Tropical Depression Two Forms in the Northeastern Gulf

Expected to remain weak, short-lived, and offshore

The Atlantic hurricane season kicked off yesterday with the formation of a new Tropical Depression, only the seventh time since records began in 1851 that a tropical cyclone formed on June 1^st.

Air Force Hurricane Hunters investigating the disturbance dubbed Invest 91L on Thursday found a defined surface circulation, and – with persistent thunderstorm activity near the center – the National Hurricane Center upgraded the disturbance to Tropical Depression Two by late afternoon.

Another Hurricane Hunter plane took off around sunrise Friday and completed its first pass through the fledgling circulation an hour later. Though still ongoing, so far in the mission the plane has been unable to find consistent winds reaching tropical storm strength. Only a small increase in maximum winds from 35 mph to 40 mph would upgrade Tropical Depression Two to Tropical Storm Arlene, the first named storm of 2023.

Regardless of naming nuances, the system will be a flash-in-the-pan and isn’t expected to have significant direct impacts to land in the coming days. Clockwise steering around high pressure to the west will drive it southward into the teeth of a strong dip in the subtropical jet stream. By tomorrow, Tropical Depression Two should quickly fold beneath over 40 knots of blistering wind shear as its remnants approach the western tip of Cuba.

Forecast cone for Tropical Depression Two and wind shear contours. Red colors indicate hostile wind shear from a potent jet stream dip. Credit: University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (CIMSS).

Because its circulation is expected to remain offshore, no tropical storm watches or warnings are in effect.

Plentiful tropical moisture along the system’s eastern flank will keep the skies juiced over South Florida into the early part of the weekend, with rounds of locally heavy rain possible through tomorrow. Southeast Florida remains under a flood watch until this evening for the possibility of localized flooding for urban and low-lying areas.

We should return to a more typical summertime pattern of sea-breeze driven afternoon thunderstorms to start next workweek as the leftovers of Tropical Depression Two pull away.