ACUS11 KWNS 251721
SWOMCD
SPC MCD 251720
LAZ000-ARZ000-TXZ000-252015-

Mesoscale Discussion 0300
NWS Storm Prediction Center Norman OK
1220 PM CDT Mon Mar 25 2024

Areas affected...parts of western/northern Louisiana and adjacent
southern Arkansas

Concerning...Severe potential...Watch possible

Valid 251720Z - 252015Z

Probability of Watch Issuance...40 percent

SUMMARY...Potential exists for one or two supercell storms to
gradually develop this afternoon, particularly near/west of the
Alexandria through Monroe vicinities by 3-4 PM CDT, if not earlier.
This may be accompanied by increasing risk to produce
tornadoes--perhaps a strong one.

DISCUSSION...In advance of a pre-frontal low-level wind
shift/confluence zone slowly advancing eastward across parts of
western Arkansas and eastern Texas, new thunderstorm development has
initiated across upper Texas and southwestern Louisiana coastal
areas. This appears to be in response to low-level moistening and
lift within a fairly strong warm advection regime, which may be
maximized near or just above 850 mb.

This is forecast to continue to shift north-northeastward toward
north central Louisiana, near/west of Monroe, through 20-21Z, where
somewhat weaker mid-level inhibition and increasing mid/upper
forcing beneath more pronounced difluent flow aloft may support
thunderstorm intensification. Given the strong deep-layer shear,
and forecast of enlarging low-level hodographs beneath strengthening
southerly 850 flow (to 50+ kt), the structure of the near-surface
thermodynamic profiles remains the primary uncertainty concerning
severe weather potential.

For example, notable differences are evident between the NAM and
Rapid Refresh forecast soundings, with the NAM soundings suggesting
convection may remain elevated above a saturated but weakly stable
profile from the surface through around 850 mb. Lapse rates within
this layer in the Rapid Refresh forecast soundings appear at least
somewhat more unstable, and perhaps supportive of convection rooted
closer to the surface, where hodographs within the low-level inflow
layer may be more conducive to the evolution of strong low-level
mesocyclones.

..Kerr/Hart.. 03/25/2024


ATTN...WFO...JAN...LCH...SHV...

LAT...LON 30549391 32379358 33199256 32489169 31259207 30369248
29969331 30549391


= = =
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)

ACUS11 KWNS 091348
SWOMCD
SPC MCD 091348
LAZ000-TXZ000-091545-

Mesoscale Discussion 0395
NWS Storm Prediction Center Norman OK
0848 AM CDT Tue Apr 09 2024

Areas affected...Portions of central/east TX into northwestern LA

Concerning...Severe potential...Watch possible

Valid 091348Z - 091545Z

Probability of Watch Issuance...60 percent

SUMMARY...A watch may be needed as the threat for tornadoes, large
hail, and damaging winds gradually increases this morning.

DISCUSSION...Warm advection associated with a 35-45 kt southerly
low-level jet, along with ascent attendant to the left exit region
of a southwesterly mid/upper-level jet, is aiding convection across
parts of central/east TX into northwestern LA. Some of this activity
across central TX is occurring near a convectively reinforced
outflow boundary, with a rich low-level airmass present along/south
of this boundary. Steep mid-level lapse rates are supporting
1500-2000 J/kg of MLCAPE in central TX, even though daytime heating
remains muted thus far, with lesser instability into east TX and
northwestern LA. Still, strong deep-layer shear of 50+ kt will
foster updraft organization and supercell potential. Large to very
large hail will be a concern with these supercells as they spread east-northeastward this morning. An increasing potential for
severe/damaging winds may be realized if a cluster forms along the
outflow boundary/front. Sufficient low-level shear is also present
for low-level updraft rotation and some tornado threat. Watch
issuance may be needed if convection continues to increase in
coverage and intensity across central TX.

..Gleason/Thompson.. 04/09/2024

ATTN...WFO...LCH...SHV...HGX...FWD...EWX...

LAT...LON 30029806 30829766 31659640 31939477 32179397 32159343
31369333 30959394 29939603 29559685 29579786 30029806


= = =
--- SBBSecho 3.20-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)