SPC May 16, 2025 1300 UTC Day 1 Convective Outlook

SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0746 AM CDT Fri May 16 2025

Valid 161300Z - 171200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
EAST-CENTRAL AND SOUTHEAST MISSOURI...WESTERN AND CENTRAL
KENTUCKY...SOUTHERN ILLINOIS AND INDIANA...SOUTHWEST
OHIO...NORTHWEST TENNESSEE...AND NORTHEAST ARKANSAS...

...SUMMARY...
A regional outbreak of severe thunderstorms is likely this afternoon
into tonight across parts of the mid Mississippi, Ohio and Tennessee
Valleys. This will include intense supercells associated with
tornadoes, large hail and wind damage. Several strong tornadoes are
expected, and a long-track high-end tornado will be possible. From
the evening into the overnight, a bowing line segment is expected to
form with potential for tornadoes and damaging winds, some possibly
greater than 75 mph.

...Mid Mississippi and Ohio Valley/Tennessee Valley Region...
As an upper-level low near the MN/ND border shifts east today, a 
mid-level jet streak will move from the Plains into the
mid-Mississippi Valley. A surface cold front will move east across
the Great Lakes, Midwest and OH/TN Valley region this afternoon and
tonight. An expansive warm/moist sector will destabilize during the
day, setting the stage for a regional severe weather outbreak this
afternoon and tonight.

Scattered severe thunderstorms, with a history of large hail, were
ongoing at 13z from northeast AR into eastern KY. Clusters of severe
storms, including supercells, will continue moving northeast within
this corridor through at least early afternoon. The eventual
longevity of these storms remains uncertain, however downstream
diurnal destabilization could allow storms with a severe hail/wind
threat to move into WV/western VA this afternoon.

In the wake of these morning storms, destabilization will occur as a
warm front lifts north, with strong instability (MLCAPE in excess of
2500 J/kg) developing from portions of eastern MO east into the
OH/TN Valley region, and south in advance of the front into eastern
TX.  The presence of strong mid-level flow will contribute to
deep-layer shear averaging 50 kts or higher across a large area.

Vigorous redevelopment of severe storms is expected by early
afternoon across southern/eastern MO as height falls overspread the
area. More isolated development is expected southward along the cold
front towards 00Z. Initial storm development will strongly favor
supercell storm mode with all severe hazards possible, including the
potential for strong tornadoes across the Moderate/Enhanced Risk
areas where low-level shear will be strongest. Large to very large
hail will also be possible with mature supercells this afternoon
through early evening. As storms continue moving east across the
OH/TN Valley region, eventual upscale growth into multiple bowing
segments is expected. The tornado threat will continue, especially
with QLCS circulations, and significant severe gusts will also be
possible.  

...Ark-La-Tex/Lower Mississippi Valley...
Warm mid-level temperatures will tend to delay thunderstorm
initiation along the southward-trailing cold front into northeast TX
until later in the day, however at least isolated development is
expected towards 22z-00z. MLCAPE in excess of 3000 J/kg and 45-55
kts of deep-layer shear oriented favorably relative to the front
suggests a supercell mode with large to very large hail, along with
damaging gusts. Although weaker low-level shear will be present in
this area, some potential for a tornado will exist with any mature
supercell. With time, storms may increase in coverage and begin to
cluster in an environment favorable for a continued severe wind/hail
threat.

...Portions of the Mid-Atlantic/northern DelMarVa Peninsula...
As the southern portion of the long-lived MCS over PA/NY continues
moving east/southeast today, the potential will exist for
re-development of organized storms, including supercells, over
portions of southeast PA/southern NJ and the northern DelMarVa
peninsula. With moderate west/northwest flow in place to the east of
the upper level ridge, RAP/HRRR forecast soundings depict sufficient
deep shear and moderate instability for a severe hail and wind risk.
Some consideration was given for higher severe probabilities in this
area, however uncertainty remains on the location of a corridor of
greater risk.

..Bunting/Marsh.. 05/16/2025

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