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Hurricane Grace Advisory Number 21
NWS National Hurricane Center Miami FL AL072021
1100 AM EDT Wed Aug 18 2021
...AIR FORCE RESERVE AND NOAA HURRICANE HUNTERS FIND THAT GRACE
BECOMES A HURRICANE JUST WEST OF GRAND CAYMAN...
SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
ABOUT 65 MI...105 KM W OF GRAND CAYMAN
ABOUT 350 MI...560 KM E OF TULUM MEXICO
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...992 MB...29.30 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The Hurricane Watch is discontinued for the Cayman Islands.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Warning is in effect for...
* Yucatan Peninsula of Mexico from Cancun to Punta Herrero,
A Tropical Storm Warning is in effect for...
* Cayman Islands
* Yucatan Peninsula of Mexico from north of Cancun to Campeche
* Yucatan Peninsula of Mexico from south of Punta Herrero to Puerto
A Tropical Storm Watch is in effect for...
* Southern coast Cuban province of Pinar del Rio, as well as Isla
de la Juventud
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 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.
Interests elsewhere in eastern mainland Mexico should monitor the
progress of Grace.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND OUTLOOK
At 1100 AM EDT (1500 UTC), the center of Hurricane Grace was located
by Air Force Reserve and NOAA Hurricane Hunter aircraft near
latitude 19.4 North, longitude 82.2 West. Grace is moving toward
the west-northwest near 15 mph (24 km/h). A general
west-northwestward to westward motion is expected for the next
several days. On the forecast track, the center of Grace will
continue to move away from Grand Cayman today. Grace is expected to
make landfall in the Yucatan Peninsula Thursday morning, and move
over the southwest Gulf of Mexico early Friday.
Aircraft data indicate that maximum sustained winds are near 75 mph
(120 km/h) with higher gusts. Some additional strengthening is
forecast before the center of Grace reaches the eastern Yucatan
Peninsula. Weakening will occur while the center moves over the
Yucatan Peninsula on Thursday, with restrengthening expected when
Grace moves over the southwest Gulf of Mexico on Friday.
Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 115 miles
The estimated minimum central pressure is 992 mb (29.30 inches).
HAZARDS AFFECTING LAND
Key messages for Grace can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT2, WMO header WTNT42 KNHC
and on the web at
WIND: Tropical storm conditions are expected over portions of the
Cayman Islands for the next few hours. Tropical storm conditions
are possible along the southern coast of Cuba within the watch area
through today. Hurricane conditions are expected within the warning
area in the Yucatan Peninsula of Mexico late tonight or early
Thursday, with tropical storm conditions beginning as early as this
Grace is expected to produce the following rainfall amounts:
Over the Cayman Islands, portions of the Yucatan Peninsula and
Veracruz State of Mexico....4 to 8 inches with isolated maximum
totals of 12 inches are expected through Friday night. This
heavy rainfall could lead to flash and urban flooding, with
mudslides possible in Veracruz.
STORM SURGE: A dangerous storm surge will raise water levels by as
much as 3 to 5 ft above normal tide levels along the immediate
coast near and to the north of where the center makes landfall in
the northeastern Yucatan Peninsula late tonight or early Thursday.
Near the coast, the surge will be accompanied by large and
SURF: Swells generated by Grace will spread westward from Jamaica
and the Cayman Islands to the southern coast of Cuba and the Yucatan
Peninsula of Mexico. 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 PM EDT.
Next complete advisory at 500 PM EDT.