cdcollura
EF5
Good day all,
Not a whole lot to report on near the Lacross, Wisconsin area on Saturday, May 26. I was in Chicago for the weekend so going to this area was not a killer is it would have been from Dayton, OH!
Full chase report is below...
May 26, 2007 was a storm chase that should classify as the first official "bust" (where the atmosphere does not "cooperate" as expected) of the 2007 season. In some cases, the term "bust" can be ambiquous. Forecast-wise, May 26 looked like a great day for severe storms as a rather strong cold-core low was moving across North Dakota with a surface low southeast of it. This would set-up a warm front and cold front scenario with backed SE surface winds and 500 MB winds from the SW at 50-60 Knots. The primary target was set at the tri-state intersections of Iowa, Minnesota, and Wisconsin. With a trip to Chicago already planned for the weekend, why not spend Saturday, May 26 chasing this setup?
The initial target was set on Saturday as Lacross, Wisconsin. The chase began by leaving Dayton, Ohio on Friday, May 25 and heading west on Interstate 75 then Interstate 65 and Interstate 80 / 94 into Chicago to spend th evening. On Saturday, May 26, the target area was Lacross, Wisconsin and to get there I needed to take Interstate 90 to Interstate 39 to Rockford, Illinois then north into Madison, Wisconsin then take Interstate 90 to Lacross. Meanwhile, the Storm Prediction Center put out both their 16:30z and 20:00z convective outlooks and had a 5% tornado, 15% damaging hail, and 15% damaging wind in a slight-risk probability nearly bulls-eyed right over my primary target of Lacross, Wisconsin.
The biggest issue with this (otherwise great) setup was INSTABILITY. Cool and gloomy conditions persisted near the warm-front and over-spread a large portion of the warm sector with temperatures struggling to make the low 60's F. Once in the target area, the uneasy feeling of this unusually large cool pool of air messing up such a good setup became apparent, with the only hope of ANY storms being in a narrow axis of instability (< 500 CAPE) ahead of the cold front in late afternoon. SPC issued a Mesoscale Discussion (MCD 0897) for the area near Lacrosse and in western Wisconsin / Eastern Minnesota. The discussion also stated a watch was likely to be issued, but since instability was so limited, no watch ever was posted. All in all, only towering cumulus developed in the late afternoon in the target region. With such low CAPE, parcels were unable to reach the LFC (Level of Free Convection) and became easily toppled by the shear and / or got ahead of the warm-front boundary and became elevated and weakened.
The chase ended with only highly-sheared low-topped light showers developing. No "deep" convection. The chase ended in disappointment by returning along Interstates 90 and 39 back through Madison, Wisconsin then through Rockford, Illinois. The evening was spent in Chicago, Illinois with a return to Dayton, Ohio via Interstates 80, 65, and 70 the following day (Sunday, May 27). This chase would NOT have been attempted had previous plans to visit Chicago not been made. Total mileage for this trip was 1,305 miles.
Not a whole lot to report on near the Lacross, Wisconsin area on Saturday, May 26. I was in Chicago for the weekend so going to this area was not a killer is it would have been from Dayton, OH!
Full chase report is below...
May 26, 2007 was a storm chase that should classify as the first official "bust" (where the atmosphere does not "cooperate" as expected) of the 2007 season. In some cases, the term "bust" can be ambiquous. Forecast-wise, May 26 looked like a great day for severe storms as a rather strong cold-core low was moving across North Dakota with a surface low southeast of it. This would set-up a warm front and cold front scenario with backed SE surface winds and 500 MB winds from the SW at 50-60 Knots. The primary target was set at the tri-state intersections of Iowa, Minnesota, and Wisconsin. With a trip to Chicago already planned for the weekend, why not spend Saturday, May 26 chasing this setup?
The initial target was set on Saturday as Lacross, Wisconsin. The chase began by leaving Dayton, Ohio on Friday, May 25 and heading west on Interstate 75 then Interstate 65 and Interstate 80 / 94 into Chicago to spend th evening. On Saturday, May 26, the target area was Lacross, Wisconsin and to get there I needed to take Interstate 90 to Interstate 39 to Rockford, Illinois then north into Madison, Wisconsin then take Interstate 90 to Lacross. Meanwhile, the Storm Prediction Center put out both their 16:30z and 20:00z convective outlooks and had a 5% tornado, 15% damaging hail, and 15% damaging wind in a slight-risk probability nearly bulls-eyed right over my primary target of Lacross, Wisconsin.
The biggest issue with this (otherwise great) setup was INSTABILITY. Cool and gloomy conditions persisted near the warm-front and over-spread a large portion of the warm sector with temperatures struggling to make the low 60's F. Once in the target area, the uneasy feeling of this unusually large cool pool of air messing up such a good setup became apparent, with the only hope of ANY storms being in a narrow axis of instability (< 500 CAPE) ahead of the cold front in late afternoon. SPC issued a Mesoscale Discussion (MCD 0897) for the area near Lacrosse and in western Wisconsin / Eastern Minnesota. The discussion also stated a watch was likely to be issued, but since instability was so limited, no watch ever was posted. All in all, only towering cumulus developed in the late afternoon in the target region. With such low CAPE, parcels were unable to reach the LFC (Level of Free Convection) and became easily toppled by the shear and / or got ahead of the warm-front boundary and became elevated and weakened.
The chase ended with only highly-sheared low-topped light showers developing. No "deep" convection. The chase ended in disappointment by returning along Interstates 90 and 39 back through Madison, Wisconsin then through Rockford, Illinois. The evening was spent in Chicago, Illinois with a return to Dayton, Ohio via Interstates 80, 65, and 70 the following day (Sunday, May 27). This chase would NOT have been attempted had previous plans to visit Chicago not been made. Total mileage for this trip was 1,305 miles.
