000 AXNT20 KNHC 150713 AAA TWDAT Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 312 AM EDT Mon Oct 15 2018 Updated to move Gulf of Mexico gale in Special Features section 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 0515 UTC. ...SPECIAL FEATURES... Shower and thunderstorm activity has increased overnight in association with a broad area of low pressure over the southwestern Caribbean Sea centered near 14N80W. Scattered moderate convection prevails over the W Caribbean from 12N-16N between 78W-82W. The monsoon trough extends NE from the low to 16N77W and W from the low over Central America to 14N83W to 16N90W. An area of upper-level diffluence over Central America is enhancing convection over Central America. Satellite imagery shows scattered moderate isolated strong convection over southern and western Nicaragua, southern Honduras, El Salvador and the south coast of Guatemala. Scattered thunderstorms are also noted over the Mexican states of Chiapas, Oaxaca and Veracruz. The broad low is moving slowly west-northwestward, and some additional development is possible before it moves inland over Central America tonight or Tuesday. Regardless of development, locally heavy rainfall, which could cause flash flooding, is possible across portions of Central America for much of the week. In addition to the potential for heavy rain over Central America, these rains could spread to the Yucatan Peninsula and portions of southern Mexico this week. A cold front will enter the far NW and W central Gulf by Tue morning. Ahead of the front, numerous showers and thunderstorms are expected over the far NW and W central Gulf beginning late this morning and increasing this afternoon. This front will slowly shift southward over the western Gulf through Wed night. Fresh to strong northerly winds behind the front will increase to minimal gale force in the W central and SW Gulf behind the front Tue night through Thu night. Winds will diminish below gale force by Fri. Due to the combination of the front with the broad low mentioned above, expect enhanced shower and thunderstorm activity over the southwestern Gulf of Mexico by Wed. ...TROPICAL WAVES... A low amplitude tropical wave extends its axis along 44W from 01N-12N, moving west at 15-20 kt. A 700 mb trough is shown by model analyses with this wave. TPW imagery indicates abundant moisture in its environment. Scattered moderate to strong convection is occurring from 06N-14N within 180 nm of the wave axis. A tropical wave extends its axis along 51/52W from 08N-21N, moving west at 10-15 kt. A 700 mb trough is depicted by model analyses with the wave, and there is a local maximum in TPW. A recent ASCAT pass shows that the tropical wave is well-defined at the surface with 25-30 kt winds from 16N-18N within 60 nm of the wave axis. Scattered moderate to strong convection is noted from 15N-18N between 48W-52W. Scattered showers are noted from 19N- 22N between 46W-50W and along the wave's axis south of 13N. It is likely that the tropical wave along 44W will be merging with this wave over the next 24 hours. Expect plenty of convective activity near and in between both waves. Moisture associated with these waves is likely to enhance showers and thunderstorms over the Lesser Antilles Tuesday into Wednesday, and this activity will spread to the eastern Caribbean Sea during the middle of the week. A tropical wave extends its axis along 62W from 08N-21N moving west at 10 kt. Scattered showers are noted just north of the northern Leeward Islands and Virgin Islands. Additional scattered showers and storms are seen from 11N-14N between 55W-60W. The northern end of the wave is moving into an area of diffluent flow aloft this morning. Enhanced showers and thunderstorms are possible today for the Leeward Islands, Virgin Islands, and Puerto Rico. This wave is expected to continue weakening into Tuesday as it moves toward the central Caribbean. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the eastern Atlantic from the coast of Africa near 13N17W and extends to 07N23W to 07N28W. The ITCZ extends from 07N28W to 08N35W to 08N41W. Scattered moderate convection is seen along and within 180 nm south of the ITCZ between 28W-32W. Another area of scattered moderate convection is noted from 03N-06N between 18W-21W. GULF OF MEXICO... See Special Features section above for discussion of an expected gale behind a cold front in the western Gulf Tue night into Thu. An upper-level anticyclone over central Mexico extends an upper- level ridge over the western and north-central Gulf of Mexico. A surface ridge prevails across the northeastern and north-central Gulf. With this, dry air covers most of the basin. CARIBBEAN SEA... Two tropical waves will affect the Lesser Antilles over the next few days. See the Tropical Waves section for more details. See Special Features section for information relating to the broad low in the western Caribbean. A mid to upper level trough extends from 23N66W to the Mona Passage. An area of scattered moderate convection extends from the north coast of western Puerto Rico to 21N between 66W-68W. Isolated showers prevail from 14N-17N between 65W-69W. Elsewhere, scattered showers are within 60 nm of the northwest coast of Venezuela and the northeast coast of Colombia. ATLANTIC OCEAN... The three tropical waves in the Tropical Atlantic and Lesser Antilles region have been described above in the Tropical Waves section. A cold front extends across the west Atlantic from 32N59W to 30N66W, where it becomes a stationary front. The stationary front extends from that point to 28N74W, where it becomes a dissipating stationary front. The dissipating stationary front extends from that point to near 27N79W. Isolated showers are along and within 60 nm SE of the front. A 1025 mb high is centered near 30N46W, leading to relatively quiet weather elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ Hagen