[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210006
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
805 PM EDT Mon Aug 20 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
2330 UTC.

...TROPICAL WAVES...

A far eastern Atlantic tropical wave has its axis extending from
06N35W to 18N33W, moving westward at 10-15 kt. No significant
convection is noted.

A western Atlantic tropical wave has its axis extending from
05N54W to 19N52W, moving westward at 15 kt. No signficant
convection is observed.

A western Caribbean Sea tropical wave has extends from 09N81W to
20N78W. No signficant convection.

...MONSOON TROUGH/ITCZ...

The monsoon trough axis extends from western Africa at 12N17W to
08N40W, where scatterometer data indicates the intertropical
tropical convergence zone continues to the coast of South America
near 09N60W.

...DISCUSSION...

GULF OF MEXICO...

Weak ridging reaches across the northern Gulf of Mexico along
roughly 27N, maintaining light to gentle breezes and 1 to 3 ft
seas. Gentle to moderate easterly flow is noted elsewhere south
of the ridge. Scattered to numderous showers and thunderstorms are
active along the west coast of Yucatan, related to the normal
evening trough that sets up in that region, but also largely
enhanced by an upper low centered over the southwest Gulf.

Little change is expected in the pattern through Tue. By Wed, a cold front N of the area will
transition to a stationary front along the northern gulf coast and
then dissipate late at night. The remnants of the front will
transition to a surface trough from the Florida Big Bend SW to the
central basin, which is forecast to dissipate on Thu over the
Tampa Bay adjacent waters. A surface ridge will then move eastward
N of the area supporting northerly light to gentle winds across
the basin through early Fri. Return flow will resume across the
basin on Sat.

CARIBBEAN SEA...

Fresh to strong winds and 7 to 9 ft seas are noted off the coast
of Colombia, in the wake of the tropical wave over the western
Caribbean. Moderate to fresh winds are noted elsewhere with 3 to 7
ft seas. No significant convection is noted.

The fresh to strong winds will prevail in the south- central
Caribbean through Thu, increasing to near gale-force at night
along the coast of Colombia. A tropical wave along 80W will
continue west and move across Nicaragua and Honduras Tue through
Thu. A second tropical wave will reach the east Caribbean on Tue
while a third tropical wave is expected to approach the Lesser
Antilles late on Thu. Heavy showers and tstms are forecast to
develop in the SW basin Thu.

ATLANTIC OCEAN...

A surface trough is analyzed from near 30N73W to 22N75W, supported
in part by an upper trough over the same area. A few showers and
thunderstorms are noted near the northern end of the trough from
27N to 29N between 72W and 74W. A second surface trough is
analyzed from near 32N45W to 26N65W. The subtropical ridge is
displaces slightly north to along 31N.

The trough will continue to move west-northwest along the
periphery of a surface ridge that dominates the remainder
offshore waters then it will dissipate late Tue morning. A surface
pre-frontal trough extends from 30N77W SW to Cape Canaveral,
Florida to SW Florida generating scattered heavy showers and tstms
N of 26N W of 78W. Similar precipitation is in the NE offshore
waters from 25N-29N east of 67W associated with the tail of a
surface trough located in the central Atlc. Showers off the NE
coast of Florida will prevail for the next several days a weak
cold front moves N of the area on Thu.

E of the lower Windward Islands, scattered moderate convection is seen
within 45 nm either side of a line from 09.5N55W to 10N58W to
11N62W. A 1023 mb high is centered over the western Atlantic near
32N62W, with a ridge extending WSW to central Florida. A surface
trough from 32N79W to just east of central Florida briefly
interrupts the ridge. Scattered showers and thunderstorms are
within 30 nm of the trough. This activity is likely to continue
into tonight. A 1027 mb high is centered to the southwest of the
Azores near 35N35W. It is allowing for ridging and generally fair
weather to persist over the eastern Atlantic.

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

$$
Christensen
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