384
ACUS02 KWNS 041721
SWODY2
SPC AC 041720

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1220 PM CDT Thu Jul 04 2024

Valid 051200Z - 061200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM LOWER
MICHIGAN INTO THE OHIO VALLEY...CENTRAL APPALACHIANS AND
WESTERN/CENTRAL NEW YORK...AS WELL AS NORTHEAST NEW MEXICO...

...SUMMARY...
Strong to severe thunderstorms are possible from Lower Michigan into
the Ohio Valley, Central Appalachians and western/central New York.
Additional isolated strong storms are possible across northeast New
Mexico.

...Synopsis...

An upper trough will be centered over the upper Great Lakes/central
U.S. Friday morning. This feature will slowly pivot east through the
period, with a couple of embedded convectively enhanced vorticity
maxima/lead shortwave impulse migrates through southwesterly flow
over parts of the Upper OH Valley/Central Appalachians into
western/central NY. At the surface, a very moist airmass will be in
place ahead of an eastward-advancing cold front. The front is
forecast to extend from Lake Michigan south/southwest into
central/southern AR/OK and northwest TX/eastern NM during the
morning. Some showers and thunderstorms may be ongoing across parts
of the OH Valley in a modest warm advection regime and as a
continuation of convection expected in the Day 1/Thu overnight
period. Some guidance suggests an MCV related to this activity may
float east across parts of the adjacent Appalachians through the
afternoon. This general pattern should support at least
isolated/sporadic organized thunderstorms capable of mainly
strong/locally damaging gusts.

Further west, thunderstorms also will be possible across eastern NM
in a post-frontal upslope flow regime and eastward into portions of
central TX along the southward sagging cold front.

...Lower MI...

Isolated to scattered thunderstorms are expected during the
afternoon as a seasonally moist airmass destabilizes in the vicinity
of a surface low/triple point and within the cold core of the upper
trough. While instability will remain modest (less than 1000 J/kg
MLCAPE), vertical shear will support transient organized cells/small
line segments. Cool temperatures aloft and elongated forecast
hodographs suggest marginal hail to near 1 inch diameter will be
possible with any more intense/organized updrafts. Occasional strong
gusts also are possible.

...OH Valley/Central Appalachians into western/central NY...

Areas of ongoing convection and general cloudiness are expected
across the region. However, a very moist airmass will be in place
and even modest heating will allow for moderate destabilization
(MLCAPE 1500-2000 J/kg). Vertical shear will be strongest with
northward extent closer to the midlevel jet max oriented from OH
into NY. However, forecast guidance suggest a convectively enhanced
vorticity max over KY may drift east across the central
Appalachians, providing some enhancement to shear across this area.
Shear should be sufficient for at least transient organized
cells/clusters amid a high PW environment. Thunderstorms across the
region will mainly pose a risk for strong/locally damaging gusts
during the afternoon/evening. Some uncertainty exists regarding
eastward extent of damaging wind potential as vertical shear weakens
into the VA Piedmont/Chesapeake Bay vicinity. Severe probabilities
may need to be adjusted eastward in subsequent outlooks if
confidence increases in storm coverage or maintenance of an eastward
propagating cluster east of the mountains.

...Northeast NM...

Modest boundary-layer moisture will be maintained in a post-frontal
upslope flow regime Friday afternoon. Isolated thunderstorms will
develop over the higher terrain near the Raton Mesa vicinity. Cool
temperatures aloft and midlevel lapse rates near 7.5-8 C/km will
support modest instability, while vertically veering wind profiles
will be sufficient for around 30-35 kt effective shear magnitudes. A
couple of strong/severe storms producing hail and strong gusts will
be possible during the afternoon/early evening.

...OK/TX into the Southeast...

Thunderstorm clusters are expected along the southward sagging cold
front across portions of OK/TX eastward into TN Valley vicinity.
Vertical shear will be weak and lapse rates poor. However, a very
moist/high PW airmass will be in place amid 1000-2000 J/kg MLCAPE.
Locally gusty winds may accompany thunderstorms, but organized
severe potential appears low.

..Leitman.. 07/04/2024

$$