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Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1229 PM CDT Tue Apr 12 2022

Valid 131200Z - 141200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS LOWER TO MID MS
RIVER VALLEY...

...SUMMARY...
Numerous severe thunderstorms appear likely across a large portion
of the lower/mid Mississippi Valley into the Midwest, and lower Ohio
Valley on Wednesday. Damaging winds, some of which could be
significant, several tornadoes (some strong), and large to very
large hail will likely occur.

...Synopsis...
An upper-level wave, currently shifting into the northern Plains,
will largely meander over the northern CONUS for the next 24-48
hours. At the surface, a strong cold front associated with the
attendant surface low will continue to surge to the east/southeast
across the MS river valley through the day. The low to mid-level
cold surge behind the front will help pivot the upper-level trough
axis into the Great Lakes by late Wednesday. This will favor broad
height falls across the northern MS valley into the Great Lakes.
This broad scale ascent, co*bined with continued pole-ward advection
of higher theta-e air ahead of the front, will help destabilize a
broad region from the lower MS valley into the Great Lakes.
Strengthening flow along/ahead of the front will support widespread
organized convection. 

...Mid-MS/lower OH river valleys...
Thunderstorms are expected to develop along the cold front by the
mid morning hours across parts of southern MO/northern AR. Mean
storm motions along the front will favor a quick transition from
quasi-discrete cells to more linear storm modes. Convection will
continue to grow upscale as it approaches the mid-MS river valley
amid increasing low-level moisture and daytime heating. Increasing
low-level flow (up to 50-60 knots between 925-850 mb) will likely
support bowing segments and the potential for widespread damaging
winds. The potential for multiple 65+ knot wind reports and/or
significant wind damage support an upgrade to a wind-driven Moderate
risk for portions of the mid-MS/lower-OH river valleys. Elongated
0-3 km hodographs ahead of the line will also support embedded
circulations. The warm advection regime and broad scale ascent ahead
of the line may support a few more discrete cells across the lower
OH river valley by mid to late afternoon. This potential may be
conditional on the degree of destabilization that can occur behind
early-morning rain/weak thunderstorms that should exit the region by
early afternoon. However, if discrete convection can beco*e
established, all hazards will be possible, including the potential
for large hail and strong tornadoes.

...Lower MS river valley...
The surface cold front will likely lag to the west across the
Texarkana/lower MS valley regions, but this will allow for several
hours of daytime heating between cloud breaks and continued
boundary-layer moistening amid low-level theta-e advection. With 7-8
C/km mid-level lapse rates atop a deep, moist boundary layer will
likely support upwards of 1500-2500 J/kg MLCAPE by late afternoon.
Glancing upper-level ascent from the synoptic wave to the north
co*bined with isentropic ascent and lift along any confluence axes
and/or lingering outflow boundaries from overnight convection,
should be sufficient for isolated to scattered thunderstorms by mid
to late afternoon. Adequate deep-layer shear and strong flow in the
0-3 km layer will be favorable for supercells with all severe
hazards possible. Some solutions hint at forecast ESRH values
between 300-400 m2/s2, which will support the potential for strong
tornadoes. The signal for isolated convection is notable in recent
CAM solutions and in ensemble guidance, warranting an upgrade to a
Moderate risk where the tornado potential is highest. 

...New York and Pennsylvania...
A weak upper-level disturbance, currently moving over central TX, is
forecast to move into the Northeast by peak daytime heating
Wednesday. A weak surface low attendant to this wave will favor a
return to onshore flow with increasing boundary-layer moisture
through the day. Isolated to scattered thunderstorms are possible by
late afternoon as the wave moves across the region, and deep-layer
shear should be sufficient to support a few strong to severe
thunderstorms with an attendant risk for hail, wind, and possibly a
brief tornado.

..Moore/Mosier.. 04/12/2022