Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 241716
SPC AC 241716

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1216 PM CDT Tue Apr 24 2018

Valid 251200Z - 261200Z


Isolated strong/severe thunderstorms may develop along the
lower/middle Rio Grande Valley region of south Texas.

...South TX...

Upper ridging is expected to maintain its position across the Great
Basin/northern Intermountain region through the day2 period. As a
result, strong short-wave trough will dig southeast across the
central Plains into the lower MS Valley by 26/12z. In the wake of
this feature, pressure rises across the high Plains will force a
pronounced cold front into extreme northern Mexico/south-central TX
by 18z...then into the lower Valley region by early evening. Latest
guidance suggests strong boundary-layer heating will be noted ahead
of the surging cold front. Inhibition should weaken such that
convection will develop along the front and across higher terrain
west of the international border. Although the primary
moisture/instability axis will extend west of the Rio Grande River,
forecast storm motion suggests strong storms may cross the border
into the lower Valley. Several thunderstorm clusters, or perhaps a
few supercells, will propagate south-southeast within deep
northwesterly flow regime and for these reasons have added 5% severe
probs to portions of south TX. If it becomes more clear that strong
convection will propagate farther east then 15% severe probs may be
added to the lower Valley.

...Middle Atlantic/Southern New England...

Strong low-level warm advection will spread across southern New
England early in the period ahead of ejecting upper trough. Modified
warm sector will struggle to advance inland but large-scale ascent
and weak elevated instability suggest some of the stronger
convection could generate a few lightning strikes.

..Darrow.. 04/24/2018

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