Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS02 KWNS 260539
SPC AC 260538
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Sun Mar 26 2017
Valid 271200Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
LOWER AND MID MISSISSIPPI VALLEY AND LOWER OHIO VALLEY...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
AR/LA INTO THE MIDDLE OH VALLEY...
Severe thunderstorms are possible from parts of the Middle and Lower
Mississippi Valley into the Lower Ohio Valley on Monday.
...Mid/Lower MS and Lower OH Valleys...
A progressive shortwave trough currently over the Four Corners
region will move into the Southern Plains on Sunday, then into the
MS Valley on Monday. Model guidance is consistent in showing a
surface low over northwest AR at 27/12z. This low will track
east-northeastward across southern MO and into southern IL/IN during
the evening. A relatively moist and unstable air mass will be
present in the warm sector of the low, where scattered afternoon
thunderstorms will develop. Forecast soundings in this region show
relatively steep mid-level lapse rates and strong deep layer shear,
indicating a risk of large hail from northern MS into western TN/KY.
Stronger wind fields over the north half of the risk area will also
support the potential for bowing segments capable of damaging winds
or perhaps a tornado or two as storms spread across KY and southern
IN during the evening.
Isolated strong to severe storms may also affect parts of central MS
into northern and central AL on Monday, where afternoon heating and
subtle low-level forcing mechanisms help to initiate convection.
Confidence in storm intensity this far south is lower than to the
north, so will maintain a Marginal risk at this time.