[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 031804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
204 PM EDT Tue Sep 3 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 27.5N 78.7W at 03/1800 UTC,
about 55 nm N of Freeport Grand Bahama Island, moving NW at 4 kt.
Minimum central pressure is 959 mb, and maximum sustained wind
speed is 95 kt with gusts to 115 kt. Although the maximum
sustained winds in the eyewall have decreased since yesterday, the
the wind field has expanded significantly. Dorian is expected to
remain a powerful hurricane during the next couple of days.
Numerous moderate to strong convection is within 120 nm of the
center in the E semicircle and 90 nm W semicircle. Scattered
moderate convection is elsewhere within 240 nm E semicircle, 150
nm NW quad and 120 nm SW quad. A partial ASCAT pass from just
prior to 1500 UTC shows that winds over 50 kt extend out about 60
to 75 nm in the NW quad. It shows winds over 34 kt extend out 120
to 135 nm in the NW quad. A slightly faster motion to the NW or
NNW is expected later today and tonight. A turn to the N is
expected by Wed evening, following by a turn to the NNE Thu
morning. On this track, the core of extremely dangerous Hurricane
Dorian will gradually move north of Grand Bahama Island through
this evening. The hurricane will then move dangerously close to
the Florida east coast late today through Wed evening, very near
the Georgia and South Carolina coasts Wed night and Thu, and near
or over the North Carolina coast late Thu and Thu night. See the
latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT5/WTNT25 KNHC or at hurricanes.gov for more details.

Potential Tropical Cyclone Seven has been upgraded to Tropical
Storm Fernand. Tropical Storm Fernand is centered near 23.5N 95.3W
at 03/1800 UTC, about 165 nm ENE of Tampico Mexico, moving W at 6
kt. Minimum central pressure is 1004 mb, and maximum sustained
wind speed is 35 kt with gusts to 45 kt. Numerous moderate to
scattered strong convection is within 180 nm of the center on the
east, north and west sides, with no convection south of the
center. A WNW motion is forecast tonight and Wed. This motion will
bring Fernand inland near or over the coast of northeastern
Mexico late Wed. See the latest NHC forecast/advisory under
AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC or the website
www.hurricanes.gov for more details.

A 1007 mb low is embedded on a tropical wave near 18N31.5W.
Scattered moderate convection is seen within 240 nm of the low
center in the NE quad, 60 nm southern semicircle and 120 nm NW
quad. Isolated moderate convection is elsewhere within 330 nm NE
quad, 390 nm southern semicircle and 210 nm NW quad. A tropical
depression is expected to form later today while the system moves
generally northwestward across the eastern tropical Atlantic
Ocean. The chance of a tropical cyclone to develop during the next
48 hours is high.

A surface trough is located several hundred nm south of Bermuda
from 32N66W to 27.5N67.5W. Numerous moderate with embedded
isolated strong convection is near and east of the trough from
27N-32N between 60W-66W. Westerly wind shear is impinging on the
system from the west, causing the convection to be located all to
the east of the trough axis. Some development of the disturbance
is possible during the next couple of days while it moves
northward, and a tropical depression could form by Thursday.
Afterward, upper-level winds are forecast to become less favorable
for tropical cyclone formation. Interests in Bermuda should
monitor the progress of this system. Areas of heavy rainfall are
likely in Bermuda, regardless of development. The chance of a
tropical cyclone to develop during the next 48 hours is medium.

...TROPICAL WAVES...

An Atlantic tropical wave is along 31/32W from 08N-23N, moving W
at 10 kt. Refer to the Special Features section above for details.

A tropical wave has been added to the analysis along 46W from
04N-22W, moving W at 10-15 kt. Scattered moderate showers and
isolated tstorms are within 150 nm of the wave axis from 13N-16N.
This tropical wave is well depicted by TPW imagery and model
diagnostics.

The Atlantic tropical wave that was previously shown along 51W has
been repositioned to 59W from 03N-14N, moving W at 15 kt.
Scattered moderate convection is from 07N-13N between 52W-64W. An
upper-level trough over the Caribbean is enhancing the convection
west of 60W.

A central Caribbean tropical wave is along 75/76W from 09N-21N,
moving W around 15 kt. Scattered moderate convection is noted over
Haiti, NW Venezuela, and N Colombia. Isolated showers are within
120 nm of the wave axis.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of southern Guinea near
09N13W to 07N17W, ending near 08N21W. There is a break in the
monsoon trough. Further north, the monsoon trough begins again
near 15N21W to the 1007 mb low near 18N31.5W to 13N40W to 09N49W.
The ITCZ extends from 09N49W to 07N57W. Aside from the convection
mentioned in sections above, scattered moderate with embedded
isolated strong convection is along the coast of W Africa and
offshore from 03N-12N between 08W-20W.

GULF OF MEXICO...

Refer to the Special Features section above for details on
Tropical Storm Fernand in the western Gulf of Mexico.

Scatterometer data depicts moderate easterly winds across most of
the basin, with strong winds near Tropical Storm Fernand.
Elsewhere, a feeder band from Hurricane Dorian has scattered
showers and isolated tstorms over the SE Gulf and the Straits of
Florida from 23N-25N, east of 85W. Strong subsidence is over the
NE Gulf of Mexico.

CARIBBEAN SEA...

Refer to the section above for details on the tropical wave
currently across the central Caribbean.

A N-S inverted upper-level trough is over the central Caribbean
near 70W. Moisture on the east side of the upper-trough axis is
enhancing scattered moderate convection from 09N-14N, east of 65W,
including the Windward Islands, NE Venezuela and Trinidad. This
convection is also being enhanced by the tropical wave along 59W.
In the SW Caribbean, the East Pacific monsoon trough is enhancing
scattered moderate convection south of 12N between 77W-83W,
including portions of Panama. Latest ASCAT pass depicts fresh
trades in the central Caribbean to the east of the wave along 76W.

The tropical wave over the central Caribbean will reach the
western Caribbean Wed and exit west of the Caribbean Fri night.
Moderate to fresh winds are expected across the eastern and
central Caribbean, with gentle to moderate winds prevailing over
the NW Caribbean.

ATLANTIC OCEAN...

Refer to the sections above for details on Hurricane Dorian, two
disturbances, and three tropical waves.

A surface trough is over the central Atlantic from 31N40W to
27N48W. Scattered showers are within 60 nm of the trough.

$$
Hagen
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