LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1158 PM CST Sat Feb 25 2023
Valid 261200Z - 271200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF WESTERN NORTH TEXAS AND WESTERN OKLAHOMA...
...SUMMARY...
A significant damaging wind event is expected from the eastern Texas
Panhandle into much of Oklahoma and southeast Kansas late this
afternoon through this evening. Gusts greater than 75 mph will be
possible. Additionally, a few tornadoes will be possible. A couple
strong (EF-2+ intensity) tornadoes appear most probable over parts
of western North Texas into southwest Oklahoma. A damaging wind
threat will continue into parts of Missouri overnight.
...Synopsis...
A potent, negatively tilted midlevel trough will eject eastward into
the southern/central Plains late this afternoon and evening, and
become positioned over the Mid-MS Valley by Monday morning. Extreme
vertical shear will overspread the southern Plains vicinity ahead of
a deepening surface low and eastward-advancing cold front. Strong
forcing for ascent along the cold front and within a 100+ kt 500 mb
jet streak will aid in rapidly developing convection by late
afternoon across the eastern TX panhandle amid modest boundary-layer
moisture. Initially semi-discrete supercells will pose a risk for
tornadoes, a couple potentially strong (EF-2+ intensity) early in
the event across parts of western North TX into southwest OK.
Supercells are then expected to grow upscale into a fast-moving
linear convective system shifting east/northeast across much of OK
and southeast KS.
Linear convection and strong gusts are expected to continue
northeast overnight across MO and into western IL.
...TX/OK/KS...
Increasing southerly low-level flow will transport mid/upper 50s
dewpoints into far southern KS by 00z. Near-60 F dewpoints are
possible as far north as the I-40 corridor in OK by late afternoon.
While the main synoptic surface low is forecast to deepen and spread
east/northeast across the central Plains, several members of 00z
deterministic guidance suite suggest a meso-low may develop in
southwest OK, near the OK/TX border. A corridor of relatively
greater tornado potential will exist near this triple point feature
where a higher-quality warm sector will reside. Surface-based
instability will be maximized within this corridor, with SBCAPE
around 500-1000 J/kg forecast. A couple of strong tornadoes will be
possible within a corridor of enhanced low-level shear, very large,
favorably curved hodographs, and 0-1 km SRH values increasing to
near 500 m2/s2 as an 850 mb low-level jet strengthens to 65+ kt.
As initial convection spreads eastward across western OK, upscale
development into a fast moving line of storms is expected. Capping
will prevent open warm sector convection for the most part, with
strong forcing along the cold front overcoming the cap and being the
main forcing mechanism for convection. Intense mass flux along the
front, combined with extreme vertical shear is expected to be
sufficient for widespread severe and damaging gusts despite SBCAPE
values generally at or below 500 J/kg. Some threat for mesovortex
tornadoes will exist, but this threat may be mitigated by modest
low-level thermodynamics further east later in the evening.
...MO/IL...
Significant severe gusts may persist as convection spreads east into
MO through the early overnight period. However, instability will
become meager with northeast extent. Nevertheless, intense vertical
shear will continue to overspread the region and at least modest
lapse rates are present in forecast soundings. Strong gusts may
approach the Mid-MS Valley by Monday morning.
..Leitman/Squitieri.. 02/26/2023
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