766
ACUS02 KWNS 080546
SWODY2
SPC AC 080545

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1245 AM CDT Mon Jul 08 2024

Valid 091200Z - 101200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE OH VALLEY AND NEW ENGLAND...

...SUMMARY...
Isolated strong to severe storms may produce a few damaging gusts or
tornadoes across portions of the Mid-South into the Ohio Valley
tomorrow (Tuesday). A few instances of hail or strong wind gusts are
also possible over portions of New England.

...Synopsis...
A mid-level trough will translate northeastward from the MS Valley
to the OH Valley through the day tomorrow (Tuesday) while a
mid-level ridge continues to build over the Interior West. Given
rich low-level moisture along and east of the MS River and ahead of
the upper trough, widely scattered thunderstorms are possible, with
isolated thunderstorms also possible over the Intermountain West,
driven by mainly orographic lift. A stray wet downburst is possible
across any of the aforementioned regimes. However, a relatively
greater chance for strong to potentially severe thunderstorms exists
with the remnants of Beryl across the OH Valley, as well as with
stronger storms embedded in the stronger flow aloft over parts of
New England.

...OH Valley...
The remnants of Beryl will track northeast from the mid-MS Valley to
the OH Valley while merging with the mid-level trough through the
period. At least low to mid 70s F dewpoints should advect northward
ahead of the surface cyclone (characterizing Beryl`s remnants),
helping to boost surface-based instability to a degree. 20+ kts of
low-level southerly flow associated with the surface cyclone will be
overspread by 30-40 kts of southwesterly 500 mb flow from the
mid-level trough, contributing to sizable, curved hodographs. As
such, multicells and supercells are possible in the warm sector
across portions of the OH Valley, as also depicted by several
high-resolution CAM guidance members. While such conditions would be
favorable for damaging gusts and multiple brief tornadoes, concerns
remain regarding how unstable the warm sector will become.
Tropospheric lapse rates are expected to be quite poor (4.5-5.5
C/km), likely limiting MLCAPE to well below 1000 J/kg. Category
1/Marginal Risk probabilities have been maintained given buoyancy
concerns, though higher severe probabilities may be needed in later
outlooks if a mesoscale corridor of locally higher buoyancy,
coinciding with stronger low-level shear, can be ascertained. Based
on guidance trends, such a corridor (if it materializes) would most
likely be located somewhere along the OH River.

...Portions of New England...
Up to 50 kts of 500 mb westerly flow is expected to overspread much
of New England tomorrow (Tuesday) afternoon, contributing to
elongated, mostly straight hodographs and up to 40 kts of deep-layer
shear. Guidance shows that at least one small perturbation embedded
in the stronger flow aloft should traverse New England by afternoon
peak heating, encouraging storm development amid 500-1000 J/kg of
tall, thin CAPE. The straight, elongated hodographs suggest
multicells and brief, transient supercell structures will be the
likely storm modes, where a strong wind gust or two, along with some
hail, are possible with the stronger storms.

..Squitieri.. 07/08/2024

$$