000 AXNT20 KNHC 040604 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 104 AM EST Sun Mar 4 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 Gale Warning: Cold front extends from near 31N49W to 19N70W to eastern Cuba adjacent Caribbean waters near 20N77W. A very tight pressure gradient between the front and intense low pressure well north of the discussion area continues to maintain W to NW 30 to 40 kt winds north of 27N between 65W and 73W along with large seas in the 18 to 32 ft range. Gale-force SW to W winds are also N of 27N W of front to 65W with seas in the 16 to 31 ft range. Gale conditions will persist through Mon while shifting eastward to the central Atlantic, and the cold front weakens as it reaches a position from near 31N41W to 20N50W to near 14N60W. 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 04N17W to 02N21W. The ITCZ continues from 02N21W to 0N30W then along the Equator to the coast of Brazil near 0N50W. Scattered to isolated showers are within 240 nm either side of the ITCZ. Numerous moderate convection is S of 07N between 52W and 56W. ...DISCUSSION... GULF OF MEXICO... A strong and elongated ridge extends from the region of Ontario, Canada to the Great Lakes southward to the Yucatan Peninsula adjacent waters. The ridge provides 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 in the lower and middle levels, which is supporting mainly clear skies. CIRA microwave imagery at the lower levels show shallow moisture, remnant of the cold front, which is being advected back to the NW Gulf where is supporting broken to overcast skies. The surface ridge will slide eastward through Monday night, thus allowing for the next cold front to move into the NW Gulf early Tuesday morning and across the rest of basin through mid-week. CARIBBEAN SEA... The tail of a cold front associated with the intense low pressure system over the NW Atlc extends across Hispaniola and the Windward Passage to near the approaches of the Yucatan Channel. Isolated showers are highly possible in this region. 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 NE Caribbean where a surface trough prevails along 20N55W across the Leeward Islands to near 15N65W, thus supporting the continuation of scattered to isolated showers in that region. This trough will slowly become diffuse today as its moisture lifts northeastward ahead of the Atlantic cold front that is currently moving across Hispaniola. Large NE swell will impact the tropical Atlantic Ocean waters into next week as the low pressure system over NW Atlc waters deepen through today. This will produce a large N to NE swell, that will penetrate the NE Caribbean Sea Passages today into next week reaching the A-B-C Islands and coast of Venezuela. Otherwise, the low pressure center will drag the cold front into the northeast Caribbean tonight while it gradually dissipates through early next week. 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 30N50W and continues SW to 21N63W across northern Hispaniola, the Windward Passage and southern Cuba adjacent waters. Aside from scattered showers within 120 nm ahead of the front, strong to gale force winds continue to exist behind this front, which are forecast to continue through Tuesday as the front continue to move eastward towards the central Atlantic. The largest swell event thus far in this winter season will accompany this system, affecting all waters E of Florida and the Bahamas through early next week. Another strong cold front is forecast to impact the waters E of Florida Wednesday. Over the eastern Atlantic Ocean, a cold front stretches from the coast of NW Africa near 23N16W to 18N31W where it stalls to 18N40W. Isolated showers are along and within 120 nm ahead of the front. Otherwise, the surface trough mentioned in the Caribbean section is generating scattered showers NE of the Leeward Islands. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos