|D4||Monday Oct 21 2019 - Tuesday Oct 22 2019
||D7||Thursday Oct 24 2019 - Friday Oct 25 2019
|D5||Tuesday Oct 22 2019 - Wednesday Oct 23 2019
||D8||Friday Oct 25 2019 - Saturday Oct 26 2019
|D6||Wednesday Oct 23 2019 - Thursday Oct 24 2019
||(All days are valid from 12 UTC - 12 UTC)
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
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 highly unlikely during the entire
period (e.g. less than a 30% probability for a regional severe
storm area across the CONUS through the entire Day 4-8 period).
ACUS48 KWNS 170901
SPC AC 170900
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0400 AM CDT Thu Oct 17 2019
Valid 201200Z - 251200Z
The latest runs of the GFS and ECMWF appear to be in reasonable
agreement with respect to synoptic-scale features through Day 4 and
into the first half of the Day 5 period. After this, differences in
the evolution of the large trough progged to crossing the Plains
states Day 4 and then the Mississippi Day 5 begin to become fairly
substantial. As such, confidence in the predictability of the
pattern beyond day 5 is quite limited.
In the mean time, some potential for the evolution of scattered to
isolated severe storms remains apparent over the eastern Oklahoma
and Arklatex region and surrounding areas Day 4 (Sunday 10-20), as a
deepening surface low shifts out of the central and northern High
Plains and eventually reaches the Minnesota vicinity.
Correspondingly, a trailing cold front is shown crossing eastern
Kansas/Oklahoma/western Texas during the afternoon, as warm-sector
destabilization becomes diurnally maximized. As favorably strong
flow aloft overspreads the region in tandem with the advancing
surface front, at least isolated cells -- developing as residual
capping is locally breached -- will evolve within a sheared
environment likely supportive of rotating updrafts.
Storms may diminish somewhat in intensity overnight, but it appears
that reintensification of convection -- and regeneration of
accompanying severe risk -- should occur across portions of the
central Gulf Coast region, as the front continues its eastward
advance through an amply moist/destabilizing low-level airmass.
Again, potential for supercells, and all severe hazards, appears
By Day 6, model differences -- including with location of the
surface frontal position -- have become substantial enough to
preclude continuation of severe risk into the eastern Gulf
Coast/southern Atlantic Coast states.