U.S. Severe Weather Forecast (Convective Outlook)

Day Three

acus03 kwns 220711 
Storm Prediction Center ac 220710 

Day 3 convective outlook 
National Weather Service Storm Prediction Center Norman OK 
0210 am CDT sun Oct 22 2017 

Valid 241200z - 251200z 

..there is a marginal risk of severe thunderstorms Tuesday 
afternoon and evening across parts of the northern middle Atlantic 
coast region into western portions of New England... 

Thunderstorms may impact parts of the northeast on Tuesday, 
accompanied by at least some risk for potentially damaging wind 

While another short wave trough progresses inland across the 
Canadian rockies, around the crest of broad upper ridging extending 
across the eastern Pacific through much of western North America, 
models indicate that large-scale troughing east of Mississippi 
Valley may amplify further through this period. Encompassing much 
of the eastern U.S., This troughing may take on more of a negative 
tilt as it approaches the Atlantic Seaboard Tuesday through Tuesday 
night. An associated surface cold front is still expected to 
precede the upper trough, with one shallower portion surging across 
much of the remainder of the southeast, into the Florida Peninsula, 
by early Tuesday afternoon. Farther north, the front may not 
advance into the northern mid Atlantic coast and Hudson/Champlain 
valleys until late Tuesday afternoon or evening. Of particular 
concern to severe weather potential, is the possibility of rather 
strong lower/mid tropospheric wind fields (up to 50-70+ kt in the 
850-500 mb layer) within a corridor ahead of the northern portion of 
the front. 

Prospects for more than very weak boundary layer destabilization 
appear rather slim within the pre-frontal corridor with strongest 
mean lower/mid tropospheric winds, from portions of the northern mid 
Atlantic coast region into western New England, during the day 
Tuesday into Tuesday evening. And relatively warm mid/upper levels 
may preclude, or at least limit, the potential for thermodynamic 
profiles to support lightning. However, given the potential 
strength of the wind fields off the surface, the development of even 
relatively weak/low-topped convection may aid the downward Transfer 
of higher momentum, contributing to the potential for at least 
localized wind damage. 

.Kerr.. 10/22/2017