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Hurricane Delta Discussion Number  13
NWS National Hurricane Center Miami FL       AL262020
400 PM CDT Wed Oct 07 2020
 
The center of Delta has moved off the northern coast of the Yucatan
peninsula and is now located over the southern Gulf of Mexico.  The
hurricane remains well organized in satellite imagery with a large
curved band wrapping around the center and a fairly symmetric CDO.
An Air Force Reserve reconnaissance aircraft has provided a
few center fixes this afternoon, and found that Delta's passage
over land has resulted in weakening, and the initial wind speed is 
set at 75 kt, which is based on a peak flight-level wind of 81 kt.  
The aircraft also reported a minimum pressure of 977 mb on its 
final center penetration, and data from the plane indicate that 
there has been some increase in the radius of maximum winds. 
 
Re-strengthening is anticipated over the next 24-36 hours while 
Delta moves within a favorable upper-level environment and over the 
relatively deep warm waters of the southern and central Gulf of 
Mexico.  Most of the intensity guidance brings Delta back up to 
major hurricane status, and so does the official forecast. The 
global models also significantly deepen Delta during the next 36 
hours, lending confidence to re-intensification.  After 36 hours, 
increasing shear and cooler waters over the northern Gulf of Mexico 
are likely to cause some decrease in intensity before Delta makes 
landfall, however the hurricane's wind field is forecast to expand, 
which will increase the storm surge and wind threats. Regardless of 
Delta's landfall intensity, life-threatening storm surge and strong 
winds are likely over a large portion of the northwestern and 
northern Gulf coast.
 
Delta has been moving on a consistent northwestward heading of
305 degrees at about 15 kt. Delta should continue on this general
heading with some reduction in forward speed tonight and early
Thursday as it approaches the western extent of the subtropical
ridge.  A mid- to upper-level trough over Texas is forecast to
slide eastward over the next couple of days, which is expected to
cause Delta to turn north-northwestward on Thursday, and northward
toward the northern Gulf coast by Friday.  A faster northward to
north-northeastward motion in 48-60 hours will bring the center
onshore along the northern Gulf coast late Friday.  The cross track
spread in the dynamical models has decreased this cycle, with the 
model predictions converging on the previous NHC track forecast.
Therefore, little change has been made to the previous official
forecast, and it lies near the center of the now tightly clustered
guidance envelope.
 
Key Messages:
 
1. Winds and water levels along the northern coast of the Yucatan 
Peninsula will gradually subside this evening.  Heavy rainfall, 
which could lead to significant flash flooding, will affect the 
northern Yucatan Peninsula through early Thursday.

2. Delta is expected to grow in size as it approaches the northern
Gulf Coast, where life-threatening storm surge and dangerous 
hurricane-force winds are likely beginning Friday, particularly for 
portions of the Louisiana coast. Storm Surge and Hurricane Watches 
are in effect, and residents in these areas should follow advice 
given by local officials.
 
3. Flash, urban, small stream and minor to isolated moderate river 
flooding is likely Friday and Saturday from portions of the central 
Gulf Coast into portions of the Lower to Middle Mississippi Valley. 
As Delta moves farther inland, additional heavy rainfall is expected 
in the Ohio Valley and Mid Atlantic this weekend.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  07/2100Z 22.1N  89.5W   75 KT  85 MPH
 12H  08/0600Z 23.2N  91.2W   85 KT 100 MPH
 24H  08/1800Z 24.8N  92.9W   95 KT 110 MPH
 36H  09/0600Z 26.7N  93.4W  100 KT 115 MPH
 48H  09/1800Z 29.1N  92.9W   90 KT 105 MPH
 60H  10/0600Z 31.6N  91.9W   45 KT  50 MPH...INLAND
 72H  10/1800Z 33.7N  90.5W   30 KT  35 MPH...INLAND
 96H  11/1800Z 37.0N  85.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  12/1800Z...DISSIPATED
 
$$
Forecaster Brown
 
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