5pm EDT Tuesday on Delta: 145mph; 956mb
Posted by Chris in Tampa on 10/6/2020, 4:51 pm
Track:
https://www.nhc.noaa.gov/refresh/graphics_at1+shtml/?cone#contents

Satellite:
https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al262020
https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL262020

The following tweet was from the previous advisory, but it has good advice:



Current version of that graphic is here:
https://www.nhc.noaa.gov/refresh/graphics_at1+shtml/?mltoa34#contents






Hurricane Delta Discussion Number 9
NWS National Hurricane Center Miami FL AL262020
500 PM EDT Tue Oct 06 2020

Shortly after the release of the 1500 UTC advisory package, the
NOAA Hurricane Hunter aircraft measured a peak flight-level wind
of 132 kt, and during its final passage through the northeast
eyewall around 1700 UTC it reported a peak SFMR wind of 121 kt.
The aircraft continued to report an extremely small 4-to-5-nmi-wide
eye. The central pressure did level off somewhat on the final
couple of penetrations, with the latest reported central pressure
at 956 mb. The initial wind speed was raised to 120 kt on the
earlier intermediate advisory, and has been set at 125 kt for this
advisory. The next reconnaissance aircraft mission into the
hurricane is scheduled for this evening.

There has been no evidence of an outer eyewall from the aircraft
reports or earlier radar imagery from Grand Cayman. As a
result, some additional strengthening is likely to occur before
Delta reaches the northeastern coast of the Yucatan peninsula late
tonight or early Wednesday. The NHC intensity forecast is once
again a little above the various intensity aids until landfall in
Mexico. When the small inner core of Delta moves over land,
weakening is expected, but warm waters and low vertical wind shear
over the southern Gulf of Mexico should support re-strengthening,
and a second peak in intensity is likely when Delta is over the
central Gulf of Mexico in 48-60 hours. After that time, increasing
southwesterly shear and the cooler shelf waters over the
northern Gulf are expected to cause some reduction in wind speed.
The global models, however, depict a significant increase in the
size of Delta's wind field while it is over the Gulf of Mexico,
which increases the spatial extent of the storm surge and wind
threats for the northern Gulf coast. So regardless of Delta's
final landfall intensity, the projected large size of the hurricane
is likely to result in a significant storm surge and wind event for
portions of the northern Gulf coast later this week.


Delta has been moving steadily west-northwestward today at 300/15
kt. The track forecast reasoning remains unchanged from the previous
advisory. A mid-level ridge over Florida and the northeastern Gulf
of Mexico is expected to continue steering Delta west-northwestward
during the next 36-48 hours. After that time, a developing trough
over the south-central United States should cause Delta to turn
northward, and by Friday the hurricane is forecast to begin
accelerating northward or north-northeastward ahead of the trough.
This motion will bring Delta onshore along the northern Gulf coast
between 72 and 96 hours. The dynamical models continue to be
tightly clustered through 48-72 hours with some increase in spread
thereafter. The overall trend in the guidance has been slightly
westward, and the new forecast has been adjusted accordingly and
lies near the middle of the envelope. Supplemental upper-air balloon
launches at 0600 and 1800 UTC have begun at upper-air sites across
portions of the southeastern United States. In addition, a NOAA
G-IV synoptic surveillance mission is in progress and should provide
additional data for the 0000 UTC cycle of the dynamical models.

Key Messages:

1. Life-threatening storm surge and potentially catastrophic wind
damage are expected within portions of the northern Yucatan
Peninsula of Mexico beginning tonight. All preparations to protect
life and property should be rushed to completion.

2. Heavy rainfall will affect portions of the Cayman Islands,
western Cuba and the northern Yucatan Peninsula through midweek.
This rainfall could lead to significant flash flooding and
mudslides. The potential for heavy rain, flash and possible minor
river flooding will increase across portions of the central Gulf
Coast, Tennessee Valley, and southeastern United States as Delta
moves inland later this week.

3. There is an increasing likelihood of life-threatening storm surge
and dangerous hurricane-force winds, especially along the coasts of
Louisiana and Mississippi, beginning on Friday. Residents in these
areas should ensure they have their hurricane plan in place and
follow advice given by local officials. Storm surge and hurricane
watches will likely be issued for portions of the northern Gulf
Coast on Wednesday.

FORECAST POSITIONS AND MAX WINDS

INIT 06/2100Z 18.9N 84.1W 125 KT 145 MPH
12H 07/0600Z 20.2N 86.1W 135 KT 155 MPH
24H 07/1800Z 21.8N 88.8W 105 KT 120 MPH
36H 08/0600Z 23.0N 91.1W 110 KT 125 MPH
48H 08/1800Z 24.4N 92.6W 115 KT 130 MPH
60H 09/0600Z 25.9N 93.2W 115 KT 130 MPH
72H 09/1800Z 28.0N 92.9W 110 KT 125 MPH
96H 10/1800Z 32.4N 90.9W 55 KT 65 MPH...INLAND
120H 11/1800Z 35.5N 87.3W 20 KT 25 MPH...POST-TROP/REMNT LOW

$$
Forecaster Brown








Hurricane Delta Advisory Number 9
NWS National Hurricane Center Miami FL AL262020
500 PM EDT Tue Oct 06 2020

...EXTREMELY DANGEROUS CATEGORY FOUR HURRICANE DELTA HEADING
TOWARD THE NORTHEASTERN COAST OF THE YUCATAN PENINSULA...
...EXPECTED TO BRING A LIFE-THREATENING STORM SURGE AND EXTREME
WINDS...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...18.9N 84.1W
ABOUT 215 MI...345 KM ESE OF COZUMEL MEXICO
ABOUT 240 MI...385 KM ESE OF TULUM MEXICO
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...956 MB...28.23 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Cuba has discontinued the Tropical Storm Watch
for the province of La Habana.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Warning is in effect for...
* Tulum to Dzilam Mexico
* Cozumel

A Tropical Storm Warning is in effect for...
* Cuba province of Pinar del Rio
* Isle of Youth
* Punta Herrero to Tulum Mexico
* Dzilam to Progresso Mexico

A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. 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.

Interests along the northern Gulf of Mexico coast should monitor
the progress of Delta. Hurricane and Storm Surge Watches will
likely be issued for a portion of this area on Wednesday.

For storm information specific to your area, please monitor
products issued by your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM EDT (2100 UTC), the center of Hurricane Delta was located
near latitude 18.9 North, longitude 84.1 West. Delta is moving
toward the west-northwest near 17 mph (28 km/h). A west-
northwestward to northwestward motion is expected over the next
couple of days. A slower northwestward to north-northwestward motion
is forecast to begin on Thursday, and a northward motion is expected
Thursday night and Friday. On the forecast track, the center of
Delta will move over the northeastern portion of the Yucatan
peninsula late tonight or early Wednesday. Delta is forecast to
move over the southern Gulf of Mexico Wednesday afternoon, and be
over the southern or central Gulf of Mexico through Thursday, and
approach the northern Gulf coast on Friday.

Maximum sustained winds have increased to near 145 mph (230 km/h)
with higher gusts. Delta is a category 4 hurricane on the
Saffir-Simpson Hurricane Wind Scale. Some additional strengthening
is possible before the center reaches the coast Yucatan peninsula
Wednesday. Although some weakening is likely when Delta moves over
the Yucatan peninsula, re-strengthening is forecast when the
hurricane moves over the southern Gulf of Mexico Wednesday night and
Thursday.

Hurricane-force winds extend outward up to 30 miles (45 km) from the
center and tropical-storm-force winds extend outward up to 105 miles
(165 km).

The estimated minimum central pressure is 956 mb (28.23 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Delta can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT1, WMO header WTNT41
KNHC, and on the web at www.hurricanes.gov/text/MIATCDAT1.shtml.

STORM SURGE: A life-threatening storm surge will raise water levels
in areas of onshore winds by as much as 9 to 13 ft above normal tide
levels along the northern coast of the Yucatan Peninsula from Cabo
Catoche to Progresso, and 6 to 9 ft above normal tide levels along
the eastern coast of the Yucatan Peninsula from Tulum to Cabo
Catoche. Near the coast, the surge will be accompanied by large
and destructive waves.

WIND: In the Yucatan Peninsula, potentially catastrophic
hurricane conditions are expected in portions of the warning area
late tonight and early Wednesday, with tropical storm conditions
beginning later this evening. Tropical storm conditions are expected
in the tropical storm warning area tonight and Wednesday. In Cuba,
tropical storm conditions are expected tonight in the warning area.

RAINFALL: Delta is expected to produce 4 to 6 inches of rain, with
isolated maximum totals of 10 inches, across portions of the
northern Yucatan Peninsula through midweek. This rainfall may result
in areas of significant flash flooding.

Over the next few days, Delta is expected to produce 2 to 4 inches
of rain, with isolated higher amounts, across portions of the Cayman
Islands and western Cuba. This rainfall may result in areas of flash
flooding and mudslides.

Later this week, Delta is expected to produce 4 to 8 inches of rain,
with isolated maximum totals of 12 inches to portions of the central
Gulf Coast. These rainfall amounts may lead to flash, urban and
minor river flooding. Heavy rainfall will eventually spread into the
Tennessee Valley, and interior southeastern United States as well.

SURF: Swells generated by Delta will affected land areas around
the northwestern Caribbean Sea for the next day or so. These swells
are likely to cause life-threatening surf and rip current
conditions. Please consult products from your local weather office.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM EDT.
Next complete advisory at 1100 PM EDT.

$$
Forecaster Brown
61
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5pm EDT Tuesday on Delta: 145mph; 956mb - Chris in Tampa, 10/6/2020, 4:51 pm
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