'Potential Tropical Cyclone Three' Being Monitored in Gulf of Mexico; Heavy Rain and Flood Threat Expected Along Gulf Coast

June 19,2017
An area in the southern Gulf of Mexico has been deemed "Potential Tropical Cyclone Three" by the National Hurricane Center (NHC). This is the first season the NHC can issue advisories on systems that have yet to develop but pose a threat of bringing tropical-storm-force or hurricane-force winds to land areas within 48 hours.
(MORE: 5 Changes to Hurricane Season Forecasts)
This potential tropical cyclone is likely to be a soaker for parts of the Gulf Coast this week, and flooding is a significant concern. Gusty winds, rip currents, high surf and some coastal flooding will also likely impact the region.
A tropical storm warning has been issued from Intracoastal City, Louisiana, to the Mouth of the Pearl River; tropical storm conditions are expected within 36 hours. A tropical storm watch is in effect from west of Intracoastal City, Louisiana, to High Island, Texas, which means tropical storm conditions are possible within 48 hours.

Tropical Storm Watches/Warnings

Current satellite imagery shows vigorous shower and thunderstorm activity in the eastern Gulf of Mexico in association with this system. That stormy weather is located mainly to the east of the low-pressure center, which is over 300 miles south of the Mouth of the Mississippi River.
(MORE: Hurricane Central)

Current Storm Status

Potential Tropical Cyclone Three is expected to move north to northwest, reaching the Louisiana coast on Wednesday. This system is currently forecast to develop into a tropical or subtropical storm before reaching the U.S. Gulf Coast.
It's important to not focus completely on the forecast path of the low-pressure center since impacts will extend well to the east along the Gulf Coast.
Parts of southeast Louisiana, southern Alabama, southern Mississippi and the Florida Panhandle are not in the forecast path but are expected to see a substantial amount of rain, which could cause flooding; more on that can be found below in our "U.S. threat" section.

Projected Path

Tropical storm conditions are expected to first reach the Louisiana coast within the warning area by Tuesday afternoon. These conditions are possible within the watch area on Wednesday.
If this potential tropical cyclone reaches tropical storm criteria, with sustained winds of at least 39 mph and a well-organized center of circulation, the next named storm in the Atlantic Basin will be "Cindy."

US Threat: Heavy Rain, Flooding Along Gulf Coast

Most of the forecast guidance suggests the area of low pressure associated with Potential Tropical Cyclone Three will track in a north or northwest direction through the Gulf of Mexico early this week. As this occurs, parts of the Gulf Coast and Florida will see abundant moisture from southerly winds on the eastern flank of the low, which will fuel heavy rainfall.
Another ingredient in this soaking setup is a stalling frontal boundary in the South that will also provide a focus for locally heavy rain.

Abundant moisture will fuel heavy rain along the Gulf Coast on the northern and eastern side of where the low tracks.

Florida was the first area to experience this influx of moisture, resulting in heavy downpours on Monday. The northern Gulf Coast will see heavy rain from this system Tuesday through Thursday.
This heavy rain could eventually lead to flash flooding and river flooding in some areas.
It should be noted that the majority of the rain will be on the northern and eastern side of the low-pressure system and could affect areas far from its center.
What To Know

• The heaviest rain amounts are likely to be on the northern Gulf Coast, including parts of southeast Louisiana, southern Mississippi, southern Alabama and the Florida Panhandle.
• This swath could see 4 to 8 inches or more of total rainfall by Thursday. Locally extreme rain amounts of 10-plus inches could occur depending on how the weather pattern evolves this week, according to the NHC.
• Flash flooding and river flooding are both possible threats.
• Other parts of the South, including the Florida Peninsula, will also see locally heavy rain at times this week due to the abundant moisture and stalling front. Heavy rain could occur as far west as southeast Texas later this week.
• Timing begins as early as Tuesday and continues through Thursday, possibly lingering into Friday.
• A high risk of rip currents is likely along parts of the Gulf Coast. High surf and some coastal flooding are also expected.
• Gusty winds are likely near parts of the northern Gulf Coast this week, particularly north and east of where the low tracks.

Rainfall Potential Through Thursday

(MORE: Florida's Drought Has Been Reduced by 60 Percent in Just Two Weeks)

June's Typical Formation Areas

The western Caribbean and Gulf of Mexico are two of the areas we typically look for the development of tropical storms in June.

This map shows the typical formation areas and tracks for named storms in June.

Any storms that form typically track north or northeastward, which brings the Gulf Coast and the Southeast coast in play for potential impacts.
On average, there's one named storm in June in the Atlantic, Caribbean or Gulf of Mexico every one to two years.
Last June was an outlier, when Bonnie, Colin and Danielle all spun through the Atlantic Basin as tropical storms.
(MORE: What to Expect During June)
MORE: Atlantic Basin Retired Hurricanes and Tropical Storms

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