The good news is that Hurricane Dorian passed well east of Puerto Rico as it moved from the Caribbean to the Atlantic. Puerto Rico was unaffected by Dorian. The bad news is that Dorian unexpectedly passed directly over St. Thomas, U.S. Virgin Islands as a minimal category 1 hurricane causing disruption to daily life and moderate damage to island infrastructure. One elderly woman who was in bad health died as the storm passed over the Virgin Islands. viconsortium.com/…
Dorian’s track and intensity has been jumpy up to this time because Dorian has been fighting off the effects of dry Saharan air which can be seen in light pink in the satellite image above of the tropical north Atlantic. The net impact of the disruptions was to weaken Dorian while it was in the Caribbean and allow it to move on a more northerly track than forecast models predicted, taking it out of the Caribbean before it could impact large islands with large populations. This was very good news for the Caribbean.
The ugly news is for Florida. Dorian’s northwards motion will be stopped by a large high pressure area and subtropical ridge that is developing off of the Carolina coast. This is good news for people like me in the hard hit areas of the Carolinas that are not ready for another major storm, but it is very bad news for Florida. Dorian has just passed through an area of moderate wind shear as it entered the Atlantic and briefly weakened, but the pressure is dropping again and sustained winds are back up to 75 knots or about 85 mph. Dorian is entering a region north of the Greater Antilles of warm waters, low wind shear and humid air. The National Hurricane center forecasts Dorian to become a major hurricane as it approaches the main Bahama islands.
The European model has forecast a more southerly track than the American model, but the latest run of the American model has moved landfall south, closer to the European model. Both models are consistent with the NHC’s forecast of a strong category 3 hurricane at landfall.
The HWRF model predicts that Dorian will rapidly intensify over the next day and will have sustained winds of 130mph in 30 hours. This model sometimes is overly aggressive about intensifying storms, but given the favorable environment and rapidly improving structure on satellite loops, the model may be onto something. If so, this storm could be an extremely dangerous major hurricane as it approaches the Bahamas and the coast of Florida. Be prepared.
Update 3pm EDT: The latest European model run slows Dorian’s forward progress down over the Bahamas as it takes a dip south. Then it takes a track up the coast of Florida. This is not the final word and the NHC will carefully consider the implications of this new model run. What it means is that the cone of uncertainty is real and we don’t have a precise track forecast.
11 PM Update: Dorian has intensified to 90 knots or about 105 mph a solid category 2 and the NHC is forecasting Dorian to reach 120 knots a solid category 4 (140 mph) in 72 hours and landfall on the Florida coast at 140 mph. The details of landfall, both time and location are still quite uncertain.