SEVERE WEATHER THREAT: 3/17/22 - 3/18/22

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0757 PM CDT Thu Mar 17 2022

Valid 180100Z - 181200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEAST LOUISIANA AND SOUTHWEST MISSISSIPPI...

...SUMMARY...
Threats for severe thunderstorms are expected late this this evening
over parts of Oklahoma and northeast Texas, where large hail and
wind damage will be possible. A threat for tornadoes, wind damage
and isolated large hail will be possible in parts of southern
Louisiana and southern Mississippi after midnight.

...Oklahoma/Northeast Texas...
The latest water vapor imagery has a negatively tilted upper-level
trough over the southern Plains. A broad plume of mid-level moisture
extends from the Red River Valley northward into the central Plains,
wrapping southwestward around the system into the southern and
central High Plains. At the surface, a 999 mb low is locate in
southwest Oklahoma. A narrow corridor of maximized low-level
moisture is located from north-central Texas into central Oklahoma,
where surface dewpoints range from the upper 40s to mid 50s F. The
RAP is estimating MLCAPE along this corridor in the 1000 to 1200
J/kg range. Scattered thunderstorms have developed along the
instability axis this evening. The storms will move
north-northeastward across central Oklahoma and develop
southeastward into southern Oklahoma and northeast Texas later this
evening.

In addition to moderate instability, RAP forecast soundings this
evening in central and southern Oklahoma have 40 to 50 knots of 0-6
km shear with 700-500 mb lapse rates near 8.5 C/km. This environment
will be favorable for supercells and large hail. Hailstones of
greater than 2 inches in diameter will be possible with the more
dominant cells. The potential for very large hail should develop
southeastward across south-central Oklahoma and into far north Texas
late this evening. Wind damage may also accompany the stronger
thunderstorms as well.

...Southern Louisiana/Southern Mississippi...
The upper-level trough in the southern Plains will move toward the
Arklatex tonight as a 40 to 60 kt low-level jet strengthens in the
lower Mississippi Valley. At the surface, a warm front will move
from east Texas eastward across Louisiana tonight. Surface dewpoints
along and southwest of the front will be in the 60s F, with MLCAPE
likely reaching the 1500 to 2500 J/kg range. Thunderstorms are
expected to form this evening in east Texas near the axis of the
low-level jet and expand quickly in coverage, moving
east-northeastward across the Arklatex tonight. Thunderstorms are
also expected to develop southward across central and southern
Louisiana after midnight.

RAP forecast soundings along the most favorable corridor for severe
from southern and central Louisiana eastward into southwest
Mississippi late tonight have MLCAPE near 2500 J/kg, 0-6 km shear
around 40 knots and 0-3 km storm relative helicities in the 275 to
325 m2/s2 range. This should be favorable for supercells and
tornadoes. A strong tornado will be possible, mainly in southeast
Louisiana and southwest Mississippi, after 08Z when low-level shear
will become maximized across the lower Mississippi Valley.
Supercells will also be capable of producing wind damage and
isolated large hail. Due to increasing potential for tornadoes
overnight, will add an enhanced across parts of southeast Louisiana
and southwest Mississippi.

..Broyles.. 03/18/2022