Tropics Tracker: Tranquility, for the most part, continues in the Atlantic

Slight chance for development off US coast this weekend

Tropical development
Tropical development

ORLANDO, Fla. – As a whole, the tropics continue to be quiet. There is an area of low pressure that could develop off of the southeast coast of the U.S. along a dying cold front, but that chance is low. Even with the Atlantic being in a large-scale suppressed phase, areas close to home always need to be monitored as northern cold fronts weaken off the coast.

That area of low pressure will emerge over the Atlantic stretched out and disorganized. Over the weekend, it could consolidate and become a little more organized. Wind shear, however, will be working against this entity.

Mid-level spin from European model shows some development possible this weekend. The tighter the and darker the color, the stronger the spin.

Systems forming from a cold front moving over the warmer waters of the Atlantic is how a lot of early-season storms develop.

We can thank our stretch of tranquility in the tropics largely to the Madden-Julian Oscillation. The dust from the Saharan Desert is also helping things.

What is the MJO?

Similar to El Nino or La Nina, the oscillation known as the Madden-Julian Oscillation, or MJO, can impact weather globally. The MJO is a disturbance of clouds and rain that makes a trip or several trips around the world during the spring and summer. When it comes to the tropics, the MJO can either enhance activity or suppress it.

The Madden-Julian Oscillation can enhance or suppress tropical development as the disturbance moves around the world. Photo from climate.gov (NOAA)

This system of upward motion, enhanced storm activity, and downward motion, suppressed storm activity, moves east around the globe every 30 to 60 days.

When the Atlantic is under the influence of downward motion or sinking air, tropical development becomes less likely. When the convective or enhanced phase of the MJO sneaks into the Atlantic Basin, tropical development can become more likely.

Atlantic outlook into August:

With the exception of possible development of off the southeast coast over the weekend, the remainder of the Atlantic Basin should remain quiet through the end of the July.

The Atlantic will continue to be under the influence of the suppressed phase (brown) of the MJO.

Velocity potential anomaly. Green represents rising motion, areas more favorable for thunderstorm development. Brown represents sinking motion, areas not as favorable for thunderstorm development. (Tropicaltidbits.com)

Tropical activity looks to increase late in the first week or second week of August as large-scale rising motion (green) associated with the MJO moves into the Gulf of Mexico and Caribbean.

Velocity potential anomaly. Green represents rising motion, areas more favorable for thunderstorm development. Brown represents sinking motion, areas not as favorable for thunderstorm development. (Tropicaltidbits.com)

That may start a pretty active period as a whole as the MJO moves through the main development region through the month. Climatologically speaking, tropical activity as a whole starts to ramp up.


About the Author:

Jonathan Kegges joined the News 6 team in June 2019 as the Weekend Morning Meteorologist. Jonathan comes from Roanoke, Virginia where he covered three EF-3 tornadoes and deadly flooding brought on by Hurricanes Florence and Michael.