Press "Enter" to skip to content

SPC Aug 19, 2024 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1251 AM CDT Mon Aug 19 2024

Valid 191200Z - 201200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
EASTERN COLORADO...

...SUMMARY...
Isolated severe thunderstorms with damaging winds will be possible
across several areas of the Continental U.S. this afternoon evening.
An organized large hail threat may materialize over eastern Colorado
during the afternoon and evening.

...Synopsis...
A mid-level trough will meander along the eastern seaboard as an
upper ridge prevails across the Southwest into the Plains and
another mid-level trough remains in place along the West Coast
today. Given adequate moisture and instability, scattered to
potentially numerous thunderstorms (some strong to locally severe)
are expected along the periphery of both mid-level troughs and the
upper ridge.

...North Carolina into the Northeast...
At least scattered thunderstorms will develop amid weak vertical
wind shear this afternoon ahead of a cold front. Pulse cellular and
occasional multicells are the expected storm mode. Rich low-level
moisture preceding the front will contribute to 1000-2000 J/kg
MLCAPE, which may support a few strong, potentially damaging gusts
with some of the stronger storms.

...North Florida...
A couple of strong thunderstorms may develop along the trailing
portion of a cold front by afternoon. Similar to the Northeast, rich
low-level moisture will promote 2000-3000 J/kg MLCAPE, fostering wet
downburst/strong wind gust potential with pulse single cells and
multicells.

...Portions of the Lower Mississippi Valley...
2000-3000 J/kg MLCAPE may materialize across portions of southern AR
into LA and far western MS during the afternoon on the backside of
the East Coast mid-level trough. Tropospheric unidirectional
northwesterly flow may contribute to enough deep-layer speed shear
to support multicells capable of producing wet downbursts and
subsequent strong/damaging wind gusts.

...Eastern Colorado...
Moist upslope flow during peak surface heating will result in
thunderstorm initiation off of the higher terrain. Surface dewpoints
in the low 60s F beneath 7.5-8 C/km mid-level lapse rates will
support over 2000 J/kg MLCAPE. Modest veering and strengthening of
the vertical wind profile will contribute to 30-40 kts of effective
bulk shear and modestly elongated hodographs. Multicells and
occasional supercells are expected, with large hail the main threat,
though a couple of severe gusts are also possible.

...Portions of the central and Northern Rockies...
Broad 40+ kt southwesterly 500 mb flow will overspread portions of
the central into the northern Rockies as an impulse embedded in the
West Coast mid-level trough grazes the region. Steep mid-level lapse
rates will overspread a deep boundary layer extending up to 500 mb.
Scattered pulse-cellular and multicells should initiate over higher
terrain areas during the afternoon and progress eastward through the
afternoon and evening hours. Given the deep boundary layer and
corresponding steep lapse rates, severe gusts are the primary
threat, though a couple instances of large hail cannot be ruled out.

..Squitieri/Darrow.. 08/19/2024

Read more