It's January, one of the coldest months of the Northern Hemisphere winter. And yet a decidedly tropical weather phenomenon is taking place: an Atlantic Ocean hurricane.

The National Hurricane Center announced that subtropical storm Alex, which was named on Wednesday, had intensified into a hurricane, making it the first hurricane to form in January since 1938. It is also the first hurricane to occur in January since Hurricane Alice in 1955 (Alice did not form in January, but maintained its intensity into the month). The typical Atlantic hurricane season lasts from June 1 to Nov. 30.

As of 4 p.m. ET on Thursday, Hurricane Alex had sustained winds of 85 miles per hour and was located 350 miles south of the Central Azores Islands, which is a Portuguese territory. Hurricane warnings are out for parts of the Azores, with hurricane conditions expected to develop there in the next 24 hours. The storm was moving to the north-northeast near 23 miles per hour, and the Hurricane Center is predicting it will turn to the north with an increase in forward speed, putting it near or on top of parts of the Azores on Friday morning.

#Alex is the first January #hurricane to form since 1938 and the first to occur in this month since Alice of 1955. pic.twitter.com/qk6puLIVg2 — NHC Atlantic Ops (@NHC_Atlantic) January 14, 2016

The 2016 Atlantic hurricane season has already recorded more hurricanes than were observed in 1907 and 1914. #Alex pic.twitter.com/JaiqlzvXPP — Philip Klotzbach (@philklotzbach) January 14, 2016

The storm has a small, compact appearance on satellite imagery, but it clearly has a well-formed core of thunderstorms surrounding a nearly cloud-free eye.

Not only is the storm rare for its timing, but it is especially odd for its location in the far northeastern Atlantic. As the storm moves past the Azores, it is likely to encounter strong jet stream winds in the upper atmosphere and cooler ocean temperatures, both of which should assist in a transformation into an extratropical storm (i.e. non-tropical storm system).

#Alex is in a rare spot for Sept, much less Jan- It is only the 2nd #hurricane on record to form N of 30N E of 30W pic.twitter.com/odoNX0gUzO — Eric Blake (@EricBlake12) January 14, 2016

On Wednesday, the storm had characteristics present in both tropical and non-tropical storm systems, which is why forecasters were surprised it made a rapid transition into a fully tropical entity. The Hurricane Center's forecast discussion on Thursday morning states: "Remarkably, Alex has undergone the transformation into a hurricane."

For typically sober-minded tropical analysts, that "remarkably" translates into "how did this happen?"

The forecaster who wrote the discussion noted that it is rare to see a hurricane form above waters that have a temperature colder than 20 degrees Celsius, or 68 degrees Fahrenheit. However, temperatures in the upper atmosphere in that area are extremely cold, down to around minus-60 degrees Celsius, or minus-76 degrees Fahrenheit. This temperature difference is helping to fuel the storm by making the atmosphere more unstable, and encouraging air to rise.