MD 0300 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PARTS OF WESTERN/NORTHERN LOUISIANA AND ADJACENT SOUTHERN ARKANSAS
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
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…JAN…LCH…SHV…
LAT…LON 30549391 32379358 33199256 32489169 31259207 30369248
29969331 30549391
