John Metcalfe was CityLab’s Bay Area bureau chief, covering climate change and the science of cities.
Comparing the storm’s weird track against more than 150 years of records.
The fact that Hurricane Alex exists is weird enough. It is spinning well outside the Atlantic hurricane season of June to November, and in fact is the first January hurricane to appear in the Atlantic since 1938 (which as the National Weather Service notes, was a year FDR was in office and Orson Welles was broadcasting The War of the Worlds).
But that’s not the only odd feature about this tempest. Its location is also exceedingly rare. Check out Alex’s track compared to other big storms in NOAA records dating back to 1842:
Here’s a close shot from a larger version of the map:
Hurricanes do not typically form when sea surface temperatures are below 26° Celsius (78.8 degrees Fahrenheit), so it seemed uncanny for Alex to form when water temperatures in the northeast Atlantic were roughly 22°C. But as NASA research meteorologist Scott Braun pointed out, the water temperatures were 0.5 to 1.0 degrees above normal. More importantly, a low-pressure trough in the upper atmosphere meant air temperatures aloft were quite cool compared to the water below. “The decrease in temperature from the surface to upper levels was strong enough to create convective instability,” Braun said. “The thunderstorm activity gradually caused upper level warming such that the system transitioned from an extra-tropical to a tropical cyclone.”
The storm is expected to meander north today over the Azores, where it could deliver powerful winds, mudslides, and coastal flooding.