SPC AC 260526
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1226 AM CDT Wed Apr 26 2017
Valid 271200Z - 281200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM A PORTION
OF THE SOUTHEASTERN STATES INTO THE OHIO VALLEY AND GREAT LAKES...
At least a marginal risk for a few severe storms capable of isolated
damaging wind gusts and hail is expected from the Southeast States
into the Ohio Valley and Great Lakes on Thursday.
Lead shortwave trough embedded within a broad synoptic trough will
continue northeast through the Ohio Valley and Great Lakes early
Thursday. Farther upstream, a series of vorticity maxima north of an
evolving, strong upper jet core will advance southeast through the
Great Basin, southern Rockies and southern Plains. The surface
cyclone attending the lead shortwave trough will occlude over the
Great Lakes, while trailing front continues through the OH and TN
valleys. The southwestern extension of this front will stall and
return north as a warm front across TX in response to lee
cyclogenesis over the southern High Plains.
Richer low-level moisture with dewpoints in the 60s F will reside
over a portion of the Southeast States warm sector, contributing to
marginal to moderate instability. It is likely that storms will be
ongoing from middle TN into AL and the FL Panhandle, and some of
this activity could pose an ongoing severe risk as it continue east
during the morning into the early afternoon given favorable wind
profiles but modest instability. Tendency will be for the deeper
forcing and stronger low-mid level winds to gradually shift north of
this region in association with shortwave trough moving northeast
through the Ohio Valley and Great Lakes. This may serve as a
limiting factor for a longer duration, organized severe threat.
Nevertheless, this area will continue to be monitored for a possible
slight risk in future updates.
...Ohio Valley and Great Lakes...
The feed of richer low-level moisture will become limited as the
cyclone occludes over the Great Lakes region. However, at least
marginal instability within a strong shear environment will exist in
pre-frontal warm sector, and storms might pose some risk for a few
instances of isolated damaging wind gusts and hail as they develop
east during the day. This region will also be monitored for a
possible slight risk in later updates.
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z