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Hurricane GRACE


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Hurricane Grace Discussion Number  22
NWS National Hurricane Center Miami FL       AL072021
500 PM EDT Wed Aug 18 2021
 
A ragged eye appeared for a while on visible satellite imagery, but 
it has recently been obscured by cumulonimbus tops.  The overall 
cloud pattern has been maintaining its organization with some 
convective banding features and very cold cloud tops, mainly over 
the eastern portion of the circulation.  The current intensity 
estimate is set at 70 kt, which is a blend of Dvorak estimates from 
TAFB and SAB.  Another Air Force Reserve Hurricane Hunter aircraft 
is scheduled to investigate the hurricane in a few hours to provide 
another intensity estimate.
 
Grace will continue to move over waters of very high oceanic heat 
content prior to reaching the east coast of the Yucatan Peninsula, 
which of course favors intensification.  Aside from moderate 
northwesterly shear, a possible impediment to strengthening is a 
northeast to southwest-oriented shear axis located just to the 
northwest of the hurricane.  Nonetheless, some intensification is 
anticipated before landfall in Yucatan, with restrengthening over 
the Bay of Campeche.  The official intensity forecast continues to 
be in general agreement with the multi-model consensus predictions, 
IVCN and HCCA.

Grace is moving west-northwestward, or about 285/14 kt.  There has 
been essentially no change to the track forecast philosophy.  Grace 
should maintain a west-northwestward to westward motion, on the 
southern periphery of a strong subtropical ridge, for the next 
several days.  The official track forecast is very similar to the 
previous one and about on top of the latest multi-model consensus, 
TVCA.
 
A Hurricane Watch will likely be required for a portion of the
coast of eastern mainland Mexico tonight.

Key Messages:
 
1. Hurricane conditions and a dangerous storm surge are expected
in portions of the Hurricane Warning area in the eastern Yucatan
Peninsula of Mexico beginning late tonight or early Thursday.
Preparations to protect life and property should be rushed to
completion.
 
2. There is an increasing risk of hurricane conditions and dangerous
storm surge in portions of eastern mainland Mexico beginning late
Friday, and a Hurricane Watch will likely be issued for part of this
area tonight.
 
3. Through the weekend, heavy rainfall across the Cayman Islands as 
well as portions of the Yucatan Peninsula and Veracruz State should 
lead to flash and urban flooding.  In addition, the heavy rainfall 
from Grace will be capable of producing mudslides in Veracruz.  

FORECAST POSITIONS AND MAX WINDS
 
INIT  18/2100Z 19.7N  83.7W   70 KT  80 MPH
 12H  19/0600Z 20.2N  86.1W   75 KT  85 MPH
 24H  19/1800Z 20.7N  89.3W   55 KT  65 MPH...INLAND
 36H  20/0600Z 20.9N  92.2W   60 KT  70 MPH...OVER WATER
 48H  20/1800Z 20.8N  94.6W   70 KT  80 MPH...OVER WATER
 60H  21/0600Z 20.4N  97.3W   75 KT  85 MPH...INLAND
 72H  21/1800Z 20.0N  99.9W   30 KT  35 MPH...INLAND
 96H  22/1800Z 19.5N 104.0W   20 KT  25 MPH...POST-TROP/INLAND
120H  23/1800Z...DISSIPATED
 
$$
Forecaster Pasch
 
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