[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 112332
TWDAT

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
632 PM EST Tue Dec 11 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
2300 UTC.

...SPECIAL FEATURES...

Atlantic Gale Warning: A cold front extends from 32N50W to 27N69W
to across the SE Bahamas into eastern Cuba with a reinforcing cold
front extending from 1001 mb rapidly intensifying low pressure
near 35N70W, racing well NE of the area, through 32N71W to near
28N80W. Scattered moderate and isolated strong convection is N of
27N within 90 nm E of the initial front, with scattered showers W
of the boundary. While this low has developing hurricane force
winds well N of the area, a recent scatterometer pass showed gale
force winds reaching well S of the low into the discussion waters,
extending N of 28N within 210 nm E of the reinforcing front. Seas
are also 10 to 13 ft in this same area. Gale force winds are
expected to persist across the northern waters E of the
reinforcing front into early Wed before diminishing. Elsewhere,
fresh to strong northerly winds will continue W of the initial
front through Wed morning, while fresh to strong southerly winds
ahead of the front diminish by late Wed afternoon. Please read the
latest High Seas Forecast under AWIPS/WMO headers HSFAT2/FZNT02
KNHC for more details.

...MONSOON TROUGH/ITCZ...

The monsoon trough extends from the coast of Africa near 07N11W
to 04N23W. The ITCZ continues from that point to 03N37W to near
the coast of Brazil at 04N52W. Scattered moderate and isolated
strong convection is noted from 02N to 03N between 10W and 13W,
from 03N to 04N between 26W and 28W, and also generally from the
equator northward to 05N between 31W and 47W. Scattered moderate
convection is from 04N to 07N between 39W and 51W.

GULF OF MEXICO...

A weak surface trough is located within 60 nm offshore of the
coast of Veracruz, Mexico. Otherwise, a 1030 mb high pressure is
centered over Louisiana near 31N92W with a surface ridge extending
across the entire Gulf. An upper-level trough just offshore of the
eastern seaboard of the U.S. extends southward over the Florida
peninsula into the eastern Gulf of Mexico. Broken low-level
stratocumulus cover the eastern and central Gulf of Mexico, while
low-level stratus is noted in the SW Gulf of Mexico and Bay of
Campeche.

High pressure will persist across the basin through early Thu
while gradually shifting eastward as the next cold front
approaches. Return southerly flow will develop on the western side
of the high, with increasing winds to fresh to strong over
western portions by early Thu. The cold front will move into the
NW Gulf of Mexico by late Thu morning, quickly reaching the
eastern Gulf late Thu night, then pushing SE of the basin Fri
night. Strong winds will follow the front, possibly reaching gale
force Thu night into Fri over the NW, N central and W central Gulf
of Mexico waters.

CARIBBEAN SEA...

In the northwest Caribbean Sea, a stalling cold front extends from
near the coast of eastern Cuba at 20N78W to eastern Honduras near
16N86W. A surface trough is located just SE of the front near
from 17.5N81W to 14N82.5W. Scattered showers are noted in the
vicinity of the trough and the frontal boundary. Water vapor
imagery shows very dry air across most of the eastern and central
Caribbean, with more moderately dry air filling into the NW
Caribbean Sea.

Fresh to strong trade winds will prevail in the S central
Caribbean through Sun night with nocturnal pulses to near gale
force off the northwest coast of Colombia. The front will become
stationary in the next few hours, then will gradually dissipate
through Thu. Fresh to strong northerly winds will continue W of
the front through Wed afternoon before diminishing. Another cold
front will enter the NW Caribbean on Fri afternoon, dissipating
over the NW Caribbean during the upcoming weekend.

ATLANTIC OCEAN...

Please see the Special Features section for information on a Gale
Warning associated with a pair of cold fronts across the SW N
Atlantic basin.

Otherwise, a ridge of high pressure extending from 1028 mb high
pressure near 32N22W dominates the remainder of the basin E of the
cold fronts. Isolated to widely scattered shower activity is noted
mainly S of 23N across the tropics outside of heavier activity
discussed in the Monsoon Trough/ITCZ section.

A strong ridge will build N of the SW N Atlantic area on Thu
ahead of the next cold front with fresh to near gale force
southerly return flow developing N of the Bahamas beginning Thu
night and continuing through Sun evening. The cold front itself is
forecast to move E off Florida Fri evening, moving across the SW
N Atlantic basin during the upcoming weekend.

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

$$
Lewitsky
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