Tropical Tracker: Quiet stretch coming before Atlantic comes alive

Peak season may live up to its name this year

The peak of hurricane season is Sept. 10.

ORLANDO, FLa.- – Isaias is out of here and we won’t have to deal with that name until 2026. It did cause a lot of damage in the Mid-Atlantic and Northeast so there is an outside chance it gets retired.

It’s a great name, just really hard to pronounce on TV.

Isaias was able to develop tall storms at it moved over the extremely warm Gulf Stream waters. This was able to factor in enough to take the out-to-sea track highlighted in last week’s Tropical Tracker.

As it moved by Florida, it was still being beaten up by shear and dry air on the western side of the storm. This allowed for most of Central Florida to receive some heavy rain and relatively calm wind while the real nasty stuff stayed over the water, which was expected.

Thankfully, while the Atlantic has been cranking out tons of named storms this year, the Atlantic has a whole has had trouble supporting them. There has been dust, shear and other things holding storms at bay even with bath water in the Atlantic. That is all likely to change as climatology factors in and we head toward peak season.

Through the next 7-10 days

We should be headed into a well-deserved quiet stretch in the tropics through at least the next week. Can we get a storm to develop? Sure. But it’s going to be much more difficult.

The MJO is in its unfavorable phase for the Atlantic and widespread sinking air will dominate the basin. It is much harder to get storms to develop when sinking air is around. As we saw with Isaias, there is also dry air and shear present.

Getting into the third week or so of August, the opposite looks true and rising motion will dominate the Atlantic. Increased activity off of Africa appears likely and thunderstorm activity in the Gulf/Caribbean look prolific.

Yes, we are getting into peak season and increased activity is expected, but a higher frequency of storms look to be lining up with climatology. As mentioned, there is still wind shear and dry air dominating the basin, but that tends to go away as we close in on the climatological peak.

MJO forecast from the Climate Prediction Center. Credit: NOAA/CPC

By the second week of August, the MJO will slide into Phase 8. That phase is favorable for development in the Gulf of Mexico and would be the main region to watch for tropical development in the second to third week of August.

The lines, models, in the MJO forecast graphic above move through phases 4-7, unfavorable for development in the Atlantic over the next week or so. Those phases represent the different regions that the MJO, more on what that is below, move in and out of.

Now, it’s impossible to tell if we would be impacted at this point, but it’s always good to be ready as we move closer to the middle of September.

What’s the MJO?

Here’s a refresher....

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 (NOAA)

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

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.