000 AXNT20 KNHC 050603 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 103 AM EST Mon Mar 5 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 0545 UTC. ...SPECIAL FEATURES... Atlantic Storm Warning: Cold front extends from near 32N43W to 22N54W to the NE Caribbean near 16N66W where it starts to dissipate westward to the Gulf of Honduras. A very tight pressure gradient between the front and intense 976 mb low pressure centered well north of the discussion area near 38N56W continues to maintain 30 to 35 kt winds north of 28N between 52W and 60W, and between 65W and 69W. Large seas in the 19 to 27 ft range is forecast in that region. The cold front will continue to weaken this morning. However, a second round of vigorous winds and seas can is expected tonight and Tue morning as tight low pressure develops within a trough that rotates around the south side of the parent low over the Western Atlantic. Gale to storm conditions can be generally expected N of 28N between 50W and 70W during this time frame. Gale conditions will persist through Wed while shifting eastward over the central Atlantic. 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 Sierra Leone near 08N13W to 02N21W. The ITCZ continues from 02N21W to 0N40W to Brazil coastal waters near 01N50W. Isolated showers are over coastal waters of Liberia and Sierra Leone Africa and within 150 nm either side of the ITCZ W of 37W. ...DISCUSSION... GULF OF MEXICO... A strong and elongated ridge along the eastern CONUS continue to extend southward and across the Gulf of Mexico. This ridge provides light to moderate NE to E winds over the eastern half of the basin and E to SE moderate flow across the western Gulf. GOES-16 water vapor imagery show very dry air present in the mid to upper levels, which is restricting convection and supporting mainly clear skies. The surface ridge will slide eastward through tonight, thus allowing for the next cold front to move into the NW Gulf early Tuesday morning. A secondary surge of cold air will push the front across the rest of basin by Thu morning. CARIBBEAN SEA... The tail of a cold front associated with the intense low pressure system over the NW Atlc extends across Anguilla to NE Caribbean waters near 16N68W where the front starts to weaken westward to the Gulf of Honduras. No significant convection accompanies this weakening boundary. Aside from shallow moisture associated with the front, deep layer dry air is over most of the basin, which supports mostly clear skies and fair weather conditions. The exception is the SE Caribbean where a small area of convergent low-level flow is supporting the continuation of cloudiness as well as isolated showers over the southern Windward Islands and NE Venezuela. Large NE swell will continue affecting the tropical Atlantic Ocean waters through mid week as the low pressure system lingers over NW Atlc waters and secondary low pres develops on the S side of the system. This will generate large N to NE swell that will penetrate the NE Caribbean Sea Passages through Thu and reach the A-B-C Islands as well as the coast of Venezuela. Otherwise, the low pressure center will drag the weakening tail of the cold front SE to the northern Windward Islands through tonight when it is forecast to dissipate. A new cold front will move over the NW Caribbean by Thu afternoon. ATLANTIC OCEAN... Please read the SPECIAL FEATURES section for more details about the ongoing gale event over the western and central Atlantic. A cold front associated with an intense low pressure system over the NW Atlc, enters the area of discussion near 32N43W and continues to 22N54W to the NE Caribbean near 16N66W where it starts to dissipate westward to the Gulf of Honduras. Scattered showers and isolated thunderstorms are occurring along and up to 120 nm ahead of the front N of 23N. Strong to gale force winds continue to persist behind this front. These conditions are forecast to continue through Thursday as the front moves E into the central Atlantic and weakens. The largest swell event thus far this winter is already in progress and will be reinforced by the development of a secondary low pres near 35N60W on Tue morning. The large swell will continue to affect all waters E of Florida and the Bahamas through Wed. Another strong cold front is forecast to impact the waters E of Florida Wednesday through early next weekend. Gales will be possible along the front N of 28N as the front emerges from the Georgia and Florida coasts. Otherwise, surface ridging anchored by a 1020 mb high near 23N28W dominates the remaining central and eastern Atlantic Ocean waters. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos