SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 PM CDT Fri Aug 11 2023
Valid 121200Z - 131200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTION OF
THE OHIO VALLEY AND NORTHEAST...AND OVER THE SOUTHERN HIGH PLAINS
VICINITY...
...SUMMARY...
Severe thunderstorms are possible across portions of the Ohio Valley
and Northeast, parts of the Plains region, and the Mid
South/southern Appalachians on Saturday.
...Ohio Valley/Northeast...
A belt of 40 to 60 kt mid-level westerlies is forecast to overspread
the mid and upper Ohio Valley and Northeast on Saturday, as a
short-wave trough initially over the Upper Great Lakes area shifts
eastward across the region. Storms are forecast to develop by
afternoon as the warm-sector airmass heats/destabilizes -- over
parts of New York and northeastern PA near the warm front and
evolving lake-breeze boundaries, and over northwestern Ohio and
Indiana along the southeastward/moving cold front. Given moderately
strong flow through the lower and middle troposphere, damaging winds
are expected with stronger storms as convection moves rather quickly
eastward.
Some increase in storm coverage should continue through the
afternoon and persist into the evening. Still, it appears that
overall coverage may remain sufficiently sparse so as to limit
overall coverage of severe-weather occurrences. WIth that said,
this area may require upgrade to 30% wind/ENH risk, as multiple
rounds of scattered storm clusters may affect some areas.
...Southern High Plains vicinity...
Short-wave troughing is progged to rotate northeastward across New
Mexico and the central/southern High Plains region, and then
east-northeastward into Kansas and northern Oklahoma, around the
western periphery of the mid-level ridge. As the afternoon airmass
heats/destabilizes, storms are expected to develop from southeastern
Colorado/northeastern New Mexico to the Texas Panhandle, which would
then spread eastward across parts of Kansas and Oklahoma in
conjunction with an enhanced belt of mid-level westerlies
accompanying the aforementioned short-wave troughing. Given a
relatively deep mixed layer anticipated during the afternoon and
early evening, locally damaging wind gusts appear to be the primary
severe threat, along with some hail risk. Storms may increase in
coverage during the evening/overnight as a southwesterly low-level
jet develops. Convection may spread eastward into Missouri late,
though likely with diminishing severe risk due to diurnal
stabilization of the boundary layer.
...Mid South/southern Appalachians...
An MCS is forecast to be ongoing at the start of the period, moving
eastward across the Mid Mississippi Valley vicinity. As the
downstream airmass destabilizes through the day, storms will likely
be maintained, with some reintensification possible -- aided by
presence of increasing mid-level west-northwesterly flow with
northward extent. Locally damaging wind gusts and hail will be
possible with the strongest storms/storm clusters as convection
moves across the Mid South/Tennessee Valley region, with some hints
that a southeastward advance into/across the southern Appalachians
may occur. As such, have expanded MRGL risk into northern parts of
Alabama/Georgia, and into the western Carolinas/western Virginia, to
cover any local/isolated severe risk.
...South Dakota/Nebraska area...
Weak height falls associated with a short-wave trough advancing
southeastward from the Canadian Rockies, in conjunction with
low-level warm advection, should result in isolated afternoon storm
development as ample diurnal destabilization occurs. Given
sufficient shear expected over the area, a couple of the strongest
storms will likely become capable of producing hail and a damaging
gust or two. As a southerly low-level jet evolves through the
evening, a continuation of isolated storms is expected, with some
increase in coverage possible. Local severe risk may persist into
the overnight hours with the strongest storms.
..Goss.. 08/11/2023
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