a TCFA may be issued depending on Dvorak trends, and if a system gets 39 points or more a TCFA should be issued. Surface 500 mb height 200 mb height Sea surface temperature Satellite data Miscellaneous See also National Hurricane Center, which normally issues advisories without a TCFA being issued if certain conditions are met. References Fleet Weather Center Norfolk Tropical Page External links JTWC Advisories Page Tropical cyclone meteorology