Severe Storm Outlook Narrative (AC)
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000
ACUS48 KWNS 150830
SWOD48
SPC AC 150828

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0328 AM CDT Sat Jun 15 2019

Valid 181200Z - 231200Z

...DISCUSSION...
Multiple low-amplitude shortwave troughs, some of them convectively
enhanced/induced, will likely move eastward through quasi-zonal flow
over the central and eastern CONUS both Day 4/Tuesday and Day
5/Wednesday. A large warm sector should remain across much of the
CONUS from the Plains eastward in this time frame, and potential
exists for isolated severe thunderstorms (probably in the form of
one or more MCSs) each day due to the reservoir of instability that
should be present. However, there remains too much uncertainty
regarding the placement of these shortwave troughs, weak surface
boundaries, and convection from prior days to include 15% severe
probabilities.

By Day 5/Wednesday into Day 6/Thursday, medium-range guidance
continues to indicate that an upper trough/low will amplify over the
Pacific Northwest, northern Rockies, and western Canada. An
attendant mid-level jet should overspread portions of the
northern/central Plains on Day 6/Thursday and Day 7/Friday.
Depending on the quality of low-level moisture return, organized
severe thunderstorms may occur from the northern/central Plains into
the Upper Midwest and perhaps as far south as the mid MS Valley.
However, considerable timing/amplitude differences regarding the
upper trough/low are evident in guidance at this extended time
frame, and predictability remains too low to delineate any areas.

..Gleason.. 06/15/2019


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