Northwest, however, seems to think otherwise as far as NYC airports are concerned...
Affected cities include: Baltimore, MD, Charlotte, NC, Greensboro/High Point, NC, Greenville/Spartanburg, SC, Harrisburg/Middletown, PA, Myrtle Beach, SC, Norfolk, VA, Philadelphia, PA, Raleigh/Durham, NC, Richmond, VA and Washington D.C. (Dulles International & Reagan National)
http://www.nwa.com/features/weather.shtml