Wednesday, June 27, 2012

6/27 - 10:40am MDT - On the Border

Yesterday's chase logged us a marathon 814 miles as we traveled from just north of Rapid City, South Dakota up to the Canadian border in Montana and then back down again to I-94 in Montana just west of Miles City. The good thing is that it was worth the drive because storms that formed in Sasketchewan had a tail-end just across the border in Montana. This tail end, referred to as "tail-end Charlie" by chasers, had quite a bit of rotation in it and put down quite a few finger funnels that were clearly in rotation. The dry winds from the west pushing this line of storms along were insane too, causing a nearly constant 50 mph crosswind for us as we drove northward from Glasgow, Montana. Our target area shifted considerably north and west during the day because temperatures in Eastern Montana and Western South Dakota got much warmer than expected and drove the best environment toward the border. As we suspected the best storms were in Canada across the border from us, but we can't go there since we're not equipped nor allowed to enter there. It was certainly an exciting day yesterday and we're happy we made the drive! I can now say that I've been to both the Mexican and Canadian borders this chase season.

Today we're diving southward toward the Northeast Colorado and Western Nebraska to catch some storms that a cold front moving down that way will generate. Surface winds may turn out of the east a little bit near and along the front, so it is possible that we'll get some upslope flow to aid storm genesis along with the front. Dew points will be near 50 degrees, which may sound low but is actually just fine for storms given the high elevation.

Upper-level winds around 18,000 feet (500 mb) will actually be quite favorable today because of a shortwave trough embedded in the overall disturbance moving through the northern part of the country and Canada. Winds at that level out of the southwest at around 35 kt are being forecast by the RAP model and that's not too bad given some of the past environments we've chased in this week. The main issue today will be the strong cappping we've dealt with all week due to warm air at the mid-levels, but surface heating should be enough to break the cap and form a few storms.

The Storm Prediction Center has issued only a general thunderstorm risk for our target area today, but it does include a 5% severe wind risk. We're still quite a few hours out from being in the area since we're still in Montana, but we should make good time and be there as storms begin to form.

The latest updates on our chase are available on my Twitter and Facebook accounts!


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