Tropical storm Emily continues to move westward at 14 mph towards the island of Hispaniola on which lies Haiti and the Dominican Republic. Its current position is 125 miles south of Santo Domingo in the Dominican Republic. Maximum sustained winds are estimated by the National Hurricane Center to be near 50 mph, and little strengthening is likely before it encounters Hispaniola this evening.
The storm has prompted tropical storm warnings for Hispaniola, the southeast Bahamas, Turks and Caicos Islands, and a section of eastern Cuba. A tropical storm watch is in effect for the central Bahamas.
The storm has effectively passed Puerto Rico, and the tropical storm warnings there have been canceled. However, heavy rain showers linger. Radar indicates up to 4-8 inches of rain has already fallen over the island - particularly the east side, and flash flood warnings continue in several areas.
How does the storm look now?
A core of deep convection - or tall thunderstorms - has remained close to the low-level swirl for the last day or so. Visible satellite images from this morning indicate, however, that they have separated a bit in recent hours. This is an indication that Emily is struggling to get its act together. The closer the thunderstorms are to one another, the more effectively the convection can vertically stretch and spin-up the overall circulation (like an ice skater pulling her arms in) - intensifying the system.
Overall, the intensity has changed little in the last 36 hours. The layer of extremely dry air that has been situated just to the north of Emily for the last couple of days (outlined in yellow in the satellite picture above) may be partially responsible for the lack of vertical structure.
Emily’s predicted trek across the mountainous terrain of Hispaniola will surely disrupt the circulation, perhaps irreversibly. Even so, the vast majority of the models still suggest it will intensify once it emerges back out over the Atlantic Ocean late Thursday (at the 36 hour mark in the plot below). The National Hurricane Center predicts the storm will attain minimal hurricane status by early Monday but that’s predicated on the storm surving the trip over Hispaniola..
Emily’s forecasted motion for the next few days still basically points toward the Southeast U.S. However, most of the forecast tracks include a gradual turn northward prior to reaching 80°W longitude, and then a northeastward curve away from the U.S. before ever crossing the coast.
One feature we are counting on to make this seaward turn happen is the upper trough that is right now resting comfortably just off the East Coast (outlined in orange to the right). The winds around it are expected to soon tug Emily northward across Hispaniola and bring it into the Bahamas.
In a couple of days, this trough is expected to move northeastward and leave Emily behind off Florida’s east coast. Fortunately, there may be more help on the way to push Emily out to sea.
One of the other features that may finish the job is a second trough that is expected to move in to a similar position over the weekend. A forecast from the GFS weather model depicts this scenario. Unfortunately, this one is ostensibly weaker and still 100 hours away from being in position. There is thus plenty of wiggle room for things to turn out meaningfully different.
To make matters more complicated, another of the critical issues affecting Emily’s future track is how strong it will get. This is because the steering flow is dependent on the strength of the tropical cyclone itself.
For example, a weaker-than-expected system might slide underneath these upper level features, follow the easterly trades instead, and take a more westward course toward Florida or points further south. Recent observations suggest that the easterly trade winds are indeed pushing the low-level vortex westward faster that the primary thunderstorm complex. This is evidence that favors a more westward course in the immediate future.
If indeed the storm remains slightly distorted, disorganized, and not entirely upright –to a degree that the trade winds win the steering battle over the day or so just as they are now- the track guidance could shift westward closer to the U.S. in subsequent updates. I wouldn’t be surprised to see this happen.
The good news with that outcome is that Emily is a weaker storm. In any case, I’ll root for trough #2 to arrive in time with enough influence to ensure Emily never makes it to our shores.
Effects on Hispaniola
The National Weather Service predicts 6-12 inches of rain are possible over the Dominican Republic and Haiti, with isolated totals to 20 inches. Such rains may well produce life-threatening flash flooding and mudslides. The population of Haiti is particularly vulnerable to heavy rainfall, with thousands living in tent camps after the January 2010 earthquake.
Effects on Southeast and mid-Atlantic coast?
The two most likely scenarios are 1) Emily heads out to sea or 2) brushes up somewhere along the Southeast coast. In scenario 1, high surf and rip currents may develop late in the weekend into early next week In scenario 2, wind, rain and high surf could affect anywhere from south Florida to the Outer Banks of North Carolina between late Friday night (south) and late Sunday (north).
Because of the large uncertainty in both the track and intensity forecast, continue to stay tuned for updates.
Here’s a video report from the Associated Press:
Jason Samenow contributed to this report