SPC Mar 29, 2025 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1228 PM CDT Sat Mar 29 2025

Valid 301200Z - 311200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS A BROAD
AREA CENTERED OVER THE OHIO/MID MISSISSIPPI/TENNESSEE VALLEYS...

...SUMMARY...
A widespread/substantial severe-weather episode is forecast across
an area centered on the Ohio/Mid and Lower Mississippi/Lower
Missouri/Tennessee River Valleys.  Very large hail, damaging winds,
and strong tornadoes are expected.

...Synopsis...
Mid-morning water vapor imagery depicts an upper-level shortwave
trough across the Southwest that is the leading impulse within a
longwave trough building across the eastern Pacific/western CONUS.
This wave is expected to overspread the southern/central Plains
today before migrating into the Great Lakes region through the day
tomorrow. A secondary disturbance is expected to move into the
southern Plains late tomorrow evening into early Monday. At the
surface, the surface low analyzed across KS is forecast to intensify
as it moves northeast along a frontal zone into the Great Lakes in
tandem with the leading upper disturbance. The intensification of
the low will result in a cold frontal surge across the Midwest/OH
Valley tomorrow afternoon and across the Mid-MS Valley to Texarkana
region tomorrow evening. Scattered to widespread thunderstorm
development is anticipated along and ahead of the frontal zone with
the potential for widespread large hail/severe winds and several
tornadoes. 

...Central TX...
Latest guidance suggests convection may be ongoing across central TX
along/ahead of a migratory dryline early Sunday morning. The
southern extent of a pronounced EML casts doubt on storm
coverage/longevity. However, buoyancy and deep-layer wind shear
should be supportive of supercells with an attendant severe
hail/wind threat if mature updrafts can develop along the boundary
as the primary upper-level trough axis passes over the region.

...IL, IN, and OH...
Consensus among recent forecast guidance is that kinematic fields
will steadily strengthen across the Midwest and middle OH River
Valley regions through the day as the surface low intensifies.
Increasing southerly flow ahead of the primary cold front should
allow for dewpoints in the upper 50s to low 60s to spread into the
region by mid-afternoon. Scattered thunderstorm development along
the cold front appears likely as early as 18-20z across IL, and
while a few initially discrete cells are possible, strong forcing
along the front should promote upscale growth into an organized line
by late afternoon. Strong low-level flow (nearly 50 knots 0-1 km
BWD) may promote bowing segments and embedded mesovorticies within
the line - especially across northern IN/northwest OH. 30% wind
probabilities have been expanded northward to account for this
potential.

While this is the most probable scenario based on morning guidance,
it could be complicated by any ongoing showers/thunderstorms and/or
remnant outflow boundaries associated with nocturnal convection over
MO late Saturday/early Sunday morning. This could limit diurnal
heating/destabilization or may provide pre-frontal foci for
convective initiation and promote more discrete storm modes.  

...Mid-MS Valley to Texarkana region...
Scattered, initially discrete supercells are expected to develop
from the confluence of the OH/MS rivers southwestward into the
Texarkana region Sunday afternoon along the cold front and dryline.
Strong flow associated with the intensifying cyclone will promote
elongated hodographs featuring nearly uni-directional wind profiles
and effective bulk shear values on the order of 50-60 knots. This
will promote splitting supercells with the potential for large to
very large (2+ inch) hail. A more appreciable supercellular tornado
threat may emerge through early evening across the lower OH
Valley/mid-MS Valley where stronger veering in the lowest 1-2 km is
anticipated amid weak pre-frontal isentropic ascent between 925-850
mb. While the tornado threat may be maximized through this corridor,
low confidence in storm mode (due to the potential for splitting
cells/destructive interactions) limits confidence in this potential
to warrant higher probabilities at this time.

However, upscale growth is anticipated through mid/late evening as
the secondary upper disturbance migrates into the Texarkana region.
Consolidation of multiple clusters into one or more organized linear
segments is expected as storms push east towards the MS Valley with
a gradual increase in the potential for damaging/severe winds.
Additionally, low-level shear will remain favorable for embedded
mesovorticies as the line pushes into western TN/northern
MS/northwest AL through the overnight hours. 

...Florida...
A weak mid-level impulse (currently over the northern Gulf) is
expected to meander across northern FL by peak heating. Somewhat
strong mid-level winds (25-30 knots) associated with this feature
may provide sufficient organization to thunderstorms developing
across eastern central/northern FL to pose an isolated hail/wind
threat.

..Moore.. 03/29/2025

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