I didn't see this discussion thread till now. I orignally targeted down by Harrington, NE. As I was heading through Sioux Falls, I started seeing things on SPC Mesoanaylsis and Vis Sat that made me like the SW/SC MN area. However, it just wasn't enough to draw me and I went for the more conservative bet of Harrington, NE. This still wielded a couple of nice supercells, including a brief mothership appearance.
Some of the things I noticed:
-By mid-afternoon clouds had cleared up to the Minnesota border.
- 2 or 3pm mesoanaylsis started to indicate 0-3km CAPE in this area.
- The highest areas of low level shear 150m2/s2 was moving in SW MN.
- Higher Td's were coming out of Iowa, well into the mid 70's.
- The cell was north end Charlie and was fairly isolated for most of it's life. While cells further south went quicker. Surface obs show winds completely backed to the east in advance of SFC LOW.
The 0z MPX sounding indicated a VERY deep moist layer with ML LCL's of 500m. It also indicated 250 m2/s2 0-1km SRH and 575 m2/s2 0-3km SRH so it's not to suprising that this tornado was significant.
This is what got the F3 rating, the house was completely destroyed just showing the exposed basement. This would normally get an F4 but they found it was poorly attached and went with F3 instead.
PERHAPS THE MOST NOTEWORTHY ASPECT OF THIS TORNADO WAS ITS ERRATIC
PATH. IT FIRST MOVED EAST FOR 1/4 MILE... THEN SOUTHEAST ABOUT 1/2
MILE... THEN NORTHEAST FOR ANOTHER 3/4 MILE... THEN EAST AGAIN FOR
ANOTHER 1/4 MILE...AND FINALLY IT TOOK A SHARP TURN TOWARD THE NORTH
FOR 1/4 MILE. THE TOTAL PATH LENGTH WAS TWO MILES. ITS MAXIMUM
WIDTH WAS 100 YARDS. THE SECOND TORNADO WARNING FOR WATONWAN COUNTY
WAS ISSUED AT 739 PM.[/b]
Interesting.
UPDATE: It appears this signficant tornado occured without any sort of watch in place, the tornado watch came out right after the last tornado. The SVR watch was stated 'extreme SW MN'.
-Scott.
