[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141744
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
144 PM EDT WED SEP 14 2016

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...
Tropical Storm Julia is centered near 31.8N 80.8W at 14/1800 UTC
or about 20 nm SE of Savannah Georgia moving NE at 5 kt.
Estimated minimum central pressure is 1011 mb. Maximum sustained
wind speed is 35 kt with gusts to 45 kt. Scattered moderate
convection is from 28N-34N between 75W-81W. See latest NHC
Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT1/
WTNT31 and the full forecast/advisory under AWIPS/WMO headers
MIATCMAT1/WTNT21 KNHC for more details.

Tropical Storm Ian is centered near 31.4N 53.0W at 14/1500 UTC or
about 600 nm E of Bermuda moving N at 17 kt. Estimated minimum
central pressure is 998 mb. Maximum sustained wind speed is 45 kt
with gusts to 55 kt. Scattered moderate convection is from 32N-37N
between 48W-57W. See latest NHC forecast/advisory under AWIPS/WMO
headers MIATCMAT5/WTNT25 KNHC for more details.

Tropical Depression Twelve is centered near 17.0N 25.0W at
14/1500 UTC or about 80 nm NW of the Cape Verde Islands moving
W-NW at 12 kt. Estimated minimum central pressure is 1009 mb.
Maximum sustained wind speed is 30 kt with gusts to 40 kt.
Scattered moderate and isolated strong convection is from 15N-20N
between 22W-27W. Scattered moderate convection is elsewhere from
12N-15N between 22W-31W. See latest NHC forecast/advisory under
AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC for more details.

...TROPICAL WAVES...
Tropical wave extends from 10N42W to 19N43W moving W at 15 kt.
The wave is likely the hybrid feature of an African easterly wave
that emerged off the coast of Africa a few days ago and mid-
latitude energy that moved SW away from a middle to upper level
trough currently across western Europe. Widely scattered moderate
convection remains confined to the southern portion of the wave
axis in close proximity to the Monsoon Trough axis from 07N-11N
between 40W-44W.

...ITCZ/MONSOON TROUGH...
The Monsoon Trough extends from 16N25W to 08N48W. The
Intertropical Convergence Zone axis extends from 08N48W to 06N56W.
Aside from convection associated with Tropical Depression Twelve
and the tropical wave along 43W...widely scattered moderate
convection is within 180 nm either side of the axis between 33W-
56W.

...DISCUSSION...

GULF OF MEXICO...
Water vapor imagery indicates a middle to upper level trough over
the central Gulf focused in the vicinity of 25N91W with axis
extending S-SE to over the Yucatan peninsula region. The
troughing aloft supports a weak 1013 mb low centered across the NW
Gulf waters near 27N92W and a surface trough extending from the
low eastward to 28N85W. Low-level moisture convergence along and
to the south of the trough axis across the eastern Gulf and
favorable middle to upper level dynamics are generating scattered
showers and tstms from 23N-28N between 85W-93W. Isolated showers
and tstms are elsewhere across much of the eastern and
northwestern Gulf waters within a relatively broad and weak area
of lower surface pressure values. The overall weak pressure
gradient is resulting in mostly gentle to moderate cyclonic winds
as the 1013 mb low is forecast to drift westward towards the Texas
coast through Thursday night into Friday. Elsewhere...gentle to
moderate E-SE winds are anticipated Thursday through the
remainder of the week into the upcoming weekend as surface ridging
re- establishes itself across the SE CONUS.

CARIBBEAN SEA...
Overall the Caribbean basin remains fairly tranquil this
afternoon. On water vapor imagery...an upper level low and
associated troughing is noted over the central Caribbean centered
SW of Hispaniola near 17N75W with the trough axis extending NE to
over the Turks and Caicos Islands...and to the S-SE over the SW
Caribbean near 12N76W. Much of the western Caribbean is under the
influence of NE flow aloft with only a few isolated showers and
tstms occurring across the NW Caribbean...notably in the vicinity
of Jamaica and the Cayman Islands. To the east of the trough
axis...moist S-SW flow is advecting moisture and cloudiness across
the SE Caribbean with isolated showers and tstms occurring across
the ABC Islands and adjacent coastal waters including S of 13N
between 62W-71W. Otherwise...gentle to moderate trades prevail
and are expected to persist through the remainder of the week.
One exception...occasional fresh trades are anticipated to
develop across the south-central Caribbean Thursday generally S of
13N between 67W-74W...and pulse to fresh breeze conditions in the
early morning hours off the coast of Colombia through early next
week.

...HISPANIOLA...
An upper level low is centered SW of the island near 17N75W with a
trough axis extending NE to over the Turks and Caicos Islands. The
upper level low continues to provide relatively dry and stable
conditions aloft...however a few isolated afternoon and evening
showers are possible within gentle to moderate trades...however no
significant prolonged convection is expected.

ATLANTIC OCEAN...
Aside from Tropical Storm Julia...the remainder of the SW North
Atlc is under the influence of weak and broad ridging supported
aloft by an upper level anticyclonic circulation centered near
28N79W. Water vapor imagery indicates fairly dry air within N-NE
winds on the eastern periphery of the upper level ridge resulting
in mostly clear skies and fair conditions N of 20N W of 60W. One
exception is a weakening shortwave mid-level trough noted in the
vicinity of 31N62W. A surface trough is analyzed from 29N65W to
31N61W as a reflection of the shortwave with isolated showers
occurring from 28N-32N between 60W-65W. While Tropical Storm Ian
continues to move N of the discussion area in the central Atlc...a
trailing line of scattered showers and isolated tstms is within 60
nm either side of a line from 30N49W to 20N52W. South of this
convergence line a surface trough extends from 21N54W to NW of
Barbados near 13N60W. Isolated showers are noted within 90 nm W of
the boundary. Otherwise...the remainder of the eastern Atlc is
under the influence of a broad surface ridge generally N of 23N
anchored by a 1027 mb high centered SE of the Azores near 36N24W.

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

$$
HUFFMAN
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