Mesoscale Discussion 1801
   NWS Storm Prediction Center Norman OK
   0233 PM CST Sun Nov 15 2020

   Areas affected...Portions of the Mid Atlantic into southern New
   England

   Concerning...Severe potential...Watch possible 

   Valid 152033Z - 152300Z

   Probability of Watch Issuance...60 percent

   SUMMARY...The damaging wind threat will increase later this
   afternoon into the evening, in association with low-topped
   convection. Watch issuance will become increasingly probable later
   this afternoon once development of an organized squall line appears
   imminent.

   DISCUSSION...A cold front is expected to accelerate eastward through
   much of PA and adjacent portions of the Mid Atlantic and southern
   New England late this afternoon into the evening, as a powerful
   mid/upper-level trough moves from the Great Lakes into the
   Northeast. While a long-lived line of severe-wind producing
   thunderstorms will stay primarily northwest of the MCD area, one or
   more additional bands of convection are likely to develop along the
   front by late afternoon. 

   While widespread cloudiness will limit heating across this region,
   continued low-level moist advection should support the development
   of weak buoyancy (SBCAPE of 100-200 J/kg) immediately in advance of
   the cold front. Despite the weak instability, strong low-level mass
   response in association with the front should support the
   development of a low-topped band of convection. Convection may
   produce little-to-no lightning, but very strong low-level flow
   (50-60 kt in the lowest 1km) will support a threat of damaging wind
   gusts. Given the potential for widespread 50+ mph wind gusts and at
   least widely scattered severe (60+ mph) gusts, severe thunderstorm
   watch issuance may be required later this afternoon.

   ..Dean/Grams.. 11/15/2020

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...BOX...OKX...ALY...PHI...BGM...AKQ...CTP...LWX...

   LAT...LON   38797807 39787765 40617726 41217687 41647664 42087604
               42427560 42737442 42597320 42297278 41857288 41067311
               39827398 38477517 37827653 38347782 38797807