ZCZC SPCSWOMCD ALL ACUS11 KWNS 152340 SPC MCD 152340 CTZ000-NYZ000-NJZ000-PAZ000-DEZ000-MDZ000-160145- Mesoscale Discussion 0222 NWS Storm Prediction Center Norman OK 0640 PM CDT Fri Mar 15 2019 Areas affected...Parts of central Maryland....southeastern Pennsylvania...northern New Jersey...southeastern New York Concerning...Severe potential...Watch unlikely Valid 152340Z - 160145Z Probability of Watch Issuance...5 percent SUMMARY...A narrow line of storms may be accompanied by some risk for potentially damaging wind gusts through about 8-9 PM EDT across the northern Mid Atlantic Coast region, mainly west and northwest of the Greater Philadelphia and New York City metropolitan areas. DISCUSSION...An evolving narrow line of generally low-topped thunderstorm activity appears to have formed within lee surface troughing, in response to an area of enhanced mid/upper forcing for ascent and and lower/mid tropospheric cooling spreading to the east of the Allegheny mountains. The latest Rapid Refresh suggests that a secondary surface low may be in the process of forming across the northern Mid Atlantic coast region into southern New England by this evening. Peak boundary layer CAPE appears limited to around 500 J/kg or so, and should begin waning with the onset of radiational surface cooling during the next couple of hours. So current vigorous convective intensities are not anticipated to be particularly long-lived. However, strongly sheared, 40-50 kt mean southwesterly flow in the convective layer could still support some increase in potential for damaging convective gusts through 00-01Z, before storms begin to weaken. ..Kerr/Hart.. 03/15/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OKX...ALY...PHI...CTP...LWX... LAT...LON 40457579 41477391 41337356 40917368 40207481 39467617 39347667 39497699 39707688 40457579 NNNN