Areas affected…Northern South Dakota…Southeast North
Concerning…Severe Thunderstorm Watch 667…
Valid 300637Z – 300830Z
The severe weather threat for Severe Thunderstorm Watch 667
SUMMARY…The severe threat currently located in WW 667, will
continue and is expected to affect areas just to the east-northeast
of the watch early this morning. New weather watch issuance can not
be ruled out downstream of the current watch and the situation will
continue to be monitored.
DISCUSSION…Latest surface analysis shows a 997 mb low over
southern South Dakota with a warm front extending east-northeastward
from the low into northeastern South Dakota and southwestern
Minnesota. North of the warm front, a corridor of thunderstorm
development is ongoing. This activity is located just to the north
of an axis of moderate instability concentrated mostly above 700 mb.
MUCAPE was estimated by the RAP in the 2500 to 3500 J/kg across
northeast South Dakota. This maximum of instability will continue to
expand east-northeastward into west-central Minnesota over the next
few hours as a low-level jet strengthens in the northern Plains.
This combined with effective shear of 35 to 45 kt will support an
isolated large-hail threat. The hail threat should decrease with
northeastward extent to due weaker instability currently analyzed
across northwest and north-central Minnesota. For this reason, the
threat appears marginal for weather watch issuance.
…Please see www.spc.noaa.gov for graphic product…
LAT…LON 47809530 47629754 46979916 46320054 45910116 45670118
45460098 45320042 45319955 45279887 45369816 45459719
45789594 46649463 47809530