US Impacts Possible From New Tropical Waves

Two more tropical storms could form later this week that could pose some threats to Bermuda and possibly parts of the Southeast U.S. as the Atlantic Basin's active period continues following Hurricane Gabrielle.

There is considerable uncertainty as to the details of how this will all shake out into next week, but we could be dealing with at least Tropical Storm Humberto, if not Tropical Storm Imelda, in the days ahead.

Here's our latest thinking, then a potentially weird wild card to the forecast.

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The Two Areas

The map below shows the two areas where tropical development is likely in the next few days, color-coded by the chance of development according to the National Hurricane Center.

Both are well-defined ripples of low pressure known as tropical waves, which are often seeds of future tropical storms during the Atlantic hurricane season.

Easternmost area: This tropical wave — designated as Invest 93L — is still about 1,000 miles east of the Lesser Antilles. Some model forecasts suggest this wave could develop first, and eventually strengthen to a hurricane that could be of some threat to Bermuda early next week.

Westernmost area: This second tropical wave — designated as Invest 94L — will bring showers with locally heavy rain to the Leeward Islands, Puerto Rico, the Virgin Islands, Hispaniola and the Bahamas through Friday. But it may also take longer to develop, assuming it does at all.

(MORE: What An 'Invest' Means In Hurricane Season)

The NHC may schedule a Hurricane Hunter reconnaissance aircraft mission into this system as soon as Wednesday afternoon, if it's showing enough organization to merit a further look.

It could become at least a tropical depression late this week or weekend somewhere near the Bahamas. Beyond that, there is a lot of uncertainty in the forecast.

Some computer forecast models pull this system north toward some part of the Southeast U.S. coast early next week, possibly as soon as Sunday. Others stall it off the Southeast coast for a time before it shoves eastward into the open Atlantic.

For now, those in the Bahamas, the Southeast U.S. and Bermuda should simply monitor the progress of this forecast.

As usual for late September, there is plenty of deep, warm ocean water that could fuel tropical development in this area, as was the case with Hurricane Gabrielle.

A Weird Possibility

One other outcome suggested by some computer models is that both systems could be close enough to each other to do a kind of circular dance, what meteorologists call the Fujiwhara effect.

Sometimes the larger system can grab hold of the smaller one and absorb it. Other times, both systems can creep closer and spin around each other before going on their own paths.

This happened in recent years most often in the Pacific Basin, including last year with tropical storms Emilia and Fabio.

We'll keep an eye on this possibility in the coming days and spell out what it could mean for you if this "dance" becomes more likely.

Check back with us at weather.com for the latest on these systems.