07/31/2020

The Hurricane Watch Net (HWN[1]) activated on 14.325 MHz on July 31 at 1500 UTC as Hurricane Isaias heads toward the US on an uncertain trajectory.ÿ The Volusia County, Florida, and State emergency operations centers were reported at a Level 3 (Monitoring) status.

"For years I've said, 'Just when you think you have Mother Nature figured out, she changes her mind,'" HWN Manager Bobby Graves, KB5HAV, said. "Shortly after Advisory 11 for then-Tropical Storm Isaias was issued [at 0300 UTC], an Air Force Reserve hurricane hunter aircraft found that the tropical storm had strengthened to a hurricane. The maximum winds had increased to 80 MPH with higher gusts making the storm a Category 1 hurricane."

The National Hurricane Center (NHC[2]) forecast for 0900 UTC called for Isaias to strengthen into a Category 2 hurricane during the next 24 hours.

"Unfortunately, Isaias appears to be taking a somewhat similar track along the US east coastline, such as Matthew in 2016 and Dorian in 2019," Graves said. "Interests throughout the Bahamas, Florida, Georgia, South and North Carolina, and farther north need to keep a close watch on Isaias. This means the Hurricane Watch Net could be running another marathon activation."

An NHC Intermediate Advisory issued at 1200 UTC called for strong winds and heavy squalls lashing the southeastern Bahamas and Turks and Caicos, and hurricane conditions are expected today over portions of the Bahamas.

As of 1200 UTC, Hurricane Isaias was located about 30 miles northwest of Great Inagua Island, and some 340 miles southeast of Nassau. Maximum sustained winds were 80 MPH, and Isaias is moving northwest at 17 MPH. A Tropical Storm Watch is in effect for parts of the Florida coast, and the NHC said interests in Florida and elsewhere along the southeast coast of the US should monitor the progress of this weather system. "Additional watches or warnings may be required for a portion of the Florida peninsula later today," the NHC said.

Isaias is predicted to produce heavy rains and potentially life-threatening flash flooding and mudslides across the Dominican Republic, northern Haiti, Turks and Caicos, and the Bahamas.

"Tropical storm conditions are possible along portions of the Florida east coast beginning Saturday, and a tropical storm watch remains in effect. While storm surge watches are not currently needed for this area, they may be required later today, if the forecast track shifts closer to the coast. Heavy rains associated with Isaias may begin to affect south and east-central Florida beginning late Friday night, and the eastern Carolinas by early next week, potentially resulting in isolated flash and urban flooding, especially in low-lying and poorly drained areas. Isolated minor river flooding is possible in the Carolinas early next week," the NHC said. "Hurricane conditions and dangerous storm surges are expected in portions of the Bahamas today and Saturday, and hurricane warnings are in effect for these areas. Preparations to protect life and property should be rushed to completion."

"There is a risk of impacts from winds, heavy rainfall, and storm surges late this weekend from the northeastern Florida coast and spreading northward along the remainder of the US east coast through early next week. The details of the track and intensity forecast remain uncertain, and it is too soon to determine the magnitude and location of these potential impacts."

The HWN seeks "observed ground-truth data from those in the affected area," including wind velocity and gusting, wind direction, barometric pressure, and, if available, rainfall, damage, and storm surge. "Measured weather data is always appreciated, but we do accept estimated," Graves noted.


[1] http://www.hwn.org/
[2] https://www.nhc.noaa.gov/

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