[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 051804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 PM EDT Thu Sep 5 2019

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 32N. The following information is based on satellite
imagery, weather observations, radar and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through
1730 UTC.

...SPECIAL FEATURES...

Hurricane Dorian is centered near 32.8N 78.9W at 05/1800 UTC or
50 nm S of Myrtle Beach South Carolina moving NNE at 7 kt. Minimum
central pressure is 958 mb. Maximum sustained wind speed is 95 kt
with gusts to 115 kt. The eye of Dorian passed directly over a
NOAA buoy around 1500 UTC this morning. The buoy measured a
minimum pressure of 959.6 mb. Numerous moderate with embedded
scattered strong convection is seen within 150 nm N semicircle and
75 nm S semicircle. Scattered moderate to isolated strong
convection is seen elsewhere within 300 nm NE quad, 120 nm SE
quad, 150 nm SW quad, 180 nm NW quad. This includes the eastern
half of South Carolina as well as eastern North Carolina. On
radar, the eye is about 30 nm in diameter, and on satellite, the
eye is about 35 nm in diameter. The South Carolina coast between
McClellanville and North Myrtle Beach is currently experiencing
the core of Dorian as of 1730 UTC. On the forecast track, the
center of Dorian will continue to move close to the coast of South
Carolina this afternoon, and then move near or over the coast of
North Carolina tonight and Friday. The center should move to the
southeast of extreme southeastern New England Friday night and
Saturday morning, and approach Nova Scotia later on Saturday.
Dorian is a category 2 hurricane on the Saffir-Simpson Hurricane
Wind Scale. Slow weakening is expected during the next few days.
However, Dorian is expected to remain a powerful hurricane as the
center moves near the coasts of the the Carolinas. See the latest
NHC forecast/advisory under AWIPS/WMO headers MIATCMAT5/WTNT25
KNHC or the website hurricanes.gov for more details.

Tropical Storm Gabrielle is centered near 22.8N 35.5W at 05/1500
UTC or 770 nm NW of the Cabo Verde Islands moving NW at 9 kt.
Estimated minimum central pressure is 1000 mb. Maximum sustained
wind speed is 45 kt with gusts to 55 kt. Scattered moderate
convection is seen on the north side only, extending from 90 to
360 nm N of the center. Gabrielle's NW motion is expected to
continue for the next few days with an increase in forward speed.
See latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT3/WTNT23 KNHC or the website hurricanes.gov for more
details.

...TROPICAL WAVES...

An eastern Atlantic tropical wave extends its axis along 20W,
from 20N southward, moving W at 10-15 kt. Scattered moderate
showers are seen from 03N-17N between 14W-25W. Environmental
conditions appear to be conducive for gradual development. A
tropical depression could form early next week while it moves
westward across the tropical Atlantic Ocean.

An Atlantic tropical wave extends its axis along 54/55W from
05N-22N, moving W at 10-15 kt. Scattered moderate to isolated
strong convection is located about 435 nm east of the Leeward
Islands from 15N-21N between 51W-57W. Scattered showers are
elsewhere within 90 nm of the wave axis. Any development from the
northern portion of this wave is expected to be slow to occur
while it moves slowly northwestward. The chance of tropical
cyclone formation during the next 48 hours is low.

An eastern Caribbean tropical wave extends its axis along 67W,
from 02N-17N, moving W at 10 kt. Scattered moderate to isolated
strong convection is inland over W Venezuela and E Colombia from
01N-10N between 68W-72W. Scattered showers are also seen over
eastern portions of the ABC Islands.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 17N16W to 07N25W to 11N38W to
11N46W. The ITCZ is from 11N46W to 15N52W, then resumes W of a
tropical wave from 14N58W to 12N64W. Aside from the convection
mentioned in the section above, scattered moderate showers are
seen from 02N-14N between 25W-33W, and from 10N-13N between 39W-
48W.

GULF OF MEXICO...

A tail of enhanced moisture about 60 nm wide extends from the east
side of Dorian to the Florida Keys to 24N90W to the lower Texas
coast to the remnants of Fernand, which are analyzed as a surface
trough well inland over northern Mexico from 28N100W to 25N101W.
Scattered showers and isolated tstorms are underneath this swath
of enhanced moisture, except for scattered moderate to isolated
strong convection seen in the west-central Gulf of Mexico from
25N-27N between 95W-97.5W. Drier air is over the northern Gulf of
Mexico, with a 1018 mb surface high centered just W of Houston
Texas. The latest ASCAT pass shows moderate W winds over the far
NE Gulf of Mexico, with gentle winds elsewhere in the basin. Weak
high pressure will prevail across the basin through the weekend,
producing gentle to moderate winds, that will strengthen some
early next week.

CARIBBEAN SEA...

Refer to the section above for details on the tropical waves
moving across the basin.

An upper-level trough is over the W Caribbean with upper-level
ridging over the eastern Caribbean. Scattered moderate convection
is seen from 13N-18N between 78W-81.5W, including over western
Jamaica. To the south of 13N in the SW Caribbean, numerous
moderate with embedded isolated strong convection is being
enhanced by the upper-level trough and the East Pacific monsoon
trough from 08.5N-13N between 76W-85W. Elsewhere, scattered
showers and tstorms are see in the far NW Caribbean just south of
the Yucatan Channel and just south of western Cuba. The latest
ASCAT pass shows strong trades in the south-central Caribbean from
11N-15N between 73.5W-77W.

A weak Atlantic ridge extends from the central Atlantic to the SE
Bahamas. Fresh to strong tradewinds will pulse in the S central
Caribbean tonight. Otherwise, mainly moderate to fresh tradewinds
are expected.

ATLANTIC OCEAN...

Refer to the sections above for details on Dorian, Gabrielle and
two tropical waves moving across the basin.

Scattered showers and tstorms extend over the southern tip of
Florida, the Florida Keys, Florida Straits and NW Bahamas. This
activity is due to a tail of enhanced moisture that emanates from
the eastern side of Hurricane Dorian. Farther east, a 1011 mb low
pressure center is near 35N61W, a few hundred nm NE of Bermuda. A
surface trough extends from the low to 31N61W to 29N63W. Scattered
moderate convection is from 28N-33N between 57W-63W. Increasingly
unfavorable upper-level winds, produced by Hurricane Dorian, are
expected to inhibit further development during the next several
days as the system moves northeastward into the central north
Atlantic. The chance of a tropical cyclone developing during the
next 48 hours is low. Elsewhere, an upper-level low near 26N45W is
producing scattered showers and isolated tstorms from 25N-30N
between 41W-49W.

The center of Hurricane Dorian is forecast to be near or over the
Outer Banks of North Carolina Friday morning at 1200 UTC. Winds
of tropical storm force and seas over 18 ft associated with
Hurricane Dorian's southern extent will move north of 31N latitude
this afternoon. However, winds of 25-33 kt and seas of 12-17 ft
will continue tonight north of 29N between 73W-80W. Winds of 25-30
kt and seas of 12-14 ft will continue Friday north of 30N between
72W-76W. The large northerly swell from Dorian will dominate the
SW N Atlantic through the weekend. Much more tranquil marine
conditions are forecast by early next week.

$$
Hagen
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