Ok so Alex has reached hurricane status which is truly bizarre because there has never been a subtropical storm that has reached the category one threshold. So there are a number of possibilities, either Alex is a unique and unprecedented storm or the categorization of alex as subtropical was in error. I'd be tempted to go with the 2nd scenario and suggest that although alex started as a subtropical/hybrid system that it became fully tropical before obtaining catogary one status.

Looking at it on the satellite, it has a lot of tropical features; subtropical storms don't tend to have such uninterrupted banding plus they tend to have other features like large eyes that are not apparent here. The small size and rather coherent formation reminds me of Atlantic periphery systems such as hurricane Vince. The low sea surface temperature of 21C seems to confirm this. So personally I think this is a fully tropical system that is very similar to other northern systems like Vince, Epsilon and Grace. Interestingly all these systems were small and formed late; when I talked about medicanes I proposed that these systems sit somewhere between a normal atlantic tropical storm and a medicane; medicanes tend to be even smaller and form over colder waters.

Quite a little beauty and I notice hurricane centre have dropped the sub tropical part...

http://www.nhc.noaa.gov/text/refresh/MIATCPAT1+shtml/141433.shtml

Apparently this is the first such system since 1938 - which was then followed by the harsh winter of 1947.  

But being serious now, IF it does actually become an active Atlantic storm system later on down the line, will it get to be renamed as Gertrude using the Met Office naming system? Chances are it'll get absorbed in the Atlantic depression train and totally lose it's identity, but it might effect changes further upstream anyhow. That'll give the various models a headache, as if they aren't struggling as it is.

The predicted route takes it to Greenland almost in a straight line north by Sunday so really not sure what impacts if any it will have its uncharted territory I would guess.

There is a hurricane, it's predictive path is to towards the north and the tip of Greenland....then you look at the calendar and it's the middle of January....it's bonkers.

We just need another two of them and we might be in business... 

Phwoar.

I was kind of thinking 'super-medicane' as an analogy. Making good use of the large vertical temperature differential to overcome the relatively low SSTs (several short of the 26*C threshold for 'standard' tropical cyclones).

At least 85 mph peak sustained winds as of the last NHC update, perhaps higher now.

http://edition.cnn.com/2016/01/14/world/hurricane-alex-atlantic/

Explains that the differential between - 60C uppers and 20C SSTs provide enough contrast for suitable uplift as stated in SC post above.

I tend to divide them into three categories.

Normal Atlantic tropical storm ex(Katrina)

Track: Forms in the central western Atlantic, initially moves westward before turning sharply and contuining north east.

Season: June-November

SST requirement: 26C

Peripheral Atlantic tropical storm ex(Vince)

Track: Forms in the NE Atlantic, usually same latitude as Morocco, usually moves north eastward.

Season: August-December

SST requirement: 20C

Medicane ex(1996 storm)

Track: Forms in the western Mediterranean, usually moves eastward.  

Season: September-January

SST requirement: 15C

When you account for the fact that Alex is a peripheral storm rather than a normal one its timing becomes less unusual in the scheme of things and it would only be a month (if that) out of season compared to 2 months.