Valid 182000Z – 191200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEAST MINNESOTA AND NORTHERN WISCONSIN…
A few strong storms are possible this evening from northern and
central Wisconsin into southeast Minnesota.
The only change to the outlook is to remove thunder from parts of
western and northern Minnesota where dry air advection is reducing
instability and reducing the chance for thunderstorm development.
.PREV DISCUSSION… /ISSUED 1116 AM CDT Wed Sep 18 2019/
A strong negatively-tilted shortwave trough is rotating
northeastward across ND into northern MN. A trailing cold front
extends across MN into northwest IA. Clouds are prevalent along the
front, but should slowly dissipate by mid afternoon, allowing some
heating/destabilization to occur. This is expected to result in
scattered thunderstorm development near the MN/WI border – mainly
after 00z. Forecast soundings suggest sufficient winds aloft and
CAPE to promote a few gusty/damaging wind reports, but organized
severe activity is not anticipated.
A broad precipitation shield continues with Imelda, with the only
areas of more discrete convective elements along the far eastern and
southern peripheries of the complex. Local VAD profiles show that
low-level shear is not particularly strong in these outer bands.
While transient rotation is possible in the strongest cores, the
tornado threat appears to remain low.