(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 220934
SPC AC 220934
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0334 AM CST Fri Nov 22 2019
Valid 251200Z - 301200Z
Monday (day 4) model consensus is that partially modified Gulf air
will begin returning through eastern TX and the lower MS Valley, but
the resulting instability will likely be insufficient for a severe
Tuesday (day 5) Within a broad cyclonic upper flow regime, a
shortwave trough is forecast to amplify as it emerges over the
southern and central Plains. This feature will induce a lee cyclone
that will move through OK and the middle MS Valley during the day
before reaching the Great Lakes late Tuesday night. Moisture return
and destabilization ahead of the trailing cold front might become
sufficient for a severe threat within the strongly sheared
environment from east TX into the lower MS Valley. The ECMWF
shortwave trough is a bit slower and slightly deeper than the GFS
indicating somewhat greater severe potential. However, ensemble 500
mb spreads increase substantially during this period, suggesting low
predictability for now.
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