Tropical Storm Isaias Advisory Number 20
NWS National Hurricane Center Miami FL AL092020
1100 PM EDT Sat Aug 01 2020
...ISAIAS CONTINUES TO SLOWLY APPROACH THE SOUTHEAST FLORIDA
SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
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ABOUT 80 MI...130 KM ESE OF FORT LAUDERDALE FLORIDA
ABOUT 105 MI...165 KM SE OF WEST PALM BEACH FLORIDA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...995 MB...29.39 INCHES
CHANGES WITH THIS ADVISORY:
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Warning is in effect for...
* Boca Raton to the Volusia/Flagler County Line Florida
* Bimini, the Berry Islands, and Grand Bahama Island
A Storm Surge Watch is in effect for...
* Jupiter Inlet to Ponte Vedra Beach Florida
A Tropical Storm Warning is in effect for...
* North of Ocean Reef to south of Boca Raton Florida
* Volusia/Flagler County Line to Ponte Vedra Beach Florida
A Tropical Storm Watch is in effect for...
* North of Ponte Vedra Beach Florida to South Santee River South
Interests elsewhere along the southeast and mid-Atlantic coasts of
the United States should monitor the progress of Isaias. Additional
watches or warnings may be required tonight or Sunday.
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. Preparations to protect life
and property should be rushed to completion.
A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.
At 1100 PM EDT (0300 UTC), the center of Tropical Storm Isaias was
located near latitude 25.5 North, longitude 79.1 West. Isaias is
moving toward the northwest near 9 mph (15 km/h). A general
northwestward motion with some decrease in forward speed is expected
for the next day or so, followed by a north-northwestward motion by
late Sunday. A turn toward the north and north-northeast is
anticipated on Monday and Tuesday with an increase in forward speed.
On the forecast track, the center of Isaias will approach the
southeast coast of Florida tonight and early Sunday and move near or
along the east coast of Florida Sunday and Sunday night. On Monday
and Tuesday, the center of Isaias will move from offshore of the
coast of Georgia into the southern mid-Atlantic states.
Maximum sustained winds are near 70 mph (110 km/h) with higher
gusts. Some restrengthening is possible, and Isaias could regain
hurricane strength early Sunday. Slow weakening is expected to
begin Sunday night and continue through Monday.
Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center. A Weatherflow site in Morningside Park in Miami
recently reported a wind gust to 41 mph (66 km/h). An unofficial
observing station on Great Harbour Cay recently reported a wind gust
The minimum central pressure estimated from Air Force Hurricane
Hunter observations is 995 mb (29.39 inches).
Key messages for Isaias can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4, WMO header WTNT44 KNHC, and
on the web at www.hurricanes.gov/text/MIATCDAT4.shtml.
STORM SURGE: The combination of a dangerous storm surge and the
tide will cause normally dry areas near the coast to be flooded by
rising waters moving inland from the shoreline. The water could
reach the following heights above ground somewhere in the indicated
areas if the peak surge occurs at the time of high tide...
Jupiter Inlet to Ponte Vedra Beach FL...2-4 ft
North Miami Beach to Jupiter Inlet FL...1-3 ft
The deepest water will occur along the immediate coast near and to
the right of the center, where the surge will be accompanied by
large waves. Surge-related flooding depends on the relative timing
of the surge and the tidal cycle, and can vary greatly over short
distances. For information specific to your area, please see
products issued by your local National Weather Service forecast
A dangerous storm surge will raise water levels by as much as
3 to 5 feet above normal tide levels in areas of onshore winds in
the Northwestern Bahamas.
WIND: Hurricane and tropical storm conditions will continue over
portions of the Northwestern Bahamas through Sunday morning.
Hurricane conditions are expected to reach the coast within the
hurricane warning area in Florida Sunday morning and will spread
northward through Sunday night. Winds are expected to first reach
tropical storm strength later tonight, making outside preparations
difficult or dangerous. Preparations to protect life and property
should be rushed to completion. Tropical storm conditions are
expected within the tropical storm warning area in South Florida
Tropical storm conditions are expected in the warning area in
northeast Florida by Sunday night, and are possible in the watch
area from northeast Florida to South Carolina on Monday.
RAINFALL: Isaias is expected to produce the following rain
Bahamas: 4 to 8 inches, with isolated maximum totals of 12 inches.
Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches.
Eastern Florida: 2 to 4 inches, with isolated maximum totals of 6
Northeast Florida and coastal Georgia: 1 to 3 inches.
Carolinas and the mid Atlantic, including the southern and central
Appalachians: 2 to 5 inches, with isolated maximum totals of 7
Southeast New York and much of New England: 2 to 4 inches, with
isolated maximum totals of 6 inches.
Heavy rainfall from Isaias could result in potentially
life-threatening flash flooding in the Bahamas and flash and urban
flooding along the East Coast of the United States. Minor river
flooding and isolated moderate river flooding is possible across
portions of the Carolinas and mid Atlantic.
SURF: Swells generated by Isaias are affecting portions of
Hispaniola, eastern Cuba, the Turks and Caicos, and the Bahamas.
These swells will spread along the east coast of Florida and the
southeastern United States coast through Sunday. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.
