Unprecedented: Simultaneous January Named Storms in the Atlantic and Central Pacific

As we ring in the New Year with record to near-record warm temperatures over much of Earth's oceans, we are confronted with something that would have been unimaginable a few decades ago: simultaneous January named storms in both the Atlantic and Central Pacific. The earliest named storm on record in the Central Pacific, Hurricane Pali, formed on January 7, and now the Atlantic has joined the early-season hurricane party, with Subtropical Storm Alex spinning up into history with 50 mph winds in the waters about 785 miles south-southwest of the Azores Islands. The average date of the first named storm in the Atlantic is July 9; the Central Pacific also typically sees its first named storm in July. Alex could retain its subtropical characteristics till as late as Friday, when it will be shooting northward toward Greenland en route to being absorbed in a high-latitude storm. Meanwhile, Pali is predicted to remain a tropical cyclone for at least the next five days, perhaps coming within 2° latitude of the equator--something only two other tropical cyclones in world history have been observed to do--as the storm arcs toward the southwest and eventually back northwest, potentially becoming a typhoon when it crosses the Date Line.


Figure 1. VIIRS visible satellite image of Subtropical Storm Alex on the afternoon of January 13, 2016. Image credit: NASA Worldview.

A January named storm in the Atlantic--how rare?
Alex is just the fourth Atlantic named storm to form in January since record keeping began in 1851. The others:

An unnamed 1938 hurricane became a tropical storm on January 3 well east of the Lesser Antilles Islands and lasted until January 6.

Subtropical Storm One of January 18 – 23, 1978 gained subtropical depression status over waters of about 75 °F (24 °C) about 1,700 miles east-northeast of Puerto Rico.

Tropical Storm One of 1951 was a tropical storm from January 4 - 9 in the waters a few hundred miles northeast of Puerto Rico. This was likely really a subtropical storm.

Two other named storms that formed in late December managed to last into January--Tropical Storm Zeta, which formed on December 30, 2005 and survived until January 7, 2006, west of the Cape Verde Islands, and Hurricane Alice, which formed on December 30, 1954, and tracked west-southwest into the Caribbean, where it dissipated on January 7, 1955.

Alex's genesis
Alex can trace its genesis to an area of low pressure that formed off the Southeast U.S. coast on January 7. Between January 8 and 12, pre-Alex tracked generally eastwards over ocean waters that were 22 - 25°C (72 - 77°F); these temperatures were near-record warm for this time of year (about 2 - 4°F above average). These temperatures were just high enough so that Alex was able to gradually gain a warm core and become a subtropical storm. It is unlikely that Alex would have formed if these waters had been close to normal temperatures for this time of year. The unusually warm waters for Alex were due, in part, to the high levels of global warming that brought Earth its warmest year on record in 2015. Global warming made Alex's formation much more likely to occur, and the same can be said for the formation of Hurricane Pali in the Central Pacific. To get both of these storms simultaneously in January is something that would have had a vanishingly small probability more than 30 years ago, before global warming really began to ramp up.


Figure 2. MODIS visible satellite image of Hurricane Pali taken on the afternoon of January 12, 2016. At the time, Pali was at peak strength--a Category 2 storm with 100 mph winds. Image credit: NASA.

Jeff Masters