(All days are valid from 12 UTC - 12 UTC the following day)
Note: A severe weather area depicted in the Day 4-8 period indicates 15%, 30% or higher probability for severe thunderstorms within 25 miles of any point.
PREDICTABILITY TOO LOW is used to indicate severe storms may be possible based on some model scenarios. However, the location or occurrence of severe storms are in doubt due to: 1) large differences in the deterministic model solutions, 2) large spread in the ensemble guidance, and/or 3) minimal run-to-run continuity.
POTENTIAL TOO LOW means the threat for a regional area of organized severe storms appears unlikely (i.e., less than 15%) for the forecast day.
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 010851
SPC AC 010851
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0351 AM CDT Wed Nov 01 2017
Valid 041200Z - 091200Z
Substantial height falls will occur across the Plains and into the
Midwest on Sun/D5 with parallel shortwave troughs. The strongest
wave will move across the northern Plains, with the secondary one
across the central Plains into the Midwest. At the surface, a cold
front will extend roughly from MI into MO and OK, with the
possibility of mid 60s dewpoints ahead of it and MUCAPE values in
excess of 1500 J/kg. This may result in severe thunderstorms from IL
and southern WI across lower MI and IN Sunday and Sunday night. The
main threat will be large hail and damaging winds with long
hodographs and steep lapse rates aloft. Both supercell and linear
storm modes will be possible.
By Mon/D6, the main upper trough will rapidly progress into Quebec,
with a cold front moving across the Northeast. By this time,
instability will be quite weak, but scattered storms and some minor
wind threat appears likely.
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