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Hurricane Delta Discussion Number   6
NWS National Hurricane Center Miami FL       AL262020
1100 PM EDT Mon Oct 05 2020

A few hours ago, data from the NOAA Hurricane Hunters supported 
upgrading Delta to a hurricane.  Very recent reports from the Air 
Force Hurricane Hunters, who are currently in Delta, support 
increasing the intensity a little more to 70 kt.  The minimum 
pressure has also decreased a few mb from the NOAA mission, and is 
now estimated to be 977 mb.  Delta has strengthened at a rapid rate 
of 40 kt since genesis occurred just 24 hours ago.  The hurricane is 
quite compact with a developing tight inner core, and even the 
tropical-storm-force winds extend only up to 60 n mi or so from the 
center.  
 
After moving westward for much of the day, aircraft fixes from NOAA
and the Air Force indicate that the hurricane has resumed a
west-northwest motion, with the latest initial motion estimated to
be 295/6 kt.  Delta is expected to move to the northwest at a fairly
quick pace on Tuesday and Wednesday as it moves in the flow between
a subtropical high over the western Atlantic and Post-Tropical
Cyclone Gamma over or near the Yucatan Peninsula.  This motion
should take Delta over or very near the northeastern portion of the
Yucatan Peninsula by Tuesday night and over the southern Gulf of
Mexico on Wednesday.  After that time, the western part of the ridge
is expected to slowly erode as a trough moves eastward across the
south-central U.S.  This change in the steering pattern should cause
Delta to slow down and then turn northward toward the northern Gulf
coast, and it will likely make landfall there in a little more
than 4 days.  The models are in fair agreement, and the NHC
track forecast is only a touch to the west of the previous one.
 
The hurricane has taken advantage of the near ideal conditions of
low vertical wind shear, high amounts of moisture, and very warm
29-30 C SSTs.  These favorable environmental conditions for the
hurricane will persist for the next 2 or 3 days or so, and
therefore, it seems reasonable to believe that rapid intensification
will continue in the short term. Delta is expected to become a major
hurricane in about 24 hours when it is near the Yuctan Peninsula.
If Delta makes landfall on that landmass, it would likely temper
the cyclone's strength for a period of time.  Beyond a few days,
when Delta is forecast to approach the northern Gulf coast, there
will likely be an increase in southwesterly wind shear.  These less
conducive upper-level winds and cooler shelf waters should end the
strengthening trend prior to the U.S. landfall.  The NHC intensity
forecast is largely an update of the previous one and lies close to
the HCCA and IVCN consensus models.
 
Users are reminded to not focus on the details of the track or
intensity forecasts, as the average 4-day track error is around 150
miles and the average 4-day intensity error is close to 15 mph.
 
Key Messages:
 
1. Dangerous storm surge and hurricane conditions are expected
within portions of the northern Yucatan Peninsula of Mexico 
beginning Tuesday night, and a Hurricane Warning is in effect.
 
2. Heavy rainfall will affect portions of Jamaica, the Cayman 
Islands, western Cuba and the northern Yucatan Peninsula during the 
next few days. This rainfall could lead to significant flash 
flooding and mudslides.   
 
3. Tropical storm conditions are expected in portions of the Cayman
Islands beginning early Tuesday, and a Tropical Storm Warning is in 
effect.
 
4. Delta is forecast to approach the northern Gulf Coast late this
week as a hurricane. While there is large uncertainty in the track
and intensity forecasts, there is an increasing risk of dangerous
storm surge, wind, and rainfall hazards along the coast from
Louisiana to the western Florida Panhandle beginning Thursday night
or Friday. Residents in these areas should ensure they have their
hurricane plan in place and monitor updates to the forecast of
Delta.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  06/0300Z 16.8N  80.3W   70 KT  80 MPH
 12H  06/1200Z 18.1N  82.0W   85 KT 100 MPH
 24H  07/0000Z 19.8N  84.6W  100 KT 115 MPH
 36H  07/1200Z 21.5N  87.1W  105 KT 120 MPH...INLAND
 48H  08/0000Z 23.0N  89.5W  105 KT 120 MPH
 60H  08/1200Z 24.0N  90.8W  105 KT 120 MPH
 72H  09/0000Z 25.2N  91.7W  100 KT 115 MPH
 96H  10/0000Z 28.6N  91.2W   85 KT 100 MPH
120H  11/0000Z 33.6N  88.4W   35 KT  40 MPH...INLAND
 
$$
Forecaster Cangialosi
 
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