[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040002
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
702 PM EST Sat Mar 3 2018

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 1800 UTC surface analysis and satellite imagery through
2345 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: Cold front extends from near 30N53W to
23N64W to eastern Cuba near 20N74W continuing into the NW
Caribbean. A very tight pressure gradient between the front and
intense low pressure well north of the discussion area continues
to maintain W to NW 30 to 40 kt winds north of 27N between 65W and
73W along with large seas in the 18 to 33 ft range. Gale-force SW
to W winds are also N of 27N W of front to 65W with seas in the 13
to 31 ft range. Gale conditions will persist through Mon while
shifting eastward to the central Atlantic, and the cold front
weakens as it reaches a position from near 32N41W to 20N50W to
near 14N60W. Please refer to the Atlantic High Seas Forecast under
the AWIPS header MIAHSFAT2 and under the WMO header FZNT02 KNHC
for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends through the coastal sections of
southern Sierra Leone near 07N11W to 03N15W. The ITCZ continues
from 03N15W dipping to S of the Equator to 01S22W to 03S32W to
coastal waters of Brazil near 03S38W. Scattered moderate
convection is from 03S to 03N between 20W-30W.

...DISCUSSION...

GULF OF MEXICO...

A cold front has pushed southward to central Cuba, and extends
northwestward from there to 25N86W, where it becomes stationary
to 26N90W and continues as a dissipating stationary boundary to
26N92.5W and to 27N95W. Three surface troughs are over the SW
Gulf, the first one is along a line from 19N95W to 23N96W to
inland the coast of Mexico at 24N97.5W. The second one is along a
position from 10N93W to 21N94W to 24N94W, and the third one is
the thermal trough that moved offshore the Yucatan Peninsula this
morning, and is along 92W S of 21N. Yet another trough is just
offshore the Texas coast from 28N96W to 26N97W. No deep convection
is noted with these troughs, only some areas of rain and isolated
showers are along and to the west of the first two troughs.
Patches of overcast low clouds and fog are seen from 26N to 28N
and west of 95W. These clouds and fog will erode during the
afternoon, and the rain and isolated showers will lift north-
northwest inland the Texas coast late this afternoon or evening as
the Texas coastal trough lifts northward and inland. Strong high
pressure is present over the NE and N central gulf waters this
afternoon, with the associated gradient providing fresh NE to E
winds along with seas of 4 to 6 ft there. These winds will
diminish to moderate intensity tonight as the ridge weakens.

The stationary front will will weaken and dissipate tonight as
the cold front over Cuba weakens and dissipate by early Sun. A
reinforcement ridge will build across the northern Gulf on Sun and
Mon. It is possible that another cold front may move into the NW
Gulf on Mon night and across the rest of basin through mid-week.

CARIBBEAN SEA...

A surface trough, with a good track history, is analyzed from near
17N63W to 14N65W to near 11N66W. It is moving westward at 10 kt.
Scattered showers are within 900 nm west of the trough. Isolated
showers are east of the trough north of 14N, including much of
the Leeward Islands. This trough will slowly become diffuse
through Sun as its moisture lifts northeastward ahead of
the Atlantic cold front that is currently moving through the SE
Bahamas.

An upper level trough/shear axis extends from 15N66W, to 11N76W,
continuing SW beyond 10N83W in Costa Rica. 12N73W, to the coast
of Panama near 09N80W. Isolated showers are possible elsewhere
within areas of scattered to broken low level clouds present
over the Caribbean Sea and over portions of the adjacent
Atlantic Ocean S of 20N and west of about 60W.

Large NE swell will impact the tropical Atlantic Ocean waters
into next week. A low pressure system will deepen across the NW
Atlantic Ocean through Sun. It will produce a large N swell, that
will penetrate the NE Caribbean Sea Passages from Sun into next
week reaching the A-B-C Islands and coast of Venezuela. The low
pressure center will drag a cold front into the northern Caribbean
tonight, gradually dissipating through early next week.

ATLANTIC OCEAN...

Please read the SPECIAL FEATURES section for more details about
the ongoing gale event over the western and central Atlantic.

An eastern Atlantic Ocean cold front stretches from 32N10W to
25N18W to 21N30W, where it becomes stationary to 18N39W and NW
to 19N43W and warm front to 23N48W. Scattered showers are along
and within 180 nm southeast of the front. A surface trough is
along 49W/50W from just S of the Equator northward to near 08N,
moving westward at 10 to 15 kt. Scattered showers and isolated
thunderstorms are within 120 nm west of the trough from 04N-06N,
while isolated showers and weakening thunderstorms are noted
elsewhere to the west of the trough.

A western and central Atlantic cold front extends from near
32N54W to to 26N64W to 23N74W to across N central and NW Cuba.
Scattered moderate to isolated strong convection is within 180 nm
east of the front north of 29N, while scattered moderate
convection is within 60 nm east of the front from 25N to 29N and
isolated showers and thunderstorms are elsewhere along the front.
Strong to gale force W to NW winds will continue to exist behind
this front into early next week while shifting eastward across the
central Atlantic. The aforementioned cold front will shift
southeast of the area on Sun, with gale force wind conditions
shifting east of the area. The largest swell event thus far in
this winter season will accompany this system, affecting all
waters E of Florida and the Bahamas through early next week. It is
possible that another strong cold front may impact the waters E
of Florida on Tue night. This front will move eastward after
during the middle portion of next week.

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

$$
JA/NR
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