Hurricane Lee Discussion Number 28
NWS National Hurricane Center Miami FL AL132023
500 AM AST Tue Sep 12 2023

Lee continues to exhibit a concentric eyewall structure in
conventional satellite imagery. This has been confirmed by the Air
Force Reserve Hurricane Hunters that investigated Lee early this
morning, and they reported the outer eyewall had a large diameter of
80 n mi. The maximum 700-mb flight-level wind measured by the
aircraft was 112 kt in the northeast quadrant, while the SFMR winds
peaked around 90 kt. Although the satellite intensity estimates have
fallen a bit this morning, the reduced flight-level winds support
holding the initial intensity at 100 kt for this advisory. The
minimum pressure of Lee remains 948 mb based on dropsonde data.

Lee is still moving slowly west-northwestward (290/6 kt), with
mid-level ridging established to the north and west of the
hurricane. This steering pattern is expected to change during the
next couple of days as a deep-layer trough moves across the eastern
United States and produces a weakness in this ridge. As a result,
Lee is forecast to turn northward and gradually accelerate during
the middle and latter parts of this week. The track guidance
envelope shows little cross-track spread during the first 3 days of
the forecast period, and this portion of the NHC forecast is fairly
similar to the previous one. While the core of the hurricane is
forecast to pass west of Bermuda, the large wind field of the storm
is likely to bring wind impacts to the island later this week, and
tropical storm watches could be required later today. At days 4-5,
there has been a slight westward shift in the guidance envelope, and
accordingly the NHC track forecast was nudged in that direction
toward the HCCA and TVCA aids.

Based on Lee's current satellite structure, as well as its slow
forward motion and large wind field, little near-term strengthening
is expected. Going forward, the large hurricane appears likely to
begin upwelling cooler waters along its path, and in a few days it
will encounter the cool wake left behind by recent western Atlantic
hurricanes. Thus, gradual weakening is forecast through midweek.
Later, the aforementioned trough is expected to produce stronger
deep-layer shear over Lee, and the hurricane is forecast to move
over significantly cooler waters as it passes north of the Gulf
Stream. As a result, more significant weakening is shown at days
4-5, along with completion of its extratropical transition. Despite
the weakening that is forecast, keep in mind that the expanding wind
field of Lee will produce impacts well away from the storm center.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. There is an increasing risk of strong winds, rainfall, and high
surf impacts to Bermuda later this week, and tropical storm watches
could be required for the island later today.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 24.0N 65.4W 100 KT 115 MPH
12H 12/1800Z 24.4N 66.2W 100 KT 115 MPH
24H 13/0600Z 25.3N 67.0W 100 KT 115 MPH
36H 13/1800Z 26.6N 67.5W 95 KT 110 MPH
48H 14/0600Z 28.3N 67.9W 90 KT 105 MPH
60H 14/1800Z 30.4N 68.0W 85 KT 100 MPH
72H 15/0600Z 32.9N 67.6W 80 KT 90 MPH
96H 16/0600Z 39.0N 66.7W 70 KT 80 MPH
120H 17/0600Z 44.5N 66.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

Hurricane Lee Advisory Number 28
NWS National Hurricane Center Miami FL AL132023
500 AM AST Tue Sep 12 2023

...LEE REMAINS A LARGE AND POWERFUL HURRICANE...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...24.0N 65.4W
ABOUT 575 MI...925 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in Bermuda should monitor the progress of Lee. Watches
could be required for Bermuda later today.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Hurricane Lee was located
near latitude 24.0 North, longitude 65.4 West. Lee is moving toward
the west-northwest near 7 mph (11 km/h). A slow west-northwest to
northwest motion is expected during the next day or two, followed by
a turn toward the north by midweek. On the forecast track, Lee is
expected to pass near but to the west of Bermuda in a few days.

Data from the Air Force Reserve Hurricane Hunters indicate that
maximum sustained winds are near 115 mph (185 km/h) with higher
gusts. Lee is a category 3 hurricane on the Saffir-Simpson Hurricane
Wind Scale. Gradual weakening is forecast during the next few days.

Lee is a large hurricane. Hurricane-force winds extend outward up
to 80 miles (130 km) from the center and tropical-storm-force winds
extend outward up to 185 miles (295 km).

The estimated minimum central pressure is 948 mb (28.00 inches)
based on dropsonde data from the aircraft.


HAZARDS AFFECTING LAND
----------------------
Key messages for Lee can be found in the Tropical Cyclone Discussion
under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC and on the
web at hurricanes.gov/text/MIATCDAT3.shtml

SURF: Swells generated by Lee are affecting portions of the Lesser
Antilles, the British and U.S. Virgin Islands, Puerto Rico,
Hispaniola, the Turks and Caicos Islands, the Bahamas, and Bermuda.
These swells are likely to cause life-threatening surf and rip
current conditions. Dangerous surf and rip currents are affecting
portions of the southeastern U.S. coast, and these conditions are
forecast to spread northward along much of the U.S. East Coast
during the next couple of days. Please consult products from your
local weather office.


NEXT ADVISORY
-------------
Next complete advisory at 1100 AM AST.

$$
Forecaster Reinhart