SPC MD 686

Sun, 19 May 2019 16:52:04 +0000 UTC

MD 0686 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR MUCH OF UPSTATE NEW YORK

Mesoscale Discussion 0686
NWS Storm Prediction Center Norman OK
1151 AM CDT Sun May 19 2019

Areas affected...Much of Upstate New York

Concerning...Severe potential...Watch possible 

Valid 191651Z - 191845Z

Probability of Watch Issuance...60 percent

SUMMARY...There appears increasing potential for strong to severe
storm development across the region through 4-6 PM EDT.  Trends are
being monitored for the possibility of a severe weather watch within
the next hour or two.

DISCUSSION...Low-level warm advection along a stalling frontal zone,
perhaps aided by convergence near the lake breeze, appears to have
provided the support for thunderstorm initiation near the southern
Lake Ontario coast.  Further intensification and upscale growth of
this convection appears possible during the next few hours,
supported by inflow of increasingly unstable air emanating from a
destabilizing boundary layer to the south of the front.  With
further insolation, models suggest that mixed-layer CAPE near the
front may increase from 500 J/kg to in excess of 1000-1500 J/kg by
20-22Z.

Embedded within sheared, 30-40 kt southwesterly to westerly deep
layer mean ambient flow, potential exists for the evolution of a
small but increasingly organized convective system as activity
spreads into/through the Adirondacks vicinity and portions of the
Mohawk Valley later this afternoon.  This probably will be
accompanied by at least some risk for hail and potentially damaging
surface gusts.  

Additional thunderstorms may gradually initiate across the higher
terrain of the Southern Tier of New York through the afternoon. 
However, potential coverage across this area is more unclear and may
remain fairly isolated.

..Kerr/Hart.. 05/19/2019

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

ATTN...WFO...BTV...ALY...BGM...BUF...CTP...

LAT...LON   42797796 43087745 43267658 43937565 44177332 42867375
            42027504 41907743 42057801 42797796