SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1200 PM CDT Wed Mar 15 2023
Valid 161200Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF
NORTHEAST TEXAS...SOUTHERN OKLAHOMA AND INTO THE ARKLATEX...
...SUMMARY...
Scattered severe thunderstorms capable of producing large hail,
damaging winds, and a few tornadoes appear likely Thursday afternoon
and evening across parts of the southern Plains. Some of the hail
could be very large over south-central Oklahoma and north-central
Texas.
...Synopsis...
A low-amplitude shortwave trough will move quickly east across the
South Plains on Thursday, into the Ozarks during the evening and to
the OH Valley by 12Z Friday. This wave will provide height falls
over a broad region with midlevel winds increasing to 70 kt,
enhancing shear. A northern-stream trough will also move toward the
Upper MS Valley, with a tight midlevel temperature gradient and
rapid cooling expected.
At the surface, low pressure will exist over southern KS Thursday
morning, with a cold front moving rapidly southeast to a Green Bay
WI to Dallas TX line by 00Z Friday. A warm front will extend
southeastward from the KS low across eastern OK and TX to start the
day, moving north across the Arklatex by 00Z and into southwest AR
by evening.
Strengthening southerly winds will aid moisture return across the
warm sector, with 60 F dewpoints meeting the front over southern OK,
and mid 60s F over much of east/northeast TX and perhaps to the
Arklatex by around 00Z.
Surface pressures will increase ahead of the cold front over the
Southern Plains into the lower MS Valley through the period as the
cold air undercuts the warm sector and primary low rapidly deepens
over the upper Great Lakes. Even so, the combination of
destabilization over the southern Plains, strengthening shear and
lift along the cold and warm fronts will likely lead to swaths of
severe storms beginning Thursday afternoon, mainly from southern OK
into northeast TX and toward the Arklatex and Sabine River.
...OK and TX Late afternoon through early evening...
As the cold front pushes south, storms are expected to form by 20Z
over central and southern OK, with additional activity building
south and translating east across much of North TX through 00Z.
Storms forming near the low and riding along the warm front into
southeast OK will have tornado potential as given effective SRH over
300 m2/s2. Storms farther southwest toward the Red River and into TX
may produce very large hail due to better lapse rates and
instability. With time, the front will undercut the activity, with
wind damage along with elevated hail expected.
Farther south along the front into central/eastern TX, the front
will continue to push rapidly south overnight, with increasing storm
coverage. Ample instability will interact with the front, with
parallel deep-layer shear vectors and weakening winds in the low
levels. Hail appears to be the main threat as the storms become
undercut by the cold air, but a narrow zone of damaging wind
potential could materialize should storms propagate fast enough to
keep up with the front. The cells over southern OK and North TX
prior to 00Z in particularly may produce damaging hail and a tornado
or two before the front undercuts the activity. Any cells or bows
that can propagate with a strong eastward component may reside along
the boundary longer, enhancing both severe wind and tornado threat.
Another area of potential will be over northeast TX ahead of the
cold front during the afternoon and evening. Initially, these storms
will be elevated as they move into AR, beneath a 50+ kt low-level
jet. As the warmer air moves into this region, a few supercells will
be possible with tornado, hail and wind potential. Instability is
forecast to be limited farther east, but strong shear may allow a
few severe storms to produce damage into northern LA and southern
AR.
...Lower MS Valley overnight...
Height falls as well as increasing winds aloft will overspread the
region despite the main wave passing well to the north. Winds around
850 mb will still be over 40 kt, veering to west/southwesterly. This
will essentially parallel the cold front which will push into MS and
central LA by 12Z Friday.
Given the cool/dry air mass initially in place, temperatures will
likely be limited to the 60s F from afternoon into the overnight.
The moistening boundary layer will maintain warmth overnight, but
MUCAPE values are forecast to be very low. Many models indicate zero
SBCAPE north of about I-10. Nonetheless, strong lift along the front
will result in showers and thunderstorms, and some of this activity
could potentially produce strong wind gusts given flow magnitudes
just off the surface.
..Jewell.. 03/15/2023
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