Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 150917
SPC AC 150915

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0315 AM CST Fri Dec 15 2017

Valid 181200Z - 231200Z

...Monday/Day 4 and Tuesday/Day 5...
The medium-range models including the ECMWF, GFS, UKMET and Canadian
show anticyclonic southwest mid-level flow across the Southeast on
Monday and Tuesday. A moist airmass is forecast to be in place
across the Gulf Coast region where scattered thunderstorms should
persist early in the week. Although large-scale ascent will be
lacking across the Gulf Coast States, lift associated with enhanced
low-level flow should support scattered thunderstorm development
Monday and Tuesday. Strong low-level and deep-layer shear will be
enough for a marginal severe threat. A few damaging wind gusts and a
marginal tornado threat will be possible.

...Wednesday/Day 6 to Friday/Day 8...
On Wednesday, the models develop an upper-level trough in the
northwestern states and move this feature quickly into the central
U.S. on Thursday. West to southwest mid-level flow is forecast to
remain in the Southeast as a cold front moves into the region on
Friday. Thunderstorm development will be possible along the front
during the day. This convection may move eastward to southern
sections of the Eastern Seaboard Friday afternoon as is suggested by
the GFS solution. However, other model solutions do not move the
front that quickly east and show much less convective potential. For
this reason, uncertainty is substantial on Thursday and Friday.

..Broyles.. 12/15/2017 is the U.S. government's official web portal to all federal, state and local government web resources and services.