2017-06-13 EVENT: NE/SD/ND/MN/IA

Discussion in 'Target Area' started by Royce Sheibal, Jun 13, 2017.

  1. Royce Sheibal

    Royce Sheibal Member

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    Here's the short, short version, since somehow no one has written an event area for today.

    Nice trough finally digging south into Nebraska. Weak surface low is located over the Cherry county and basically has stalled out. Occluded front breaks north into the Dakotas, with a warm front branching east into MN. Nice lobe of vorticity located over Central NE and N KS, ejecting northeast. Secondary punch over the black hills.

    Let's focus on the meso since we're only a few hours away. Convection has cleared most of the north target (SE SD). And the south target (all of E Neb) has cleared as well, with some CU field already appearing. A low stratus deck and fog is still present in SD. Meso analysis shows heavy moisture convergence in 3 areas: #1 SW MN near the edge of the MCS, which is being advected up toward Fargo, ND. #2 NC Nebraska near Oneil where winds are slightly backed from the SSE. SREF Plumes indicate this area will be betwen 50-60 kts of shear late this afternoon. #3 NC KS, where winds are more SW and moisture will be pushed into SC / E Neb.

    There are outflows and gravity waves all over the place in SD and MN. For those of you on the northern target I would suggest finding a good intersection of the gravity waves and the differential heating from the stratus deck near the warm front and ride that out. The north target is a more sure bet for tors today.

    For those of you in the southern target, pretty much all of E Nebraska, you've got 3 issues to deal with. #1 - The north central Nebraska Target between Oneil / Broken Bow / Norfolk will likely fire early before shear maximizes, this could lead to big cold pool and a lineout before good STP's occur. Issue #2 - The SC Nebraska target isn't much better, as whilst storms should fire later and be untouched by the north storms, your overall shear profile is weak and your coverage might be poor. Issue #3, E Central Nebraska. Parameters on most CAMS and GFS all setup a nice Goldilocks zone between Columbus and Omaha post 7pm where STP's and SCP's max out as the LLJ kicks up. However, if the storms to the west go linear too fast they could undercut that juicy air.

    Overall, a very complicated chase day should you stay south, less complicated up north but still not outstanding. As for myself, I'll be chasing from home today, so good luck out there. My targets today if I wasn't working: Starting location: O'Neil, NE, moving toward Norfolk, NE.
     
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  2. Jeff House

    Jeff House Member

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    First target did indeed work out best per Dean Baron REPORT thread. Appears the outflow boundary performed better (chaser perspective) than other boundary intersections. Sure storms unzipped all the way to Kansas, and the ENH was correct for coverage. However we are interested in chasable supercells. Nice forecast above SW Minnesota.

    Outflow boundary of course offered excellent low level turning of winds. Research also shows more local vorticity to work with along an outflow boundary. In cases where winds are questionable, even slightly veered, at the TP I favor the OFB. In this case the surface low and fronts included tornado warned cells in the Dakotas; however, surface winds were not backed relative to those in Minn. CF/DL intersected in Kansas, with a LLJ, but the surface winds were not backed. Despite slightly weaker upper level winds, low level features favored Minnesota.
     

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