Analysis of a super explosive cyclone with frontal "T-bone" structure over the Northern Atlantic in January 2018

A super explosive cyclone with frontal "T-bone" structure over the Northern Atlantic from 3 to 6 January 2018 is investigated based on the ERA-Interim data issued by the European Centre for Medium-Range Weather Forecasts (ECMWF), the Geostationary Operational Environment Satellite-EAST (GOES-EAST) infrared satellite data supplied by Cooperative Institute for Meteorological Satellite Studies (CIMSS), and the Weather Research and Forecasting (WRF) modeling results. This explosive cyclone originated over the Gulf Stream and developed rapidly northeastward along the strong gradient of sea surface temperature. It deepened explosively within 6 hours after the cyclogenesis, and its central sea level pressure decreased about 48.7 hPa in 24 h. The upper-level trough, positive vorticity advection and lower-level atmospheric baroclinicity provided a favorable condition for the rapid development of this cyclone. With the rapid development of the cyclone, the relative vorticity in the lower-level increased sharply. The cold and dry air coming from the northwest advanced eastward rapidly in association with a cyclonic circulation, and met with the warm and moisture air coming from the southeast, and frontogenesis enhanced significantly. The warmer sea surface heated of the cold air, that gradient of air temperature decrescent. The weak and eastward cold front became nearly perpendicular to the warm front and formed a frontal "T-bone" structure. The diagnostic analysis based on the Zwack-Okossi equation shows that latent heat release, thermal advection and positive vorticity advection resulted in its explosive development. At the initial developing stage, due to abundant surface heat fluxes and latent heat release, diabatic heating made a great contribution. With the rapid development, the frontal "T-bone" structure was significant. Temperature advection played an important role in the development and maintenance of the cyclone because of its large net contribution.