[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141805
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT Fri Sep 14 2018

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
1745 UTC.

...SPECIAL FEATURES...

The center of Hurricane Florence at 14/1800 UTC is near 34.0N
78.4W, or 55 km WSW of Wilmington in North Carolina. FLORENCE is
moving WSW, or 245 degrees, 03 knots. The estimated minimum
central pressure is 968 mb. The maximum sustained wind speeds are
70 knots with gusts to 85 knots. FLORENCE made landfall earlier
today, around the time of sunrise, in the SE part of the coastal
areas of North Carolina. Scattered to numerous strong rainshowers
are from 33N to 35N between 76W and 79W. Scattered moderate to
strong rainshowers are elsewhere from 32N to 38N between 73W and
82W. The PUBLIC ADVISORIES for Florence are transmitted via the
WMO header WTNT31 KNHC, and via the AWIPS header MIATCPAT1.
The FORECAST/ADVISORIES for Florence are transmitted via the WMO
header WTNT21 KNHC, and via the AWIPS header MIATCMAT1.

The center of Tropical Storm Helene at 14/1800 UTC is near 33.8N
37.1W. HELENE is moving N, or 010 degrees, 20 knots. The
estimated minimum central pressure is 988 mb. The maximum
sustained wind speeds are 60 knots with gusts to 75W knots.
Scattered moderate to isolated strong rainshowers are from 31N to
33N between 42W and 45W. The PUBLIC ADVISORIES for Helene are
transmiteed via the WMO header WTNT33 KNHC, and via the AWIPS
header MIATCPAT3. The FORECAST/ADVISORIES for Helene are
transmitted via the WMO header WTNT23 KNHC, and via the AWIPS
header MIATCMAT3.

The center of Tropical Storm Joyce at 14/1500 UTC is near 31.6N
44.6W. JOYCE is moving southward, or 180 degrees, 07 knots.
The estimated minimum central pressure is 1003 mb. The maximum
sustained wind speeds are 35 knots with gusts to 45 knots.
Scattered moderate to isolated strong rainshowers are from 33N to
35N between 35W and 40W. The PUBLIC ADVISORIES for Joyce are
transmitted via the WMO header WTNT35 KNHC, and via the AWIPS
header MIATCPAT5. The FORECAST/ADVISORIES for Joyce are
transmitteed via the WMO header WTNT25 KNHC, and via the AWIPS
header MIATCMAT5.

The center of Tropical Depression Isaac at 14/1500 UTC is near
14.9N 67.3W. ISAAC is moving westward, or 270 degrees, 14 degrees.
The estimated minimum central pressure is 1007 mb. The maximum
sustained wind speeds are 30 knots with gusts to 40 knots.
Numerous strong rainshowers are from 13N to 17N between 66W and
69W. Widely scattered to scattered moderate and isolated strong
rainshowers are elsewhere in the Caribbean Sea between 60W and
70W. The PUBLIC ADVISORIES for ISAAC are transmitted via the WMO
header WTNT34 KNHC, and via the AWIPS header MIATCPAT4. The
FORECAST/ADVISORIES for ISAAC are transmitted via the WMO header
WTNT24 KNHC, and via the AWIPS header MIATCMAT4.

Scattered moderate to isolated strong rainshowers are in the
western part of the Gulf of Mexico, from the upper Texas Gulf
coast, at the border with Louisiana, southward, into the SW corner
of the Gulf of Mexico, from 90W westward. A surface trough is
along 96W/97W from 28N southward. A 1008 mb low pressure center is
along the trough near 26N, off the coast of the Deep South of
Texas. The system is almost onshore in Texas. Heavy rainfall and
gusty winds are likely across parts of northeastern Mexico and
Texas through Saturday. Residents and anyone with interests in
these areas should monitor the progress of this system, and refer
to weather bulletins and forecasts from their local weather
office. Please read the latest TROPICAL WEATHER OUTLOOK, that is
listed under the WMO header ABNT20 KNHC, and under the AWIPS
header MIATWOAT, for more details.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 29W/30W from 21N
southward. Any nearby precipitation, from 10N southward, is part
of the monsoon trough precipitation. Rainshowers are possible
within 60 nm to 120 nm on either side of the tropical wave from
10N to 21N.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from Mauritania in W Africa near
18N16W to 11N22W to 08N32W. The ITCZ continues from 08N32W to
10N48W to 15N60W. Aside from the convection associated with the
tropical wave near 28W, scattered moderate and isolated strong
convection is occurring from 05N to 07N between 16W and 21W.

...DISCUSSION...

GULF OF MEXICO...

Please refer to the SPECIAL FEATURES section for details about
a western Gulf of Mexico area of disturbed weather.

An upper level cyclconic circulation center is in the north
central/NE part of the Gulf of Mexico. Upper level cyclonic wind
flow covers the NE corner of the area. Isolated moderate
rainshowers covers the Gulf of Mexico from 23N northward from 90W
eastward.

A NW-to-SE orientated surface ridge will set up from central
Louisiana to Florida Bay tonight. A surface high pressure center
will develop along the ridge near 27N92W late on Saturday. The
surface high will shift slightly southward on Sunday, and the
ridge will extend southeastward to the Yucatan Basin. A weak
surface trough, extending southwestward from the remnants of
tropical cyclone Florence, will pass eastward, slowly, across
the north central Gulf waters through early next week.

CARIBBEAN SEA...

Please refer to the the SPECIAL FEATURES section for details
about Tropical Storm Isaac. Tropical Depression ISAAC is
influencing the weather in the eastern one-third of the
Caribbean Sea.

An upper level cyclonic circulation center is about 100 nm to the
west of Jamaica, in the NW corner of the Caribbean Sea. Isolated
moderate rainshowers are from 15N northward from 80W westward.

Isolated moderate rainshowers cover the area that is between
70W and 80W.

Tropical Depression Isaac near 14.9N 67.3W 1007 mb at 11 AM EDT
moving W at 14 kt. Maximum sustained winds 30 kt gusts 40 kt.
Isaac will move to 15.0N 69.0W this evening, 15.1N 71.3W Sat
morning, 15.2N 73.3W Sat evening, 15.6N 75.3W Sun morning, 17.0N
79.5W Mon morning and dissipate early Tue. The highest winds and
seas are expected mainly north of the center. Expect gentle to
moderate trade winds elsewhere, to the west of Isaac. Moderate
to locally fresh trade winds are forecast to the east of Isaac.
Strong nocturnal trade winds are forecast off the northwest coast
of Colombia on Monday night and on Tuesday night.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section, for details about
Hurricane Florence, Tropical Storm Helene, and Tropical Storm
Joyce.

An upper level trough extends from 31N45W to 26N48W to 20N54W,
and to 16N56W. Upper level cyclonic wind flow is within 360 nm on
either side of the trough. Isolated moderate rainshowers are
in the area of upper level cyclonic wind flow.

Hurricane Florence inland north of area at 34.0N 78.0W 958 mb at
11 AM EDT moving W-SW at 3 kt. Maximum sustained winds 70 kt gusts
85 kt. Florence will move to near 33.9N 78.9W this evening, near
33.8N 79.7W Sat morning, near 33.9N 80.8W Sat evening, weaken to
a tropical depression near 34.7N 82.0W Sun morning and continue
to move away from area. A surface ridge will meander from 31N69W
to southeast Florida through Sunday. The ridge will shift
northward, to a position from 31N74W to central Florida by the
middle of the next week.

For additional information please visit
http://www.hurricanes.gov/marine

$$
MT
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