During the 2015 Atlantic hurricane season, this blog will focus on tropical systems that impact The Bahamas and Turks & Caicos Islands.
By: BahaHurican, 4:24 PM GMT on August 23, 2011
Category 2 Hurricane Irene as it approaches the Turks and Caicos Islands and Southeastern Bahamas. Notice an eye is becoming visible.
Irene, the ninth storm and first hurricane of the 2011 hurricane season, is poised to deliver a major blow to the island archipelago of The Bahamas and the Turks and Caicos Islands. The NHC issued the following positon statement at 11 a.m. this morning:
SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
ABOUT 70 MI...110 KM S OF GRAND TURK ISLAND
ABOUT 50 MI...85 KM NNW OF PUERTO PLATA DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...100 MPH...160 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...980 MB...28.94 INCHES
Our Department of Meteorology is currently issuing Alert #17 based on the same information. A list of shelters in the warning area is also being issued.
At 10:30 a.m. the National Emergency Management Agency held a press conference, during which the Bahamian prime minister, Hubert Ingraham addressed the nation. He emphasised the size and serious nature of the storm, along with the potential for serious flooding, and encouraged residents to remain alert and vigilant.
The Southeastern Bahamas should begin to feel Irene's effects sometime later this afternoon, while the Central Bahamas can expect effects to begin for them on Wednesday.
According to the NEMA director, assessment teams will move through the islands after the storm to determine what level of assistance will be provided.
According to the latest advisory, Irene is expected to impact the entire Bahamas over the next three days and to become a major storm as it moves through the islands. The potential for category 4 impacts appears greatest on Thursday morning, based on NHC's Maximum Wind Probability chart.
Forecast Cone for Hurricane Irene.
Irene is expected to be rounding the western periphery of the mid-Atlantic high as it passes through the Bahamas, heading nortward into a weakness left behind by a trough currently moving through the northeastern United States. NHC confidence in the forecast track is high during the next 48 hours, but somewhat lower after that, since the forecast models differ on how much the trough will impact the high and how quickly Irene will respond to the resulting weakness.
On this track, the eyewall of Irene will pass sufficiently east of New Providence to keep the worst of the storm's effects from impacting the country's most heavily populated island. It also would lower the potential for storm surge impacts along the flood-prone southern coast. However, Category 2 impacts would still be likely.
SLOSH map showing surge potential in the Central Bahamas, where Irene is expected to have its greatest impact. Special thanks to Dr. Jeff Masters
According to the Weather Underground's storm surge maps, portions of islands in the Bahamas can expect flooding and storm surge on the order of 9-12 feet in a category storm. Bahamian residents who live in areas that are lowlying or prone to flooding were urged by NEMA officials to identify appropriate shelter and monitor news updates for evacuation orders.
As the storm progresses, I will be adding updates and whatever local reports I get in the comments section below. I will probably make a new blog entry on Thursday morning.
By: BahaHurican, 10:24 PM GMT on August 02, 2011
5:08 p.m. EDT
At 5 p.m. today, the Bahamian government posted watches for the Southeast Bahamas and the Turks and Caicos Island in advance of the arrival there on Thursday of Tropical Storm Emily. Emily, the 5th named storm of the 2011 season, is currently located near latitude 15.8°N and longitude 65.4°W or about 185 miles south of San Juan, Puerto Rico. This position is also about 600 miles southeast of Providenciales and Inagua. Emily is expected to move generally west-northwest and northwest over the next two to three days, crossing the island of Hispaniola and transversing Bahamian waters before moving northward into the wider Atlantic Ocean.
Emily had a rough birth; as Invest 91L the system was characterized by a broad area of surface low pressure and numerous ill-defined low- and mid-level centres forming, disippating, and reforming. However, at 7:30 p.m. on Monday 1st August the National Hurricane Centre was able to locate a relatively well-defined centre and Emily was named.
Despite this rather disorganized structure, Tropical Storm Emily brought gusty winds and heavy rainfall to Dominica, Martinique, and other Eastern Caribbean islands for more than 12 hours on 1st and 2nd August. This resulted in widespread flooding and numerous landslides in these islands. Reports from StormCarib.com suggest that at least one person died due to the flooding in Martinique.
This squally weather has since spread to the Virgin Islands and Puerto Rico. Since organization has improved somewhat in the last 12 hours, residents in the Dominican Republic and Haiti will likely expect more of the same during Wednesday and into Thursday of this week.
Emily's projected track takes the storm [or what's left of it after crossing the rugged Hispaniola landscape] up the length of the archipelago. In fact, the Bahamas has been in Emily's sights, so to speak, even before it was formally named. This is because there is a large and persistent Azores High to the northeast of us that has helped to maintain a similarly persistent ridge of high pressure across the sub-tropical Atlantic, across our area and at times even across Florida. However, this week a trough or area of low pressure will be pushing this high back towards the east, making a path of sorts around the edge of the ridge for Emily to follow.
The high pressure ridge in retreat on Friday, with TS Emily passing along its western edge.
While the exact track Emily takes is still somewhat uncertain, we can expect that most, if not all, of the Bahamas will experience some impact from the tropical storm.
What is of greater interest to most of us is the potential strength, or intensity, of Emily as she passes through our waters. Two factors are creating a great deal of uncertainty about the state Emily will be in by Friday morning.
First, TS Emily is still a very disorganized system. While it has improved in appearance and organisation since last night, it still is being disrupted by moderate shear and quite a bit of dry air in its environment. NHC officials are not expecting it to strengthen very much before it crosses Hispaniola on Wednesday.
Tropical Storm Emily at 5:15 p.m. on Tuesday, 2nd August 2011
Second, Emily's passage across the mountainous terrain of Hispaniola is likely to create some disruption to the storm's already tenuous circulation. Certainly on the forecast track Emily would find it difficult to strengthen while crossing the Dominican Republic and Haiti.
Map of Hispaniola, with the areas in tan, grey and white representing higher elevations.
However, once whatever is left of Emily crosses into Bahamian waters, the system will find conditions which are somewhat more conducive to restructuring than it met previously in the Caribbean. Sea surface temperatures are at their highest for the season; mid and low level shear is expected to be lower than seen in the Caribbean. Additionally, while rounding the ridge Emily may not move as quickly has she is expected to move tomorrow. Therefore there are still a lot of variables which may yet influence what Bahamians and Turks Islanders experience from Emily later this week.
Emily is expected to emerge into waters south of Inagua, Mayaguana and Providenciales on Thursday afternoon as a tropical depression. Some reorganization of the system is expected as it moves northwest over the archipelago on Thursday night, Friday, and into Saturday. Currently the NHC forecast does not call for sufficient strengthening to bring Emily up to hurricane force before departing our waters. However, the forecast models used by NHC still show varying scenarios ranging from complete dissipation to a category two hurricane near New Providence. This means that we should expect tropical storm conditions to impact our islands, but also insure that we are prepared to cope with hurricane conditions if they eventuate. This is particularly true in the Northwestern Bahamas, where any hurricane impacts would be most likely to occur.
Residents in the Southeast and Central Bahamas, along with the Turks and Caicos, will likely experience any impacts on Thursday night into Friday. These are expected to spread into the Northwestern Bahamas on Friday.
I'll continue updates regarding the progress of Emily in the comments section below.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.