Severe Storm Outlook Narrative (AC)
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ACUS03 KWNS 210707
SPC AC 210706

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0206 AM CDT Mon May 21 2018

Valid 231200Z - 241200Z


Isolated severe thunderstorms are possible across much of the Plains
while strong storms may develop across Virginia/North Carolina.


Remnants of an upper low over southern CA will eject across the
Great Basin into MT during the day3 period as a corridor of somewhat
stronger mid-level flow translates across eastern WY into the Black
Hills region. Even so, this belt of stronger flow will only be on
the order of 30-40kt at 500mb, but more than adequate for sustaining
organized updrafts along western plume of moisture/instability. One
negative for widespread convection across the northern High Plains
region will be the neutral/weak height rises despite the presence of
the aforementioned short wave. Latest thinking is strong
boundary-layer heating and orographic influences will contribute to
convective development, some of which will likely be robust in
nature. Low-level warm advection will likely induce strong
convection across the Dakotas as LLJ is expected to veer into
southeast SD during the latter half of the period.


Northwesterly flow will deepen across the Middle Atlantic/Southeast
into the day3 period as a strong short-wave trough digs across
northern New England. This northwesterly flow will encourage a
surface front to surge into VA early in the period before moving off
the Carolina coast during the overnight hours. Strong heating ahead
of this boundary, along with modest mid-level flow, suggest any
storms that form along the front could produce gusty winds/hail.

..Darrow.. 05/21/2018

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