It's a deep layer low (i.e. pretty much extending through the depth of the troposphere) that has been sitting and spinning for awhile now. Definitely not anything tropical or subtropical, though -- check out the frontal band to the east and you'll see an extratropical system. Cyclone phase analyses show a developing cold core system as it moves off to the north and east with time; could be a player for England in a few days if the current pattern ever shifts.

Interesting to note -- the system that was near Bermuda last week (this might be the same one; I've been off forecasting for Barrow, AK and Buenos Aires, Argentina this weekend so I'm not sure) had a shallow warm-core for a period of time last week. The wind field never contracted, however, and the convective pattern was never indicative of anything near subtropical structure -- so that goes to show you that yes, there can be (and often are) warm-core extratropical cyclones....in fact, some of the strongest extratropical systems tend to grow during a warm-core phase in their lifetime. But I digress.

SSTs have a long ways to go before we really need to be peeking that way....though with a subtropical storm in April 2003 and a South Atlantic storm in March 2004, why not something again in February 2005? Anything can happen, but I'm going to say pretty confidently that we won't see a storm this month.