Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1130 AM CDT Sun Mar 15 2026
Valid 151630Z - 161200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND TONIGHT ACROSS MUCH OF THE LOWER/MID MISSISSIPPI VALLEY...LOWER
OHIO VALLEY...TENNESSEE VALLEY...AND SOUTHEAST...
...SUMMARY...
Numerous to widespread severe/damaging winds and embedded tornadoes
will accompany an intense squall line across much of the lower/mid
Mississippi Valley this afternoon and evening. A couple of strong
tornadoes are also possible within and just ahead of this line
across parts of the lower Ohio Valley into the Mid-South and Gulf
Coast regions. The severe wind and tornado threat will likely
persist through tonight across portions of the Ohio
Valley/Southeast.
...Lower Mississippi Valley/Southeast into the Ohio
Valley/Midwest...
Pronounced upper troughing over the northern/central Plains late
this morning will further amplify through the period as it ejects
east-northeastward across much of the MS Valley/Midwest. A 992 mb
surface low over northern MO will likewise develop northeastward
across the Midwest through the day, reaching northeast IL/northwest
IN by this evening and northern Lower MI by the end of the period.
Primary low-level jet will focus northward across the OH
Valley/Midwest this afternoon and evening, with a trailing/southern
portion present across parts of the Mid-South and lower MS Valley.
Associated strong low-level warm/moist advection will continue to
occur ahead of a sharp surface cold front that is expected to sweep
quickly east-southeastward through tonight over much of the
lower/mid MS Valley, OH/TN Valleys, and Southeast.
Low-level moisture remains fairly shallow/limited ahead of the cold
front per latest surface observations and area 12Z observed
soundings (ILX, SGF, JAN, LIX). Still, generally 50s surface
dewpoints should be present in a narrow warm sector across the OH
Valley/Midwest by late afternoon/early evening, with somewhat
greater moisture (upper 50s to low 60s surface dewpoints) southward
into the lower/mid MS Valley. Large-scale ascent attendant to the
approaching upper trough will aid in the erosion of a substantial
cap noted along/ahead of the cold front by early afternoon (18-20Z).
With even modest/filtered daytime heating, at least weak instability
should develop in a narrow corridor ahead of the front. This gradual
destabilization will support the potential for rapid thunderstorm
development within the next few hours.
General consensus of latest guidance is that a QLCS will quickly
strengthen/consolidate through the mid to late afternoon into the
evening as it moves quickly eastward across AR/MO and the lower/mid
MS Valley and lower OH Valley. Deep-layer shear of 40-50+ kt
associated with a strengthening west-southwesterly mid-level jet
overspreading the warm sector will support organization with the
maturing QLCS. Given the expected strength of the flow in the
boundary layer (50-60+ kt), numerous to potentially widespread
severe/damaging winds up to 60-80 mph are expected wherever the QLCS
can remain surface based. Strong low-level shear will also be
present to foster embedded mesocirculations and the potential for
several QLCS tornadoes.
The opportunity for supercells to develop ahead of the squall line
remains uncertain, as residual low-level capping may inhibit open
warm sector development. Still, greater instability should be
present from the western KY/TN vicinity southward into the lower MS
Valley. Any supercells that can form ahead of the line across these
areas and/or remain at least semi-discrete within the line could
produce strong (EF-2+) tornadoes, as low-level shear and related
elongated/curved hodographs will be quite favorable for updraft
rotation. Although boundary-layer instability will become
increasingly weak with northward extent into the OH Valley tonight,
a continued threat for numerous severe/damaging winds will likely
continue with the QLCS as it shifts eastward across the OH/TN
Valleys and much of the Southeast this evening through early Monday
morning. Have therefore expanded/combined the wind-driven Enhanced
Risk areas in southern/central MS/AL into western GA and eastern TN.
Some chance for pre-frontal supercells and strong tornado potential
ahead of the QLCS may also exist late tonight across portions of
southeast AL, the FL Panhandle, and southwest GA.
...Florida Peninsula into the Carolinas...
Low-level moisture will gradually spread northward through tonight
from the FL Peninsula to the southern Appalachians and into parts of
the Carolinas, well ahead of the amplifying upper trough over the MS
Valley. While forcing will remain generally weak/nebulous, there is
some chance for isolated hail/damaging winds with thunderstorms this
afternoon across much of the FL Peninsula and the Keys. The severe
threat across coastal GA/SC/NC appears conditional on thunderstorms
spreading inland from the Gulf Stream tonight into early Monday
morning. However, an isolated threat for damaging winds and perhaps
a tornado would exist in a gradually improving environment if these
cells form and move inland. Have therefore maintained the Marginal
Risk across this region with no changes.
..Gleason/Lyons.. 03/15/2026
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