Joaquin Becomes a Hurricane, Could Impact the US East Coast

Joaquin, which became a tropical storm Monday evening (EDT) midway between the Bahamas and Bermuda, has now formed into a hurricane, the 3rd of the season--the difference is Joaqin could impact the US East Coast.

Joaquin Becomes a Hurricane, Could Impact the US East Coast

GPM captured this image of Joaquin late yesterday afternoon at 21:39 UTC (5:39 pm EDT) on the 29th of September as Joaquin was moving very slowly towards the west-southwest about 400 miles east of the northwestern Bahamas. This first image shows rain rates derived from GPM's GMI microwave imager (outer swath) and DPR space-borne precipitation radar (inner swath) overlaid on IR data from the GOES-East satellite. At the time, Joaquin had been battling northerly wind shear, which was impeding the storm's ability to strengthen. However, compared to earlier in the day, the system was beginning to gain the upper hand as the shear began to relax its grip. At the time of this image, Joaquin's low-level center of circulation was located further within the cloud shield, and the rain area was beginning to wrap farther around the center on the eastern side of the storm while showing signs of increased banding and curvature, a sure sign that Joaquin's circulation was intensifying.

Joaquin Becomes a Hurricane, Could Impact the US East Coast

GPM shows a large area of very intense rain with rain rates ranging from around 50 to 132 mm/hr (~2 to 5 inches, shown in red and magenta) just to the right of the center. This is a strong indication that large amounts of heat are being released into the storm's center, fueling its circulation and providing the means for its intensification. This is further confirmed in the next image, which shows a 3D view of Joaquin via GPM's DPR space-borne radar. Associated with the area of intense rain is an area of tall convective towers, known as a convective burst, with tops reaching up to 16.3 km (shown in orange). These towers when located near the storm's core are a strong indication that the storm is poised to strengthen as they too reveal the release of heat into the storm.

At the time of this image, the National Hurricane Center reported that Joaquin's maximum sustained winds had increased to 65 mph from 40 mph earlier in the day, making Joaquin a strong tropical storm but poised to become a hurricane, which occurred this morning at 8:00 am EDT. With the inhibiting wind shear expected to continue to diminish and the system moving over warm waters, the National Hurricane Center is forecasting Joaquin to intensify farther, possibly into a major hurricane within the next few days. There is still some uncertainty in the forecast track. Joaquin is expected to continue moving towards the Bahamas for the next day, taking the center very close to the islands, before turning northward ahead of an upper-level trough over the Southeast US. At present, Joaquin is not expected to make landfall south of North Carolina, but is forecast to approach the Mid-Atlantic coast in about 4 days. All interests should pay close attention to the latest developments from the National Hurricane Center.