not a necessary ingredient for significant tornado activity in these areas as I know of quite a few good tornado setups that did not feature a boundary like this. Link to comment Share on other sites More sharing options...
Harry Posted January 6, 2011 Share Posted January 6, 2011 I posted about this in another thread but I figured I'd start a separate one. When we think of the dryline, we think of the Plains because that's where it is usually found due to favorable proximity to the GOM and elevated/mountainous terrain. However, I've found at least 4 cases where this feature or a modified version of it moved much farther east and significant tornado activity occurred. They are 4/3/56, 4/11/65, 4/3/74 and 4/19/96 (I know some of these affected other areas too but my main focus is on the states listed). Cells fired on or ahead of this boundary in all cases. Here are a couple surface maps. This one is from 4/3/56. Anyone living in western Michigan should know about this day. http://www.ejssm.org/ojs/index.php/ejssm/article/viewFile/36/36/672 4/19/96 http://journals.ametsoc.org/na101/home/literatum/publisher/ams/journals/content/wefo/2006/15200434-21.4/waf944.1/production/images/medium/i1520-0434-21-4-433-f02.gif A seasonably strong to unseasonably strong surface low was present every time. Interestingly, all occurred in La Nina years that had a drought in the southern Plains to varying degrees. Perhaps there was some sort of feedback that played a role in tandem with the overall favorable storm setup? It would be fairly time consuming but it would be interesting to see how often this type of thing happens. Clearly this is not a necessary ingredient for significant tornado activity in these areas as I know of quite a few good tornado setups that did not feature a boundary like this. Great work! Here is the GRR NWS take on the 4-3-56 event. http://www.crh.noaa.gov/grr/science/19560403/ Link to comment Share on other sites More sharing options...
Indystorm Posted January 7, 2011 Share Posted January 7, 2011 I had known of the unusual eastward progression of the dry line as a factor in the 1965 Palm Sunday and Superoutbreak but did not know of the others you mentioned. Good research. Yes, we don't need the dryline around here for tornadoes, but it seems to be an extra added ingredient that can really ramp up our svr weather just like in the Plains. Link to comment Share on other sites More sharing options...
blackjack123 Posted January 7, 2011 Share Posted January 7, 2011 It has been quite some years since Indiana and Michigan had a violent tornado. At least 20 to 30 years ago. The last one in Illinois was the Roanoke F4 on July 13, 2004. It probably was a high-end F4 for homes were swept away and a plant was almost completely destroyed. Link to comment Share on other sites More sharing options...
oldlogin Posted January 7, 2011 Share Posted January 7, 2011 Harry---excellent ! are those map types available for different dates , or did you generate them ??? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 7, 2011 Share Posted January 7, 2011 some really great info here on the 4/19/96 outbreak http://ww2010.atmos.uiuc.edu/(Gh)/arch/cases/960419/data/home.rxml Link to comment Share on other sites More sharing options...
Harry Posted January 7, 2011 Share Posted January 7, 2011 Harry---excellent ! are those map types available for different dates , or did you generate them ??? You mean Hoosier? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 7, 2011 Share Posted January 7, 2011 12z sounding from ILX on 7/13/04....LI of -11 at 7am...geez Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 7, 2011 Share Posted January 7, 2011 at the time it was destroying the Parsons plant, had a max delta V of 108kts at that time. This was an insane day going over some things. dew points were pushing 80 degrees and getting over that and some areas with CAPE values around 6,400 j/kg with tops to 64kft Link to comment Share on other sites More sharing options...
blackjack123 Posted January 7, 2011 Share Posted January 7, 2011 at the time it was destroying the Parsons plant, had a max delta V of 108kts at that time. This was an insane day going over some things. dew points were pushing 80 degrees and getting over that and some areas with CAPE values around 6,400 j/kg with tops to 64kft There were not a lot of tornadoes that day but the environment that cell was in just exploded. How do they measure the winds in a tornado on doppler radar? I think its based on knots inbound and knots outbound. I think the Greensburg was around 200kts which is about 220-230mph. Link to comment Share on other sites More sharing options...
Hoosier Posted January 7, 2011 Author Share Posted January 7, 2011 It has been quite some years since Indiana and Michigan had a violent tornado. At least 20 to 30 years ago. The last one in Illinois was the Roanoke F4 on July 13, 2004. It probably was a high-end F4 for homes were swept away and a plant was almost completely destroyed. Indiana had an F4 in 1998. Link to comment Share on other sites More sharing options...
Hoosier Posted January 7, 2011 Author Share Posted January 7, 2011 12z sounding from ILX on 7/13/04....LI of -11 at 7am...geez That first cell in northwest IL was a monster. It produced softball size hail around Dixon. Link to comment Share on other sites More sharing options...
Hoosier Posted January 7, 2011 Author Share Posted January 7, 2011 Harry---excellent ! are those map types available for different dates , or did you generate them ??? Not sure...they are part of a couple of case studies: http://www.ejssm.org/ojs/index.php/ejssm/article/viewArticle/36/36 http://journals.ametsoc.org/doi/abs/10.1175/WAF944.1 Link to comment Share on other sites More sharing options...
Thundersnow12 Posted January 7, 2011 Share Posted January 7, 2011 There were not a lot of tornadoes that day but the environment that cell was in just exploded. How do they measure the winds in a tornado on doppler radar? I think its based on knots inbound and knots outbound. I think the Greensburg was around 200kts which is about 220-230mph. I dont know if the greensburg tornado had that much delta v on radar but greensburg #2 on 5/23/08 did. believe it was around 220kts of gtg shear this supercell is my favorite of any radar image of any one I've seen on radar, what helped was being in VCP 212 and so close to the DDC radar Link to comment Share on other sites More sharing options...
oldlogin Posted January 7, 2011 Share Posted January 7, 2011 You mean Hoosier? Oops--- Sorry Hoosier Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.