New Watch May Be Coming Soon for Extreme West Alabama as Severe Weather Threat Ramps Up

Mesoscale Discussion 0253
NWS Storm Prediction Center Norman OK
0637 AM CDT Sat Apr 14 2018

Areas affected…southeast Louisiana…southern and eastern
Mississippi…and into far west central Alabama

Concerning…Severe potential…Watch likely

Valid 141137Z – 141300Z

Probability of Watch Issuance…80 percent

SUMMARY…Severe/isolated tornado risk should gradually increase
over the next 1-2 hours, which will likely require new watch
issuance.

DISCUSSION…As the main upper trough advances gradually eastward,
increasing ascent — apparently tied to a subtle/embedded upper
disturbance moving northeastward across the western Gulf Coast
region at this time — is supporting some increase in convective
intensity along southern portions of the remnant convective band.
The strongest storms are indicated from eastern Louisiana and
adjacent southwest Mississippi south-southwestward. With a
moist/amply unstable airmass (1000 to 1500 J/kg mixed-layer CAPE per
objective analysis) in place ahead of the band, expect steady storm
intensification to continue.

Latest JAN and LIX WSR-88D VWPs indicate veering/increasing flow
with height through the lowest few km of the troposphere, which will
aid in potential for storm organization and the
anticipated/associated uptick in severe potential. While primary
storm mode should remain linear, and thus the main severe risk being
locally damaging winds, some tornado risk also appears likely evolve
— both with rotating elements within the evolving convective line,
as well as with any cells which may develop later this morning just
ahead of the main band. Given the increasing risk, a new tornado
watch will likely be required in the next hour.

..Goss/Grams.. 04/14/2018

Tags: exp03

Category: Alabama's Weather, ALL POSTS