LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1142 PM CST Tue Jan 17 2023
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE MISSISSIPPI VALLEY INTO THE SOUTHERN OHIO VALLEY...
...SUMMARY...
Severe thunderstorms are possible from far east Texas and the Lower
Mississippi Valley into the Tennessee and Lower Ohio Valleys today.
...Synopsis...
A mid-level trough will amplify today as it moves from eastern
Colorado to the Missouri Valley. A 100+ knot mid-level jet will move
from the southern Plains to the Lower Ohio Valley during this
period. A surface low will move from the TX/OK Panhandle this
morning to Missouri to western Illinois by 12Z Thursday. As this
surface low moves northeast, a cold front will move quickly east
across the southern Plains and Mississippi Valley.
...Mid Mississippi Valley...
Low-level moisture advection has begun this morning across eastern
Texas and Louisiana with mid 60s dewpoints now approaching I-20.
This low-level moisture advection will increase after sunrise as the
low-level jet strengthens to 50+ knots. This warm-air advection will
likely initiate some storms across eastern Texas, northern
Louisiana, and southern Arkansas. Strong shear (50-60 kts) and
MLCAPE around 750-1000 J/kg should support supercells in an
environment with 0-500m SRH in excess of 150 m2/s2. However, these
storms will be occurring before any appreciable surface heating, and
therefore, low-level lapse rates will be weak. Therefore, while a
tornado or two cannot be ruled out with this activity, the limited
low-level buoyancy should mostly limit the tornado threat.
By mid-day, some heating will likely occur across the warm sector.
However, warm mid-level temperatures and a lack of strong forcing to
aid updraft acceleration will likely keep warm sector storms
limited. Farther west, storms are expected along the cold front as
it moves east through the afternoon. The progressive nature of the
cold front and southerly lower tropospheric flow will support mostly
anafrontal convection. Some severe storms are possible along the
front with a primary threat of damaging wind and perhaps a tornado
or two. As this line of storms moves farther east and buoyancy
decreases after sunset, expect convection to become increasingly
anafrontal which will significantly decrease the severe weather
threat overnight.
...Eastern Oklahoma into the Ozarks...
Mid to upper 50s dewpoints will advect into southeastern Oklahoma
early this morning which will lead to weak destabilization. A few
thunderstorms are possible in a strongly sheared atmosphere. These
storms may pose a threat for marginally severe hail and a few
damaging wind gusts. Upscale thunderstorms growth farther southeast
should limit destabilization across the Ozarks, but weak instability
is expected into the afternoon which should continue the damaging
wind/hail threat. The strongly sheared atmosphere could support a
tornado, but weak instability will likely mitigate the tornado
threat this far north.
...Missouri Bootheel into the Lower Ohio Valley...
Widespread thunderstorm activity is expected across this region for
most of the day which should keep instability limited. However,
strong low-level flow will likely bring low 60s dewpoints into the
region ahead of the fast moving cold front which may lead to some
weak instability. This could support some threat for damaging winds
along the cold front as it moves east.
..Bentley/Broyles.. 01/18/2023
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/Sh3Dvy
