Severe Storm Outlook Narrative (AC)
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ACUS11 KWNS 152042
SPC MCD 152042

Mesoscale Discussion 0271
NWS Storm Prediction Center Norman OK
0342 PM CDT Sun Apr 15 2018

Areas affected...the southern Florida Peninsula

Concerning...Tornado Watch 51...

Valid 152042Z - 152145Z

The severe weather threat for Tornado Watch 51 continues.

SUMMARY...Tornado watch 51 will expire at 22Z. A threat for mainly
isolated damaging wind will linger over the southern half of the
peninsula into the evening, but it is uncertain at this time whether
the threat will be sufficient for another WW.

DISCUSSION...Late this afternoon thunderstorms associated with a
convergence zone along the east coast are in the process of moving
offshore. Additional storms have moved inland along the west coast
and extend southward into the Gulf just west of the Keys. These
storms will continue east into the evening and may pose a modest
threat for mostly isolated damaging wind. The downstream atmosphere
is moderately unstable with 1000-1500 J/kg MLCAPE. However mid-level
lapse rates are very weak due to warm temperatures aloft. Moreover,
tendency will be for low-level winds to continue to veer as a more
significant shortwave trough passes well north of this region. While
vertical wind and shear profiles should undergo some increase with
35-40 kt bulk shear supportive of organized storms, the marginal
nature of the thermodynamic environment lowers confidence in a more
robust severe threat. As as result any additional WW issuance for
southern FL will depend on convective trends.

..Dial.. 04/15/2018

...Please see for graphic product...


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