The Groundhog Day Storm was a February tropical storm, the only February tropical or subtropical cyclone in recorded Atlantic history.
While still moving rapidly to the northeast, the system passed just west of Miami, Florida in the morning of February 3. There, the National Weather Service stationed in Miami recorded sustained tropical storm force winds for 4 hours, as well as a minimum central pressure of 1004 millibars (29.66 inches of mercury). The storm also produced peak gusts of , with sustained winds of for 5 minutes. This shows how large the storm's wind field was, an indicator of possibly being a subtropical cyclone.
After crossing Florida, the storm accelerated to the northeast. Over the western Atlantic, the storm strengthened, likely baroclinically, to a peak of winds as a tropical cyclone. On February 4, the Groundhog Day Storm became extratropical east of South Carolina, and the extratropical storm brought heavy wind to the coastline. It continued racing to the northeast, and after hitting Cape Cod and eastern Maine on the 5th, the storm lost its identity over New Brunswick.
While off the coast of North Carolina, a 26-man crew freighter was driven aground as the storm passed by it. The ocean caused waves up to high, but all of the crew were saved.
In the northeast United States, the strong winds caused power outages to 15,000 people, with minor tree damage.
Because of its unknown structure at the time, it was treated as an unnamed storm in post-analysis. Had it been named operationally, it would have been Tropical Storm Able.
The only other off-season storm in the western Caribbean Sea between December and April is Tropical Storm Odette, which developed in December in 2003. The storm is one of only 32 tropical storms to develop in the off-season , and was the earliest a tropical storm has ever hit the United States.
The effect of spaceborne microwave and ground-based continuous lightning measurements on forecasts of the 1998 Groundhog Day Storm
Aug 01, 2001; ABSTRACT This study seeks to evaluate the impact of several newly available sources of meteorological data on mesoscale model...