Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 290808
SWOD48
SPC AC 290807

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0307 AM CDT Thu Jun 29 2017

Valid 021200Z - 071200Z

...DISCUSSION...
On D4/Sun, a low-amplitude upper trough will be over the Great Lakes
and Northeast region, with surface trough just offshore coastal New
England and extending into the Mid Atlantic. Modest instability may
exist across the Carolinas, but shear will be weak.

To the west, a weak northwest flow regime will exist over the
Plains, with southerly surface winds maintaining a moist and
unstable air mass, and a lee trough aiding afternoon thunderstorm
development across the High Plains. At least marginally severe hail
or wind is likely across the High Plains and extending into the
central Plains Sun evening.

A similar setup will exist on D5/Mon and D6/Tue across the central
Plains, but with the aid of a weak shortwave trough crossing the
Rockies. This trough may enhance 500 mb flow to around 35 kt, but
predictability with each day gets lower given the likelihood of
antecedent convection, outflow boundaries and generally weak upper
flow.

..Jewell.. 06/29/2017



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