SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0743 AM CDT Fri Apr 04 2025
Valid 041300Z - 051200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FROM THE
ARKLATEX INTO SOUTHEAST MISSOURI...
...SUMMARY...
Several clusters of severe storms are expected from central Texas
across the ArkLaTex and into the lower Ohio Valley through tonight.
The greatest threat for tornadoes, large hail and damaging winds
will be from the ArkLaTex across western Arkansas into southeast
Missouri, including potential for strong to potentially intense
tornadoes.
...Synopsis...
Early morning satellite imagery shows a deep upper trough extending
across the western CONUS, with an embedded shortwave trough moving
through the southern High Plains. Another embedded shortwave trough
exists farther west and is currently moving across the central Baja
Peninsula. The lead wave is forecast to continue northeastward into
the central Plains throughout the day, while the second wave
continues eastward into northern/central Mexico.
At the surface, a stalled frontal boundary currently extends from a
weak low near DRT northeastward to another weak low in northeast TX.
Widespread showers and thunderstorms are ongoing north of this
boundary, supported by a warm-air advection from a strong low-level
jet that covers much of central/eastern TX and the Lower MS Valley.
Expectation is for the low-level jet to persist throughout the day,
gradually shifting eastward in response to modest eastward progress
of the upper troughing. Eastern portion of the stationary front
should transition to a warm front while elevated thunderstorms
continue north of this boundary. Northward progression of this front
will allow the very moist airmass in place across east TX and LA to
surge northward into more of the Mid-South/Mid MS Valley, resulting
in a broad and unstable warm sector by early afternoon. At the same
time, the portion of the front over TX will begin drifting
southeastward as a cold front. Severe thunderstorms are expected as
this front interacts with the moist and unstable warm sector in
place.
...Eastern OK into the Mid MS Valley this morning...
Ongoing showers and thunderstorms across eastern OK and
northern/western AR are expected to shift northeastward this
morning, gradually losing intensity as buoyancy weakens with
northern extent. Expectation is for these storms to stay elevated
north of the warm front, but there should still be enough buoyancy
for large hail within the strongest storms.
...Arklatex through the Mid-South this afternoon/evening...
As mentioned in the synopsis, the warm front across the region is
expected to surge quickly northward, with very moist air expected to
advect into the region in its wake. 70s dewpoints are already in
place across east TX and northwest LA and consensus within the
guidance takes these 70s dewpoints into central AR and western TN by
later this afternoon. Modest heating within this airmass will bring
temperatures into the upper 70s/low 80s. These surface conditions
beneath a residual EML will support robust destabilization and a
large area of 2000+ J/kg of MLCAPE. A vigorous low-level jet will
extend across this region as well, resulting in robust low-level
shear. Some mid-level weakness is noted in forecast hodographs, but
the bulk shear is still more than enough to support supercells.
A combination of convergence along the front and strengthening
large-scale ascent is expected to result in initial development
around 18Z from far west-central/southwest OK through the Arklatex
into northeast TX. Given the strong buoyancy and shear, this
development should mature quickly into supercells capable of all
severe hazards, including strong to intense tornadoes and very large
(i.e. greater than 2" in diameter) hail. With the increasing ascent
and little to no convective inhibition, overall storm coverage will
be high and storm interactions could have a large role in
determining supercell longevity. That being said, environmental
conditions do support the potential for long-track tornadoes.
...Lower MO Valley into the Mid MS and Lower OH Valleys this
afternoon/evening...
A persistent low-level jet coupled with modest height falls and
perhaps even some convectively enhanced vorticity maxima will
support widespread elevated thunderstorms. Some hail is possible
with the stronger, more consistent cores as this activity moves
northeastward. There is some chance that storms along the
southernmost tier of this activity begin to interact with the warm
front (and potentially a weak frontal low) in the southeast
MO/southern IL/far western KY vicinity. As a result, there could be
a period where a more organized convective line develops, with an
attendant threat for damaging wind gusts.
...Southwest TX/TX Hill Country tonight...
Second shortwave trough mentioned in the synopsis is forecast to
cross northern/central Mexico and move into the southern High Plains
late tonight. Steep mid-level lapse and associated significant
elevated buoyancy will be in place, and thunderstorm development is
anticipated as the shortwave moves into the region. Strong shear
will also be in place, which will likely aid in the development of
supercells capable of large to very large hail.
..Mosier/Kerr.. 04/04/2025
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