Tropical Weather Discussion

axnt20 knhc 140557

Tropical weather discussion
NWS National Hurricane Center Miami FL
1257 am EST Fri Dec 14 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 0000 UTC surface analysis and satellite imagery through 
0530 UTC. 

...Special features...

...Gulf of Mexico Gale Warning...

As of 0300 UTC, a cold front extends over the western Gulf of
Mexico from near Lake Charles Louisiana to 27n94w to the coast of
Mexico near 24n98w and inland into Mexico. A recent ascat pass
from around 0300 UTC shows gale force winds behind the front from
24n-29n, W of 94.5w. The front will reach from the Florida Big 
Bend to the Yucatan Channel by late today, then move through the 
Bahama channel on Sat. The gale force winds will continue this 
morning west of the cold front, spreading southward through the 
west-central Gulf. Winds are forecast to be below gale force by 
late this afternoon. Seas of 13 to 17 ft are expected to affect 
waters today from 22n-28n between 90w-97w. Please read the latest 
High Seas Forecast under AWIPS/WMO headers hsfat2/fznt02 knhc for 
more details.

...Possible gale off the coast of Morocco...

Widespread strong to near gales with localized winds to gale 
force are expected later today within 120 nm of the coast of 
Morocco between 30n-32n in Agadir, according to the latest forecast
from Meteo France. These winds are being caused by a strong 
pressure gradient between a strong low over the western 
Mediterranean Sea and a high pressure to the west over the 
Atlantic near 32n18w. Winds will diminish by early Sat.

...Monsoon trough/ITCZ...

The monsoon trough extends from the coast of Sierra Leone near
09n13w to 08n15w. The ITCZ continues from that point to 04n20w to
00n32w to 01s44w. Scattered moderate convection is seen from
04n-08n between the W coast of Africa and 21w. Isolated to
scattered showers are seen from 07n southward between 34w and the
coast of South America.

Gulf of Mexico...

A cold front and associated gale force winds in the western Gulf
are described above in the special features section. A strong,
deep-layered low pressure system is located over east-central
Texas. CIRA layered precipitable water imagery indicates that
southerly flow east of the low is drawing a large amount of moist
air northward from the western Caribbean into the NE and north- 
central Gulf of Mexico. Well ahead of the cold front, over the 
eastern Gulf of Mexico, numerous moderate and scattered strong 
convection is noted from 24n-29n between 83w-88w. Elsewhere N of 
24n and E of 89w, scattered moderate convection is seen. In 
addition, a line of showers and thunderstorms is occurring along 
with, or just ahead of the cold front over Louisiana. This line
extends southward into the northern Gulf off the coast of south- 
central Louisiana, moving eastward.

Fresh to strong southerly flow will continue today east of the 
cold front that is currently over the western Gulf of Mexico. The
strong thunderstorms currently over the NE Gulf will continue 
through this morning. Strong wind gusts and locally enhanced seas
are expected with the stronger thunderstorms. The pressure 
gradient will relax tonight and Sat, with moderate west flow 
expected on Sat evening as the seas subside to less than 8 ft. The
gradient will continue to relax with light northerly winds on 

Caribbean Sea...

there are no significant features or convection over the Caribbean 
at this time. Water vapor imagery shows relatively dry air over 
the eastern and central Caribbean. Other than some light trade 
wind showers in the vicinity of Puerto Rico and Trinidad, the 
basin is quiet.

Fresh to strong trade winds will prevail across the south-central
Caribbean through the upcoming weekend, with nocturnal pulses to 
near gale-force off the northwest coast of Colombia. These winds 
will expand north across the central Caribbean today. A cold 
front will enter the Yucatan Channel late this afternoon, then 
stall and gradually dissipate over the NW Caribbean into early 
next week. Strong north winds are forecast west of the front 
across the Gulf of Honduras late tonight and Sat. Large north 
swell will reach the leewards on Sat, and spread south through the
northeast Caribbean passages during the weekend.

Atlantic Ocean...

Scattered showers and isolated thunderstorms originating from the
activity occurring over the NE Gulf of Mexico are now starting to
spread into the Atlantic waters east of Georgia and northern 
Florida west of 78w and north of 28n. Expect strong thunderstorms 
to become widespread in this area later today.

A cold front passes through 32n42w to 27n50w to 24n61w then 
transitions to a warm front at that point, extending to 23n67w to
the central Bahamas. Scattered showers are within 60 nm of the
front north of 31n. Elsewhere along and north of the front,
isolated showers are noted. Farther to the southeast, a surface 
trough is analyzed from 28n42w to 17n45w. Broken clouds and 
isolated showers accompany the trough.

The frontal boundary that extends eastward from the central
Bahamas will continue to drift northward today, then gradually 
wash out as it continues north across the northeast portion on 
Sat. Strong to near-gale southerly return flow will develop north
of the Bahamas today ahead of another cold front that will sweep 
east across the northern waters during the upcoming weekend, 
extending from Bermuda to northwest Cuba on Sun night and from 
31n71w to central Cuba on Mon. The front will stall as it passes 
across the waters north of the Antilles early next week. 

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