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Categorical Day2 1730Z Outlook
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Probability of severe weather within 25 miles of a point.
Hatched Area: 10% or greater probability of significant severe weather within 25 miles of a point.
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Images courtesy of the NWS Storm Prediction Center
000
ACUS02 KWNS 301733
SWODY2
SPC AC 301732
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1232 PM CDT Thu Mar 30 2023
Valid 311200Z - 011200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
IOWA INTO NORTHWEST ILLINOIS AND FAR NORTHEAST MISSOURI...AND ALSO
ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...EXTREME WESTERN
KENTUCKY...WESTERN TENNESSEE...AND FAR NORTHWEST MISSISSIPPI...
...SUMMARY...
Intense and widespread severe thunderstorms are expected Friday
afternoon into the overnight hours across portions of the Middle
Mississippi Valley and Mid-South vicinity, eastward to the Lower
Ohio and Tennessee Valleys. Intense, damaging gusts and several
tornadoes (some strong and long-track) are expected.
...A regional outbreak of severe storms is expected on Friday across
parts of the Mid-Mississippi Valley and also into the Mid-South...
...Synopsis...
A deep mid/upper-level trough and attendant 100 kt midlevel jet will
move quickly eastward from the central Plains into parts of the MS
Valley and Midwest on Friday. A surface low will deepen as it moves
across IA toward the Great Lakes region, as a cold front sweeps
eastward through parts of the Great Plains into the mid-MS Valley.
In advance of the cold front, low-level moisture will stream
northward across a broad warm sector from the ArkLaTex region into
parts of the lower/mid MS Valley and Midwest.
...Mid-MS Valley vicinity into IN/lower MI...
Rapid destabilization and increasing large-scale ascent will support
thunderstorm development by early/mid afternoon across parts of IA
into northern MO. Very strong deep-layer shear (effective shear in
excess of 60 kt) and MLCAPE increasing to 1000-1500 J/kg (locally
greater) will support organized convection, with initial supercell
development expected somewhere over central IA into north-central
MO. Very large hail will be the initial threat, given steep midlevel
lapse rates and cold temperatures aloft.
Some uncertainty remains regarding the convective mode evolution
with time, but a few semi-discrete supercells are expected to move
into an environment with stronger low-level shear/SRH across eastern
IA into northwest IL by late afternoon, posing a threat for a couple
strong tornadoes. Evolution into small clusters or bowing segments
is expected, resulting in an increasing threat of severe/damaging
winds in addition to a continued threat of a few tornadoes and
sporadic hail.
Organized convection will spread eastward into parts of IN/southern
MI Friday night. Instability will weaken with eastward extent, but
some threat for damaging wind and a couple of tornadoes will persist
before a more definitive weakening trend occurs overnight into early
Saturday morning.
...ArkLaTex/Mid South vicinity into the TN/lower OH Valleys...
A concerning scenario still appears possible across portions of the
MO Bootheel, northeast AR, western TN/KY and far northwest MS
vicinity during the afternoon/evening. At least mid-60s F dewpoints
are expected beneath modest midlevel lapse rates. This will support
1500-2000 J/kg MLCAPE amid intense vertical shear. Forecast
soundings indicate 0-1 km SRH increasing to around 400 m2/s2 by
early afternoon. Thunderstorms are expected to develop by early
afternoon ahead of the cold front within a pre-frontal
trough/low-level confluence zone. Storm motion near 50 kt with
supercell wind profiles will support cells capable of significant
and long-track tornadoes. With time, upscale growth into a QLCS is
expected, and intense wind gusts will be possible in addition to
mesovortex tornadoes. The threat for damaging gusts and a few
line-embedded tornadoes will spread into parts of the TN and lower
OH Valleys Friday night, with a gradual weakening trend eventually
expected overnight as storms move into increasingly weak buoyancy
with eastward extent.
..Dean.. 03/30/2023
$$
