At a Glance

A broad area of low pressure will likely become Tropical Storm Isaias in the eastern Caribbean.Tropical storm warnings and watches are posted from the Leeward Islands to the southeast BahamasHeavy rain is expected through Thursday from the Leeward Islands to Puerto Rico and Hispaniola.The rainfall could trigger flash flooding and mudslides.The forecast for this system beyond the Caribbean is highly uncertain because of multiple factors.First impacts could be felt in parts of Florida as soon as this weekend, but it's too early to know any details.

Tropical storm warnings have been issued for parts of the Lesser Antilles and Caribbean as a disturbance expected to become Tropical Storm Isaias could eventually approach Florida this weekend.

The National Hurricane Center (NHC) dubbed this system "Potential Tropical Cyclone Nine" Tuesday, a procedure allowing the NHC to issue advisories, watches and warnings for a system that hasn't yet developed, but poses a threat of tropical storm-force or hurricane-force winds to land areas within 48 hours.

(MORE: Hurricane Season Terms You Need to Know)

The latest watches and warnings are shown in the map below, from the Leeward Islands to the southeast Bahamas. A warning means tropical storm conditions are expected in the next 36 hours. A watch means tropical storm conditions are possible within 48 hours.

Current Watches and Warnings

(A watch is issued when tropical storm or hurricane conditions are possible within 48 hours. A warning is issued when those conditions are expected within 36 hours.)

While this large system is slowly consolidating its thunderstorms, it has not yet developed a well-defined closed low-pressure center.

Once it develops enough thunderstorms near a closed low-pressure center, this system will be designated Tropical Storm Isaias).

Below is a look at what we know about the forecast for any potential U.S. and Caribbean impacts.

Florida, Southeast U.S. Concern?

The NHC projected path below shows that this system could be located near or on either side of the Florida Peninsula by this weekend. However, this forecast is not as straightforward as it might seem.

Current Information and Forecast Path

(The red-shaded area denotes the potential path of the center of the system. It's important to note that impacts (particularly heavy rain, high surf, coastal flooding, winds) with any tropical cyclone usually spread beyond its forecast path.)

There are a number of reasons for this uncertainty, which is rather common for tropical cyclones heading into the Caribbean Sea.

First, this system is in a formative state, without a clear surface low-pressure center.

Eventually, one cluster of thunderstorms should begin to take over in this large disturbance. Where that occurs is uncertain, and could cause a significant shift to the position, and, hence, the forecast path of this system.

In addition to the uncertain track forecast, this system has multiple obstacles to combat with the next few days.

One of those obstacles is the expected track of this system over the mountainous terrain of Hispaniola (Dominican Republic and Haiti). That land interaction could disrupt the system, at least for a time.

This system may also have to battle unfavorable upper-level winds - producing what meteorologists refer to as wind shear - and/or dry air along its Caribbean and Bahamas track. These are both nemeses of tropical cyclones.

Current Satellite, Wind Shear Analysis

(Areas of clouds are shown in white. Areas of strong wind shear, the difference in wind speed and direction with height, are shown in purple. High wind shear is hostile to mature tropical cyclones and those trying to develop.)

The bottom line is that it's too early to precisely determine this system's future track and intensity, especially with regard to the mainland U.S.

If this system were to threaten the mainland U.S., it could do so first in the Florida Peninsula as soon as this weekend.

However, the possible outcomes with regard to the mainland U.S. ranges from a track into the eastern Gulf of Mexico to a track over at least parts of the U.S. East Coast to a near miss of the Eastern Seaboard.

Residents along the Southeast and Gulf Coasts should monitor the progress of this system closely and have their to go, in case they're needed.

Caribbean Forecast

This system is tracking through the Leeward Islands with heavy rain and gusty winds right now.

Current Wind Field

(The orange circle shows the extent of the system's tropical-storm-force winds (at least 39 mph). The purple circle indicates the extent of hurricane-force winds (at least 74 mph), according to the National Hurricane Center.)

It should then spread rain and gusty winds into Puerto Rico and the Virgin Islands beginning Wednesday afternoon and pass near or over Hispaniola Thursday.

While some rain is needed to help the long-term in eastern and southern Puerto Rico and the Virgin Islands, locally heavy rainbands may lead to dangerous flash flooding and mudslides, particularly in higher terrain.

The NHC says rainfall totals of up to 10 inches are possible in these islands.

Hispaniola's mountainous terrain will also make it very prone to flooding and mudslides. Locally up to 8 inches could fall in some areas through Thursday.

Rainfall Forecast

(This should be interpreted as a broad outlook of where the heaviest rain may fall and may shift based on the forecast path of the tropical cyclone. Higher amounts may occur where bands of rain stall over a period of a few hours. )

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