Mesoscale Discussion:

The threat of severe weather is there for this afternoon and as Scott reported recently, the storms are building. We still have a severe thunderstorm warning for Lawrence County for a storm near Moulton that likely has quarter sized hail.

The threat of hail will be fairly significant this afternoon as the height of our wet bulb zero parameter is fairly low, under 10,000 feet.

The threat for damaging winds will be increasing however, with downdraft CAPE values over 1,000 joules/KG.

CAPE values are climbing from 1200-1500 joules right now, but will be increasing as the afternoon rolls along and sunshine works on the temperatures.

Precipitable water values are high, but not as extreme as the ones we have been noticing over South Alabama.

The SPC says that they do not anticipate having to issue a watch this afternoon, but I think that could change.

The storms should shift southeast through the afternoon, reaching the I-59 Corridor by late afternoon or early evening.

Keep an eye to the sky and have your warning mechanisms in place and running if you are out enjoying the day or working.

Mesoscale Discussion 0824
NWS Storm Prediction Center Norman OK
1144 AM CDT Sat May 18 2024

Areas affected…Northeast MS into northern AL and southern middle
TN

Concerning…Severe potential…Watch unlikely

Valid 181644Z – 181845Z

Probability of Watch Issuance…20 percent

SUMMARY…Isolated hail and damaging gusts may accompany storms this
afternoon.

DISCUSSION…Convection associated with a compact midlevel low
(which is centered near the TN/AR/MS border) is gradually
intensifying late this morning from northeast MS into northern AL
and southern middle TN. Some continued increase in storm coverage
and intensity may continue into this afternoon, within a moist and
uncapped environment (with MLCAPE increasing to near/above 1000
J/kg). This region is on the northern periphery of stronger flow
aloft, but effective shear of 25-35 kt could occasionally support
some modestly organized storm structures through the afternoon.
Isolated hail could accompany any storms that remain semi-discrete,
while a bowing segment or two could evolve with a threat of isolated
damaging gusts as storms spread eastward across northern AL and
southern middle TN.

..Dean/Hart.. 05/18/2024

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