Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1246 AM CDT Sun Oct 13 2024
Valid 131200Z - 141200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM
CENTRAL/EASTERN WV TO MIDDLE/EASTERN TN...
...SUMMARY...
Strong to locally severe thunderstorms are possible, mainly this
evening, across parts of the central/southern Appalachians and
Tennessee Valley. Isolated wind damage and marginally severe hail
are the expected hazards.
...Central/southern Appalachians and the TN Valley...
A vigorous shortwave impulse will dig through the basal portion of a
mid/upper trough and yield amplification of this trough southward
across the Great Lakes through Monday morning. Appreciable mid-level
height falls will overspread the central/southern Appalachians into
the TN Valley, mainly during the evening and overnight. A leading
and weaker mid-level impulse should yield the primary surface
cyclone moving east across PA during the afternoon to early evening.
A surface cold front will extend southwest of this low into the TN
Valley. Convective development along the front appears likely to be
delayed until early evening, as the strengthening large-scale ascent
aids in increasing low-level convergence along the boundary amid
pervasive veered flow within the warm sector. Surface dew points
should largely range from the mid 50s in WV to a narrow corridor of
low 60s in Middle TN, yielding a plume of modest buoyancy between
500-1500 J/kg amid initially steep mid-level lapse rates.
Guidance differs greatly in the degree of storm coverage, from nil
to scattered, perhaps in response to the ascent strengthening after
peak diurnal heating. The strongest 700-mb westerlies, in excess of
50 kts, should be confined northeast of TN. Forecast hodographs
above this level appear small, owing to weakening winds with height
as fast mid/upper flow lags to the north-northwest. This suggests
supercell structures may struggle to develop/be sustained. But the
strong 700-mb flow could support localized damaging winds in any
multicell clusters. Farther southwest, somewhat greater buoyancy
could foster small to marginally severe hail as well. The overall
severe threat appears likely to remain marginal and isolated.
..Grams/Halbert.. 10/13/2024
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