Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 190520
SWODY2
SPC AC 190519

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1219 AM CDT Tue Sep 19 2017

Valid 201200Z - 211200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM
NORTHEASTERN KANSAS NORTHEASTWARD TO THE WESTERN GREAT LAKES
REGION...

...SUMMARY...
A few severe storms are possible from northeastern Kansas
northeastward to the Upper Peninsula of Michigan Wednesday afternoon
and evening.

...Synopsis...
A long-wave trough will amplify across the West throughout the day
Wednesday, while a vigorous lead shortwave pivots northeastward from
the Dakotas into western Ontario.  Farther southeast, a
low-amplitude mid-level ridge will extend from south Texas into the
Mid-Mississippi Valley.  The circulation associated with TC Jose
should meander slowly eastward over Atlantic waters just southeast
of New England.  See National Hurricane Center advisories for more
information on Jose.

At the surface, a cold front initially located from central
Minnesota south-southwestward to central Kansas will migrate
eastward through the afternoon before stalling along an axis from
central Wisconsin southwestward to northeastern Kansas.  Ahead of
this front, a buoyant airmass (characterized by 60s to low 70s F
dewpoints) will foster development of a few thunderstorms.

...Western Great Lakes southwestward to northeastern Kansas...
Scattered thunderstorms early in the day across Minnesota should
diminish as they migrate northeastward into Canada.  South of this
area of precipitation, insolation should foster moderate to strong
destabilization - maximized during peak heating hours - and the lack
of convective inhibition should foster development of a few
wind/hail producing thunderstorms along the front despite mid/upper
forcing lifting away from the region into Canada.  Shear profiles
should be strongest in Wisconsin and the Upper Peninsula of
Michigan, where a couple of supercellular structures may develop
before low-levels stabilize overnight.  Farther southwest toward
Kansas/Missouri, models suggest that storms will develop after 00Z
along the slowly retreating surface boundary.  Despite marginal
vertical shear profiles, favorable thermodynamic profiles (including
steep mid-level lapse rates) will foster a risk for isolated hail
and damaging wind gusts.

..Cook.. 09/19/2017

$$


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