LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0719 AM CDT Thu Jul 13 2023
Valid 131300Z - 141200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
HIGH PLAINS...NORTHERN PLAINS...UPPER OH VALLEY...AND NORTHEAST
STATES...
...SUMMARY...
Scattered severe thunderstorms capable of producing damaging winds,
large hail, and perhaps a couple of tornadoes are possible Thursday
across parts of the Ohio Valley into the Northeast, and portions of
the southern/central Plains. Isolated very large hail may occur
across parts of the central Plains.
...NY into New England...
Morning water vapor loop shows a strong upper shortwave trough
moving across southern Ontario. A surface cold front currently
extends across Lake Erie into western OH. This front will sweep
eastward today into NY where thunderstorm development is likely by
early afternoon. Surface dewpoints in the mid 60s and strong
heating will yield pockets of MLCAPE over 2000 J/kg, along with
moderately steep low and mid-level lapse rates. Shear profiles are
also rather strong, conducive for organized/supercell structures.
Activity is expected to intensify over eastern NY in the Hudson
Valley vicinity before spreading into western New England. A
mixture of discrete supercell storms and bowing structures is
expected, capable of large hail and damaging wind gusts. A tornado
or two is also possible. Storms should weaken around sunset as
activity moves into a more stable environment over NH.
...KY/WV/OH...
The aforementioned surface cold front will sag southward into the
upper OH Valley by mid-afternoon. Scattered thunderstorms are
expected to develop across this region, where sufficient westerly
flow aloft and MLCAPE around 1500 J/kg will promote a few organized
clusters capable of damaging winds and hail.
...High Plains from SD to TX...
A broad upper ridge is present today over the southwest states, with
the southern fringe of stronger westerlies extending across CO/KS.
A surface dryline will become established by late afternoon
extending from the Black Hills vicinity across eastern CO. Forcing
will be subtle, but a weak cap and ample moisture/instability will
result in widely scattered intense storms along the dryline -
spreading southeastward through the evening. Supercells capable of
very large hail appear possible. Storms over western SD/NE may
persist well into the night and spread eastward across those states.
Several model solutions also suggest that sufficient coverage of
strong/severe storms may affect parts of southern MN and northwest
IA to support an extension of the SLGT risk into those areas.
..Hart/Leitman.. 07/13/2023
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