570
ACUS02 KWNS 291723
SWODY2
SPC AC 291721

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Sat Jun 29 2024

Valid 301200Z - 011200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
NORTHEAST AND MID ATLANTIC...AND FROM PARTS OF MONTANA INTO NORTH
DAKOTA...

...SUMMARY...
Scattered damaging winds will be possible across parts of the
Northeast and Mid-Atlantic States on Sunday. Hail and damaging winds
may also occur from eastern Montana into western North Dakota.

...Synopsis...
An upper trough will proceed eastward from the upper Great Lakes
into the Northeast, with a primary midlevel speed max sweeping
across northern New England during the day. Behind this initial
feature, a positive tile wave will push southeastward toward the Mid
Atlantic, with most of the height falls occurring late. A surface
low will likely be over Maine, with a trough/wind shift extending
southwestward across eastern PA/NJ, VA/Delmarva, and into the
Carolinas.

Behind that trough, high pressure will be centered over the upper MS
valley, with an east-west oriented boundary sinking south across the
OH/TN Valleys, becoming stationary over the central Plains.
Southeast surface winds will maintain moisture into the central and
northern High Plains, in advance of a shortwave trough moving across
the Great Basin and northern Rockies. This system will induce low
pressure over southern MT into northern WY, with increasing ascent
into that area late in the day.

...Much of the Northeast and Mid Atlantic...
The initial midlevel wave will move across NY and into northern New
England, providing strong mid and high level wind fields/shear.
Instability by midday over this area will gradually increase, with
an environment favoring a few supercells developing across northern
New England. Hail and perhaps a couple tornadoes will be possible
near the surface low into Maine and where the air mass can recover
sufficiently from the southwest.

Farther south, scattered rain and storms will be ongoing along the
length of the front early in the day across PA/WV/KY, with the
primary ramp up in intensity occurring after 18Z and as the
convection crosses int MD/VA. At that time, heating of the moist air
mass will maximize instability with over 3000 J/kg MUCAPE possible.
Low-level wind fields will be rather weak, but modest westerlies and
the progressive trough will keep storms moving, while the
uncapped/warmed boundary layer favors widespread outflow winds, some
damaging and locally severe.

...MT into ND...
Relatively cool southeast winds will maintain stable conditions for
much of the day, but by late afternoon/early evening the air mass
near the surface low should become heat and uncapped, with storms
forming from southwest into central MT initially. Ascent with the
developing cold front and progressive upper wave should then aid
further storm development during the evening across much of eastern
MT, with storms into ND after 03Z. It is expected that sufficient
cold pools will develop to maintain at least isolated strong to
severe storms despite potential capping. Damaging gusts should be
the primary severe mode.

..Jewell.. 06/29/2024

$$