ACUS01 KWNS 301247
SWODY1
SPC AC 301245

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Sun Mar 30 2025

Valid 301300Z - 311200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
THE LOWER/MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY AND SOUTHERN
GREAT LAKES...

...SUMMARY...
Numerous severe thunderstorms are expected today and tonight across
a broad portion of the Southeast and lower/mid Mississippi Valley
into the Ohio Valley and southern Great Lakes. Multiple swaths of
widespread damaging winds appear likely. Large to very large hail
and several tornadoes will also occur with supercells. A few of
these tornadoes could be strong.

...Synopsis...
A broad area of severe potential remains apparent today and tonight,
with all severe hazards likely. The main mid-level shortwave trough
of interest will move quickly northeastward from the Ozarks/mid MO
Valley to the Upper Midwest and Great Lakes today, as larger-scale
upper troughing gradually becomes more established over the MS
Valley through the period. At the surface, the primary surface low
over eastern IA this morning is expected to develop northeastward
towards northern Lower MI by this evening, and eventually into
southern Ontario/Quebec late tonight. An attendant cold front will
sweep east-southeastward over much of the Midwest/OH Valley and
mid/lower MS Valley through the period, while a warm front lifts
northward in tandem with the surface low over portions of the Great
Lakes. A dryline will mix eastward this afternoon across parts of
north-central to south-central TX.

...Midwest/Ohio Valley to the Great Lakes...

Mainly elevated thunderstorms are ongoing this morning across parts
of northeast MO in associated with the northeastward-advancing
shortwave trough. This activity should generally remain sub-severe,
although isolated strong/gusty winds could occur with modest daytime
heating this morning. Otherwise, a corridor of weak to moderate
instability is expected to develop ahead of the cold front by early
afternoon. Robust convection appears likely to initiate by 18-19Z,
and it will spread quickly northeastward across much of the OH
Valley and southern Great Lakes regions this afternoon and evening.
A 50-70 kt southwesterly mid-level jet attendant to the shortwave
trough will provide ample deep-layer shear for organized convection.

Current expectations are for an initially more discrete mode, with
supercells posing a threat for large to very large hail (around
1.5-2.5 inch diameter) given the presence of steep mid-level lapse
rates and favorable deep-layer shear. A fairly quick transition
(within a few hours of initiation) to a more linear/cluster mode is
anticipated as the cold front surges eastward. Multiple swaths of
numerous to potentially widespread severe/damaging winds appear
likely as one or more clusters moves quickly east-northeastward over
the OH Valley and southern Lower MI. With a 35-45 kt
south-southwesterly low-level jet also present, strong low-level
shear will likely support a threat for tornadoes, both with initial
supercells and any lines/clusters that eventually form. Given the
strength of the low-level flow, some of the tornadoes could be
strong, especially with sustained supercells in the lower OH Valley
vicinity. The threat for damaging winds and tornadoes should
continue this evening into the overnight hours, until convection
outpaces the low-level moisture return and eventually weakens over
the upper OH Valley and central Appalachians.

...Central/East Texas into the Lower/Mid Mississippi
Valley/Mid-South and Southeast...

A band of mostly elevated convection developed earlier this morning
over portions of north-central/east TX, likely in association with
large-scale ascent preceding a westerly mid/upper-level jet nosing
into central TX. While the overall environment remains quite
favorable for organized severe convection, messy convective modes
have tended to keep the severe hail threat isolated so far. Still,
some risk for hail will continue through the morning. Strong
destabilization is anticipated today ahead of this convection and a
separate area of elevated thunderstorms over southern MO. Mid to
upper 60s surface dewpoints will continue to stream northward across
TX ahead of the dryline, and the lower/mid MS Valley and Southeast
ahead of the cold front. This rich low-level moisture, combined with
very steep (8-9 C/km) mid-level lapse rates and daytime heating, are
expected to foster around 2000-3000 MLCAPE by early to mid afternoon.

Rapid and intense thunderstorm initiation will likely occur by
18-21Z from parts of north-central/east TX to the Mid-South/mid MS
Valley. Supercells are expected initially, with 40-50+ kt of
deep-layer shear supporting robust updraft organization and
rotation. A very favorable setup remains apparent for large to very
large hail, as strong instability and deep-layer shear combine with
steep mid-level lapse rates and low freezing levels. Some of this
very large hail could reach up to 2-3 inches in diameter. With the
primary shortwave trough ejecting to the northeast, low-level winds
are forecast to remain fairly subdued through the afternoon and
early evening, before gradually strengthening again tonight through
early Monday morning. A risk for several tornadoes should be focused
over parts of the Mid-South, a few of which could be strong given a
favorable supercell mode. Similar to farther north in the OH Valley,
a transition to more linear/cluster mode is expected this evening
and overnight as the cold front continues advancing southeastward. A
risk for line-embedded tornadoes should continue, and an increase in
the severe/damaging wind threat is likely through the end of the
period. Based on latest guidance trends, and to overlap with the Day
2 Convective Outlook, adjustments have been made to the
southern/eastern extent of the risk areas across the lower MS Valley
and Southeast.

...Florida Peninsula...

A weak mid-level perturbation will move eastward over FL today.
Modestly enhanced winds aloft, and a veering profile with height
through mid levels, should support sufficient deep-layer shear for
some thunderstorm organization. Any convection that develops in
tandem with daytime heating this afternoon and early evening could
pose an isolated threat for severe hail and damaging winds. Some
adjustments have been made to the Marginal Risk across the FL
Peninsula based on latest guidance trends.

..Gleason/Leitman.. 03/30/2025

$$
--- SBBSecho 3.20-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)