[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 060556
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1256 AM EST Mon Mar 6 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 0000 UTC surface analysis and satellite imagery through
0515 UTC.

...SPECIAL FEATURES...

...CARIBBEAN SEA GALE WARNING...

The conditions starting at 06/0000 UTC: NE gale-force winds, and
sea heights ranging from 10 feet to 17 feet, in the coastal waters
of Colombia, from 10.5N to 12.5N between 74W and 77W. ALSO: NE
gale-force winds, and sea heights reaching 11 feet, to the N of
18N between 73W and 76W, including in the Windward Passage. NE-
to-E gale-force winds, and sea heights to 11 feet, to the N of 16N
between 70W and 73W. Please read the latest NWS High Seas
Forecast under the AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for
more details.

...ATLANTIC OCEAN GALE WARNING...

The conditions starting at 06/0000 UTC: A cold front is along
31N49W 22N68W 21N60W 20N76W. NE-to-E gale- force winds and sea
heights ranging from 8 feet to 12 feet in the open waters, to the
S of 24N to the W of 74W. Please read the latest NWS High Seas
Forecast under the AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for
more details.

...GULF OF MEXICO GALE WARNING...

The conditions starting at 06/0000 UTC: NE-to-E gale-force winds,
and sea heights ranging from 9 feet to 15 feet, to the S of 25N to
the E of 83W, including in the Straits of Florida. Please read the
latest NWS High Seas Forecast under the AWIPS/WMO headers
MIAHSFAT2/FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough passes through the coastal sections of Liberia
near 06N10W, to 03N20W. The ITCZ continues from 03N20W, to the
Equator along 30W and 36W, to the coast of Brazil near 03S42W.
Convective precipitation: Isolated moderate to locally strong
from 07N southward from 60W eastward.

...DISCUSSION...

...THE GULF OF MEXICO...

A middle level to upper level trough is moving through the central
sections of the Gulf of Mexico. Scattered to broken multilayered
clouds and possible rainshowers are from 95W eastward.

A surface ridge extends from the Florida Panhandle into the SW
corner of the area.

...LOW LEVEL CLOUD CEILINGS AND WEATHER FOR THE OFFSHORE OIL
PLATFORM SITES THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N
NORTHWARD AND FROM 88W WESTWARD...

LIFR: none.

IFR: KMZG, KVAF, and KGRY.

MVFR: KBBF, KBQX, KXIH, KHHV, KVAF, KHQI, KEHC, KGUL, KVQT,
KGHB, and KATP.

LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF
THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...

TEXAS: MVFR in the Lower Valley/the Deep South, and in Rockport.
light rain in Victoria. MVFR from Bay City to the Houston
metropolitan area and surrounding smaller communities, to
Huntsville, and from Beaumont/Port Arthur to Jasper. LOUISIANA:
MVFR in Slidell. MISSISSIPPI: light rain has ended for the moment
in parts of the Hattiesburg metropolitan area. MVFR at the Stennis
Airport. ALABAMA and FLORIDA: VFR.

...THE CARIBBEAN SEA...

Upper level SW wind flow covers the area to the east of the line
that runs from the SE coast of Nicaragua to SW Haiti. Upper
level anticyclonic wind flow is moving across the area that is to
the west of the aforementioned Nicaragua-to-Haiti line. NE wind
flow from 600 mb to 800 mb spans the entire area.

Rainshowers are possible, in areas of broken low level clouds,
mainly from 70W eastward, and from 15N northward from 70W
westward.

The 24-hour rainfall amounts, for the period ending at 06/0000
UTC...according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION
TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.20 in Guadeloupe.

...HISPANIOLA...

NE-to-E wind flow from 600 mb to 800 mb is moving across the
area. NE wind flow from 350 mb to 500 mb approaches the NE corner
of Hispaniola. NW wind flow from 350 mb to 500 mb moves across
Cuba toward Haiti. Rainshowers are possible inland and in the
coastal waters. Comparatively drier air in subsidence is apparent
in water vapor imagery across Hispaniola.

SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the
DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo/La Romana/Punta
Cana: VFR. earlier light rain in Santo Domingo ended a few hours
ago. Santiago: moderate rain. MVFR. ceiling 1400 feet. Puerto
Plato: VFR.

The GFS MODEL forecast for 250 MB shows that SW wind flow will
move across the area during the next 48 hours, with a ridge from
the SW corner of the Caribbean Sea toward the NW corner of the
Caribbean Sea. The GFS MODEL forecast for 500 MB shows that the
wind flow will be from the NW, first with a W-to-E oriented ridge,
and then later just with NW wind flow, for the rest of day one.
Expect more NW wind flow for the first 12 to 18 hours of day two.
Expect anticyclonic wind flow during the last 6 hours to 12 hours
of day two, with an Atlantic Ocean to Hispaniola E-to-W oriented
ridge. The GFS MODEL forecast for 700 mb shows that an
anticyclonic circulation center moves from a position that is just
to the E of the SE Bahamas to a position that is to the NE of
Puerto Rico during the first 24 hours of the 48=hour forecast
period. Expect NE to E to SE wind flow during day one. The
anticyclonic circulation re-organizes itself and it remains quasi-
stationary to the north of the Mona Passage for the first 12 to 18
hours or so of day two. Expect anticyclonic wind flow across
Hispaniola during this time. Expect NE wind flow for the last half
of day two.

...THE ATLANTIC OCEAN...

Deep layer cyclonic wind flow, with a trough, covers the area
from 20N from 40W westward. A cold front passes through 32N46W
to 23N60W 20N70W, across northern sections of Hispaniola, to
20N77W between SW Cuba and Jamaica.

An upper level trough extends from a 25N27W cyclonic circulation
center, to 20N40W and 20N53W. A surface trough is along 29N24W
25N25W 20N26W.

A surface ridge passes through 32N30W to 27N37W and 22N47W.
A second surface ridge is along 25N58W 28N68W beyond 32N74W.

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

$$
MT




...Caribbean Gale Warning...

A strong pressure gradient between a high pressure anchored
across the southeast CONUS and lower pressure analyzed across
northwestern South America will support near-gale to gale force
winds each night and early morning within about 90 nm of the
northwest coast of Colombia. These conditions will continue
through Wednesday night. See the latest NWS High Seas Forecast
under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details.

...Florida Straits/Windward Passage Gale Warning...

Strong high pressure is centered across the southeast CONUS and
continues to build in across the Florida Straits region behind a
cold front analyzed from 26N56W to the eastern coast of Cuba near
21N74W. Near-gale to gale-force east winds will continue across
the Straits and are expected to persist through early Monday. As
the front moves east of the Windward Passage region by tonight
into early Monday...near-gale to gale-force northeast winds are
expected through the Windward Passage and adjacent Caribbean Sea
waters. See the latest NWS High Seas Forecast under AWIPS/WMO
headers MIAHSFAT2/FZNT02 KNHC for more details.

...ITCZ/MONSOON TROUGH...

The Monsoon Trough extends from the African coast near 07N12W to
00N23W. The Intertropical Convergence Zone extends from 02N23W to
03S42W. Isolated showers are observed within 100 nm on either side
of the ITCZ mainly west of 35W.

...DISCUSSION...

GULF OF MEXICO...

A mid to upper-level shortwave trough is noted on water vapor
imagery over the west Gulf waters and eastern Texas. While no
lower-level or surface feature has materialized across this
area, isolated showers are occurring between 88W-94W. Elsewhere, the
southwestern periphery of a surface ridge prevails across the
remainder of the basin anchored by a 1039 mb high centered across
Virginia and North Carolina. Fresh to strong easterly winds are
prevailing across the basin except over the Florida Straits (see
section above for details). These conditions will to continue
through Monday. Winds will gradually diminish through early
Tuesday from west to east as the high center moves eastward into
the west Atlantic region.

CARIBBEAN SEA...

Aside from the near-gale to gale-force winds forecast off the
coast of Colombia during the next few days, the Caribbean is
under the influence of dry and stable air aloft, along with
fairly tranquil conditions at the surface. A few quick-moving
isolated showers are possible across the Lesser Antilles, Puerto
Rico, and Hispaniola as low level moisture continues to be
transported by the fresh to strong trades. These conditions are
expected to prevail through early Friday. The high pressure will
be anchored across the west Atlantic region for much of the week
ahead.

...HISPANIOLA...

Water vapor imagery depicts strong subsidence over the island
with west-southwesterly flow aloft. Low-level moisture
transported by trade wind flow is supporting isolated showers
this afternoon across the island and adjacent coastal waters. A
cold front lies to the N along 21N/22N and will reach the island
by tonight increasing the northeast winds into fresh to strong
levels. These winds are forecast to persist through Wednesday
night.

ATLANTIC OCEAN...

A cold front extends across the west/central Atlantic from 31N50W
to 20N74W. A strong high pressure is building in the wake of the
front centered over the North Carolina/Virginia boundary. The
pressure gradient in the area is strong enough to support gale-
force winds currently occurring across the Florida Straits area
and soon to begin in the Windward Passage. Refer to the section
above for details. To the east of the cold front, a pre-frontal
trough extends from 25N57W to 20N63W. No significant convection is
related to the trough at this time. The remainder of the basin is
under the influence of a surface ridge anchored by a 1028 mb high
centered near 34N22W. South of this feature, an upper-level low
is reflected at the surface as a trough that extends from 28N29W
to 22N30W.

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

$$
MT
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