Green Sky Chaser

13 July 2010 Chase Log

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Target Area: Aberdeen, South Dakota (Click on city names for Yahoo! maps links)

Chase Area: Wahpeton, South Dakota to Pelican Rapids/Fergus Falls, Minnesota

Observations: one supercell, at least two wall clouds, lightning, two pheasants, and a meteor

Distance: 710 miles

Time: 14.5 hours

Chase Team: Jeff Makowski, Dean Narramore, and myself

SPC Convective Outlook: Slight Risk (Click to see SPC products, data, and storm reports)

Chase Setup: A vigorous shortwave trough was moving through the Dakotas. A surface low was situated just north of North Dakota with a warm front extending southeast through Minnesota and a cold front extending southwest through central North Dakota. Winds were from the southeast in western Minnesota with surface dewpoints in the mid-60s. In west central Minnesota, northeast South Dakota, and southeast North Dakota, MLCAPE values were between 1500 and 3000 J kg -1. The 0 to 6 km bulk shear in these areas was 40 to 50 knots, with effective SRH values as high as 450 m2 s-2.


Chase Log: We left Grand Island, Nebraska in the morning, and headed up to Aberdeen, South Dakota. The day looked fairly promising for tornadic supercells, but the cap was so strong that we worried we might have to go further north and that storms might not even form until near dark.

After waiting for at least a couple of hours in Aberdeen, we decided to just drive up to North Dakota as none of us had been there before. We wandered around southeast North Dakota for a little while as we watched storms pop up to our east.

Figuring that the storms were too far east for us to catch up with them before dark, we ultimately decided to start heading back south. However, with a bit of light left, we noticed the base on the nearest storm was starting to lower...so we changed direction again and drove in to Minnesota!

We chased the supercell up to Pelican Rapids, where we stopped atop a hill and watched the lightning after dark. There was a tornado reported on the storm at this time, but all we saw were some brief lowerings in between lightning strikes. Eventually we just had to call off the chase, and drove back down to Watertown, South Dakota for the night.


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