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BULLETIN
Hurricane Grace Intermediate Advisory Number 23A
NWS National Hurricane Center Miami FL       AL072021
100 AM CDT Thu Aug 19 2021
 
...GRACE APPROACHING THE EASTERN YUCATAN PENINSULA...
...EXPECTED TO PRODUCE STRONG WINDS AND A DANGEROUS STORM SURGE...
 
 
SUMMARY OF 100 AM CDT...0600 UTC...INFORMATION
----------------------------------------------
LOCATION...19.9N 86.4W
ABOUT 60 MI...115 KM ESE OF TULUM MEXICO
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...W OR 280 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...986 MB...29.12 INCHES
 
 
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
 
None.
 
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
 
A Hurricane Warning is in effect for...
* Yucatan Peninsula of Mexico from Cancun to Punta Herrero,
including Cozumel
 
A Hurricane Watch is in effect for...
* The coast of mainland Mexico from Puerto Veracruz to Cabo Rojo
 
A Tropical Storm Warning is in effect for...
* Yucatan Peninsula of Mexico from north of Cancun to Campeche
* Yucatan Peninsula of Mexico from south of Punta Herrero to Puerto
Costa Maya
 
A Tropical Storm Watch is in effect for...
* Southern coast Cuban province of Pinar del Rio, as well as Isla
de la Juventud
* The coast of mainland Mexico north of Cabo Rojo to Puerto de
Altamira
 
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
dangerous.
 
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 100 AM CDT (0600 UTC), the center of Hurricane Grace was located
by an Air Force Reserve Hurricane Hunter aircraft and Cuban radars 
near latitude 19.9 North, longitude 86.4 West. Grace is moving 
toward the west near 18 mph (30 km/h).  A general westward to west-
northwestward motion is expected through Friday, followed by a 
general westward to west-southwestward motion.  On the forecast 
track, Grace is expected to make landfall in the eastern Yucatan 
Peninsula during the next six hours, move across the Yucatan 
Peninsula today, and move over the southwest Gulf of Mexico late 
tonight through Friday.
 
Data from the reconnaissance aircraft indicate maximum sustained 
winds remain near 80 mph (130 km/h) with higher gusts.  Some 
strengthening is expected before landfall on the Yucatan Peninsula. 
Grace is expected to weaken as it crosses Yucatan, but 
re-intensification is expected when the center reaches the Gulf of 
Mexico.
 
Hurricane-force winds extend outward up to 35 miles (55 km) from
the center and tropical-storm-force winds extend outward up to 140
miles (220 km).  A Weatherflow station located at Cancun, Mexico, 
recently measured a sustained wind of 45 mph (72 km/h) and a gust 
to 58 mph (93 km/h).  Another Weatherflow station located at Puerto 
Morelos, Mexico, recently measured a gust to 48 mph (77 km/h).
 
The latest minimum central pressure reported by the aircraft is 
986 mb (29.12 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
www.hurricanes.gov/graphics_at2.shtml?key_messages.
 
WIND:  Hurricane conditions are expected within the warning area in
the Yucatan Peninsula of Mexico later this morning, and tropical 
storm conditions have already begun to spread onshore.  Hurricane 
and tropical storm conditions will spread inland across the Yucatan 
Peninsula during the day today.  Hurricane conditions are possible 
in the hurricane watch area in mainland Mexico by late Friday, and 
tropical storm conditions are possible in the tropical storm watch 
area in mainland Mexico by late Friday.  Tropical storm conditions 
are possible along the southern coast of Cuba within the watch area 
for the next several hours.
 
RAINFALL:
The system is expected to produce the following rainfall amounts:
 
Over central and northern portions of the Yucatan Peninsula...4 to 8
inches of rain with isolated maximum totals of 12 inches are
expected through Friday. Heavy rainfall from Grace will likely
result in areas of flash and urban flooding.
 
Over central to northern Veracruz...5 to 10 inches of rain with
isolated maximum totals of 15 inches are expected from Friday
through Sunday. Heavy rainfall from Grace will likely result in
areas of flash and urban flooding, and will also be capable of
producing mudslides.
 
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 later this morning, and along the 
eastern mainland coast of Mexico Friday night or early Saturday. 
Near the coast, the surge will be accompanied by large and 
destructive waves.
 
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 through today.  These swells are likely to
cause life-threatening surf and rip current conditions.  Please
consult products from your local weather office.
 
 
NEXT ADVISORY
-------------
Next complete advisory at 400 AM CDT.
 
$$
Forecaster Stewart
 
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