[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 291201
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
701 AM EST THU DEC 29 2016

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
1045 UTC.

...SPECIAL FEATURES...

...Gulf of Mexico Gale Warning...

The 12-hour forecast consists of: a cold front from 30N85W to
26N97W. to the north of the front: NE winds 20 to 30 knots, with
frequent gusts to gale force. Sea heights less than 8 feet. The
24-hour forecast consists of: a cold front from 26N82W to 23N96W
to 21N97W. Gale-force NW-to-N winds and sea heights ranging from
10 feet to 14 feet to the south of 23N to the west of the cold
front. Please read the High Seas Forecast under AWIPS/WMO Headers
MIAHSFAT2/FZNT02 KNHC for more details.

...THE MONSOON TROUGH/THE ITCZ...

The Monsoon Trough passes through the Prime Meridian along 02N
to 04N10W, to 02N13W and 02N15W. The ITCZ continues from 02N15W
to 04N27W, crossing the equator along 32W, to 01S35W, and to the
equator along 39W. Convective precipitation: isolated moderate in
random clusters from 06N southward from South America eastward.
Rainshowers are possible elsewhere from 06N to 10N between 50W and
60W.

High level moisture is being pushed northeastward by the upper
level SW wind flow in the Atlantic Ocean. The high level moisture
is to the south of the line 28N13W 27N30W 23N40W 14N46W 14N60W.

...DISCUSSION...

...THE GULF OF MEXICO...

An upper level ridge is along 102W/103W in Mexico. Upper level NW
wind flow spans the Gulf of Mexico. Comparatively drier air in
subsidence is apparent in water vapor imagery from 26N southward.
A separate upper level anticyclonic circulation center is in the
SW corner of the area near 22N94W.

A surface trough is along 94W/95W from 23N southward. No
significant deep convective precipitation is apparent.

Rainshowers are possible from 25N southward east of 87W, in
random scattered/broken low level clouds.

A 1020 mb high pressure center is near 28N84W. Surface
anticyclonic wind flow covers the Gulf of Mexico from 24N
northward.

Gale-force winds are blowing in the Gulf of Tehuantepec on the
eastern Pacific Ocean side of southern Mexico. Please read the
Eastern Pacific Ocean HIGH SEAS FORECAST...MIAHSFEP2/FZPN03
KNHC...and the Eastern Pacific Ocean TROPICAL WEATHER
DISCUSSION...MIATWDEP/AXPZ20 KNHC...for more details.

...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: KBQX, KXIH, KVBS, KMIS.

IFR: none.

MVFR: KMZG, KBBF, KHHV, KVAF, KGHB, and KEIR.

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

TEXAS: IFR in the Lower Rio Grande Valley. Mostly LIFR/some IFR in
the Middle Texas Gulf coastal plains. MVFR from Galveston to
Beaumont/Port Arthur to Jasper. MVFR mostly in the Houston
metropolitan area...IFR at KEFD. LOUISIANA: MVFR in the SW and S
central coastal plains sections...IFR in Patterson and LIFR in Galliano.
MVFR around Lake Pontchartrain. MISSISSIPPI: IFR in Gulfport and
Pascagoula. MVFR at Stennis. MVFR from Natchez to McComb to
Hattiesburg. ALABAMA: MVFR everywhere in the southern sections/
coastal plains. LIFR in Gulf Shores. IFR in Fort Rucker. FLORIDA:
IFR from Destin westward. steady rain in IFR in Milton. LIFR in
Tallahassee. light rain and MVFR in the NW part of the Panama
City metropolitan area. heavy rain and LIFR in Perry. LIFR in Cross
City. IFR at the Tampa Executive Airport. LIFR in Sarasota. IFR in
Punta Gorda. MVFR in parts of the Ft.Myers metropolitan area.

...THE CARIBBEAN SEA...

Upper level NW wind flow is sweeping across the area, from Cuba
to the Greater Antilles and eastward. Upper level NE wind flow is
moving into the NW corner of the Caribbean Sea.

Upper level SW wind flow is from 17N southward from 76W eastward.

Comparatively drier air in subsidence is apparent in water vapor
imagery, nearly everywhere, except in the area that is from 17N
southward from 76W eastward.

Scattered to broken low level clouds and possible rainshowers are
to the south of 13N73W 16N67W 13N64W 13N60W.

The monsoon trough is along 07N/08N between 75W and beyond
85W in the eastern Pacific Ocean. No significant deep convective
precipitation is apparent.

24-HOUR rainfall totals in inches for the period ending at
29/0000 UTC...according to the PAN AMERICAN TEMPERATURE AND
PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are 0.01 in
Guadeloupe.

...HISPANIOLA...

Upper level NW wind flow is moving across Hispaniola, with an
Atlantic Ocean-to-Caribbean Sea trough. Comparatively drier air
in subsidence is apparent in water vapor imagery, across the
entire area.

SURFACE OBSERVATIONS...for the DOMINICAN REPUBLIC: Barahona: VFR/
no ceiling. few cumulonimbus clouds. Santo Domingo/La Romana/Punta
Cana: VFR/no ceiling. Santiago: IFR visibility and mist. Puerto
Plata: VFR/no ceiling.

The GFS MODEL forecast for 250 MB shows that NW wind flow will
move across the area during the next 48 hours. A ridge will be in
the Caribbean Sea, combined with an Atlantic Ocean trough. The
GFS MODEL forecast for 500 MB shows that N-to-NE wind flow will
move across the area during the next the first 18 hours to 24
hours. A trough will be across the Mona Passage at the start of
the forecast period. A ridge will settle in, across Hispaniola,
with time, during day one. Expect anticyclonic wind flow with the
ridge during day two. The GFS MODEL forecast for 700 mb shows
that NE wind flow will move across the area during the first 12
hours to 18 hours of the 48-hour forecast period. The wind
direction will be variable during the remaining 12 hours or so,
with a possible inverted trough, and some possible anticyclonic
wind flow with a ridge.

...THE ATLANTIC OCEAN...

An upper level trough passes through 32N52W to 21N54W.
A second upper level trough is along 63W/64W from 22N northward.
One surface trough is along 31N67W 27N69W. A second surface trough
is along 25N65W 22N68W. A third surface trough is along 25N71W
20N73W. Convective precipitation: scattered moderate from 25N to
28N between 60W and 63W. Rainshowers are possible from 20N northward
to the line 22N60W 23N67W 25N73W between 60W and 73W, in areas of
scattered/broken low level clouds. A cold front passes through
32N67W to 31N73W. A stationary front continues from 31N73W to the
coast of SE Georgia. Convective precipitation: broken to overcast
multilayered clouds and possible rainshowers are from 27N
northward from 60W westward.

An upper level trough extends from a 34N30W cyclonic circulation
center to 28N38W, to an 18N45W cyclonic circulation center, to
14N48W and 14N57W. The upper level trough supports a cold front
that passes through 32N23W to 31N24W. A stationary front continues
from 31N24W 23N30W and 20N43W. A surface trough continues from
20N43W to 20N54W. Convective precipitation: Rainshowers are
possible from 17N northward between 22W and 60W.

Surface anticyclonic wind flow covers the Atlantic Ocean from 21N
northward between 38W and 63W, to the W and NW of the cold front.
A 1025 mb high pressure center is near 31N48W.

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

$$
MT
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