Tropical Weather Discussion
Issued by NWS
AXNT20 KNHC 180551
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
1251 AM EST Sat Feb 18 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
...GALE WARNING FOR THE ATLANTIC OCEAN...
A cold front passes through 31N52W to 26N59W to 21N67W. S-to-SW
gale-force winds, and sea heights ranging from 12 feet to 15
feet, are to the north of 30N within 180 nm to the east of the
cold front. Expect these conditions for the next 24 hours or so.
Please read the HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...and
the OFFSHORE FORECAST...MIAOFFNT3/FZNT23 KNHC...for more details.
The Monsoon Trough passes through coastal sections of Sierra Leone
near 08N13W to 07N15W and 02N20W. The ITCZ continues from 02N20W,
to the equator along 24W, to 03S34W, to Brazil near 04S39W.
Convective precipitation: Scattered moderate to strong from 01N
to 03N between 06W and 13W, from 04N to 07N between 11W and 14W,
and from 01N to 04N between 17W and 22W. Isolated moderate
elsewhere from 10N southward from 60W eastward.
...THE GULF OF MEXICO...
The middle level-to-upper level cyclonic circulation center and
trough from West Texas to Mexico 24 hours ago, now extend from
Oklahoma to Texas, to the NW corner of the Gulf of Mexico, to the
Mexico coast near 21N97W. Cyclonic wind flow covers the Gulf of
Mexico from 90W westward. Middle level-to-upper level
anticyclonic wind flow covers the rest of the Gulf of Mexico.
A ridge is along 80W. The cyclonic center and trough are
supporting a 1008 mb low pressure center that is near 29N94W,
just to the south of the upper Texas Gulf coast, and a trough that
runs from the 1008 mb low center, to 24N98W in NE Mexico.
Convective precipitation: widely scattered moderate to isolated
strong from 26N northward between 83W and 93W. Upper level high
clouds are curving anticyclonically through the SE corner of the
Gulf of Mexico.
...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: KSPR and KMDJ.
IFR: KEIR, KGRY, and KDLP.
MVFR: KHIH, KVBS, KEHC, KVQT, KGHB, and KMIS.
LOW LEVEL CLOUD CEILINGS AND WEATHER...FOR THE COASTAL PLAINS OF
THE U.S.A. FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...
TEXAS: LIFR in Victoria and Port Lavaca. IFR in Bay City. MVFR in
Angleton/Lake Jackson and Galveston. LIFR in Jasper. LOUISIANA:
MVFR from Baton Rouge southeastward. Rain from Slidell, across
Lake Pontchartrain southward, right up to the coast. MISSISSIPPI:
IFR in Natchez. LIFR in McComb. light rain in parts of the
Hattiesburg metropolitan area. MVFR at the Stennis Airport, and in
Pascagoula. ALABAMA: rain in the Mobile metropolitan area. The
rain has ended for the moment in Gulf Shores. FLORIDA: light rain
in parts of the Pensacola metropolitan area.
...FROM THE CENTRAL ATLANTIC OCEAN, ACROSS THE BAHAMAS AND CUBA,
INTO THE YUCATAN PENINSULA...
Deep layer cyclonic wind flow covers the Atlantic Ocean from 23N
northward from 50W westward. A deep layer trough passes through
32N58W to 23N61W. A cold front passes through 32N50W in the
Atlantic Ocean, to 25N60W and 21N70W. A dissipating frontal
boundary continues from 21N70W to 24N78W, across NW Cuba, and
along a NE-to-SW line across the Yucatan Peninsula. Convective
precipitation: scattered moderate to isolated strong in the
Atlantic Ocean from 28N northward between 46W and 52W. widely
scattered moderate elsewhere from 26N northward between 43W and
56W. rainshowers are possible within 90 nm on either side of
...THE CARIBBEAN SEA...
Broad middle level-to-upper level anticyclonic wind flow spans
the entire Caribbean Sea. High level clouds are moving through the
NW corner, across the Greater Antilles, and moving from South
America into the Caribbean Sea from 70W eastward.
Comparatively drier air in subsidence is apparent in water vapor
imagery elsewhere across the area.
Rainshowers are possible elsewhere across the Caribbean Sea, in
areas of broken low level clouds, primarily from 17N southward
from 66W eastward, and elsewhere from 70W westward.
The 24-hour rainfall amounts, for the period ending at 18/0000
UTC... according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION
TABLES...MIATPTPAN/SXCA01 KNHC...are: only a TRACE in Guadeloupe.
Upper level NW wind flow is moving across the area. NE wind flow
is present from 600 mb to 800 mb. Comparatively drier air in
subsidence is apparent in water vapor imagery across Hispaniola.
Convective precipitation: Rainshowers are possible inland, and in
the coastal waters.
SURFACE OBSERVATIONS...for Port-au-Prince in Haiti, VFR. for the
DOMINICAN REPUBLIC: Barahona: VFR. Santo Domingo: MVFR. ceiling
1600 feet. earlier rain has ended for the moment. La Romana/Punta
Cana: VFR. Santiago/Puerto Plato: VFR.
The GFS MODEL forecast for 250 MB shows that NW wind flow, with a
ridge, will move across the area during the 48-hour forecast
period. The GFS MODEL forecast for 500 MB shows that an
anticyclonic circulation center will be in the Windward Passage at
the beginning of the 48-hour forecast period. The anticyclonic
center will move on top of Hispaniola after the first 12 hours,
and it will spread anticyclonic wind flow across the area during
the rest of day one. The anticyclonic circulation center
eventually will move into the SE corner of the Caribbean Sea by
the end of the 48-hour forecast period. SW wind flow will move
across the area during most of day two. Expect NW-to-W wind flow
at the end of day two, with a trough. The GFS MODEL forecast for
700 mb shows that N-to-NE wind flow, with a ridge, will move
across the area during day one. expect northerly wind flow during
...THE REST OF THE ATLANTIC OCEAN...
A middle level to upper level trough passes through 32N11W to the
Canary Islands, to a 22N27W cyclonic circulation center, to
16N32W, and 07N36W. Convective precipitation: rainshowers are
possible from 10N northward between 23W and 50W.
A surface ridge passes through 32N33W, to 27N42W, 22N50W, to
18N62W, across the Greater Antilles, to 21N80W. A 1020 mb high
pressure center is near 28N76W. Surface anticyclonic wind flow
covers the Atlantic Ocean to the northwest of the frontal
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