Visible satellite image of 92L from 8:45am EDT. (NASA)

12:55 p.m. update: This vigorous area of thunderstorms has been named Tropical Storm Claudette by the National Hurricane Center. It’s the third named storm of the 2015 Atlantic hurricane season. Claudette has sustained winds of 50 mph and is tracking northeast away from the Mid-Atlantic coast.


(NHC)

Original story:

The third tropical cyclone of the hurricane season might be just around the corner, if the system can quickly capitalize on a favorable environment that’s not expected to last long.

A trough of low pressure swept east into the Atlantic off the North Carolina coast early Sunday morning. Since then, it has been moving eastward and gradually acquiring some tropical characteristics. As of Monday morning, it is located about 400 miles east of Norfolk, Va., and tracking east-northeast and out to sea.

This area of thunderstorms hasn’t become a fully-fledged tropical cyclone yet, but the National Hurricane Center is monitoring it for potential development, and has named it Invest 92L in the meantime. If the stormy area continues to become more organized it would be named Tropical Depression Three, or even Tropical Storm Claudette if its winds are strong enough. The Hurricane Center is giving the area a 40 percent chance of developing into a tropical cyclone over the next five days.

Thunderstorm activity in the area has increased and become centralized, both signs that it is shifting more into the tropical end of the cyclone spectrum. The sea surface temperatures under it are plenty warm to support tropical development today, but the wind shear is only marginally conducive for tropical cyclones. By Tuesday, though, both environmental conditions will become outright hostile.

Shear and SST forecasts from the GFS global model for 92L. Note that by Tuesday, shear increases to over 30kts, and SST decreases to under 26C... and then GFS is unable to track a coherent vortex. (CIRA/RAMM)
Shear and SST forecasts from the GFS global model for 92L. Note that by Tuesday, shear increases to over 30kts, and SST decreases to under 26C… and then GFS is unable to track a coherent vortex. (CIRA/RAMM)

If 92L gets named today, it would be 43 days earlier than last year’s third named storm. The average date of third named storm formation in the Atlantic (using 1981-2010 climatology) is August 14.


Average seasonal progression of cumulative number of tropical cyclones in the Atlantic, split into named storms, hurricanes, and major hurricanes (Category 3+).

Across the rest of the Atlantic Ocean, environmental conditions are historically hostile for hurricane development — record-setting in some places and parameters. Plus, as a very strong El Niño begins to settle in, the tropical Atlantic conditions will not become more supportive. More on that soon!