ACUS11 KWNS 192225
SWOMCD
SPC MCD 192224=20
KYZ000-INZ000-ILZ000-200030-

Mesoscale Discussion 0248
NWS Storm Prediction Center Norman OK
0524 PM CDT Wed Mar 19 2025

Areas affected...portions of the lower Ohio River Valley

Concerning...Tornado Watch 58...

Valid 192224Z - 200030Z

The severe weather threat for Tornado Watch 58 continues.

SUMMARY...Thunderstorms are beginning to develop across southeast
Illinois into western Kentucky. These storms are expected to
intensify and pose a severe threat as they move eastward across the
lower Ohio River Valley over the next few hours.

DISCUSSION...Very gradually deepening convection, cooling cloud-top
temperatures, and occasional lightning flashes have been noted over
the past 30-60 minutes across the lower OH River Valley. Despite the
slow convective evolution thus far, a combination of steadily
improving low-level moisture (in the form of mid 50s dewpoints) and
increasing deep-layer ascent within the left-exit region of the
mid-level jet should lead to a gradual increase in storm coverage
over the next 1-2 hours across southern IN and western KY. Buoyancy
within the narrow warm sector will remain fairly meager (around 500
J/kg MLCAPE), but low to mid-level winds have been increasing over
the past hour with the approach of the mid-level jet, which is
bolstering low to mid-level wind shear per regional VWPs. This
favorable kinematic profile should compensate for the limited
buoyancy and support organized convection downstream from where
cells are currently developing. Given nearly 300 m2/s2 0-1 km SRH
and 50-60 knot flow sampled within the lowest 1-2 km, severe gusts
and tornadoes should remain the primary hazard.

..Moore.. 03/19/2025

ATTN...WFO...LMK...IND...PAH...

LAT...LON   36858879 37378858 38198811 38398792 38508771 38588640
            38528602 38358581 37938585 37668601 37368625 37138646
            37058674 36698840 36728869 36788878 36858879
            
ACUS11 KWNS 192334
SWOMCD
SPC MCD 192334=20
ALZ000-TNZ000-KYZ000-MSZ000-200130-

Mesoscale Discussion 0249
NWS Storm Prediction Center Norman OK
0634 PM CDT Wed Mar 19 2025

Areas affected...Western and middle Tennessee into northern
Mississippi and northwest Alabama

Concerning...Severe potential...Watch unlikely=20

Valid 192334Z - 200130Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm development is expected between 7-9 PM CDT
across western Tennessee and northern to central Mississippi with a
downstream risk for severe hail and damaging winds. The risk is
expected to remain sufficiently isolated to preclude watch issuance.

DISCUSSION...GOES visible imagery shows gradually deepening cumulus
along and just ahead of a diffuse dryline/Pacific front from western
TN southward into MS. This trend is expected to continue as
mid-level temperatures continue to cool with the eastward
progression of the primary trough axis, resulting in improving
700-500 mb lapse rates that will be more favorable for sustained
convection. This trend is already being observed further north
across the lower OH River Valley, suggesting that thunderstorm
development is becoming more likely for areas further south. Modest
surface moisture (mid 50s dewpoints) will continue to limit overall
buoyancy values (MLCAPE should be maximized around 500-750 J/kg),
but wind fields over the region are supporting elongated hodographs
that will promote organization of the more intense updrafts. Weak
off-boundary storm motions/deep-layer shear vectors suggest that a
combination of semi-discrete cells and clusters is likely later this
evening as storms move into middle TN and northwest AL. Given the
convective environment and trends in latest CAM guidance, a few of
the more intense cells/clusters may pose a severe hail/wind threat
through the late evening.

..Moore/Hart.. 03/19/2025

ATTN...WFO...OHX...BMX...HUN...PAH...MEG...JAN...

LAT...LON   32909031 35998919 36458887 36538846 36628750 36588700
            36448652 36178623 35758610 35048619 34208674 33358759
            32638848 32468899 32458937 32478982 32549002 32679022
            32909031
$$
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