786
ACUS02 KWNS 220555
SWODY2
SPC AC 220554

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Sat Jun 22 2024

Valid 231200Z - 241200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF PA/NY
INTO VT/NH...WESTERN MA...NORTHWEST CT...EXTREME WESTERN ME...

...SUMMARY...
Scattered damaging winds and a few tornadoes are possible across
parts of the Northeast on Sunday.

...Northeast...
A Slight Risk has been added for parts of the Northeast on Sunday,
with potential for scattered damaging winds and a few tornadoes
during the afternoon and early evening.

Guidance still varies regarding the amplitude of embedded shortwaves
moving through a large-scale upper trough from the Great Lakes into
the Northeast on Sunday, which in turn results in uncertainty
regarding the strength/track of a related surface low. In general,
potential for rather strong low/midlevel flow to overspread a
moderately unstable environment remains evident across much of the
Northeast.

Scattered thunderstorm development will be possible by afternoon,
both along and in advance of the cold front. Organized
cells/clusters will be possible, including the potential for a few
supercells. A zone of relatively backed surface winds may persist
through the day from central/eastern NY into parts of NH/VT/western
MA, in closer proximity to the surface warm front. Locally enhanced
low-level shear/SRH and sufficient deep-layer shear will support
some potential for tornadic supercells across this area. Otherwise,
scattered damaging winds will be possible with both frontal and
prefrontal convection across the broader region during the afternoon
and evening, before an expected weakening trend by later Sunday
night.

...OH/TN Valley vicinity...
The cold front trailing from the New England system will move across
parts of the Ohio Valley during the afternoon and evening.
Thunderstorm development will be possible along/ahead of the front,
within a moderately unstable and modestly sheared environment. A few
stronger cells or small clusters will be possible within this
regime, with a threat of locally damaging wind. Some convection may
spread into parts of northern MS/AL Sunday night, though the
potential severity of any nocturnal convection in this area remains
uncertain.

...Eastern MT into northwest ND...
A shortwave trough is forecast to move east-northeastward from the
Pacific Northwest into parts of BC/AB by Sunday evening. A deepening
surface cyclone will accompany this shortwave, with a cold front
trailing southward into parts of MT. Low-level southeasterly flow
will transport modest low-level moisture into parts of eastern MT,
resulting in the potential for moderate destabilization. Deep-layer
shear will be favorable for organized convection, but large-scale
ascent attendant to the shortwave trough may tend to remain north of
the international border. Development of a strong/severe storm or
two across eastern MT cannot be ruled out by early evening, which
would then potentially spread into northwest ND Sunday night. A
Marginal Risk has been added for this conditional scenario.

..Dean.. 06/22/2024

$$