[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 190005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Tue Sep 18 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 1800 UTC surface analysis and satellite imagery through
2330 UTC.

...SPECIAL FEATURES

The center of Tropical Depression Joyce at 18/2100 UTC is near
30.9N 27.8W. JOYCE is moving SSW, or 205 degrees, 06 knots.
The estimated minimum central pressure is 1010 mb. The maximum
sustained wind speeds are 25 knots with gusts to 35 knots. Widely
scattered moderate to isolated strong rainshowers are from 31N to
32N between 26W and 27W. 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.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 15W/16W from 23N
southward, partially in Africa and partially in the ocean.
The accompanying precipitation is in Africa.

An Atlantic Ocean tropical wave is along 59W/60W from 19N
southward. Isolated moderate to locally strong rainshowers cover
the Atlantic Ocean and the Caribbean Sea from 10N to 20N between
54W and 63W.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal areas of Guinea-
Bissau near 12N16W, to 09N20W. The ITCZ continues from 09N20W
to 08N30W, 08N40W, and to 06N56W. Scattered moderate to isolated
strong rainshowers are within 180 nm on either side of the line
that runs from 08N13W 05N30W 05N37W 10N46W. Isolated moderate
rainshowers are elsewhere from 13N southward between Africa and
60W.

...DISCUSSION...

GULF OF MEXICO...

A weak 1015 mb surface high is over the western Gulf near 27N94W.
Another 1017 mb surface high is centered over northern FL near
30N82W. Light to gentle breezes and minimal seas will continue
over most of the Gulf during the next few days. An upper-level low
is near 26N94W with upper-level cyclonic flow covering the
western Gulf. A surface trough, associated with the remnants of
Isaac, is over the northwest Caribbean along 83W from western Cuba
to near Cabo Gracias a Dios, Nicaragua.

Weak high pressure extends across the northern Gulf,
supporting light breezes and minimal seas. A trough over the
northwest Caribbean will move across the Yucatan Channel through
Wed, into the southwest Gulf Thu and Fri, then dissipating Sat.

CARIBBEAN SEA...

A trough over the northwest Caribbean along 83W from western Cuba
to near Cabo Gracias a Dios, Nicaragua is associated with the
remnants of Isaac. Scattered moderate convection is within 60 nm
west and 120 nm east of the trough axis from 17N-21N. The trough
will move west of the area on Wednesday.

A trough in the northwest Caribbean will pass west of the area
through Wed. A tropical wave near Barbados will move into the
eastern Caribbean tonight, the central Caribbean Thu into Fri, and
pass west of the area through late Sat into Sun. Meanwhile high
pressure building from the central Atlc into the central Bahamas
will support moderate to fresh trade winds and building seas
across the entire basin late Wed through Fri.

ATLANTIC OCEAN...

Please refer to the Special Features section for details on
Tropical Depression Joyce.

An upper-level low with a surface reflection is spinning just
south of Bermuda. A surface trough extends from this feature
southwestward to the southeastern Bahamas. Scattered showers and
thunderstorms are located along and east of the trough axis west
of 65W. This convective activity is affecting the southeast
Bahamas and the Turks and Caicos Islands. Abundant cloudiness and
showers extend elsewhere east of the trough from 20N-31N between
56W-65W. The surface trough will likely weaken over the next
24-48 hours. Another trough extends into the forecast area from
T.D. Joyce southward to near 21N32W. A narrow band of mainly low
clouds with showers is associated with the trough. A 1023 mb
surface high is located in between the two aforementioned troughs
near 31N47W.

A surface trough reaching from roughly Bermuda to
the southern Bahamas will shift slowly NW and weaken through
tonight as the central Atlantic ridge builds into the central
Bahamas. Low pressure moving off the Carolinas will drag an
attendant frontal trough across the waters north of 27N Thu and
Fri. The low will move to near 31N71W Fri evening then drift W
and slowly weaken Sat and Sun.

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

$$
mrf/ec/mt
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