[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 080005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Fri Sep 7 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...

Tropical Storm Florence is centered near 24.8N 52.5W at 2100 UTC
or 710 nm NE of the northern Leeward Islands, moving W at 7 kt.
Estimated minimum central pressure is 996 mb. Maximum sustained
winds are 55 kt with gusts to 65 kt. Scattered moderate to strong
convection is within 120 nm north of the center. Florence is
expected to move west and intensify to a minimal hurricane by Sat.
See the latest NHC forecast/advisory under AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

Tropical Depression Eight is centered near 13.2N 18.6W at 2100
UTC or 270 nm ESE of the Cabo Verde Islands, moving W at 9 kt.
Estimated minimum central pressure is 1002 mb. Maximum sustained
winds are 30 kt with gusts to 40 kt. Scattered moderate
convection is noted within 90 nm of the center. See latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC
for more details.

Tropical Depression Nine is centered near 13.6N 34.9W at 2100 UTC
or 950 nm E of the Windward Islands, and stationary. Estimated
minimum central pressure is 1007 mb. Maximum sustained winds are
30 kt with gusts to 40 kt. Scattered moderate convection is noted
within 120 nm NW of the center. See latest NHC forecast/advisory
under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details.

...TROPICAL WAVES...

All previous tropical waves in the Atlantic have transitioned in
tropical cyclones, namely Tropical Depression Eight and Tropical
Depression Nine.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from 13N17W through T.D. Eight and T.D.
Nine to 09N48W. The ITCZ begins from this point to 09N61W. Aside
from the convection related to the tropical depressions, scattered
moderate convection is from 09N to 12N between 22W and 27W.

...PREVIOUS DISCUSSION...

GULF OF MEXICO...

Upper-level cyclonic flow is located over eastern Louisiana and
southern Texas and strong northeast upper-level winds are over
eastern Gulf of Mexico along the western periphery of the large
upper low that is over the northwestern Bahamas. A moist and
unstable atmosphere along with plenty available instability is
allowing for scattered showers to be over much of the eastern
Gulf waters mainly east of 87W. Expect for this activity to
remain through at least tonight.

Weak ridging from the Carolinas to the Texas coast will shift
northward through Sat, supporting gentle to moderate easterly
winds and modest seas into early next week. The exception will be
fresh winds pulsing off west of the Yucatan peninsula, mainly
during the late evenings through the next few days due to the
thermal trough that will develop over the Yucatan Peninsula and
move west over the Bay of Campeche.

CARIBBEAN SEA...

An upper-level trough axis stretches from western Cuba to northeastern
Honduras. Associated cyclonic flow covers the western Caribbean
west of a line from Hispaniola to Panama. Upper-level
anticyclonic flow covers the eastern Caribbean as the culprit
anticyclone remains anchored near 15N68W. At this time, scattered
moderate convection is noted south of 16N between 75W-81W.

A relatively weak surface ridge in the western Atlantic Ocean
will maintain moderate to fresh trade winds in most of the region
into Sun. Building high pressure over the eastern Gulf of
Mexico will allow fresh to strong E to SE winds and building
seas over portions of the NW Caribbean late Sun and Mon.

ATLANTIC OCEAN...

Please read the Special Features section above for details about
T.S. Florence, T.D. Eight, and T.D. Nine.

A large upper-level low centered over South Florida and the
northwestern Bahamas extends a trough southwestward across west
Cuba. The low continues progressing in a westward motion. Its
associated upper-level cyclonic flow covers the Atlantic west of
66W, and northward to about 35N. A surface trough is analyzed
from 31N79W to 24N80W. Another surface trough is analyzed from
near 31N71W to 27N73W. Scattered showers prevail west of 74W while
scattered to numerous moderate convection is noted north of 30N
between 62W-75W.

A weak pressure pattern will maintain gentle to moderate easterly
winds across the western Atlantic area into early next week.
Tropical Storm Florence is forecast by the latest NHC advisory to
move across the northeastern NHC/TAFB offshore waters zones Mon
through Tue of next week. Easterly swell, in advance of Florence,
are forecast to propagate through the open waters east of the
Bahamas beginning this upcoming weekend.

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

$$

Mundell
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