Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 180658
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1258 AM CST Tue Jan 18 2022
Valid 191200Z - 201200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
EAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY...
...SUMMARY...
Isolated severe thunderstorms may occur Wednesday from parts of east
Texas into the lower Mississippi Valley. Occasional severe hail,
damaging wind gusts, and a tornado or two all appear possible.
...Synopsis...
A low-amplitude shortwave trough over the southern High Plains
Wednesday morning will advance eastward over the ArkLaTex and lower
MS Valley by Wednesday evening. A weak surface low initially over
northeast TX/southeast OK should likewise develop eastward in tandem
with the shortwave trough. A strong cold front is forecast to sweep
south-southeastward over the southern Plains, Mid-South, and lower
MS Valley through the period.
Modest low-level moisture return will continue ahead of the cold
front from coastal TX into much of LA/MS and southern AR by
Wednesday afternoon. Due to a prior frontal passage shunting rich
low-level moisture well south into the Gulf of Mexico, this moisture
return will likely remain fairly muted, with only mid 50s to no
greater than low 60s surface dewpoints present across much of the
warm sector.
...East Texas into the Lower Mississippi Valley...
Generally weak instability should develop ahead of the front through
Wednesday afternoon as filtered diurnal heating occurs. Most
guidance suggests that around 250-1000 J/kg of MLCAPE (greater
values with southward extent) will be present by late Wednesday
afternoon in a fairly narrow corridor from east TX into LA, southern
AR, and western MS. Isolated to scattered convection should develop
along/ahead of the front in this time frame as residual MLCIN
finally erodes. A 50-60 kt mid-level jet attendant to the shortwave
trough will overspread this region through the day. Related 35-50 kt
of effective bulk shear will likely support thunderstorm
organization.
An initial mix of supercells and multicells appears possible, with
an isolated threat for both severe hail and damaging wind gusts.
With time into Wednesday evening, convection should tend to grow
upscale into clusters along or just ahead of the cold front as both
develop south-southeastward. Occasional strong/damaging winds will
probably become the main threat as this mode transition occurs. A
tornado or two also may also occur as a 25-35 kt southwesterly
low-level jet persists over this region through much of the
afternoon, enhancing 0-1-km SRH. This convection will eventually
outpace the modest low-level moisture return, and a gradual
weakening trend is anticipated Wednesday night across southern LA/MS
into AL.
..Gleason.. 01/18/2022
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