LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1148 PM CST Mon Jan 02 2023
Valid 031200Z - 041200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM SOUTHEAST
LOUISIANA TO CENTRAL/SOUTHERN ALABAMA...
...SUMMARY...
Severe thunderstorms are expected across the central Gulf states
into the Tennessee Valley Tuesday. Tornadoes, damaging winds, and
large hail are all possible. The greatest risk is expected from
southeast Louisiana into southern/central Alabama where a couple of
strong tornadoes are possible.
...Central Gulf States/Tennessee Valley...
Strong mid-level short-wave trough is currently ejecting northeast
across the central Plains. 500mb speed max affiliated with this
feature is forecast to translate across MO into IL by 18z. As a
result strong 500mb height falls (150m in 12hr) will overspread the
mid MS Valley region as a warm front advances north across central
IL/IN.
Latest model guidance suggests the primary synoptic cold front will
arc from southeast IA-eastern MO-lower Sabine River Valley by 18z,
then into the lower OH Valley, extending into the lower MS Valley by
04/06z. Low-level warm advection will likely contribute to early-day
convection ahead of the aforementioned short wave with the primary
corridor of strong convection likely extending from western KY into
northern TN. This band of storms should sag southeast as the
strongest mid-level forcing spreads north of this region. While
strong updrafts/scattered severe may be noted with this early
activity, boundary-layer destabilization across the central Gulf
states is expected to aid buoyancy for potentially more robust
convection later in the afternoon. Surface temperatures will likely
warm into the lower 70s across much of the lower MS Valley into
central AL. With dew points in the mid 60s to near 70F,
surface-based CAPE should approach 2000 J/kg in the presence of
strong shear. Any updrafts that evolve within this environment could
obtain supercell characteristics. Long-lived updrafts capable of
generating tornadoes, and even a strong tornado, seem possible.
Damaging winds are also a risk along with hail.
While convection that evolves through early evening will not be
strongly forced, a secondary, notable short-wave trough will eject
across TX by 06z, and this feature should encourage renewed
convection during the overnight hours as height falls increase ahead
of the cold front. Frontal convection should organize and propagate
across LA/MS into AL after midnight.
...IL...
Surface warm front is forecast to advance north across MO/IL/IN this
morning. Instability will also increase as dew points recover across
this region. There is some concern that isolated strong/severe
thunderstorms could initiate ahead of the cold front over IL around
17-18z but strengthen downstream where temperatures warm into the
lower 60s . This activity will be strongly sheared and a few
supercells may ultimately evolve. If so, hail and wind are possible,
along with some tornado risk. Have extended severe probabilities
north into IL to account for this risk.
..Darrow/Wendt.. 01/03/2023
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