Tropical Storm Dorian Continues West While Florida Low Offshore & Heading Northeast
Tropical Storm Dorian continues on a west to west northwest course toward the Leeward Islands and a Tropical Storm Watch is posted for the island of Barbados. Additional watches will likely be posted later today for some of the other islands in the Lesser Antillies. Dorian remains a small cyclone and while it didn’t strengthen overnight, it has held its own. Meanwhile off the Florida coast we still a broad low pressure area that remains disorganzied through we have noticed an increase in clouds and convection near where the low center is. None of the clouds or showers are impacting any land areas along the Southeast US Coast.
While upper air conditions around Dorian are conducive for strengthening there are issues in that much of the tropical and subtropical Atlantic is covered with dry air and dust from the Sahara Desert. Dorian seems to be encased inside a moisture rich air mass but that moisture field is a narrow one. We have seen small storms in the past strengthen in situations like this. The core of the storm seems well defined and intact so we will see how things go today. Thunderstorms have been increasing in and around the center this morning.
TROPICAL STORM DORIAN
Tropical Storm Dorian Intermediate Advisory Number 4A
NWS National Hurricane Center Miami FL AL052019
800 AM AST Sun Aug 25 2019
…DORIAN CONTINUES WESTWARD OVER THE WESTERN TROPICAL ATLANTIC…
SUMMARY OF 800 AM AST…1200 UTC…INFORMATION
ABOUT 515 MI…830 KM ESE OF BARBADOS
MAXIMUM SUSTAINED WINDS…40 MPH…65 KM/H
PRESENT MOVEMENT…W OR 280 DEGREES AT 13 MPH…20 KM/H
MINIMUM CENTRAL PRESSURE…1008 MB…29.77 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Tropical Storm Watch is in effect for…
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
Additional watches will likely be issued later today for portions
of the Windward and Leeward Islands. Elsewhere, interests in Puerto
Rico and Hispaniola should monitor the progress of Dorian.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
At 800 AM AST (1200 UTC), the center of Tropical Storm Dorian was
located near latitude 11.1 North, longitude 52.1 West. Dorian is
moving toward the west near 13 mph (20 km/h), and this motion should
continue today, followed by a motion toward the west-northwest on
Monday and Tuesday. On the forecast track, Dorian is expected to be
near the central Lesser Antilles late Monday or early Tuesday.
Maximum sustained winds remain near 40 mph (65 km/h) with higher
gusts. Some strengthening is forecast during the next 48 hours, and
Dorian could be near hurricane strength over the eastern Caribbean
Tropical-storm-force winds extend outward up to 25 miles (35 km)
from the center.
The estimated minimum central pressure is 1008 mb (29.77 inches).
HAZARDS AFFECTING LAND
RAINFALL: Dorian is expected to produce total rain accumulations of
2 to 4 inches in portions of the Lesser Antilles, with possible
isolated maximum amounts of 6 inches.
WIND: Tropical storm conditions are possible within the watch
area by late Monday.
SURF: Swells generated by Dorian will be affecting portions of the
Lesser Antilles by late Monday. These swells could cause life-
threatening surf and rip current conditions. Please consult
products from your local weather office.
The future of Dorian hinges on two important factors. One is whether it strengthens. If Dorian strengthen it will track further to the north and have a larger impact on the islands including Puerto Rico and the Dominican Republic. If it remains weaker it will track with a more westerly component. Once it gets into the Eastern Caribbean it may have to deal with increasingly hostile upper air winds that are forecast to develop in that area. This could mean Dorian will be a much weaker system overall. We should get some idea over the next 24 to 36 hours while Dorian remains in a favorable window for strengthening.
Meanwhile the broad low off the Florida coast is now offshore and drifting northeastward over the open ocean. The low may be trying to reform underneath some of the heavier thunderstorms but the circulation remains very broad in nature and lacks the tightness you need to see when a tropical depression is forming. Nonetheless the system has an 80 percent chance for becoming a tropical depression or a tropical storm over the next couple of days.
Even if this system develops into a tropical storm upper air steering winds along the East Coast are going to take any low out to the northeast out to sea. Upper air winds from the Carolinas to off the New England coast are either from the west southwest or west. In fact there is an upper air storm over Nova Scotia that actually strengthens that westerly flow and keeps things nice and dry here humidity wise into Tuesday. We are totally unconcerned with this system and we are watching it for meteorological purposes only at this stage of the game.
MANY THANKS TO TROPICAL TIDBITS FOR THE USE OF MAPS
Please note that with regards to any tropical storms or hurricanes, should a storm be threatening, please consult your local National Weather Service office or your local government officials about what action you should be taking to protect life and property.