(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.
Forecast Discussion
ZCZC SPCSWOD48 ALL
ACUS48 KWNS 210825
SPC AC 210825
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0325 AM CDT Thu Jun 21 2018
Valid 241200Z - 291200Z
...DISCUSSION...
Substantial low-level moisture will remain over the eastern half of
the CONUS through the period, with generally weak flow aloft. One
possible focus for severe weather will be a slow-moving shortwave
trough that is forecast to affect the central and northern High
Plains on Sun/D4, and progress eastward across the mid MO and upper
MS Valleys through Tue/D6. Moisture and instability will spread
northward across the Plains ahead of this feature, with only a weak
surface trough and nocturnal warm advection to focus development. As
such, MCSs will be the primary storm mode, with areas of damaging
wind as well as heavy rain. At this time, predictability is low. One
possible area for a future upgrade will be eastern CO into KS on
Sun/D4, as the shortwave trough emerges into the Plains. However,
models indicate the potential for ongoing rain/storms over the area
Sunday morning which decreases predictability.
..Jewell.. 06/21/2018
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