Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 230538
SWODY2
SPC AC 230536

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1236 AM CDT Sat Sep 23 2017

Valid 241200Z - 251200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Scattered showers and storms are expected in the southern and
central High Plains, although any severe threat should be sparse.

...Synopsis...
A persistent longwave trough in the West will make very slow
eastward progress throughout the day as a ridge - initially centered
over the Northeast - moves slowly eastward toward northwestern
Atlantic waters late in the period.  Between these two large-scale
features, meridionally oriented mid-level flow will persist from the
southern Rockies/High Plains north-northeastward to Minnesota.

At the surface, a cold front will migrate southward across the
central Plains, extending from far southeastern Colorado
northeastward to eastern Minnesota at around sunset.  An expansive
anticyclone across the East, combined with weak low pressure in the
lee of the Rockies, will foster a broad area of southerly low-level
flow that should maintain a modified maritime airmass (characterized
by 60s F dewpoints) across much of the center of the country ahead
of the front.

...Eastern NM/western TX north to eastern Nebraska...
Models suggest that an arc of showers and thunderstorms should be
ongoing at the start of the forecast period across this region, with
some expansion/intensification of this activity during peak heating
hours.  Despite warming surface temperatures and sufficient deep
shear for loosely organized clusters/linear segments, meager
mid-level lapse rates and expansive cloudiness/precipitation should
limit overall destabilization in most areas.  This will result in a
limited damaging wind threat that will likely be too sparse for
severe probabilities.  Any existing threat should also wane with the
loss of surface heating.

..Cook.. 09/23/2017

$$



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