Tropical Storm Erika continues to defy forecasts made earlier in the week. At this point in time Erika was supposed to be much further north of the island of Hispaniola and in a much better overall environment for intensification. However, Erika is currently 90 miles southeast of Santo Domingo, DominicaRepublic, in an environment that is not at all conductive to tropical cyclone development.

 

Erika_TrackError2015

TS Erika NHC forecast made Tuesday afternoon showing the track error as Erika continues to defy forecasts

This further westward movement calls for drastic changes to the probabilities forecast options provided in my last update as we play another round of model roulette. In the last update I highlighted the overall uncertainties in tropical cyclone forecasting, and Erika has definitely met expectations with regard to those uncertainties.

Tropical Storm Erika continues to battle an incredibly unfavorable environment. The wind shear, which acts to tear apart tropical cyclones, is already quite strong – about 20 mph from the west – and it is forecast to increase to nearly 30 mph today. That amount of shear is hard for a well-developed storm to fend off, and Erika isn’t even well developed , which increases the overall probability of dissipation.

ShearAndTendency

Erika is in a area of 20 kts shear and is moving into an areas where shear could be as high as 30 kts. Tropical storms / hurricanes don’t like areas of high shear.

If Erika manages to make it over the mountains of Hispaniola intact and fight of this high shear area, she could quickly intensify again in the extremely warm waters off the coast of Florida. In fact history would suggest a tropical storm tracking up the west coast of Florida could be quite destructive such as the 1935 Labor Day hurricane.

Here is my updated break down of Erika’s forecast options at the moment:

  • Stalled hurricane in the Bahamas (0% chance) – Unlike the last update, this is now the least likely option for Erika, given its westward track.
  • Hurricane landfall in south Florida (30% chance) – A category 1 hurricane near south Florida on Monday morning with the storm stalling over the state of Florida during the middle of next week.  This would caused 6-8” or rain to fall over much of the state.
  • Tropical storm landfall in south Florida, but a hurricane on the Florida panhandle (35% chance) – Maintain a west-northwest heading, gradually intensifying and heading for south Florida as a tropical storm. Then tracking into the western Gulf of Mexico and becoming a hurricane along the west coast of Florida and into the Florida panhandle.
  • Death in the Caribbean (35% chance) – Failure to reach the mainland U.S.; and the storm stays further south and tracks over Hispaniola, Cuba, and maybe even northern Jamaica.

Once again there are forecast uncertainties and one can’t rule out Erika playing more forecasting tricks over the weekend as this weak disorganized system tries to stay alive. Hispaniola is historically a tropical cyclone blender.  If the NHC forecast is correct with a tropical storm landfall or close encounter to Florida much of the state may well be affected by the storm’s rainfall.  The last tropical cyclone to make landfall on south Florida was tropical storm Bonnie on July 23, 2010. Before that, the previous one was tropical storm Ernesto on August 30, 2006.  So indeed named storm activity has been very sparse since the wild 2004 and 2005 seasons.

Remember that  tropical storms are still quite capable of causing flash floods and power outages, as well as coastal erosion and flooding, and the winds can throw around unsecured loose objects. Tropical cyclones can also cause insured loss, case in point tropical storm Bill impacting Texas earlier this June.

Looking ahead there are no other tropical systems that should develop in the Atlantic Ocean next week.