EDIT: The new outlook has a better picture
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.