ACUS02 KWNS 260638
SWODY2
SPC AC 260637

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1237 AM CST Mon Feb 26 2024

Valid 271200Z - 281200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST-CENTRAL
MISSOURI INTO ILLINOIS...INDIANA...NORTHWEST OHIO AND SOUTHERN LOWER MICHIGAN...

...SUMMARY...
Scattered strong to severe thunderstorms, associated with large hail
(some near 2 inch diameter), damaging gusts, and a few tornadoes
will be possible from late Tuesday afternoon, into the evening and
overnight from parts of the mid Mississippi Valley, and southwestern
Great Lakes.

...Mid-MS Valley/Southwest Great Lakes Vicinity...

An upper trough over the northern Rockies/Intermountain West will
shift east on Tuesday, becoming oriented from the Upper MS Valley
and Mid-MO Valley by Wednesday morning. Fast deep-layer
southwesterly flow ahead of this feature will overspread the Ozark
Plateau into the Great Lakes. At the surface, a low will deepen as
it shifts east from MN toward southern Ontario. A cold front
attendant to the low will quickly shift east/southeast across the
Plains and the Mid/Upper MS Valley during the afternoon and into the
overnight period. Initial thunderstorm activity may develop in warm
advection regime near the quasi-warm front/moisture gradient from
northern IL into IN/NW OH/southern MI around 21-00z. Additional
activity will then develop along the cold front as it develops east
and the main upper wave ejects into the region around 00-03z.

Warm advection and southerly low-level flow ahead of the front will
allow for modest airmass modification into the Midwest. However,
forecast dewpoints are only expected to reach into the 50s to near
60 F. Nevertheless, a plume of steep midlevel lapse rates will
overspread the IL/IN/MI/OH vicinity from afternoon into the evening.
This will support modest destabilization with MLCAPE generally
forecast to be less than 1000 J/kg, though a narrow corridor of up
to 1500 J/kg MLCAPE may be possible for a brief period around 00z.
Forecast soundings across the region indicate most of available
instability will be located above the 850-700 mb layer.

Initial thunderstorm activity may be slightly elevated as some
forecast soundings indicate a warm nose between 850-700 mb during
late afternoon/early evening. Nevertheless, effective shear greater
than 50 kt, and enlarged low-level hodographs becoming elongated
above 3 km indicate initial supercells will be possible near the
quasi-warm front/moisture gradient from northeast IL into northern
IN and vicinity. With most instability focused above the 850-700 mb
layer, and in conjunction with poor boundary-layer dewpoints, the
tornado risk may be somewhat lower than typically expected given
shear profiles in the 0-2 km layer. Nevertheless a couple tornadoes
are possible, especially if greater moisture than forecast can make
it this far north. Large hail, with a few instances near 2 inch
diameter, will be possible with any semi-discrete supercells, along
with damaging gusts.

Once linear forcing along the front increases in the 00-03z period,
a line of storms is forecast to develop east from the Mid-MS Valley
toward the Lower OH Valley during the nighttime hours. Damaging
gusts will be the main concern with this activity.

..Leitman.. 02/26/2024

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ACUS02 KWNS 120600
SWODY2
SPC AC 120558

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CDT Tue Mar 12 2024

Valid 131200Z - 141200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MO VALLEY...

...SUMMARY...
Severe thunderstorms capable of large to very hail and a tornado or
two are possible across the Lower Missouri Valley from Wednesday
afternoon through Wednesday night.

...Synopsis...
Deep upper troughing is expected to be in place across the western
CONUS early Wednesday morning, with strong mid-level flow extending
from the Pacific Northwest into the Southwest states throughout the
western and southern periphery of the trough. Several shortwave
troughs will be embedded within this larger trough, including one
that is forecast to eject northeastward through the central Plains
during the day.

Surface low associated with this shortwave is expected to progress
into the central Plains just ahead of its parent shortwave, likely
ending the period near the KS/NE/MO border intersection. A dryline
will accompany this low, gradually pushing eastward across KS and OK
throughout the day and into the early evening before then stalling
until the cold front arrives early Thursday morning. A warm front is
also expected to extend southeastward from this low, with this front
gradually moving northward throughout the day. By 00Z this warm
front is expected to extend from the low over north-central KS east-southeastward into central MO. Thunderstorm development is
anticipated in the vicinity of the surface low and warm front, with
isolated development possible south along the dryline as well.

...Lower MO Valley...
Dewpoints will likely be in the mid 50s across much of eastern KS by
the late afternoon, possibly reaching into far southeast NE. Some
locally higher dewpoints are possible along the warm front as well.
These dewpoints, combined with surface temperatures in the mid 70s
and cold mid-level temperatures, should be sufficient for airmass destabilization. Large-scale ascent attendant to the approaching
shortwave trough coupled with low-level convergence near the surface
low and warm front are expected to provide the lift needed for
convective initiation. Initiation is currently expected to occur in
the 21Z to 00Z time frame over north-central/northeast KS. The
strongest mid-level flow will likely be displaced south of the
region, but vertical shear should still be strong enough for
supercells. Given the steep mid-level lapse rates some large to very
large hail is possible. Veering low-level wind profiles with height
also suggest some tornado potential exists, particularly near the
warm front where low-level southeasterlies are more likely.

Thunderstorm coverage will likely grow during the evening as the
low-level jet strengthens, with a warm-air advection increasing as
well. These storms would likely be elevated north of the warm front,
with steep mid-level lapse rates and moderate vertical shear
supporting hail with any more mature updrafts.

...Southeast KS...Central/Eastern OK...Far Northeast TX...
A more conditional severe threat exists in this region versus
farther north across the Lower MO Valley. Here, upper 50s to low 60s
dewpoints are likely, but warmer mid-level temperatures look to cap
the airmass, precluding widespread destabilization. Even so,
convergence along the dryline may be able to overcome this
inhibition in isolated instances, and the overall environmental
conditions support supercell thunderstorms capable of all severe
hazards if convective initiation is realized.

..Mosier.. 03/12/2024

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