Severe Storm Outlook Narrative (AC)
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ACUS01 KWNS 081934
SPC AC 081933

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0133 PM CST Thu Dec 08 2016

Valid 082000Z - 091200Z


No severe thunderstorms are expected across the contiguous U.S.
through tonight.

No changes have been made to the ongoing forecast.

..Cohen.. 12/08/2016

.PREV DISCUSSION... /ISSUED 1029 AM CST Thu Dec 08 2016/

Broad cyclonic flow currently covers the CONUS with enhanced flow
arcing from northern California through the central Plains, Ohio
Valley, and Northeast. Strongest flow within this belt currently
exists at the base of a shortwave trough tracking through the Ohio
Valley. This shortwave trough and associated jet streak are expected
to continue northeastward off the Northeast coast by Friday morning
while the broadly cyclonic flow persists. Surface pattern is
characterized by a strong polar high, currently centered over the
northern High Plains and extending through the southern Plains and
lower Mississippi river valley. This high is expected to gradually
shift eastward throughout the day.

Cold and stable airmass associated with the surface high will keep
overall thunderstorm prospects very low. Cold front has pushed off
the south coast of Florida, with observations at MTH and EYW both
reporting north winds. A strike or two is possible with any
afternoon convection that develops as a result of a second frontal
push but weak lapse rates and cool surface conditions are expected
to keep thunder coverage below 10%. Weak upper forcing may glance
the region during the second half of the period but the elevated
nature of this convection and overall continued weak lapse rate
should preclude thunder.

Isolated lightning strikes are also possible over and/or in the lee
of Lake Erie and Ontario within any lake effect bands. Conditions
for lake effect snow band induced lightning appears most favorable
along and in the lee of Lake Ontario, where long wind fetches and
slightly cooler temperatures aloft exist. As mentioned in the
previous outlook discussion, anticipated lightning coverage is on
the margins for inclusion, but it is close enough to maintain
consistency with previous products.

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