Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 220842
SPC AC 220840

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0340 AM CDT Sun Oct 22 2017

Valid 251200Z - 301200Z

The medium range models continue to suggest that initial amplified
upper troughing, approaching the Atlantic Seaboard by the middle of
the coming work week, will lose amplitude and accelerate toward the
north Atlantic, as another amplifying wave develops upstream, across
the interior U.S. late this week into next weekend.  Guidance
suggests that this will be accompanied by at least some potential
for significant surface cyclogenesis to the lee of the Rockies.  The
varied depictions of this evolution within the model output
currently seem most conducive to severe weather potential across
parts of the central Plains on Thursday, before an associated
southeastward surging cold front tends to interrupt return flow off
the Gulf of Mexico.  However, in the wake of the preceding system,
appreciable moisture return appears unlikely by this time.  Somewhat
more substantive moistening off the Gulf appears possible by Friday,
along and ahead of the front across parts of Texas into the Ozark
Plateau and middle Mississippi/lower Ohio Valley region. However,
this still appears likely to be considerably more modest than that
available to the prior system, which may remain confined to areas
along and south of a remnant frontal zone over the southern Gulf of
Mexico into the Florida Straits vicinity.  Due to low predictability
issues, and generally low potential, severe weather probabilities
currently appear less than 15 percent through this period.

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