Bryan Norcross: Hurricane Oscar rapidly develops, shocking computers and forecasters

Surprise hurricanes are extremely unusual, but they do occasionally occur. Hurricane Humberto in 2007 comes to mind; it intensified from a tropical depression to a hurricane in one day just offshore of the upper Texas coast, setting a record for rapid development and intensification.

Yesterday, it was a tropical disturbance that looked unlikely to develop, and today, it’s a rapidly strengthening hurricane. No computer forecast models anticipated Hurricane Oscar’s sudden development. Hurricane warnings were hurriedly issued for the southeastern Bahamas and the Turks and Caicos Islands.

Oscar is a tiny hurricane, which presents a significant forecast challenge. These small storms can spin up quickly, but they can also fall apart just as fast if they encounter hostile upper-level winds. Computer forecasts are based on a grid, and important aspects of smaller storms can fall within the grid spacing.

Hurricane-force winds extend only about 6 miles from the center on the north and east sides of the circulation, so Oscar’s most significant impacts will be over a very small area. Hurricane-force gusts extend out about 25 miles.

It appears that the center of Hurricane Oscar will pass over or through the Turks and Caicos Islands this afternoon and evening. It’s possible that the hurricane’s small core will directly impact one or more of those islands.

The storm quickly intensified into a Category 1 hurricane, and now that it has a core, indications are that intensification will continue. Residents should prepare for at least a Category 2 storm.

Hurricane Oscar is forecast to drift toward the northeast coast of Cuba before strong upper-level winds begin to take their toll. The weakening storm will lift to the north and dissipate by the middle of the week.

OSCAR STRENGTHENS INTO A HURRICANE IN SOUTHWEST ATLANTIC AS WATCHES, WARNINGS ISSUED FOR BAHAMAS, CUBA

Surprise hurricanes are extremely unusual, but they do occasionally occur. Hurricane Humberto in 2007 comes to mind; it intensified from a tropical depression to a hurricane in one day just offshore of the upper Texas coast, setting a record for rapid development and intensification.

Oscar looks likely to beat Humberto’s record by many hours once the data is carefully analyzed. Humberto was also a small storm that took advantage of a pocket of atmosphere highly conducive to development.

Hurricane Oscar poses no threat to the U.S.

Oscar is the 10th hurricane of the eventful 2024 season, marking the 10th time in the record books that a season has produced this many hurricanes, according to stats guru Dr. Phil Klotzbach of Colorado State University. There’s no guarantee, of course, that another hurricane won’t develop this season.

Tropical Storm Nadine made landfall late this morning in Belize but is still spreading tropical storm conditions across the northern half of that country and Mexico’s Yucatán Peninsula. Heavy rain may cause flooding and possible landslides over southern Mexico and surrounding parts of Central America. Nadine’s circulation is expected to dissipate tomorrow, but the rain threat will continue.

Looking ahead, the tropics are expected to calm after these systems fade out—at least through Halloween. November storms are not impossible, so we’ll see after that.