[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060015 CCA
TWDAT

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
805 PM EDT Wed Sep 5 2018

Corrected Atlantic Ocean section

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
2345 UTC.

...SPECIAL FEATURES...

Hurricane Florence is centered near 22.7N 46.6W at 05/2100 UTC,
which is about 965 nm ENE of the northern Leeward Islands or 1125
nm ESE of Bermuda moving NW at 11 knots. The estimated minimum
central pressure is 953 mb. The maximum sustained are 115 kt
with gusts to 140 kt. Florence has continued to intensify during
the day and early evening as evident by its very symmetrical
cloud pattern and clear eye feature. The conventional IR imagery
and water vapor imagery reveal cirrus clouds fanning outward
over all quadrants of the cyclone as a well pronounced
anticyclone above it provides a medium for excellent exhaust of
its deep convection. Latest imagery shows scattered strong
convection within 60 nm of the center, except 30 nm in the W
quadrant. Scattered moderate isolated strong convection is
located to the NE of the center from 23N to 25N between 44W and
46W. The latest NHC advisory forecasts Florence to continue in
its present motion through Thu, before it turns to the west-
northwest Thu night as it weakens. Public Advisories for
Florence are issued under WMO/AWIPS headers WTNT31 KNHC/
MIATCPAT1. Forecast Advisories for Florence are issued under
WMO/AWIPS headers WTNT21 KNHC/MIATCMAT1.

Tropical Depression Gordon is inland over central Mississippi
centered near 32.8N 90.7W, which is about 45 miles NW of Jackson.
It is moving NW, or 320 degrees at 8 knots. The estimated minimum
central pressure is 1012 mb. The maximum sustained wind speeds
are 25 knots with gusts to 35 knots. The threat continues for
heavy rain and flooding as Gordon is expected to produce total rain
accumulations of 4 to 8 inches over the western Florida
Panhandle, southwest Alabama, central Mississippi, Arkansas,
Missouri, southern Iowa and Illinois, with isolated maximum
amounts of 12 inches through early Sat. This rainfall will cause
flash flooding across portions of these areas. Scattered moderate
isolated strong convection is occurring north of 29N between 85W
and 88W. Scattered showers and isolated thunderstorms are north
of 27N between 85W and 91W. Future information on Gordon can be
found in Public Advisories issued by the Weather Prediction Center
under AWIPS header TCPAT2, WMO header WTNT32 KWNH, and on the web
at https://www.wpc.ncep.noaa.gov. For specific local information
on Gordon for the affected states, please refer to products issued
by your located National Weather Service office.

A tropical wave has its axis along 29W from 03N to 20N. It is
moving westward at 10 to 15 kt. A 1008 mb low pressure center is
analyzed on the wave axis at 13N29N. Deep convection associated
with this system is gradually increasing. Latest satellite
imagery shows scattered strong convection in clusters ahead of
this system from 10N to 13N between 30W and 32W. Scattered
moderate convection is within 60 nm of the low in the NE
quadrant. Scattered moderate convection is within 30 nm of line
from 15N29N to 14N32W. Environmental conditions are forecast to
be increasingly conducive for additional development, and a
tropical depression is expected to form during the next couple
of days while the system moves west-northwestward across the
tropical Atlantic Ocean. 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 western Caribbean Sea tropical wave has its axis along 84W south
of 22N to across northeastern Honduras, eastern Nicaragua and to
across Costa Rica reaching to the eastern Pacific near 05N,
moving westward at 10 to 15 kt Scattered moderate convection is
within 240 nm east of the wave axis from 10N to 11N, and within
120 nm east of the wave axis from 21N to 22N. Scattered moderate
convection is over much of northern and central Honduras, and
over just about the entire country of Costa Rica. Isolated
showers and thunderstorms are elsewhere within 60 nm of the wave
axis. Scattered moderate convection is also within 120 nm east
of the wave axis from 21N to 22N.

...MONSOON TROUGH/ITCZ...

The monsoon trough passes through the coastal sections of
Mauritania near 19N16W, to the 1008 mb low that is associated with
the Special Features section tropical wave along 29N. It
continues from this system to 09N34W and to 09N40W. The ITCZ
extends from 09N40W to 08N46W and to 07N52W. Outside convection
described with the Special Features tropical wave and low along
29W, only scattered strong convection is noted within 120 nm
north of the monsoon trough between 32W and 35W. Scattered
moderate isolated strong convection is over the far eastern
Atlantic offshore the coast of Africa from 09N to 13N east of 20W
to inland the coast of Africa.

...DISCUSSION...

GULF OF MEXICO...

Upper-level cyclonic wind flow, with an inverted trough, covers
the western one-third of the Gulf of Mexico. Upper level
anticyclonic wind flow, with a ridge, covers the rest of the Gulf
of Mexico. Scattered moderate isolated strong convection is
concentrated over the western gulf to the west of 94W and south of
27N. Isolated showers and thunderstorms are elsewhere across the
gulf.

A weak surface ridge will build from the Carolinas to the coast
of Texas in the wake of Gordon. 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 wind flow covers the Caribbean Sea to the
west of the line that runs from Puerto Rico to La Peninsula de la
Guajira of northern Colombia. Isolated moderate to locally strong
rainshowers are in the area of upper level cyclonic wind flow.

The easternmost part of the eastern Pacific monsoon trough is
along 09N/10N from 74W in Colombia beyond western sections of
Costa Rica. Scattered moderate isolated strong convection is seen
from 11N to 12N between 77W and 80W.

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...Corrected

Please read the Special Features section above for details about
Hurricane Florence. A second area of interest pertains to a
developing area of broad low pressure in the far eastern
Atlantic Ocean, with a high chance of tropical cyclone formation
during the next 48 hours.

An upper-level trough extends from near Bermuda to a nearly
stationary broad upper-level low at 26N72W, and southwest to the
Windward Passage. From there it continues to Nicaragua and Costa
Rica and to southwestern Caribbean Sea. Upper-level cyclonic
wind flow covers the Atlantic Ocean from the Greater Antilles
northward from 60W westward. A surface trough is analyzed from
near 31N60W to 25N64.5W to just northeast of the eastern tip of
the Dominican Republic. Satellite imagery shows an increasing
area of scattered showers and thunderstorms from 23N to 30N
between 66W and 74W. Scattered showers and thunderstorms are
also seen south of 22N between 66W and 70W.

A weak pressure pattern will maintain gentle to moderate easterly
winds across the area through Sunday night. Easterly swell from
Hurricane Florence will move into the open waters east of the
Bahamas from late tonight through Sun.

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

$$
MT/Aguirre
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