Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 170851
SWOD48
SPC AC 170849

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0249 AM CST Sun Dec 17 2017

Valid 201200Z - 251200Z

...DISCUSSION...
...Wednesday/Day 4 and Thursday/Day 5...
The medium-range models including the ECMWF, GFS, UKMET and Canadian
move an upper-level trough across the Southeast on Wednesday.
Thunderstorms will be possible ahead of the system during the day
across Alabama and Georgia. The upper-level trough is forecast to
move eastward into the western Atlantic on Thursday. Further west,
an upper-level trough is forecast to move into the Four Corners
region as low-level moisture advection takes place in the southern
Plains.

...Friday/Day 6 to Sunday/Day 8...
The upper-level trough is forecast to move into the Great Plains on
Friday as a moist airmass moves into the lower Mississippi Valley. A
marginal severe threat will be possible along and ahead of a cold
front moving into the lower Mississippi Valley. The ECMWF and GFS
remain similar on Saturday with the cold front moving into the
eastern U.S. and an upper-level trough moving into the central
states. The upper-level trough is forecast to remain in place on
Sunday as a cold and dry airmass settles over much of the CONUS. For
this reason, thunderstorm activity should be limited on Saturday and
Sunday.

..Broyles.. 12/17/2017


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