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Hurricane Isaias Advisory Number 17
NWS National Hurricane Center Miami FL AL092020
500 AM EDT Sat Aug 01 2020
...CENTER OF ISAIAS APPROACHING ANDROS ISLAND...
...EXPECTED TO APPROACH THE SOUTHEAST COAST OF FLORIDA LATER TODAY
SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
ABOUT 80 MI...125 KM SSE OF NASSAU
ABOUT 210 MI...335 KM SSE OF FREEPORT GRAND BAHAMA ISLAND
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...988 MB...29.18 INCHES
WATCHES AND WARNINGS
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
* Northwestern Bahamas
* Central Bahamas
A Hurricane Watch is in effect for...
* Hallandale Beach to south of Boca Raton Florida
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
* Lake Okeechobee
A Tropical Storm Watch is in effect for...
* Volusia/Flagler County Line to Ponte Vedra Beach Florida
Interests elsewhere along the southeast coast of the United States
should monitor the progress of Isaias. Additional watches or
warnings may be required later today.
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. A warning is typically issued
36 hours before the anticipated first occurrence of
tropical-storm-force winds, conditions that make outside
preparations difficult or dangerous. Preparations to protect life
and property should be rushed to completion.
A Hurricane Watch means that hurricane conditions are possible
within the watch area. A watch is typically issued 48 hours
before the anticipated first occurrence of tropical-storm-force
winds, conditions that make outside preparations difficult or
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 within 36 hours.
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.
DISCUSSION AND OUTLOOK
At 500 AM EDT (0900 UTC), the center of Hurricane Isaias was located
near latitude 23.9 North, longitude 77.1 West. Isaias is moving
toward the northwest near 12 mph (19 km/h), and a general
northwestward motion with some decrease in forward speed is expected
for the next day or so, followed by a turn toward the
north-northwest by late Sunday. On the forecast track, the center
of Isaias will move near or over the Central Bahamas this morning,
near or over the Northwestern Bahamas later today and near the east
coast of the Florida peninsula tonight through Sunday.
Maximum sustained winds are near 85 mph (140 km/h) with higher
gusts. Little change in strength is expected through Sunday, and
and Isaias is forecast to remain a hurricane during this time.
Hurricane-force winds extend outward up to 35 miles (55 km) from the
center and tropical-storm-force winds extend outward up to 175 miles
The estimated minimum central pressure is 988 mb (29.18 inches).
HAZARDS AFFECTING LAND
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 Bahamas.
WIND: Hurricane conditions are occurring over portions of the
Central Bahamas and will spread over the Northwestern Bahamas later
Hurricane conditions are expected to reach the coast within the
hurricane warning area in Florida tonight and will spread northward
through Sunday. Winds are expected to first reach tropical storm
strength later today, 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, and are possible within the
watch area, over southern Florida by this afternoon or evening.
RAINFALL: Isaias is expected to produce the following rain
Bahamas: 4 to 8 inches.
Cuba: 1 to 2 inches, with isolated maximum totals of 4 inches.
These rainfall amounts could lead to life-threatening flash and
urban flooding, especially in low-lying and poorly drained areas.
From Friday night through Tuesday:
South Florida into east-Central Florida: 2 to 4 inches, with
isolated maximum totals of 6 inches.
Northeast Florida into coastal Georgia: 1 to 2 inches.
Carolinas into the mid Atlantic, including the southern and central
Appalachians: 2 to 4 inches, with isolated maximum totals of 6
Heavy rainfall from Isaias could result in potentially
life-threatening flash and urban flooding, especially in low-lying
and poorly drained areas. Minor river flooding is possible across
portions of the Carolinas and into Virginia.
SURF: Swells generated by Isaias are affecting portions of
Hispaniola, eastern Cuba, the Turks and Caicos, and the southeastern
and central Bahamas. These swells will spread along the east coast
of Florida and the southeastern United States coast today. 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 800 AM EDT.
Next complete advisory at 1100 AM EDT.