Mesoscale Discussion 1041
NWS Storm Prediction Center Norman OK
1142 PM CDT Wed Jul 11 2018
Areas affected...Northern MN and extreme northwest WI
Concerning...Tornado Watch 271...
Valid 120442Z - 120645Z
The severe weather threat for Tornado Watch 271 continues.
SUMMARY...Severe-weather threat continues across the remaining
portion of tornado watch 271 until 1 AM CDT. A new weather watch
may be needed, if a fast-moving line of storms evolves from the
ongoing storms in north-central Minnesota and tracks to the
DISCUSSION...At 0430Z, mosaic radar imagery showed a broken band of
storms across northern MN, extending from southern Koochiching
County to Becker County, and moving to the east-southeast at 20-25
kt. This activity was continuing to become intense at times, given
the presence of strong instability (MUCAPE up to 3000 J/kg) across
the warm sector. Although the CAMs suggest damaging winds could
become the primary severe-weather threat, especially if a
forward-propagating line can evolve from the ongoing storms, any
storms interacting with the warm front could produce a tornado.
However, further increase in surface-based inhibition should limit
the tornado threat into the overnight.
Meanwhile, the Operational HRRR, while indicating the current
presence of storms in north-central MN, suggests this activity will
weaken during the next 2-3 hours. This scenario is possible, given
the lack of forcing aloft and strengthening surface-based inhibition
each limiting upscale growth.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 46689609 47659507 48239449 48589327 48369252 47959174
47329154 46729121 46139176 45899292 45819344 45879422
46079519 46459582 46689609