[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 131753
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
153 PM EDT TUE SEP 13 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 Ian is centered near 25.4N 52.3W at 13/1500 UTC or
about 780 nm E-SE of Bermuda moving N-NW at 11 kt. Estimated
minimum central pressure is 1005 mb. Maximum sustained wind speed
is 40 kt with gusts to 50 kt. Scattered moderate convection is
within 210 nm NE of a line from 24N48W to 27N55W. See latest NHC
forecast/advisory under AWIPS/WMO headers MIATCMAT5/WTNT25 KNHC
for more details.

An upper level trough is over the eastern Gulf of Mexico and to
the east...an upper level ridge extends from over western Cuba NE
to 31N75W. The upper level troughing supports a 1011 mb low
centered near Cape Canaveral Florida with numerous showers and
scattered tstms occurring N of 25N W of 76W...including the
eastern coast of the Florida peninsula. The low is expected to
track N-NW and nearly parallel the Florida coast through the
overnight hours. Gusty winds and heavy rainfall will continue
across northern Florida.

...TROPICAL WAVES...
Tropical wave extends from 13N21W to 20N23W moving W at 10-15 kt.
A 1010 mb low is centered at the southern extent of the wave axis
and remains embedded within the Monsoon Trough. Convection
continues to organize and currently forms two bands of scattered
moderate convection from 11N-15N between 19W-27W...and from 15N-
18N between 18W-24W. The low is expected to track W-NW across the
southern Cape Verde Islands and bring increased precipitation and
possible gusty winds to the islands through Wednesday night.

Tropical wave extends from 11N35W to 20N35W moving W at 10-15 kt.
The wave is likely the merging 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 moving across western Europe. Scattered moderate
convection remains confined to the southern portion of the wave
axis in close proximity to the Monsoon Trough axis from 08N-12N
between 35W-41W.

...ITCZ/MONSOON TROUGH...
The Monsoon Trough extends from the Africa coast near 14N17W to
13N30W to 06N44W. Aside from convection associated with the
tropical waves...widely scattered moderate convection is elsewhere
from 04N-12N between 23W-48W.

...DISCUSSION...

GULF OF MEXICO...
Water vapor imagery indicates a middle to upper level trough over
the eastern Gulf with axis extending from over the Florida
panhandle southward along 87W to a base over the NE tip of the
Yucatan peninsula. The troughing aloft supports two separate areas
of weather this afternoon...one focused around a 1011 mb low
centered near Cape Canaveral Florida and the other a 1011 mb low
centered in the central Gulf near 25N90W. These areas of lower
pressure are linked together by a surface trough axis extending
from the Florida peninsula low to Port Charlotte then westward to
the central Gulf low. Widely scattered showers and isolated tstms
are occurring across the north-central Gulf from 24N-30N between
87W91W. Most of the convection with the Florida peninsula low is
occurring across the near shore and offshore Atlc waters.
Otherwise...the surface troughing extends from the central portion
of the basin westward to the area in the vicinity of Brownsville
Texas. Mostly clear skies prevail currently...however the central
Gulf feature is expected to drift westward to the Texas coast
through late Thursday night into Friday. Gentle to moderate E-SE
winds are anticipated through the remainder of the week.

CARIBBEAN SEA...
Overall the Caribbean basin remains fairly tranquil this
afternoon. On water vapor imagery...a broad upper level low and
associated troughing is noted over the central Caribbean near
15N73W with the trough axis extending from over Hispaniola to over
the northern Colombia coast. Much of the western Caribbean is
under the influence of NE flow aloft with only a few isolated
showers and tstms occurring N of 19N between 81W-88W in an area of
maximum middle to upper level diffluence. To the east of the
trough axis...moist S-SW flow is advecting moisture and cloudiness
across the eastern Caribbean with possible isolated showers and
tstms occurring in the adjacent coastal waters of Hispaniola N of
16N between 68W-71W. Otherwise...gentle to moderate trades prevail
and are expected to persist through the remainder of the week.

...HISPANIOLA...
Upper level troughing is noted on water vapor imagery over the
island...and continues to provide relatively dry and stable
conditions aloft. A few isolated afternoon and evening showers are
possible within gentle to moderate trades...however no
significant prolonged convection is expected.

ATLANTIC OCEAN...
An upper level trough is over the eastern Gulf of Mexico and to
the east...an upper level ridge extends from over western Cuba NE
to 31N75W. The upper level troughing supports a 1011 mb low
centered near Cape Canaveral Florida with numerous showers and
scattered tstms occurring N of 25N W of 76W...including the
eastern coast of the Florida peninsula. The remainder of the SW
North Atlc is under the influence of a weak surface ridge anchored
by a 1021 mb high centered off the coast of the Carolinas near
33N73W. Aside from Tropical Storm Ian...a surface trough trails to
the south of the cyclone analyzed from 19N53W to 11N59W. Shallow
moisture is noted in water vapor imagery...however deeper moisture
and scattered showers and tstms are occurring across Trinidad and
Tobago...and portions of NE Venezuela from 09N-12N between 58W-
63W. Finally...the remainder of the eastern Atlc is under the
influence of a weak surface ridge anchored by a 1022 mb high
centered near 31N39W. A weakening frontal boundary extends from
the Madeira Islands near 32N15W westward to 33N34W...however
exhibits little sensible weather at this time.

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

$$
HUFFMAN
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