08/13/07 DISC: ND/MN/WI

[Justin Turcotte]

08/13/07 REPORTS: ND / MN / WI

Bending the rules here as this wasn't a true chase but it isn't every day a nice looking supercell falls right in your backyard where no driving is needed. It was moving southeast at 55 mph which would have made chasing futile anyway. The cell developed about 90 miles northwest of my location in Grand Forks and then moved southeast before taking a more southerly component and missing GFK by about 20 miles. It was tor warned near the time I snapped the pic but mesoanalysis graphics and visual suggest the cell was elevated. The cell produced one to two inch hail for most of its life. Your typical supercell updraft rotation was clearly evident in the midlevel cloud layer. This cell more or less died about 60 miles southeast of GFK and was replaced by the beast that tore through central MN and the MSP metro.

 

[Tony Lyza]

Does anyone from the MSP area know more info about what happened in St. Croix County last night? The latest LSR from MPX indicates houses "down and blown over" in the Emerald area with that possible rotational signature from yesterday evening that Jeff Snyder pointed out in the now thread.


1000 PM TSTM WND DMG EMERALD 45.08N 92.26W
08/13/2007 ST. CROIX WI TRAINED SPOTTER

STRUCTURAL WIND DAMAGE HOUSES DOWN AND BLOWN OVER. 4 TO 5
BARNS DAMAGED

 

[beaudodson]

While watching the storm last night it appeared to be a good candidate for a tornado warning. I was a bit surprised that one was not issued. The storm had an impressive signature. Baron was showing 130-140 shear marker. Gibson Ridge was showing every indication that a tornado was at least possible with the cell. I will be curious to see a storm survey. Powerful storm - regardless of what type of event it was. There were a few screen shots over on Eastern. Here is a link to that discussion http://www.easternuswx.com/bb/index.php?showtopic=139714&st=120 . Also check out the hail core on some of those storms. Ouch.

Here is an image I grabbed - great job by the NWS up there. There were plenty of warnings issued. Timely and strongly worded on the wind potential. Nice job.

 

[Eric Whitehill]

While watching the storm last night it appeared to be a good candidate for a tornado warning. I was a bit surprised that one was not issued. The storm had an impressive signature. Baron was showing 130-140 shear marker.

Here's a screenshot of Baron from last night.

 

[Todd Krause]

Does anyone from the MSP area know more info about what happened in St. Croix County last night? The latest LSR from MPX indicates houses "down and blown over" in the Emerald area with that possible rotational signature from yesterday evening that Jeff Snyder pointed out in the now thread.

Hi all...
Unfortunately, we weren't able to take a look right away, so it took until Thursday afternoon/evening before anybody from MPX was able to investigate. There was still plenty of damage (especially to farm buildings, trees, and corn) that had not been cleaned up yet, so I don't think a two-three day delay resulted in a different judgment.

Anyway, with so much damage over such a wide area, it was not possible to look at every spot. Therefore I took a look at (1) the area where the velocity image suggested a look was important, and (2) the worst of the damage areas (e.g. the one house that lost its roof and some walls, a couple other houses that partially lost roofs, and a few other spots). This included a few miles west of Glenwood City. Some areas of (1) and (2) overlapped. The areas I looked at had downburst damage. It is certainly possible that there was a brief touchdown in an area that I didn't see, but I hit those areas where it seemed a tornado would have been most possible.

Unfortunately I only had access to a 35mm camera, so I'm getting the film developed and images scanned. We'll post some info on our web site in a couple days, weather permitting!

Todd
WCM Minneapolis/Chanhassen MN