[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060005
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Wed Sep 5 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
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 145 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 29N from 03N to 20N. It is
moving westward at 10-15 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 10-15 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...

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

An upper level trough extends from Bermuda to the Windward
Passage, toward Nicaragua and Costa Rica, into the SW corner of
the Caribbean Sea. Upper level cyclonic wind flow covers the
Atlantic Ocean from the Greater Antilles northward from 60W
westward. A surface trough is extends from 31N61W to 25N65W, to
the eastern part of the Dominican Republic. Scattered showers and
isolated thunderstorms are present in the area of cyclonic wind
flow.

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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