ACUS01 KWNS 051231
SWODY1
SPC AC 051230

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0730 AM CDT Sat Apr 05 2025

Valid 051300Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
SABINE RIVER VALLEY TO THE TENNESSEE VALLEY...

...SUMMARY...
Severe storms, capable of producing damaging wind gusts, large hail
and several tornadoes are expected from the Sabine River Valley
northeastward into the lower to mid Mississippi and Ohio Valleys.
Strong tornadoes, very large hail, and severe gusts will be possible
in parts of the lower to mid Mississippi Valley.

...Synopsis...
Lead shortwave trough continues to progress northeastward across the
southern High Plains, within the eastern periphery of upper trough
over the Southwest. A large area of elevated thunderstorms has
evolved ahead of this wave, covering much of central/north TX and central/eastern OK.

As this deep upper trough continues to gradually shift eastward over
the Southwest/northern Mexico, an embedded shortwave trough and
associated jet streak will progresses through its base. General
expectation is for this shortwave trough to continue quickly
eastward across northern Mexico and then more northeastward as it
enters the southern Plains. A second shortwave trough is expected to
drop southward across AZ, with this overall evolution leading to an
elongation of the upper trough throughout the period.

Surface pattern currently consists of a sharp cold front from south
TX through AR and the Mid MS Valley to a low over northern IL. A
weakening convective line is ongoing well ahead of this front across
western KY and western TN. The cold front is forecast to continue southeastward, as the upper troughing and associated shortwave move
eastward, interacting with the moist and unstable airmass downstream
to support strong to severe thunderstorms from southeast TX and
Lower MS Valley into the Lower/Middle OH and TN Valleys today.

...East/Southeast TX through the Lower MS Valley
Much of the ongoing elevated thunderstorms from central/north TX
into eastern OK and western AR are forecast to continue
northeastward over the next few hours while gradually weakening and transitioning to a broad stratiform precipitation field. Severe
potential within this area of convection will be limited due to weak
buoyancy and an unfavorable storm mode.

The portion of the cold front in TX is expected to remain
progressive as its gradually shifts southeastward with time. The
airmass downstream is already uncapped and moderately to strong
unstable. Thunderstorm development in the vicinity of this boundary
has been largely anafrontal thus far, but that is expected to change
during the late morning/early afternoon as large-scale forcing for
ascent increases. Strengthening low-level flow is anticipated from
southeast TX into LA during this time as well. These factors should
lead to an increase in thunderstorm coverage along the front while
also increasing the potential for more open warm-sector development.
The combination of a deep moist layer, strong buoyancy, and robust
low-level flow supports the potential for supercells capable of all
hazards. However, the meridional, line-parallel character to the
deep-layer flow suggests a trend towards a more linear mode will be
favored, particularly along the front. However, any storms that can
remain discrete and avoid disruptive storm interacts could mature
quickly to produce large to very large hail and tornadoes, a few of
which could be strong (EF2+). This tornado threat will be maximized
from East TX and northern/central LA into southern AR, western MS,
and southwestern TN.

The potential for open warm-sector storms will lessen with time as
the front moves across the Lower MS Valley and thunderstorms along
the boundary become dominant. A linear storm mode will favor
damaging gusts as the primary hazard, although the low-level flow
will have enough strength and veering to support a risk for
line-embedded tornadoes.

...Mid-South into the TN/OH Valleys...
Farther north, the boundary will be less progressive throughout the morning/early afternoon, particularly north of a weak low currently
over northeast TX. The boundary will likely sharpen during this
time, before then becoming more progressive once again as the
convectively augmented shortwave trough currently moving into
western OK progresses into the region. This will likely result in a
bowing line segment with damaging gusts as the primary severe risk.
However, given the strength of the low-level flow, some embedded
tornado potential exists as well.

..Mosier/Kerr.. 04/05/2025

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