As we move closer to peak hurricane season, Sept 10th, the activity has ramped up!
There are two systems we are watching in the tropics and the good news is neither will directly impact central Maryland.
Tropical Depression #6 is poorly organized and is drifting southeastward at 2 mph between the southeast U.S. coast and Bermuda. There is a weak low to mid-level steering flow between the Bermuda high to the east and a mid-level ridge over the mid-Altantic states. Maximum sustained winds remain near 35 mph with higher gusts. The minimum central pressure is 1010 MB. Some strengthening is expected and the cyclone is forecast to become a tropical storm later tonight.
The depression is forecast to move little through today as it remains in a weak steering current. Afterward, a mid-latitude shortwave trough is forecast to move toward the northeastern United States tomorrow (Wednesday) and should generate a northeastward motion with an increase in forward speed, away from the eastern seaboard.
Now, on to Tropical Storm Dorian.
Tropical Storm Warnings have been issued for portions of the eastern Dominican Republic as heavy rains and gusty winds are affecting the Northern Windward Islands and Southern Leeward Islands. The system is located 60 miles WNW of St. Lucia and about 415 miles SE of Ponce Puerto Rico. The maximum sustained winds are 50 mph and it's moving WNW at 13 mph. The minimum central pressure is 1005 MB.
Dorian continues to stay a very compact system and still lacks a well-defined inner core. Dry air in the mid-levels of the atmosphere around Dorian has been causing the storm to remain in a fairly steady state during the past day or so despite relatively low wind shear and warm sea surface temperatures. It looks as though the dry air is not going any where while the system tracks across the Caribbean during the next day or two and most likely Dorian will only gradually intensify during that time.
An increase in wind shear, plus, interaction with landmasses of Puerto Rico and Hispaniola, should cause considerable weakening when Dorian gets closer to Hispaniola in 36-48 hours. Once the system moves north of the Greater Antilles, the environmental conditions become more favorable for intensification. With that said, there remains considerable uncertainty for this part of the forecast because the future intensity of Dorian will be heavily dependent on how much land interaction there is with the mountainous island of Hispaniola.