Severe Storm Outlook Narrative (AC)
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ACUS03 KWNS 260710
SPC AC 260708

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0208 AM CDT Thu Apr 26 2018

Valid 281200Z - 291200Z


Isolated to widely scattered thunderstorms with gusty winds are
expected Saturday from the southern through northern Rockies into a
portion of the Pacific Northwest.


An omega-blocking regime will characterize the synoptic pattern on
Saturday with upper troughs over the western and eastern states and
a ridge across the High Plains.

...Western States...

Within plume of steep lapse rates and modest subtropical moisture,
isolated thunderstorms will likely develop over the higher terrain
from the southern through northern Rockies. Most of this activity
will diminish by late evening. However, a few thunderstorms over the
northern Rockies may persist into the overnight, supported by deeper
ascent within frontal zone in association with another in a series
of vorticity maxima rotating through upper low circulation. Given
deeply mixed inverted-v boundary layers, a few of the storms may
produce downburst winds during the afternoon and early evening. Low
severe probabilities may be introduced for a portion of this region
in later updates.

...Ohio Valley into the Northeast States...

Widely scattered showers may accompany a shortwave trough through
the OH Valley and Northeast States Saturday afternoon and evening.
However, limited moisture will promote a marginal thermodynamic
environment, and most of this convection will probably remain too
shallow for lightning activity.

..Dial.. 04/26/2018

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