[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 061757
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
205 PM EDT TUE SEP 6 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...

Post-tropical cyclone Hermine is centered near 39.4W 72.3W at
06/1800 UTC or about 105 nm south of the eastern tip of Long
Island moving west at 6 kt. The estimated minimum central
pressure is 999 mb. Maximum sustained wind speed is 45 knots
with gusts to 55 knots. Scattered to numerous showers are over
southeast Massachusetts, Rhode Island, Connecticut, and eastern
Long Island. Hermine is expected to continue to weaken as it
takes a slow and erratic motion during the next 24 hours. This
is the last advisory issued by the National Hurricane Center.

...TROPICAL WAVES...

Tropical wave off the coast of Africa extends along 19W from 6N-
17N moving west near 15 to 20 kt over the past 12 hours. Wave is
embedded within a surge of moisture as seen on the Total
Precipitable Water Imagery, however the wave is also embedded
within a surge of Saharan dust and dry air at the lower levels.
This is limiting convection to the south portion of the wave.
Scattered moderate to isolated strong convection is from 8N-11N
between 17W-22W.

Tropical wave in the central Atlantic extends along 39W/40W from
7N-20N moving west near 10 kt over the past 24 hours. Wave is
embedded within a narrow surge of moisture as seen on the Total
Precipitable Water Imagery. Wave is also along the leading edge
of a surge of Saharan dust and dry air at the lower levels. This
is limiting any showers or deep convection.

Tropical wave in the Caribbean extends along 69W/70W from 21N
across the Dominican Republic to the over northwest Venezuela
moving west 10 to 15 kt over the past 24 hours. Wave is embedded
within a surge of moisture as seen on the Total Precipitable
Water Imagery and is at the southwest side of an upper ridge
enhancing the associated convection. Scattered to numerous
showers and isolated thunderstorms are from 16N to over
Hispaniola between 68W-71W and within 30/45 nm of 16N from 71W-
73W.

Tropical wave in the south Gulf of Mexico and the Bay of
Campeche extends along 95W south of 20N to across south Mexico
moving west near 15 kt over the past 24 hours. Wave is embedded
within an area of moisture as seen on the Total Precipitable
Water Imagery. Scattered showers and isolated thunderstorms are
within 75 nm along the coast of Mexico from Tuxpan to Veracruz.
This wave will be moving out of the Gulf waters by tonight.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends across Africa into the east Tropical
Atlantic near 15N17W and continues along 14N20W 8N23W to 9N38W.
The ITCZ begins near 10N46W and continues to inland over South
America near 9N61W. A 1012 mb low is in the central Tropical
Atlantic near 13N46W generating small clusters of scattered
moderate to isolated strong convection from 12N-16N between 42W-
49W. Scattered moderate to isolated strong convection is from 4N-
9N between 31W-35W. Isolated moderate convection dots the area
within 120 nm of a line from 5N24W to the coast of Africa near
9N14W.

...DISCUSSION...

...GULF OF MEXICO...

A large upper ridge dominates the Gulf waters this afternoon
anchored over northeast Louisiana and extending a ridge axis
south to the Yucatan peninsula. A weak surface ridge extends
from over the southeast CONUS into the Gulf of Mexico anchored
by a series of surface highs over West Virginia and North
Carolina and a 1022 mb high over southwest Mississippi. A mid
level shortwave trough extends from 28N90W over south Louisiana
to Lake Charles generating isolated showers and possible
thunderstorms north of 27N to over the north Gulf coast between
87W-94W. An upper trough over the west Atlantic is supporting a
surface trough that extends to over south Florida generating
isolated showers and possible thunderstorms from 23N-26N east of
84W into the Straits of Florida including the Florida Keys.
Easterly surface flow across the central Gulf is generating
isolated showers from 23N-27N between 83W-96W. The surface ridge
will persist through late in the week. Tropical wave will move
out of the Gulf tonight. The next tropical wave will reach the
southeast Gulf off the Yucatan peninsula on Friday.

...CARIBBEAN SEA...

The main focus this afternoon is the tropical wave that extends
from the Dominican Republic to Venezuela. See tropical waves
above. An elongated upper low extends from central Cuba to
Honduras centered over the Cayman islands. A broad upper ridge
is anchored north of the Virgin Islands covering the remainder
of the Caribbean. The area southeast of the upper low and
southwest of the upper ridge is covered by scattered to numerous
showers and isolated thunderstorms from 12N-14N west of 77W to
inland over Nicaragua and from 14N-16N between 82W-85W including
northeast Honduras. Isolated showers and possible thunderstorms
are over the Windward Islands south of 14N between 60W-64W. This
is leaving the remainder of the Caribbean under mostly clear
skies this afternoon. The tropical wave is expected to weaken as
it moves across the central and west Caribbean today through
Thursday, then across the Yucatan peninsula early Friday. The
next tropical wave will enter the east Caribbean Thursday night.

...HISPANIOLA...

Scattered to numerous showers and isolated thunderstorms are
moving across the island west of 71W due a tropical wave. This
activity is expected to continue spread west to over the
remainder of the island through tonight. Showers and
thunderstorms will dissipate from east to west through Thursday
as the tropical wave tracks westward.

...ATLANTIC OCEAN...

Post-tropical cyclone Hermine is north of the forecast waters.
Please see the Special Features section above for details. An
upper trough covers the west Atlantic supporting an occluded
front that extends from Post-Tropical Hermine with a stationary
front extending to 32N68W. A surface trough continues from
32N68W along 29N73W to over south Florida near Fort Lauderdale.
Scattered to numerous showers and isolated thunderstorms are
from 25N-28N west of 76W to over the Florida peninsula.
Scattered showers are possible isolated thunderstorms are within
60 nm of the remainder of the surface trough. A shortwave upper
trough extends from 28N65W to beyond 32N66W generating scattered
showers and isolated thunderstorms north of 29N between 63W-65W.
A surface trough extends from 32N55W to 25N57W and is generating
scattered showers within 75 nm of a line from 28N50W to 31N57W.
A second surface trough extends along 45W from 21N-25N is
generating isolated showers from 21N-24N between 46W-48W. A
broad upper trough over the east Atlantic is supporting a cold
front that extends through 32N32W to 30N37W where it dissipates
as a stationary front along 29N43W to 30N48W. A pre-frontal
surface trough extends from 32N29W to 25N37W. Any shower
activity is north of the discussion area. A weak 1021 mb high is
to the east of the above front/trough near 28N27W. The west
Atlantic surface trough will drift north Wednesday and Thursday
while dissipating. The tropical wave moving across the Dominican
Republic will support fresh to locally strong northeast to east
winds south of 22N west of 70W through Wednesday.

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

$$
PAW
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