SPC Jul 31, 2024 0600 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0100 AM CDT Wed Jul 31 2024

Valid 311200Z - 011200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID MISSOURI VALLEY...

...SUMMARY...
Scattered thunderstorms with severe wind gusts are expected today
into tonight from the central and northern Plains southeastward into
the Ohio Valley. Isolated large to very large hail will be possible
from parts of the mid Missouri Valley northward into the Dakotas and
Minnesota this evening.

...Great Plains/Mid Missouri and Mid-Mississippi Valleys...
An upper-level ridge will move eastward into the mid to upper
Mississippi Valley today, as an upper-level trough moves into the
northern Plains. At the surface, a cold front will advance south and
eastward across the Dakotas and Nebraska. A band of strong low-level
convergence is expected to develop along the front by midday. This,
along with large-scale ascent associated with the approaching
shortwave trough, will provide support for scattered thunderstorm
development this afternoon. To the east of the front, surface
dewpoints in the 70s F will contribute to strong destabilization,
with MLCAPE forecast to peak in the 3500 to 4500 J/kg range. This
will provide plenty of fuel for MCS development.

Cells are expected to first initiate from northern South Dakota into
eastern North Dakota. Cell coverage is expected to gradually expand
southward into the mid Missouri Valley. Initially, supercell
development will be possible in areas that destabilize the most.
Strong deep-layer shear and steep mid-level lapse rates will support
a large-hail threat. The most intense cells may be able to produced
hailstones of greater than 2 inches in diameter, and damaging wind
gusts possibly in excess of 65 knots. As low-level flow gradually
increases during the late afternoon and early evening, a transition
from more isolated convection to a line is expected. The line is
forecast to grow upscale and move through far eastern Nebraska and
western Iowa, where severe wind gusts will be likely. If a
large-scale bow can form, then wind gusts above 70 knots will be
possible near the bow's apex. The severe threat is expected to move
east-southward into the mid Mid Mississippi Valley during the mid to
late evening.

Further south-southwest, into the central Plains and southern High
Plains, isolated to scattered thunderstorms are expected to develop
along and ahead of the front. Deep-layer shear will be strong enough
for an isolated severe threat. Large to very large hail will be
possible with supercells in parts of central Kansas. However, the
environment will be less favorable further southwest with only a
marginal severe threat expected in southwest Kansas and the Texas
Panhandle.

...Lower Ohio Valley/Southern Appalachians...
Northwest mid-level flow will be in place today from the mid
Mississippi Valley southeastward into the southern Appalachians. A
corridor of maximized low-level moisture will be located from
Illinois southeastward into central Kentucky, where strong
instability is expected to develop by afternoon. Although there is
some uncertainty, several model solutions suggest that an MCS will
develop and move southeastward along the instability gradient this
afternoon and evening. Forecast soundings in the areas with the
strongest instability have substantial directional shear in the
boundary layer, with northwest flow at mid-levels. This will be
favorable for linear development. A severe threat will be likely
with any cold pool that can become established. If a bowing line
segment can develop and mature, then wind-damage would be likely
along the leading edge. The severe threat should continue into the
evening due to the strong instability, with storms eventually
affecting the southern Appalachians.

..Broyles/Weinman.. 07/31/2024

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