SPC finally updated lol... here is teh disco
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 PM CDT Wed Mar 24 2021
Valid 251200Z - 261200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE LOWER MISSISSIPPI VALLEY/MID-SOUTH INTO THE TENNESSEE VALLEY AND
SOUTHEAST...
...SUMMARY...
The potential for an outbreak of severe storms including several
long-track strong tornadoes, scattered large to very large hail, and
severe/destructive winds, will exist Thursday into Thursday evening
across a portion of the lower Mississippi Valley, Tennessee Valley,
and Southeast.
...Synopsis...
A shortwave trough with attendant 70-100 kt+ mid-level jet will
eject northeastward from the southern Plains across the lower/mid MS
Valley on Thursday, and continue over the OH Valley and lower Great
Lakes region Thursday night. At the surface, a weak low over
northeast TX at the beginning of the period Thursday morning is
expected to likewise develop northeastward to the mid MS Valley
through the day while deepening. A warm front attendant to this
cyclone will likely lift northward across the lower MS
Valley/Mid-South and TN Valley towards the lower OH Valley by
Thursday evening.
...Lower Mississippi Valley and Southeast...
Storms will likely be ongoing at the start of the period from
northeast TX into southern AR and northern MS/AL and TN. This
activity will likely be supported by a southerly low-level jet and
related warm advection. These storms should shift northward through
the morning, allowing for destabilization via diurnal heating to
occur across the lower MS Valley. Rich low-level moisture with at
least mid to upper 60s surface dewpoints (perhaps lower 70s), should
advect northward across parts of the lower/mid MS Valley, TN Valley,
and Southeast by Thursday afternoon. This increasing moisture,
coupled with diurnal heating, will likely support MLCAPE of
1500-2000 J/kg developing over a fairly broad portion of these
regions.
A pronounced low-level jet (50-60+ kt) will overlie much of this
region as well, as large-scale ascent from the ejecting shortwave
trough overspreads the lower/mid MS Valley vicinity. Strongly
veering and strengthening wind profiles from the surface through mid
levels will support supercells. 0-1 km SRH along/south of the
surface warm front will likely reach 300-500 m2/s2, and low-level
mesocyclones capable of producing strong, long-track tornadoes
appear likely with any supercells that can form. Scattered large
hail, some of which may be 2+ inches in diameter, and
severe/destructive winds also appear probable, both with supercells
and any bowing line segments that can develop. At this time, the
best potential for strong tornadoes appears to extend from parts of
central/northern MS into western/middle TN and central/northern AL,
mainly Thursday afternoon and evening as storms move generally
northeastward. Concern does exist regarding the effect of storms
forming during the morning on the development of instability, and
potential for destructive interference from too many storms
developing across the warm sector at the same time. Still, given the
very favorable environment forecast across this region and the
potential for numerous supercells, an upgrade to High Risk for
multiple strong to potentially violent, long-track tornadoes may be
needed in a later outlook update.
...Ohio Valley...
Fairly widespread precipitation should occur over a majority of the
lower OH Valley through the day. This should temper diurnal
destabilization to some degree, but weak instability will probably
still develop along/east of the surface low and northward-moving
warm front. At least an isolated severe threat may develop late
Thursday afternoon into the evening as the southerly low-level jet
strengthens over this region and low-level moisture increases. The
potential for a low-topped line of storms capable of producing
damaging wind gusts and tornadoes will exist given the strength of
the low-level flow and related shear. These storms will likely be
tied to a cold front as it tracks northeastward through the evening
and overnight hours.
