Mesoscale Discussion 1901
   NWS Storm Prediction Center Norman OK
   0541 PM CDT Mon Oct 25 2021

   Areas affected...portions of northern Maryland and northern Delaware
   into southeast Pennsylvania and southern into central New Jersey

   Concerning...Severe potential...Watch unlikely 

   Valid 252241Z - 260045Z

   Probability of Watch Issuance...20 percent

   SUMMARY...A couple damaging gusts remain possible with some of the
   stronger storms over the next couple of hours. The severe threat
   should gradually diminish later this evening with boundary-layer
   stabilization. A WW issuance is not expected given the short-lived
   nature of the severe threat.

   DISCUSSION...A west-east oriented band of convection has become
   established along a confluence zone across central MD/DE over the
   past couple of hours. While mainly pulse cellular and brief
   multicellular storms comprise the convective band, a couple of the
   stronger storm cores have produced damaging gusts within the past
   hour, particularly across Fairfax County, VA. This convective band
   is progressing northward across a reservoir of 500+ J/kg MLCAPE and
   35-45 kts of effective bulk shear (driven primarily by sfc-500 mb
   speed shear within a unidirectional southerly vertical wind
   profile). As such, a couple damaging gusts remain possible with the
   longer lasting cells/clusters given the available buoyancy. However,
   RAP forecast soundings suggest that the aforementioned buoyancy is
   driven primarily by a heated/mixed boundary layer. Given nocturnal
   cooling already underway, the boundary layer is expected to
   stabilize. As such, the ongoing damaging gust threat is expected to
   be relatively brief (i.e. continuing for only a few more hours
   before diminishing), and a WW issuance is not anticipated.

   ..Squitieri/Hart.. 10/25/2021

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

   ATTN...WFO...PHI...CTP...LWX...

   LAT...LON   38907522 38987631 38977694 38987731 38987769 39157771
               39597747 40357648 40827598 40867569 40737524 40557475
               40337443 39877411 39447421 39097460 38887491 38907522