[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061804
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
203 PM EDT Thu Sep 6 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
1715 UTC.

...SPECIAL FEATURES...

Hurricane Florence is centered near 24.6N 48.6W at 06/1500 UTC or
970 nm ESE of Bermuda, moving NW at 9 kt. Estimated minimum central
pressure is 975 mb. Maximum sustained wind speed is 90 kt with
gusts to 110 kt. Scattered moderate convection is noted from 23N-
28N between 44W-50W. The latest forecast calls for Florence to
move slowly WNW with some additional weakening during the next 24
hours. See latest NHC forecast/advisory under AWIPS/WMO headers
MIATCPAT1/WTNT31 KNHC for more details.

A broad and elongated area of low pressure is centered several
hundred miles west-southwest of the Cabo Verde Islands near 13N32W.
A tropical wave extends along 32W between 03N20N. The associated
shower and thunderstorm activity has not yet increased in
organization. However, environmental conditions are conducive for
development, and a tropical depression is expected to form within
the next day or two while the system moves slowly westward or
west-northwestward across the tropical Atlantic. The chance of
this system becoming a tropical cyclone during the next 48 hours
is high. Please read the latest NHC Tropical Weather Outlook under
AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more information.

...TROPICAL WAVES...

A tropical wave is just inland along the coast of western Africa.
In advance of this tropical wave, a large area of scattered
moderate to isolated strong convection is offshore the coast of
Africa from Senegal to Sierra Leone, extending from the coast of
Africa to 21W. The tropical wave is forecast to move off the west
coast of Africa by early Fri.

A tropical wave is located along 32W from 20N to a 1008 mb low
discussed above in the special features section to 3N.

A tropical wave has its axis along 92W and south of 21N through
southeastern Mexico, extending southward to the eastern Pacific
near 05N, moving westward at 15 kt. No convection is noted with
the wave in the Bay of Campeche, with isolated showers over
southeastern Mexico.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of Senegal
near 14N17W, to the 1008 mb low that is discussed in the Special
Features section along 32W. It continues from this low to 08N40W.
The ITCZ extends from 08N40W to 07N45W to 08N55W. Aside from the
convection described above associated with the two tropical waves
along 32W and the west coast of Africa, no other significant
convection is noted.

...DISCUSSION...

GULF OF MEXICO...

Upper level cyclonic flow is located over eastern Louisiana and
Mississippi while upper-level anticyclonic flow is located over
the west-central Gulf of Mexico. Scattered moderate convection is
noted off the Texas and Louisiana coasts north of 28N and west of
90W. Scattered moderate convection is also over the southwestern
Gulf south of 24N and west of 94W. Isolated showers are elsewhere
across the Gulf.

A weak surface ridge will build from the Carolinas to the coast
of Texas in the wake of Gordon. Over the southeastern two-thirds
of the Gulf of Mexico, gentle easterly winds will prevail through
Friday. Thereafter, expect gentle to moderate easterly winds and
modest seas into early next week. The exception will be fresh
winds pulsing off the west coast of the Yucatan Peninsula, mainly
during the late evening hours, due to a daily trough that sets up
in the SW corner of the Gulf of Mexico.

CARIBBEAN SEA...

Upper level cyclonic flow covers the western Caribbean Sea west
of a Hispaniola to Panama line, while upper level anticyclonic
flow covers the eastern Caribbean. Isolated to scattered moderare
rainshowers are seen from 10N-20N, 75W-85W.

A relatively weak surface ridge in the western Atlantic Ocean
will maintain moderate to fresh trade winds in most of the region
through late Sun.

ATLANTIC OCEAN...

Please read the Special Features section above for details about
Hurricane Florence. A second area of interest pertains to a
broad area of low pressure in the eastern Atlantic near 13N32W.
It has a high chance of tropical cyclone formation during the next
48 hours.

A large upper-level low located over the Bahamas and Cuba is
moving west-northwestward. Associated upper level cyclonic flow
covers the Atlantic west of 67W from the Greater Antilles to 34N.
A westward moving surface trough was placed from 31N70W to 23N75W
at 12Z. Based on surface observations, this trough was more
confidently located at 15Z from 31N73W to 23N79W. Another surface
trough was located along 65W between 27N-31N. Scattered to numerous
moderate convection is from 22N-29N between 72W-79W. Scattered
moderate convection is also seen from 28N-32N between 61W-67W.

A weak pressure pattern will maintain gentle to moderate easterly
winds across the western Atlantic area through Sun night.
Easterly swell from Hurricane Florence will move into the open
waters east of the Bahamas starting this weekend.

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

$$
HAGEN/ERA
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