Tropical Storm Dorian:
8 am EDT/7 am CDT Statistics:
Location: 12.0 North Latitude, 57.0 West Longitude or about 205 miles to the east-southeast of Barbados.
Maximum Winds: 60 mph.
Minimum Central Pressure: 1002 Millibars or 29.59 Inches.
Forward Movement: West at a forward speed of 14 mph.

Dorian is gradually strengthening and satellite imagery indicates that the thunderstorm activity associated with the storm is fluctuating between firing off deep convection and that deep convection dying off. With that said, Dorian is becoming better organized structurally with microwave satellite imagery showing an established core in almost all quadrants except the south quadrant. All-in-all, even though Dorian is gradually strengthening, it is not rapidly intensifying at this time.

The center of Dorian will pass very close to, if not right over the island of Barbados around midnight tonight and then pass right over the island of St. Lucia during Tuesday morning. The combination of low wind shear conditions and very warm ocean water temperatures will cause Dorian to gradually strengthen. With that said, there continues to be quite a bit of dry air around the storm and this should prevent rapid intensification over the next 24-36 hours. All-in-all, Dorian will likely be a 60-70 mph tropical storm when it impacts Barbados tonight and the islands of Martinique, St. Lucia and St. Vincent on Tuesday. There is the possibility that Dorian could achieve hurricane strength while it is passing over the Windward Islands on Tuesday.

Beyond this, the forecast becomes extremely difficult as the future track and intensity of Dorian hinges on 3 main factors – (1) Wind Shear; (2) Dry Air & (3) Land Interaction with Hispaniola.

Wind Shear – The guidance as a whole forecasts that an area of 30-plus knot wind shear will drop southward into the Caribbean over the next 2 to 3 days or so. This strong shear could significant impact Dorian leading to significant weakening. It should be noted though that the SHIPS intensity guidance forecasts that the strongest shear will remain west of the storm providing an outflow jet for the storm leading it to not weaken in the eastern Caribbean.

Dry Air – There continues to be quite a bit of dry air evident across the eastern half of the Caribbean. Right now, Dorian is slowly strengthening even though there is dry air around. The reason for this is because the wind shear is low around the system, so that there is no mechanism to push that dry air into the storm. If we do see higher wind shear develop over the eastern Caribbean, it could push the dry air into Dorian and cause it to weaken.

Land Interaction With Hispaniola – How much Dorian interacts with the rugged terrain of Hispaniola will tell the final story of the storm. If Dorian moves slowly right across Hispaniola around the middle part of this week, then dissipation seems likely. On the other hand, should Dorian pass just to the east of Hispaniola, then it would be able to remain a viable system and probably go on to strengthen in the Bahamas late this week and this weekend.

It should be noted that all of the reliable model guidance members have shifted towards a forecast that brings the center of Dorian right across the Mona Passage, missing both Hispaniola and Puerto Rico. Should this occur, it would lead to a more favorable environment for Dorian to strengthen in the Bahamas on Friday and Saturday.

In addition, a majority of European EPS model guidance member now show it not dissipating in the Caribbean and making it into the Bahamas where it strengthens at the end of the week into the weekend.

Beyond this, pretty much all of the deterministic and ensemble model guidance forecast that Dorian could approach Florida’s East Coast as a tropical storm or a hurricane late this weekend. The exception to this is the GFS model, which forecasts dissipation in the Caribbean.

Finally, the National Hurricane Center’s next generation hurricane model, the Hurricane Analysis and Forecast System (HAFS), forecasts the center of Dorian to pass through the Mona Passage on Wednesday night missing both Hispaniola and Puerto Rico. From there, the HAFS model forecasts intensification into a hurricane in the Bahamas late this week into this weekend with the hurricane approaching Florida’s Space Coast late Sunday.

Bottom line is that Dorian’s forecast track and intensity is highly uncertain. On one hand, I could easily see Dorian dissipating in the eastern Caribbean due to the combination of dry air and increasing wind shear. On the other hand, Dorian seems to be a “fighter” and this is concerning as there is the possibility that the dry air in the eastern Caribbean may not be able to weaken it much. In addition, the trends in the model guidance are worrisome as a track through the Mona Passage would likely mean Dorian would be able to strengthen again in the Bahamas late this week and this weekend. All interests in the Bahamas, the Florida Peninsula and the Southeastern United States should keep an eye on the progress of Dorian.

Forecast Impacts For Barbados & The Windward Islands: Tropical storm conditions, including wind gusts of up to 50-70 mph, locally heavy rainfall and rough seas, are expected across the island of Barbados beginning late today and continuing through tonight before subsiding during Tuesday.

Tropical storm conditions, including wind gusts of up to 50-70 mph, locally heavy rainfall and rough seas, are expected on the islands of Martinique, St. Lucia and St. Vincent beginning late tonight and continuing through Tuesday before subsiding Tuesday evening.

Possible Impacts For Hispaniola & Puerto Rico: Tropical storm conditions, including wind gusts of up to 60 mph, locally heavy rainfall and rough seas, are possible across parts of the Dominican Republic and Puerto Rico beginning Wednesday afternoon and continuing through Wednesday night and part of Thursday.

Model Track Forecast For Dorian:

Model Intensity Forecast For Dorian:

Satellite Imagery Of Dorian:

The next tropical weather discussion will be issued on Tuesday Morning.