Severe Storm Outlook Narrative (AC)
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ACUS01 KWNS 201616
SWODY1
SPC AC 201614

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1114 AM CDT Fri Oct 20 2017

Valid 201630Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Scattered thunderstorms are possible today over eastern Texas, with
more isolated activity overnight into parts of the central Plains
and Midwest. A few strong storms are possible, but the severe
thunderstorm risk is expected to be low.

...Synopsis...
Downstream from a progressive midlevel trough now moving over the
Pacific Northwest and northern Great Basin, lee cyclogenesis across
the northern High Plains will begin to draw low-level moisture
northward from TX across the Plains.  Isolated lightning strikes
will be possible today from the Pacific Northwest into parts of the
northern Rockies with the midlevel thermal trough and associated
steep lapse rates.  Otherwise, a lead shortwave trough over the
southern Plains has interacted with the primary moisture return
corridor/weakening frontal zone across the upper TX coast, where
thunderstorms have persisted through the overnight hours into this
morning.  A minor boost to storm coverage could occur inland with
the diurnal heating cycle, but overall storm coverage should still
decrease later this afternoon/evening as the lead shortwave trough
ejects north-northeastward ahead of the moisture plume.  Later
tonight, some elevated convection will be possible from NE/SD to MN
within the warm advection regime on the north edge of the returning
moisture.

..Thompson/Leitman.. 10/20/2017

$$


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