Melissa made the transition to a 'tropical cyclone' late yesterday morning and has maintained that status today (Thursday) - extratropical transition is still expected tomorrow, however gale force winds are anticipated in the western Azores this evening and tonight. At 21/21Z, Melissa was located about 340 miles northwest of the Azorez and the tropical storm was moving to the east northeast to east at 25 knots. Tropical Storm force winds extend outward up to 225 miles from the center in the southern quadrants. Maximum winds are at 55 knots with higher gusts, however as the system moves over cooler SSTs, a slow weakening is anticipated. At 22/00Z Melissa was located almost due north of the westernmost island in the Azores and the core appears to finally be weakening. As well it should since the SSTs are at 18C.
The 21/21Z Tropical Discussion Bulletin had an interesting (and incorrect) comment:
"IT IS STILL ANTICIPATED THAT MELISSA WILL BECOME A POST-TROPICAL CYCLONE THIS EVENING OR EARLY TOMORROW...AND EXTRATROPICAL IN A DAY OR SO WHEN IT INTERACTS WITH A FRONTAL BOUNDARY."
The statement suggests that there is a post-tropical phase between a tropical cyclone and an extratropical cyclone - but meteorologically that is not the case, i.e., a storm system is either subtropical, tropical or extratropical. By NHC's own Glossary, Post-Tropical is a generic term to indicate a transitional state for a former tropical cyclone that has become extratropical or for a 'remnant low' with winds less that 35 knots. Since Melissa is forecast to maintain winds of at least 45 knots, it cannot meet the 'remnant low' definition - so that just leaves 'extratropical'. You can check out the various definitions in the NHC Glossary .