Tropical Storm Erika Bears Down on Puerto Rico; Warnings in the Dominican Republic; Uncertain Threat to the Bahamas, Florida, Carolinas

August 27,2015

Highlights

• Tropical Storm Erika is located near Puerto Rico, but is still poorly organized.
• Tropical storm warnings continue in Puerto Rico and the Virgin Islands. New warnings are now in effect for portions of the Turks and Caicos and the Dominican Republic.
• Deadly flooding has been reported in Dominica, in the Lesser Antilles. 
• Erika is expected to remain a tropical storm with little change in strength the next couple of days as it moves west-northwest. 
• The tropical storm brought strong winds to St. Croix and St. Thomas on Thursday. It will bring locally heavy rain to drought-suffering Puerto Rico and the Virgin Islands through early Friday.
• Erika will then bring rain and some wind to parts of Hispanola Friday, and the Bahamas this weekend.
• Erika's future track and intensity beyond that remain highly uncertain regarding potential U.S. impact, which could occur anywhere from the Florida peninsula to the Carolinas.

(MORE: Follow Tropical Storm Erika With Our New Interactive Storm Tracker)

Current Status

Erika Watches/Warnings

Erika Rainfall Outlook

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Erika Soaks the Caribbean

Tropical Storm Erika has moved into the eastern Caribbean Sea, spreading locally heavy rain in the northern Leeward Islands and now that is shifting over into Puerto Rico and the Virgin Islands.
(MORE: Heart of the Hurricane Season is Here)
A band of torrential rain resulted in deadly flash flooding on the island of Dominica in the Lesser Antilles. Roads have been washed out an airport flooded, and at least one home has collapsed.
(MORE: Flooding Hits Dominica; U.S. Prepares)
Canefield Airport near the capital of Roseau, Dominica, picked up 12.64 inches (322.4 millimeters) of rain in a 12-hour period ending just before 2 p.m. EDT Thursday.
Tropical storm force winds were reported across portions the U.S. Virgin Islands on Thursday. The highest gust was 62 mph at St. Croix shortly before 9 p.m. EDT Thursday.
A Wunderground personal weather station atop Crown Mountain Summit (elevation 1,534 feet) on St. Thomas has measured gusts up to 46 mph. Gusts over 40 mph have been clocked on Barbuda, as well.
Overall, Erika has struggled to maintain a consistent center of circulation. Thursday afternoon visible satellite images appear to have located an exposed center with convection blown off to the east and south. While organization of convection was fluctuating Thursday evening, the minimum central pressure rose 2 mb to 1008 mb Thursday night. This is perhaps a sign that Erika has been barely maintaining its intensity.
Erika held onto minimal tropical storm status through much of Thursday, with maximum sustained winds generally staying near 45 mph.
If a lack of organization persists, it raises the chance that as Erika moves over the mountains of Puerto Rico (some peaks over 4,000 feet) and the Dominican Republic (Pico Duarte is over 10,000 feet), disrupting or ripping apart its circulation, though posing a greater flood threat in those areas.
The culprit for this disheveled appearance of Erika is the long-anticipated westerly wind shear.
Erika will continue moving through an environment with vertical wind shear and some dry air, both general inhibitors for tropical cyclone intensification over the next couple of days. It is not out of the question these twin nemeses, together with a possible track over land mentioned above, may weaken Erika to a tropical wave or remnant.
At any rate, Erika is will spread rain and wind into drought-suffering areas, such as Puerto Rico and the Virgin Islands.
(INTERACTIVE: Caribbean Radar)
Bands of locally heavy rain are possible from the northern Leeward Islands across parts of Puerto Rico, the Virgin Islands and Hispanola, with locally higher amounts, through Friday.
Despite the long-term drought, this amount of rain, particularly if falling in a short period of time, may trigger flash flooding and mud/rockslides.

Erika's Possible Steering Pattern Ahead

Projected Path

Tropical Storm-Force Wind Probabilities

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

An Uncertain Future: Bahamas, U.S. Threat?

Beyond that, the forecast has a large amount of uncertainty, due the nature of the upper-level steering flow near the eastern U.S. next week.
Assuming Erika survives the hostile environment over the eastern Caribbean the next few days, the steering pattern and a more conducive environment for strengthening are more troubling for the Bahamas and the Southeast U.S. coast.
The current sharp southward dip in the jet stream in the East responsible for the cool, dry air in the Midwest and Northeast earlier this week is gradually being replaced by a northward-migrating jet into eastern Canada and northern New England. Any leftover remnant of that previous southward dip will be much weaker and farther west over the western Gulf of Mexico or southern U.S.
Coupled with the Bermuda high setting up southwest of Bermuda, an alley appears to be clearing for Erika -- assuming it survives -- to track toward or near the Florida peninsula or Southeast U.S. coast early-mid next week.
Furthermore, an environment of less wind shear and warm water may allow Erika to strengthen near the central or northwest Bahamas later this weekend into early next week.
For now, potential impacts in the Bahamas from Erika are focusing on Saturday (southeast) and Sunday-Monday (northwest).
(FORECAST: Nassau | Turks & Caicos)
The potential U.S. impact remains very uncertain. Here are the two most possible scenarios:

• If Erika takes a more westward path (and survives the two-day hostile environment), along the western/southern edge of the forecast cone, it could move inland over the southern Florida peninsula later Sunday into Monday. In this scenario, Erika would have less time to strengthen over the warm water near the Bahamas before moving inland, and would primarily be a heavy rain threat over the Florida peninsula.

(FORECAST: Miami | Daytona Beach)

• Erika may, however, remain east of the Florida peninsula, and instead track north toward coast of South Carolina or North Carolina around the middle of next week. With a track over the warm Gulf Stream, Erika would most likely strengthen to a hurricane in this scenario. Florida would not be completely off the hook in this scenario, as strong winds could lead to high surf, rip currents and beach erosion in some areas.

(FORECAST: Charleston | Myrtle Beach | Wilmington)
While unlikely at this time, we also can't rule out a sharp enough northeast turn of Erika to keep the center off the Southeast coast next week, or even a track into the eastern Gulf of Mexico.
Keep in mind we're still several days out before a potential Erika flirtation with the southeast U.S.
The average forecast track error of a National Hurricane Center five-day forecast is about 241 statute miles. Also, the average forecast intensity error of an NHC five-day forecast is 18 miles per hour. The Erika forecast remains more uncertain than typical for an Atlantic tropical cyclone.
All interests in The Bahamas and the southeast United States from Florida to the Outer Banks of North Carolina should continue to monitor the progress of Erika.
(MORE: Expert Analysis | Hurricane Central)
Check back with The Weather Channel and weather.com for the latest updates on Erika.
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