Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 222059
SPC MCD 222058

Mesoscale Discussion 0283
NWS Storm Prediction Center Norman OK
0358 PM CDT Sun Apr 22 2018

Areas affected...West-central Alabama

Concerning...Severe potential...Watch unlikely

Valid 222058Z - 222330Z

Probability of Watch Issuance...20 percent

SUMMARY...A marginal tornado threat and a few strong wind gusts will
be possible across parts of west-central Alabama late this
afternoon. The threat is expected to remain localized and weather
watch issuance appears unlikely.

DISCUSSION...The latest surface analysis shows a deepening 1008 mb
low across eastern Mississippi. Winds are backed at the surface to
the east of the surface low across most of Alabama. A moist airmass
extends northward into central Alabama where surface dewpoints are
in the mid to upper 60s F. Although little surface heating has taken
place in central Alabama, the RAP suggests that weak instability is
present. This combined with strong large-scale ascent associated
with a shortwave trough evident on water vapor imagery, will support
surface-based thunderstorm development over the next couple of
hours. The WSR-88D VWP at Birmingham shows a looped hodograph with
0-6 km shear at 55 kt and 0-1 km shear near 40 kt. This should be
sufficient for storm rotation within the stronger discrete cells. As
a result, a marginal tornado threat will be possible late this
afternoon. A few strong wind gusts may also occur.

..Broyles/Hart.. 04/22/2018

...Please see for graphic product...


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