NHC Atlantic Tropical Weather Discussion

AXNT20 KNHC 292315

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
715 PM EDT Thu Aug 29 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 18000 UTC surface analysis and satellite imagery through
2300 UTC.


Hurricane Dorian is centered near 22.5N 67.7W at 29/2100 UTC or
about 280 nm E of Mayaguana in the SE Bahamas, moving NW at 11 kt.
Minimum central pressure is near 986 mb. Maximum sustained wind
speed is 75 kt with gusts to 90 kt. Numerous moderate to strong
convection extends out 90 nm in the northern semicircle and 60 nm
southern semicircle. Scattered moderate convection extends out
180 nm in the northern semicircle, 300 nm SE quad, and 75 nm SW
quad. The NW motion will continue through Friday. A W to WNW
motion will begin Friday night and continue into the weekend. On
this track, Dorian should move well east of the southeastern and
central Bahamas tonight and Friday, approach the northwestern
Bahamas Saturday, and move near or over portions of the northwest
Bahamas on Sunday. Dorian is expected to strengthen into a major
hurricane on Friday, and remain an extremely dangerous hurricane
through the weekend. See the latest NHC forecast/advisory under
AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC or www.hurricanes.gov for
more details.


An east Atlantic tropical wave is along 22W from 04N-21N, moving W
around 10 kt. Scattered showers are noted within 150 nm of the
wave axis.

A central Atlantic tropical wave is along 50W from 05N-22N, moving
W around 10-15 kt. Saharan dry air prevails in the wave’s
environment, inhibiting convection.


The monsoon trough passes through coastal Senegal near 14N17W to
11N30W to 13N45W to 11N52W. The ITCZ extends from 11N52W to the
coast of Venezuela near 09N61W. Aside from the convection
mentioned in the Tropical Waves section, scattered moderate to
strong convection is seen over west Africa and offshore from
11N-24N between 12W-19W.


A stationary front extends from Cedar Key Florida to the Mouth of
the Mississippi River. Isolated showers and tstorms are along the
southern coast of Louisiana and over portions of the NW Gulf of
Mexico. Isolated tstorms are also near and over the Yucatan
Channel. Scattered showers and tstorms are over the Florida
Peninsula. Mainly gentle winds are seen across the basin in the
most recent ASCAT pass.

A surface trough will form in the central Gulf of Mexico this
weekend, with fresh E or NE winds expected in the northern Gulf
during that time, accompanied by increased shower and tstorm
activity. The surface trough will migrate to the western Gulf
early next week. Meanwhile, Hurricane Dorian in the Atlantic is
expected to approach Florida Sunday. Winds and seas could increase
as early as Monday or Monday night in the far eastern Gulf just
west of Florida due to Dorian’s presence over the Florida


Although the center of Hurricane Dorian is now 240 nm NNW of
Puerto Rico, a trailing band of moderate to strong convection
extends southward over Puerto Rico and the USVI and north of 17N
between 64.5W-68W. Flash flood warnings are currently in effect
for southeastern portions of Puerto Rico, and Flood Advisories are
in effect for Vieques and Culebra as of 29/2200 UTC. Dorian will
continue moving farther away from the Caribbean tonight. Refer to
the section above for more details on this system.

Upper level diffluence is enhancing scattered showers and tstorms
over the adjacent waters south of Cuba and Cayman Islands from
18N-22N between 76W-86W. In the southwest Caribbean, the East
Pacific monsoon trough is inducing scattered showers and tstorms
south of 12.5N between 70W-84W, including the area within 30 nm
offshore the NW coast of Venezuela and the N coast of Colombia.
Fair weather prevails elsewhere from 13N-17N between 60W-82W.
Latest scatterometer data depicts moderate to fresh trades in the
central and eastern Caribbean with light to gentle winds

During the next several days, moderate to fresh winds are expected
across the east and central Caribbean, with gentle to moderate
winds over the NW Caribbean. Seas should remain quiescent during
the next several days across the basin.


Refer to the sections above for details on Dorian and the
tropical waves in the Atlantic.

A surface trough extends across the west Atlantic from 24N79W to
30N76W. Scattered showers and tstorms are noted from 23N-32N
between 74W-80W. An upper-level low is just to the NW of Dorian,
near and north of the SE Bahamas. Scattered showers and tstorms
are seen from 23N-27N between 70W-73W. To the east, an upper-
level low in the central Atlantic is inducing scattered showers
and tstorms from 21N-31N between 48W-60W. The remainder of the
basin is under the influence of a surface ridge, anchored by a
1021 mb high centered near 34N38W.

Hurricane Dorian will move to near 25N70W by 2pm EDT Fri,
26.5N74W 2pm Sat, 27N78W 2pm Sun, and to the Florida coast near
27.5N80W 2pm Mon. Dorian is anticipated to become a major
hurricane as early as Friday and remain that way until landfall.


Official content courtesy of the National Hurricane Center, NOAA.gov