The presence of the Gulf Stream off the eastern seaboard during the winter season acts to dramatically enhance the low level horizontal baroclinicity within the coastal zone. This is especially true off the Carolina coastline where, on average, the Gulf Stream is closest to land north of 32 degrees latitude. During winter offshore cold advective periods, low level horizontal thermal contrasts between coastal stations and the Gulf Stream environment can exceed 25K/50km, depending on the thermal structure of the advecting airmass and the exact position of the Gulf Stream. Robust horizontal thermal gradients can result in the rapid and intense destabilization of the marine atmospheric boundary layer (MABL) directly above and shoreward of the Gulf Stream. This airmass modification or conditioning period often times precedes wintertime coastal cyclogenesis/re-development. A climatological study investigating the relationship between the severity of the pre-storm, cold advective period and subsequent cyclogenic intensification was recently undertaken. Findings from this study illustrate that the thermal structure of the continental airmass as well as the position of the Gulf Stream front (relative to land) are linked to the rate of surface cyclonic development for storms occurring off the coastlines of Virginia and the Carolinas.
The potential for producing surface coastal cyclone intensity forecasts based upon regression relationships developed from a 1982-1990, 116 winter storm study conducted by Cione et. al. (1993) was recently improved as higher temporal resolution Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) digital data became available to North Carolina State University (NCSU) researchers. Since February 1994, surface cyclone intensity forecasts have been tested and successfully implemented by the National Weather Service at the Raleigh-Durham forecast office. Operational results covering the February 1994 - March 1994 and November 1994 - March 1995 winter periods are presented in this research.
