Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Sun Apr 02 2017
Valid 021200Z - 031200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS FOR EAST
TEXAS...CENTRAL AND NORTHERN LOUISIANA...AND FAR SOUTHWEST
MISSISSIPPI...
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
CENTRAL TEXAS AND MUCH OF EAST TEXAS EASTWARD INTO SOUTHERN ARKANSAS
AND CENTRAL MISSISSIPPI...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL TEXAS
INTO THE LOWER MISSISSIPPI VALLEY...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE
SLIGHT RISK...
...SUMMARY...
Numerous severe thunderstorms are forecast from parts of Texas
eastward into the lower Mississippi Valley today and into tonight.
A concentrated area of significant wind damage is likely near and
north of the I-20 corridor in east Texas and Louisiana. The risk
for tornadoes, a few of which may be strong/damaging, will probably
maximize near and south of I-20 in Texas and Louisiana, along with
the threat for hail.
...Synopsis...
A closed mid-level low will evolve into an open wave and move from
northern Mexico/Far West TX eastward to the ArkLaTex by early Monday
morning. A broad area of surface low pressure over the Rio Grande
Valley will consolidate and develop northeast across central TX
during the day and be near the OK/AR border at the end of the
period. A maritime warm front will advance northward across the
northwest Gulf Coast region during the day as a cold front
accelerates eastward across central TX during the afternoon and into
LA during the overnight.
...Central TX eastward into the lower MS Valley...
A multi-hazard, likely multi-scenario forecast with intrinsic
complexity/uncertainty is seemingly evident for today into tonight.
Late Saturday evening surface analysis and radar imagery show rich
low-level moisture over the TX coast with a developing thunderstorm
cluster in the middle Rio Grande Valley. Strong to severe
thunderstorms will likely be ongoing over central TX. Severe
gusts/wind damage appears to be the predominate threat with the
early-day MCS. As the surface low deepens, a concurrent strong
low-level mass response will occur and the development of a 50-kt
LLJ by mid morning is expected. Strong low-level moist advection on
the nose of the LLJ will be favorable for a continuation of early
morning storms as the LLJ's terminus shifts eastward from
east-central TX into the ArkLaTex by mid-late afternoon. A
concentrated zone of higher probability wind potential may be
realized with a potential bowing system as increasing buoyancy
(1000-3000 J/kg MUCAPE) and strong shear lead to an intense bowing
MCS moving from TX into the ArkLaTex.
Coincident with the diurnal heating cycle, free warm sector
thunderstorm initiation is likely from east TX into LA on the
northern rim of the elevated mixed layer's stronger capping
inversion (north of Interstate 10). Persistent south-to-north
oriented confluence zones in the warm sector will serve as the
genesis areas with gradual thunderstorm/supercell development as
stronger updrafts penetrate the LFC---beginning as early as the late
morning and through the afternoon. A moderate to very unstable
boundary layer (MLCAPE ranging from 2000-3000 J/kg) is forecast from
eastern parts of TX into LA. Forecast soundings show large
hodographs (200-400 m2/s2 0-1 km SRH) with strong effective shear of
at least 50-kt. It seems plausible several supercells may evolve
from this activity and pose a threat for tornadoes and large to very
large hail. A couple of strong/damaging tornadoes are possible.
The latest model guidance suggests thunderstorm coverage will be
less generally south of Interstate 10. Nonetheless, models show
isolated to widely scattered storms developing perhaps in
conjunction with stronger deep forcing for ascent.
During the evening and overnight over the lower MS Valley, storms
will likely spread into the region from the west. Increasing
moisture/buoyancy as the maritime front advances northward will
favor an organized severe storm risk continuing into the region.
Thunderstorms within the strong flow fields will conditionally
support the possibility for wind damage and tornadoes after dark.
..Smith/Gleason.. 04/02/2017
