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Categorical Day2 0700Z Outlook
  

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 Forecast Discussion


000
ACUS02 KWNS 200543
SWODY2
SPC AC 200542

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1242 AM CDT Wed Sep 20 2017

Valid 211200Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE EASTERN
DAKOTAS EASTWARD TO FAR NORTHWESTERN WISCONSIN...

...SUMMARY...
A few hail-producing storms are possible in portions of Minnesota,
the eastern Dakotas, and far northwestern Wisconsin Thursday night.

...Synopsis...
An expansive longwave trough will continued to migrate slowly
southeastward across the West, fostering meridionally oriented
mid-level flow across the center of the country.  To the east, a
ridge will remain nearly stationary across Mid-Mississippi Valley
and Great Lakes regions.  Meanwhile, the circulation associated with
TC Jose will remain nearly stationary across Atlantic waters just
south of New England.

At the surface, cyclogenesis will occur along a lee trough in
portions of northeastern Colorado and Nebraska.  This lee trough
will extend southward into portions of eastern New Mexico throughout
the day and remain nearly stationary.  A weak cold front will move
slowly southward across portions of the High Plains, but stall from
around midday onward.  Meanwhile, an anticyclone will dominate
across the East.

...Eastern Dakotas into Minnesota and far northwestern Wisconsin...
Subtle mid-level height rises will occur much of the day as
mid-level flow backs in response to the amplifying trough in the
West.  These height rises should keep convective activity at a
minimum throughout the day.  After 03Z-06Z, convergence on the nose
of a 50-60 kt low-level jet across the central Plains will combine
with steep mid-level lapse rates and decent vertical shear profiles
to support scattered elevated convection in the MRGL area.  Isolated
instances of 1"+ hail will be the primary threat with this activity.

...Texas South Plains north-northeastward to central Kansas...
Despite negligible mid/upper forcing for ascent and subtle
inhibition indicated on point forecast soundings, guidance suggests
the potential for isolated convection to develop during peak heating
hours across the region.  Steep low- and mid-level lapse rates and
modest shear profiles (especially in Kansas) will foster an isolated
hail/wind threat should storms actually materialize.  This region
will be monitored for the inclusion of low (5%) severe probabilities
in later outlooks.

..Cook.. 09/20/2017

$$