[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141117
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1205 UTC Thu Sep 14 2023

Tropical Weather Discussion for North America, Central America
Gulf of Mexico, Caribbean Sea, northern sections of South
America, and Atlantic Ocean to the African coast from the
Equator to 31N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 0600 UTC surface analysis and satellite imagery through
1020 UTC.

...SPECIAL FEATURES...

The center of Hurricane Lee, at 14/0900 UTC, is near 29.1N 68.1W,
or about 255 nm SW of Bermuda, moving N at 8 kt. Maximum sustained
winds are near 85 kt with gusts to 105 kt. Minimum central
pressure is 953 mb. Lee is a very large hurricane. Hurricane force
winds extend outward up to 90 nm from the center and tropical
storm force winds extend outward up to 250 nm. Seas of 12 ft or
greater extend outward from the center 435 nm NE quadrant, 420 nm
SE quadrant, 390 nm SW quadrant and 500 nm NW quadrant. The
maximum sea heights are 46 feet. Scattered moderate to isolated
strong convection is within 180 nm S semicircle and 360 nm N
semicircle. Hurricane, Tropical Storm and Storm Surge Watches and
Warnings are in effect for portions of coastal New England,
Atlantic Canada and Bermuda.

The center of Hurricane Margot, at 14/0900 UTC, is near 35.9N
40.3W. Margot is moving toward the NNE at 5 kt. The estimated
minimum central pressure is 979 mb. The maximum sustained wind
speeds are 65 kt with gusts to 80 kt. From 29N to 31N between 39W
and 49W, seas are 10-12 ft in N swell with winds up to 20 kt. The
winds over 25 kt associated with Margot will remain N of 31N for
the remainder of the cyclone's lifetime.

Invest AL97 in the Central Tropical Atlantic: A broad area of low
pressure along a tropical wave is near 13N37W. Scattered moderate
to strong convection is noted from 10N to 19N between 36W and
44W. Environmental conditions appear favorable for further
development of this system, and a tropical depression is likely to
form during the next couple of days while the low moves west-
northwestward to northwestward at 10 to 15 kt across the central
tropical Atlantic. The chance of this feature developing into a
tropical cyclone during the next 48 hours is high. Please refer to
the latest NHC Tropical Weather Outlook at www.hurricanes.gov for
more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 33W, from 19N southward,
moving westward 10 knots. Scattered moderate to strong convection
is noted from 06N to 16N between 27W and 35W.

A 1011 mb low pressure center is nearly stationary along 15N48W.
No significant convection is currently associated with this
feature.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Senegal near 14.5N17W to AL97 low pressure near 13N37W to low pres
near 15N48W. Outside of convection described above, scattered to
numerous moderate to strong convection is from 04N to 11.5N
between 24W and the African coast. Scattered moderate to strong
convection is noted to the NW of AL97, from 19N to 25.5N between
42W and 47W.

...GULF OF MEXICO...

A stationary frontal boundary extends just inland from the coast through
the southern sections of Alabama, to southern Mississippi, to
Louisiana, to East Texas, and beyond south central Texas. A 1013
mb high pressure center is near 30N86W. Scattered moderate
convection is across the extreme SE Texas and SW Louisiana coastal
waters N of 28.5N and within 60 nm of the Mexican coast across the
Bay of Campeche. Fair skies prevail elsewhere across the basin.
Light to gentle anticyclonic wind flow prevails across the basin,
with E winds of 10 to near 15 kt across the waters NW of the
Yucatan Peninsula, and SE winds 10 to 15 kt across the upper
Mexican and S Texas coastal waters. Seas are near 3 ft across
these areas, and 2 ft or less across the remainder of the basin.

A weak ridge across the northern Gulf will dominate the basin
throughout the forecast period, supporting mainly light to gentle
winds N of 24N and gentle to moderate winds S of 24N. Scattered
thunderstorms can be expected across the western Yucatan and
eastern Bay of Campeche each late afternoon and evening through
the period.

...CARIBBEAN SEA...

Hurricane Lee continues to interrupt the pressure pattern across
the basin, with a weak and broad trough extending from Lee SSW
across Hispaniola to near 17N72W. Moderate SE to S winds are
occurring E of 70W, while gentle to moderate winds are across NW
portions. Winds across the A-B-C Islands and northern Colombia
area NE at 15 kt or less. Seas area generally slight to moderate
across the basin due to weaker than normal winds. However, large
northerly swell from Lee continues to move through the passages of
the NE Caribbean and into the eastern Caribbean waters, likely
reaching the coasts of Venezuela. Recent buoy observations along
the NW coast of Puerto Rico, and altimeter date through the Mona
Passage show seas of 7-8 ft in NNW in the northern Mona passage
diminishing to 6 ft across the Caribbean immediately to the south
along 15N.This N-NW swell from Lee is assumed to have peaked
across the adjacent Atlantic in recent hours.

Hurricane Lee will continue moving N across the western Atlantic and
pass W of Bermuda tonight. Large N-NW swell across the adjacent
Atlantic and moving through the NE Caribbean Passages will
gradually diminish this afternoon and tonight and then decrease
quickly Fri. Moderate E trade winds will return to the Caribbean
on Fri.

...ATLANTIC OCEAN...

Please, read the SPECIAL FEATURES section, for details
about Hurricane Lee, Hurricane Margot, and the INVEST AL97.

Atlantic high pressure is drapped across Hurricane Margot, and to
the NE of Hurricane Lee, and is producing moderate winds
circulating around both of these systems to the N of 20N. The
entire discussion area N of 20N is dominated by swell from Lee and
Margot. Moderate to fresh cyclonic winds are around the periphery
of Lee and are brushing the Bahamas and the Greater Antilles. Seas
across this area are 8 to 12 ft in NW swell between the NE
Caribbean Islands and 22N, and 10-12 ft in NE swell across the
nearshore Atlantic waters of the Bahamas. Strong SE swell is
moving into the coastal waters of Florida and Georgia this
morning, where coastal buoys are reporting seas around 5 ft.
However farther offshore, this swell is producing seas of 7 to 10
ft to the W of 78W.

A broad easterly wind surge is occurring to the N of AL97 from
15N and 22N between 30W and 40W, where seas are 8 to 9 ft in mixed
E and N swell. Active convection will continue across this region
for the next 24 hours or more.

For the forecast W of 55W, Hurricane Lee will continue moving
northward and reach near 30.7N 68.2W this afternoon, pass to the W
of Bermuda tonight and reach near 33.3N 67.7W Fri morning, then
continue northward across the NW Atlantic through the weekend.
Long-period swell generated by Lee is expected to impact all
waters north through east of the Bahamas through the weekend. High
pressure will build across the area late Fri through Sun. Low
pressure across the eastern Atlantic, AL97, will approach the far
eastern part of the area Mon and Mon night, possibly as a tropical
cyclone.

$$

Stripling/Hagen
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