Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 230554
SWODY2
SPC AC 230553

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1253 AM CDT Mon Apr 23 2018

Valid 241200Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST
TX INTO FAR SOUTHWEST OK...

...SUMMARY...
Isolated severe thunderstorms are possible from southwest Texas
northeastward into far southwest Oklahoma.

...Synopsis...
Mature cyclone centered over middle TN/central KY at the beginning
of the period is expected to move northeastward across the central
Appalachians. Surface low beneath the mid/upper cyclone will
continue to fill while a secondary low develops farther east and
moves northeastward across the Carolinas. Some thunderstorms are
possible in the vicinity of the secondary low as well as across FL
as the surface trough moves through.

Farther west, a shortwave trough will move southeastward into the
central Plains, encouraging a southward surge of a cold continental
airmass into the southern Plains. A warm and deeply mixed airmass
ahead of the cold front over the southern High Plains will likely
support isolated to widely scattered thunderstorms.

...Southern High Plains...
Southerly winds are anticipated across the region ahead of the
approaching cold front but only modest low-level moisture (i.e.
dewpoints in the low 50s) is expected to reach the area. Even with
this meager low-level moisture, destabilization is still expected as
the boundary layer mixes to near 700 mb and surface temperatures
climb into the low to mid 80s. This destabilization will support
isolated thunderstorms along the front. Thunderstorms are also
possible ahead of front as forcing for ascent from the shortwave
trough moving through the central Plains reaches the region.
Low-level flow is not expected to be particularly strong but
mid-level flow will gradually increase during the late afternoon and
evening, supporting the potential for updraft organization and an
isolated severe storm or two.

...Carolinas...
Predominantly elevated thunderstorms will likely be ongoing at the
beginning of the period across the region. A few surface-based
storms are possible within the warm sector confined to the coastal
regions. Limited spatial extent for strong thunderstorms as well as
the displacement of the stronger flow northward suggest any severe
threat will be too isolated to merit any severe probabilities with
this outlook.

...Central/Southern FL Peninsula...
Scattered thunderstorms are possible on both sides of a weakening
frontal zone moving slowly southward across the region. Generally
weak flow and poor lapse rates should keep the severe probabilities
below 5%.

..Mosier.. 04/23/2018

$$



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