A quiet Saturday in the tropics

It's a quiet Saturday for the tropical Atlantic today. There is one tropical wave worth mentioning, a large area of thunderstorms approaching Puerto Rico and the northeastern Leeward Islands. The shower activity has increased in this disturbance over the past 24 hours, but westerly winds associated with the subtropical jet stream are creating 20 - 30 knots of wind shear. This shear is ripping away the tops of the thunderstorms and blowing them to the east, creating a large region of high cirrus clouds downwind. The disturbance is expected to move northwest over the next few days, and not develop, due the the presence of high wind shear. There is one model--the Canadian model--which does develop this wave into a tropical cyclone that threatens Bermuda next week. However, all of the other global models are showing that wind shear will increase, preventing any development. The recent runs of most of the computer models are showing quite a bit more wind shear than before over the entire Atlantic Ocean for the upcoming week, reducing the chances that we will see any tropical storms developing. The last week of June looks like a better bet for tropical storm formation.



Also notable on today's satellite image is the presence of plenty of African dust. June and July are the peak months for African dust over the Atlantic, and any tropical cyclone that tries to form will have to battle the dry air that accompanies all this dust.

Jeff Masters