[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 052348
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Tue Sep 5 2017

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
2315 UTC.

...SPECIAL FEATURES...

The center of Hurricane Irma at 06/0000 UTC is near 17.2N 60.5W,
or about 75 NM to the E of Antigua. Irma is moving W, or about
280 degrees, at 13 knots. The estimated minimum central pressure
is down to 916 mb. The maximum sustained wind speeds are 160 kt
with gusts to 195 kt. Irma is an extremely dangerous Category
Five hurricane on the Saffir-Simpson Hurricane Wind Scale and is
the strongest hurricane observed in the Atlantic basin outside
of the Caribbean and the Gulf of Mexico. Irma has a well defined
eye about 20-25 NM in diameter surrounded by numerous strong
convection within 120 nm of the center. Scattered moderate
isolated strong convection is elsewhere within 210 Nm of the
center. Conditions are rapidly deteriorating over the northern
Leeward Islands.  For additional information please read the
latest NHC Intermediate Public Advisory under AWIPS/WMO headers
MIATCPAT1/WTNT31 KNHC and the Forecast/ Advisory under AWIPS/WMO
headers MIATCMAT1/WTNT21 KNHC for more details.

The center of Tropical Storm Jose at 05/2100 UTC is near 12.5N
40.6W, or about 1215 NM E of the Lesser Antilles, moving W, or
about 280 degrees, at 10 knots. The estimated minimum central
pressure is 1006 mb. The maximum sustained wind speeds are now
40 kt with gusts to 50 kt. Numerous strong convection is within
90 NM in the SE and 60 NM in the NW semicircles.  10N-13N
between 38W-41W. Scattered moderate convection is noted
elsewhere within 180 NM in the SE and 90 NM in the NW
semicircles. The environment in which Jose is located in appears
to be quite conducive for development for the next three days as
the SSTs are very warm, the vertical shear is very low, and
there is abundant mid-level moisture. Jose may become a
hurricane Wed night or Thu. For additional information please
read the latest NHC Forecast/ Advisory under AWIPS/WMO headers
MIATCMAT2/WTNT22 KNHC for more details.

The center of newly formed Tropical Depression Thirteen is in
the near 22.4N 96.7W or about 70 NM E of Tampico, Mexico,
drifting E at 2 kt.  The estimated minimum central pressure is
1008 mb. The maximum sustained wind speeds are 30 kt with gusts
to 40 kt. Scattered strong convection was noted within 75 NM in
the E and 45 NM in the W semicircles. The upper level shear is
forecast to gradually lessen, which combined with the very warm
Gulf of Mexico waters should result in gradual strengthening. The
system could become a tropical storm on Wed. For additional
information please read the latest NHC Forecast/ Advisory under
AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details.

...TROPICAL WAVES...

A tropical wave is off the coast of W Africa. Its axis extends
from 17N21W to 06N22W, moving W at 10 kt. SSMI TPW imagery shows
the wave is in a very moist environment. The wave is also within
a distinct 700 mb trough. Convection associated with the wave
has dissipated for now. Scattered showers are noted within 120
nm of the wave axis.

A tropical wave is in the central Caribbean with axis extending
from E Cuba near 22N76W to the coast of Panama near 09N78W,
moving W at 10-15 kt. SSMI TPW imagery shows the wave is in a
moderately moist environment. The wave is also within a distinct
surface and 700 mb trough. Scattered orographically forced
thunderstorms are occuring over Cuba with weakening activity
noted over Jamaica and Hispaniola.

...ITCZ/MONSOON TROUGH...

The monsoon trough extends from the African coast near 14N17W to
10N20W to 08N25W to 10N32W. Scattered moderate convection was
noted from 05N-07N between 30W-34W.

...DISCUSSION...

GULF OF MEXICO...

See the special feature section above for additional information
on newly formed Tropical Depression Thirteen. Water vapor
imagery and 250 mb streamlines indicated that Tropical
Depression Thirteen was being sheared by moderate to strong
westerly winds between an anticyclone over Mexico near 19N101W
and and upper level shortwave trough along the Rio Grande river.
The overall flow over the Gulf was anticyclonic and diffluent in
nature providing good ventilation for the system with an
extensive area of mid to high clouds covering the entire basin.
Scattered embedded showers were noted over the central Gulf from
23N to28N between 85W and 92W. Winds were light over most of the
remainder of the Gulf of Mexico outside the immediate area of
Tropical Depression Thirteen.

CARIBBEAN SEA...

Category 5 Hurricane Irma is approaching the northern Leeward
Islands. For additional information see the Special Features
section above. The upper level outflow from Irma is expanding
over the northeastern Caribbean including Puerto Rico and the
windward islands north of Grenada. Surface observations from
Buoy 42060 show northerly winds increasing to 20-25 KT with seas
building to 10 FT. Elsewhere over the Caribbean, the tropical
wave over the central Caribbean is lacking in convection except
over Cuba, Jamaica and Hispaniola.  The eastern extent of the
East Pacific monsoon trough traverses Costa Rica and Panama
intersecting with the tropical wave.

...HISPANIOLA...

Weakening showers and thunderstorms were over the northern
interior sections of Haiti and the Dominican Republic. Upper
level subsidence ahead of Hurricane Irma was spreading westward
over the Dominican Republic. As Hurricane Irma tracks north of
Puerto Rico, upper level outflow and eventually showers and
thunderstorms will spread over the island with increasing NW to
N winds. A Hurricane Warning is in effect for the Dominican
Republic from Cabo Engano to the northern border with Haiti.
Tropical Storm warnings are is in effect for the Dominican
Republic from Cabo Engano to the southern border with Haiti.
A hurricane watch is in effect for Haiti from the northern
border with the Dominican Republic to Le Mole St. Nicholas.
Refer to Special Features above for further details.

ATLANTIC OCEAN...

Category 5 Hurricane Irma and T.S. Jose are over the Atlantic. A
tropical wave is also off the coast of W Africa. See above for
additional information. Scattered moderate convection is over
the W Atlantic from 29N-32N between 77W-80W. A Surface trough is
also over the W Atlantic from 28N73W to the central Bahamas near
23N77W. Another surface trough is over the E Atlantic from
31N33W to 24N36W. Scattered showers are within 90 nm of this
trough. A 1030 mb high is centered over the north central
Atlantic near 39N43W. Another 1028 mb high is centered over the
E Atlantic near 42N24W. These features dominated the flow to the
north of the tropical cyclones in the basin.

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

$$
Cobb
This weather bulletin was brought to you by:
www.nashvilleweather.net