Tropical Weather Discussion
Issued by NWS
AXNT20 KNHC 300542
Tropical Weather Discussion
NWS National Hurricane Center Miami FL
142 AM EDT Sun Apr 30 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
The 12-hour forecast consists of a cold front whose position will
be 30N93W 2696W 21.5N97.5W. Expect NW-to-N gale force winds, and
sea heights to 8 feet, within the area that is bounded by 23N97W
TO 22N97W TO 22N98W TO 23N98W TO 24N97W TO 23N97W. Please read the
latest National Hurricane Center High Seas Forecast under
AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC, for more details.
Please refer to the METEO-FRANCE High Seas Forecast, that is
listed on the website: WWW.METEOFRANCE.COM/PREVISIONS-METEO-
MARINE/BULLETIN/ GRANDLARGE/METAREA2. The OUTLOOK, for the 24
hours that follow the forecast that is valid until 01/0000 UTC,
consists of: a cyclonic near gale or gale in IRVING. Expect N or
NE near gale or gale in AGADIR.
The Monsoon Trough passes through the coastal sections of Guinea
near 09N15W to 05N16W. A surface trough is along 17W/18W from 08N
southward. The ITCZ is along 02N20W 01N30W 01N36W,crossing the
Equator along 43W, to the coast of Brazil near 47W. Convective
precipitation: scattered strong from 02N to 05N between 24W and
40w, and from 02N southward between 36W and 40W. Isolated moderate
to locally strong from 07N southward from 60W eastward.
...THE GULF OF MEXICO...
An upper level ridge is along 83W/84W. High level moisture is
within 300 nm to 360 nm to the west and NW of the ridge. Numerous
strong convective precipitation in the Texas coastal plains from
A surface ridge extends from a Bermuda 1027 mb high pressure
center, into South Carolina, through the Florida Panhandle, and
continuing along 30N, to Texas.
...VISIBILITY AND WEATHER FOR THE OFFSHORE OIL PLATFORM SITES
THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N NORTHWARD AND
FROM 88W WESTWARD...
Mist and haze, with areas of 1 to 3 miles at many of the platform
sites, and some smaller areas of 3 to 5 miles.
VISIBILITY AND WEATHER...FOR THE COASTAL PLAINS OF THE U.S.A.
FROM THE DEEP SOUTH OF TEXAS TO FLORIDA...
TEXAS: light rain in Alice. mist, drizzle, and haze, and 3 to 5
miles in the middle Texas Gulf coastal plains. some light rain
from the Houston metropolitan area to Huntsville and Jasper. heavy
rain in Victoria. LOUISIANA: light rain in New Iberia. mist and
3 miles in Port Fourchon, in the coastal plains.
...THE CARIBBEAN SEA...
Upper level NW wind flow is moving across Cuba, toward an upper
level trough, whose cyclonic wind flow spans the Caribbean Sea
from 70W eastward. Upper level anticyclonic wind flow covers the
SW corner of the Caribbean Sea.
Upper level cyclonic wind flow covers the Atlantic Ocean and the
Caribbean Sea from 26N southward between 60W and 80W. Convective
precipitation: scattered moderate from 18N in the Caribbean Sea
to 21N in the Atlantic Ocean between 66W and 70W.
24-hour rainfall totals that are listed for the period that ended
at 30/0000 UTC...according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are 0.50 in
A middle level-to-upper level trough is spreading broad cyclonic
wind flow across the island. Convective precipitation: scattered
moderate from 18N in the Caribbean Sea to 21N in the Atlantic
Ocean between 66W and 70W. Rainshowers are possible, elsewhere,
inland and in the rest of the coastal waters.
SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: drizzle.
scattered cumulonimbus clouds. for the DOMINICAN REPUBLIC:
Barahona: VFR. few cumulonimbus clouds. earlier rainshowers with
thunder have weakened and dissipated for the moment. Santo
Domingo: MVFR. ceiling 1600 feet. earlier light rain has ended for
the moment. La Romana: VFR. earlier light rain has ended for the
moment. Punta Cana: light rain. Santiago: VFR. earlier light rain
has ended for the moment. Puerto Plata: light rain. MVFR. ceiling
1400 feet. few cumulonimbus clouds.
The GFS MODEL forecast for 250 mb shows that NW wind flow will
move across the area during the first 36 hours. Expect cyclonic
wind flow with a trough for the rest of the time period. The GFS
MODEL forecast for 500 mb shows that broad cyclonic wind flow will
move across the area during the next 48 hours. The GFS MODEL
forecast for 700 mb shows that cyclonic wind flow will be
associated with an inverted trough, across the entire area.
...THE REST OF THE ATLANTIC OCEAN...
A middle level-to-upper level trough passes through 32N47W, to
23N53W, and 20N55W. Convective precipitation: rainshowers are
possible from 16N northward between 40W and 60W.
An upper level cyclonic circulation center is near 27N17W. A trough
extends from the cyclonic center to 16N28W. A surface trough is
along 25N21W, to a 1016 mb low pressure center that is near 23N23W,
to 20N24W. Convective precipitation: Rainshowers are possible,
scattered to broken low level clouds, to the NW of the line that
passes through 32N09W 25N20W 18N22W 16N40W.
Surface anticyclonic wind flow covers the Atlantic Ocean from 08N
northward between 30W and 80W. A surface ridge is along 33N15W, to
a 1029 mb high pressure center that is near 34N38W, to a 1027 mb
Bermuda high pressure center, beyond South Carolina.
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The Monsoon Trough extends form the coast of west Africa near
08N13W to 05N14W. A surface trough is off the coast of west Africa
from 07N17W to 01N17W. The ITCZ extends from 02N19W to 01S26W to
01N37W to the coast of South America near 02S45W. Scattered
showers are within 90 nm of the surface trough axis. Isolated
moderate convection is along the ITCZ from 05S-04N between 20W-30W.
Widely scattered moderate convection is along the ITCZ from 04S-05N
GULF OF MEXICO...
15-30 kt SW return flow is over the Gulf of Mexico. The surface
pressure gradient is fairly tight over the W Gulf, W of 90W,
where winds are 25-30 kt. Radar imagery shows scattered showers
over W Cuba, the Florida Keys, and the Straits of Florida. Areas
of smoke are over the W Gulf W of 88W, moving NW restricting
visibility along the Texas and Louisiana coasts. In the upper
levels, a ridge is over the Gulf with axis along 82W. Broken high
clouds extend from the SW Gulf to the NE Gulf. A Gale is expected
over the NW Gulf in 18 hours behind a cold front. See above.
15-20 kt tradewinds are over the Caribbean Sea with strongest
winds over the central Caribbean. Scattered moderate convection is
over numerous locations this evening due to maximum diurnal
heating namely: E Cuba, Jamaica, Hispaniola, Puerto Rico, NW
Venezuela, N Colombia, Panama, Costa Rica, Honduras, and
Guatemala. Scattered showers are over the Leeward Islands. In the
upper levels, a ridge is over the Caribbean with axis along 82W.
Expect similar weather over the next 24 hours with the addition of
convection over the Leeward Islands.
Presently scattered moderate convection and scattered showers are
over the island due to maximum diurnal heating, and upper level
diffluence. Expect a repeat tomorrow evening especially over the
A 1028 mb high is over the W Atlantic near 32N65W. An area of
scattered showers are N of Hispaniola from 20N-23N between 66W-72W.
Another 1029 mb high is over the central Atlantic near 35N41W.
Further E, a 1012 mb surface low is SW of the Canary Islands near
23N24W. Of note in the upper levels, a small upper level low is
centered over the W Atlantic near 25N70W. An upper level trough is
over the central Atlantic N of 20N between 40W-60W. Another small
upper level low is just W of the Canary Islands near 27N20W
enhancing showers along the coast of Morocco.
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