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Tropical Storm Isaias Intermediate Advisory Number 20A
NWS National Hurricane Center Miami FL AL092020
200 AM EDT Sun Aug 02 2020
...AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT BEGINNING TO
SUMMARY OF 200 AM EDT...0600 UTC...INFORMATION
ABOUT 70 MI...115 KM ESE OF FORT LAUDERDALE FLORIDA
ABOUT 90 MI...140 KM SE OF WEST PALM BEACH FLORIDA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...995 MB...29.39 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
* 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
* Lake Okeechobee
* 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 later today.
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.
DISCUSSION AND OUTLOOK
At 200 AM EDT (0600 UTC), the center of Tropical Storm Isaias was
located near latitude 25.8 North, longitude 79.1 West. Isaias is
moving toward the northwest near 8 mph (13 km/h). A general
northwestward motion is expected today, followed by a
north-northwestward motion by tonight. 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 this morning
and move near or along the east coast of Florida later today and
tonight. On Monday and Tuesday, the center of Isaias will move
from offshore of the coast of Georgia into the southern
Maximum sustained winds are near 70 mph (110 km/h) with higher
gusts. Some restrengthening is possible today. Slow weakening is
expected to begin tonight and continue through Monday.
Tropical-storm-force winds extend outward up to 115 miles (185 km)
from the center. A Coastal Marine observing site at Settlement Point
on the western end of Grand Bahama Island recently reported a
sustained wind of 39 mph (63 km/h) with a gust to 48 mph (78 km/h).
The minimum central pressure estimated from Air Force Hurricane
Hunter observations is 995 mb (29.39 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 in areas of
onshore winds, 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 office.
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 this morning.
Hurricane conditions are expected to reach the coast within the
hurricane warning area in Florida later this morning and will spread
northward through tonight. Winds are expected to first reach
tropical storm strength early this morning, 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 this morning.
Tropical storm conditions are expected in the warning area in
northeast Florida by tonight, 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
the Central and Northwest Bahamas and will spread northward along
the east coast of Florida and the southeastern United States coast
during the next day or two. These swells are likely to cause
life-threatening surf and rip current conditions. Please consult
products from your local weather office.
Next complete advisory at 500 AM EDT.