Severe Storm Outlook Narrative (AC)
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000
ACUS48 KWNS 250852
SWOD48
SPC AC 250851

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0251 AM CST Sun Feb 25 2018

Valid 281200Z - 051200Z

...DISCUSSION...
...Wednesday/Day 4 to Thursday/Day 5...
The medium-range models including the ECMWF, GFS, UKMET and Canadian
move an upper-level trough from the Desert Southwest into the
Rockies on Wednesday. A moist airmass is forecast to be in place
from the southern Plains eastward into the lower Mississippi Valley.
The development of strong to severe thunderstorms may occur on
Wednesday or Wednesday night from northeast Texas east-northeastward
into the lower to mid Mississippi Valley as the exit region of a
strong mid-level jet approaches. This feature along with a low-level
jet in the Arklatex is forecast to create favorable shear profiles
for organized severe storms including supercells and fast moving
line-segments. A few tornadoes and some wind damage will be
possible. The models move the upper-level trough quickly eastward
into the Mississippi Valley on Thursday as a cold front advances
southeastward across the southern Appalachians. Ahead of this front,
some severe convection will be possible mainly from the eastern Gulf
Coast States northeastward into the Carolinas but predictability
remains low.

...Friday/Day 6 and Sunday/Day 8...
On Friday, all four solutions move an upper-level low across the
Mid-Atlantic and into the western Atlantic as a cold front advances
southward into the northern Gulf of Mexico. A dry airmass is
forecast to overtake most of the CONUS on Friday into Saturday
making thunderstorm potential low. On Sunday, the models have an
upper-level ridge over the east-central U.S. and show moisture
return taking place in Texas and Louisiana. Although a marginal
severe threat can not be ruled out on Sunday across parts of the
south-central U.S., the spread among solutions is large suggesting
predictability is low on Sunday.

..Broyles.. 02/25/2018



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