LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1251 AM CDT Wed Sep 06 2023
Valid 061200Z - 071200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE
ARK-LA-MISS VICINITY INTO NORTHERN MS...NORTHERN AL...AND MIDDLE
TN...
...SUMMARY...
Severe thunderstorms capable of damaging gusts and isolated hail are
possible from the Ark-La-Miss vicinity into northern Mississippi,
northern Alabama, and middle Tennessee.
...Synopsis...
Shortwave trough currently moving into the Upper MS Valley is
expected to continue gradually eastward throughout the day, ending
the period over the Lower MI. As associated surface low will take a
similar track eastward, while an attendant cold front pushes
eastward/southeastward across the OH Valley and Mid MS Valley. A
moist air mass will precede this front, with scattered to numerous
thunderstorms anticipated as the front moves eastward/southeastward.
Upper ridging will persist southwest of this shortwave trough,
centered over far west TX. To the northwest of this ridging, the
low-amplitude shortwave trough currently moving across central CA is
expected to progress northeastward through the western Great Basin
and into southern portions of the northern Rockies. Increasing
mid-level moisture and modest large-scale ascent attendant to this
shortwave will result in isolated to widely scattered thunderstorms
from the interior Pacific Northwest and northern Great Basin into
the northern Rockies.
...TN/Mid MS Valleys...
Isolated showers and thunderstorms will likely be ongoing early in
the period, supported by modest warm-air advection ahead of the
approaching shortwave trough and associated cold front. This early
activity should weaken, with strong heating and ample low-level
moisture resulting in airmass destabilization by the early
afternoon. Convergence along the front will be modest, but, given
the lack of convective inhibition, still sufficient for thunderstorm
development. Moderate mid-level flow will accompany the approaching
shortwave, with some of this enhanced flow already over the region
when thunderstorms initiate. Strong buoyancy will support robust
updrafts, with the moderate shear contribute to some limited updraft
organization and a low probability for severe hail. Storms will
likely then trend quickly towards largely outflow-dominant
structures after initial development, with water loading
contributing to strong downbursts. Shear will likely be strong
enough for some updraft/cold pool balance, with the development of
one or more forward-propagating convective lines probable. These
convective lines could take the threat for damaging gusts from the
Mid-South into more of middle TN and northern MS/AL during the
evening.
...Lower MI and Mid/Upper OH Valley...
Several rounds of showers and thunderstorms are anticipated across
the region today, starting later this morning amid broad warm-air
advection ahead of the front. Additional development, or perhaps
re-intensification of any ongoing storms, is expected as a
pre-frontal trough moves across the region during the afternoon.
Another round is possible later in the early evening as the cold
front moves through, particularly if earlier storm coverage remains
isolated. Despite poor lapse rates, moderate buoyancy is still
expected across the region, supported by temperatures in the low 80s
and dewpoints in the low 70s. However, shear will be weak, and will
likely limit the overall severity of any thunderstorms. As such,
only isolated damaging gusts are currently anticipated.
..Mosier/Wendt.. 09/06/2023
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SvhTKG
