[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 051209
TWDAT

Tropical Weather Discussion...UPDATED
NWS National Hurricane Center Miami FL
808 AM 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 0600 UTC surface analysis and satellite imagery through
1145 UTC.

...SPECIAL FEATURES...

The center of Hurricane Irma at 05/1200 UTC is near 16.7N 57.7W,
or about 235 nm to the E of Antigua. Irma is moving W, or about
280 degrees, 12 knots. The estimated minimum central pressure is
929 mb. The maximum sustained wind speeds are 150 kt with gusts to
185 kt. NOAA and Air Force Reserve Hurricane Hunter aircraft data
indicated Hurricane Irma has intensified into an extremely
dangerous Category Five hurricane on the Saffir-Simpson Hurricane
Wind Scale. Numerous strong convection is within 120 nm radius of
the center. Isolated moderate to locally strong convection from
12N to 20N between 44W and 53W, and from 10N to 12N between 51W
and 55W. Warnings and watches have been issued for the Leeward
Islands, Virgin Islands and Puerto Rico. Some strengthening is
forecast during the next 48 hours. 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.

A tropical wave is about 1150 nm to the ESE of Hurricane Irma,
along 37W/38W from 15N southward. The wave is moving W 10 to 15
knots. A 1011 mb low pressure center is along the wave near 10N.
Convective precipitation: scattered to numerous strong from 10N
to 12N between 36W and 40W. Scattered moderate to isolated strong
from 13N to 17N between 30W and 36W, and from 07N to 10N between
40W and 44W. The wave is within a distinct 700 mb trough.
Environmental conditions are expected to be conducive for gradual
development. The chance for tropical cyclone formation within the
next 48 hours is medium.

A surface trough is in the SW corner of the Gulf of Mexico,
along 25N98W 21N97W 18N95W. Convective precipitation: numerous
strong from 19N to 23N between 93W and 97W. scattered
moderate to isolated strong from 18N inland to 20N between 92W
and 96W. It is possible that a low pressure center may form along
the trough, near Tampico Mexico, during the next 24 hours or so.
The chance for tropical cyclone formation within the next 48 hours
is medium.

...TROPICAL WAVES...

An Atlantic Ocean tropical wave is along 19W/20W from 17N
southward, moving westward 10 knots. Convective precipitation:
the precipitation from six hours ago has weakened, leaving
convective debris clouds from 13N to 17N between the coast of
Africa and 22W.

A Caribbean Sea tropical wave is along 74W/75W, from Haiti to
Colombia, moving westward 10 knots. The position of the wave has
been re-located based on 700 mb wind data. Convective
precipitation: the wave is moving through the area of an upper
level inverted trough.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coastal sections of SW
Mauritania, to 12N20W, 10N23W, 09N30W, 09N40W, and 12N46W.
Convective precipitation: isolated moderate to locally strong
elsewhere from 04N to 14N between Africa and 58W.

...DISCUSSION...

...THE GULF OF MEXICO...

Upper level anticyclonic wind flow spans the Gulf of Mexico.
Multilayered clouds and possible rainshowers cover the rest of the
area, away from the surface trough that is in the SW corner of the
Gulf of Mexico.

...THE CARIBBEAN SEA...

Hurricane Irma is a major hurricane that is approaching the
Leeward Islands. Please read the Special Features section.
Expect the Leeward Islands to be under the influence of Hurricane
Irma during the next 24 to 48 hours.

The monsoon trough is along 10N/11N between northern coastal
Colombia and Costa Rica. An upper level inverted trough extends
from Hispaniola into the SW corner of the Caribbean Sea, near the
area of the monsoon trough.

24-hour rainfall totals in inches, for the period that ended at
05/0000 UTC, according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.01 in
Guadeloupe, and a trace in Tegucigalpa in Honduras.

...HISPANIOLA...

Major Hurricane Irma is forecast to approach the area of
Hispaniola early on Thursday.

An upper level inverted trough extends from Hispaniola toward
Costa Rica. Convective precipitation: Scattered strong within
120 nm of the coast of southern Cuba between 80W and 82W. widely
scattered moderate to isolated strong is from Jamaica to SE Cuba
between 74W and 78W, and from 11N southward between Colombia and
81W in the SW corner of the Caribbean Sea.

The GFS MODEL forecast for 250 mb shows that day one will consist
of SE wind flow across the area, with a cyclonic circulation
center that will move toward Jamaica. Day two will consist of
anticyclonic, and easterly, wind flow for much of the time. NE
wind flow will move across the area, replacing the anticyclonic
wind flow, around the middle of day two. The NE wind flow will be
associated with a second cyclonic circulation center that will be
approaching NE Hispaniola from the east, with Hurricane Irma. The
GFS MODEL forecast for 500 mb shows that day one will consist of E
wind flow, becoming NE by the end of the day. Day two will consist
of more NE wind flow, that is associated with the Hurricane Irma
cyclonic circulation center. The GFS MODEL forecast for 700 mb
shows that day one will consist of anticyclonic wind flow. Day two
will consist of NE and cyclonic wind flow, with the Hurricane
Irma cyclonic circulation center, that is forecast to be on the
Atlantic Ocean side of Hispaniola.

...THE ATLANTIC OCEAN...

Major Hurricane Irma represents a threat for the Leeward Islands.

An upper level trough extends from a 27N33W cyclonic circulation
center, to 15N40W. A surface trough is along 30N32W 25N34W
20N34W. Cyclonic wind flow covers the Atlantic Ocean from 15N
northward between 20W and 43W. Convective precipitation:
Rainshowers are possible in the area of the upper level cyclonic
wind flow.

An upper level cyclonic circulation center is about 800 nm to the
NNW of Hurricane Irma, near 28N64W. A surface trough is within
400 nm to the west of the 28N64W cyclonic circulation center,
along 71W/72W from 20N to 28N. Convective precipitation: isolated
moderate from 20N northward between 60W and the Bahamas. A
separate area of precipitation: scattered moderate to isolated
strong rainshowers is from 24N to 29N between 56W and 61W, on the
eastern side of the 28N64W cyclonic center.

A surface ridge passes through 34N60W, across Bermuda, to 30N80W,
to SW Louisiana.

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

$$
MT
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