Hurricane Elsa weakened to a tropical storm with 70 mph winds on Saturday morning and is not predicted to regain hurricane strength during the next five days, the National Hurricane Center said in its 11 a.m. EDT Saturday advisory. Elsa was headed west-northwest at an unusually rapid forward speed of 29 mph, with a central pressure of 999 mb – a very high reading for a storm so strong. Heavy rains from the storm were affecting Haiti, the Dominican Republic, and western Puerto Rico; Elsa’s heavy rains will spread into Cuba, Jamaica, and the Cayman Islands by Saturday night.

On Friday morning, Elsa had roared through the Lesser Antilles islands as a category 1 hurricane with 75 mph winds, later peaking with 85 mph winds after entering the eastern Caribbean. The Miami Herald reported that Elsa did considerable damage on Barbados and St. Lucia, where downed trees and power lines, damaged roofs, and blocked roads were a problem. Barbados Prime Minister Mia Mottley said on Friday that seven homes had been destroyed on the island of 290,000, and 177 roofs damaged.

Elsa brought heavy rains to the island of St. Vincent, where it was feared that rain falling on the ash from a series of eruptions April 9-22 from the Soufrière volcano could potentially lead to dangerous mud flows. Radar-estimated rainfall amounts on the island from the Barbados radar were 1-4 inches as of 2 p.m. EDT Saturday, but there have been no reports of damaging mud flows on the island.

Figure 1. Infrared satellite image of Tropical Storm Elsa at 11:40 a.m. EDT Saturday, July 3, 2021. (Image credit: NOAA)

Satellite imagery on Saturday afternoon revealed that Elsa was disorganized, with the low-level circulation center partially exposed to view, and the heavy thunderstorms confined to the southeast side. Data from the Hurricane Hunters found that Elsa was poorly aligned vertically. This lack of vertical alignment resulted from the fast forward speed of Elsa, which likely led to the weakening of the storm. It is very unusual for a Caribbean hurricane to move faster than 25 mph, let alone 31 mph, which was Elsa’s top forward speed on Friday. Because of this rapid motion, tropical storm-force winds have been mostly confined to the northern side of Elsa’s center.

Figure 2. Predicted wind speed (colors) and sea level pressure (black lines) for Tropical Storm Elsa for 8 a.m. EDT (12Z) Sunday, July 4, from the 12Z Saturday, July 3, run of the HMON model. The model predicted Elsa would be making landfall in eastern Cuba as a tropical storm with 70 mph winds and a central pressure of 1000 mb. (Image credit: Tropical Tidbits)

Forecast for Elsa

As it progresses west-northwest through Sunday, Elsa will have improving conditions for development – if it can avoid moving over any of the big islands potentially in its path. Elsa’s expected slowing down to a forward speed of 15 mph by Sunday morning should help the storm become better aligned vertically. Sea surface temperatures will increase to 30 degrees Celsius (86°F), and wind shear will stay moderate, at 10-20 knots. However, the 12Z Saturday run of the SHIPS model gave only an 8% chance that Elsa would rapidly intensify by 35 mph in the 24 hours ending at 8 a.m. EDT Sunday; the National Hurricane Center predicted little change in Elsa’s strength through Sunday.

Figure 3. Track forecasts out to eight days for Elsa from the 6Z (2 a.m. EDT) Saturday, July 3, run of the GFS ensemble model (GEFS). The black line is the mean of the 31 ensemble members; individual ensemble member forecasts are the thin lines, color-coded by the central pressure they predict for Elsa. There is still high uncertainty where in the U.S. Elsa might make landfall. (Image credit: Tropical Tidbits)

A possible historical analogue: Hurricane Ernesto of 2006

One possible historical analogue to Elsa may be Hurricane Ernesto of 2006. Ernesto formed in the eastern Caribbean in late August, peaked as a category 1 hurricane with 75 mph winds while approaching Haiti, then dramatically weakened to a tropical storm with 45 mph winds while skirting the southwestern tip of Haiti before making landfall in eastern Cuba with 40 mph winds. Ernesto spent about 18 hours over Cuba before emerging into the Florida Straits, and it was able to intensify by only 5 mph before making landfall in South Florida, after spending about 24 hours over water.

Figure 4. Track of Hurricane Ernesto of 2006, a possible historical analogue for Hurricane Elsa of 2021. (Image credit: NOAA)

Elsa primarily a heavy rain threat to Florida

At some point, Elsa will cross over one or more of the mountainous islands of Hispaniola, Jamaica, or Cuba, which is likely to significantly disrupt the storm. The terrain of eastern Cuba and southwestern Haiti are particularly mountainous, and any passage over these areas will make it very difficult for Elsa to maintain its cohesion.

Given the current disheveled state of Elsa and its upcoming encounter with Cuba (and/or Haiti and Jamaica), Elsa is likely to be a disorganized tropical storm when it emerges into the Gulf of Mexico or Florida Straits on Monday. At that point, steering currents favor a northerly track at about 10 mph, which will give Elsa a day or two over warm water to re-intensify. Conditions should be moderately favorable for development, with the waters a warm 28 degrees Celsius (82°F), wind shear a moderate 10-20 knots, and the atmosphere moist. However, Elsa will likely need more time than that to reorganize into a hurricane, and the Saturday morning runs of the reliable intensity models were showing only a 10-25 mph increase in Elsa’s winds Monday through Wednesday. Elsa will most likely be a rainy, messy tropical storm when it makes its landfall in Florida on Tuesday or Wednesday, with heavy rains of 2-6 inches the main threat.

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Jeff Masters

Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a...