000 AXNT20 KNHC 120510 TWDAT 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 0430 UTC. ...SPECIAL FEATURES... Windward Islands Ashfall Advisory: La Soufriere volcano on the island of Saint Vincent near 13.3N 61.2W is currently undergoing frequent eruptions. Volcanic ash may be reaching the ocean surface and low level visibility may be reduced. Mariners traveling within the area 18N35W to 14N55W to 13N62W to 10N56W to 06N37W to 18N35W are urged to exercise caution. The densest ash is west of 48W. If mariners encounter volcanic ash or floating volcanic debris, you are urged to report the observation to the National Hurricane Center by calling 305-229-4424. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends southward from the coast of Senegal near 13N17W to 05N21W. The ITCZ continues from 05N21W to 00N30W to 00N45W. Scattered moderate and isolated strong convection is from 05S-02N between 18W-32W. GULF OF MEXICO... A weak cold front extends from a 1005 mb low pressure near Apalachicola Florida to 26N90W to 25N95W, then stationary to a 1000 mb low pressure inland over Mexico near 25N101W. A recent ASCAT pass shows gentle wind speeds on both sides of the front. The cold front will stall out from central Florida to the Bay of Campeche today and dissipate by tonight. A squall line oriented east-west off the coast of Naples Florida is producing numerous moderate and scattered strong convection from 25N-27.5N between 81W-86W, as of 0430 UTC. During the last 6 hours, the squall line has been moving slowly southeastward at 10 kt while changing little in intensity. It has been producing frequent lightning and gusts to 40 kt. This activity is being enhanced by an upper-level shortwave trough. Expect the thunderstorms over the eastern Gulf to weaken later this morning. Scattered moderate showers extend eastward from the squall line over South Florida. Elsewhere, a weak surface trough is located in the SW Gulf of Mexico with axis extending from 25N90W to 21N94W. Seas are 3-5 ft across the Gulf of Mexico, except 1-3 ft in the southern Bay of Campeche. CARIBBEAN SEA... See the Special Features section above for details on an Ashfall Advisory issued for ongoing volcanic eruptions on St. Vincent. The latest surface analysis depicts a rather weak pressure gradient across the basin. A recent ASCAT pass shows fresh trades over the central Caribbean and Gulf of Honduras, with moderate winds elsewhere. Mainly fair weather conditions are in place across the basin, except for a few scattered showers off the coasts of Costa Rica and Panama. Wave heights are in the 4-6 ft range across most of the basin, except locally up to 7 ft in the south-central Caribbean. For the forecast, fresh southeast winds are expected over the northwestern Caribbean through the 5-day forecast period, with fresh to strong east to southeast winds in the Gulf of Honduras. Winds will pulse to strong speeds over a small area near the coast of Colombia during the afternoons and at night through Thu. Elsewhere, generally moderate to fresh east winds will change little through Fri night. ATLANTIC OCEAN... See the Special Features section above for details on an Ashfall Advisory issued for ongoing volcanic eruptions on St. Vincent. A surface trough extends from 30N74W to the N coast of Cuba near 23N79W. Upper-level diffluence to the east of Florida is enhancing a cluster of moderate to strong thunderstorms currently impacting the central Bahamas area, as of 0400 UTC. This cluster of storms should weaken later this morning. Scattered moderate showers and isolated tstorms are occurring elsewhere west of 70W from 23N-32N. ASCAT shows fresh to locally strong S to SW winds to the east of Florida, mainly north of 26N extending to 70W. A 1016 mb high pressure is centered near 28N62W. The high extends a ridge axis to the SE Bahamas. ASCAT shows moderate anticyclonic winds to the east of the SE Bahamas. Seas are 6-8 ft north of the Bahamas between 70W-77W. For the forecast west of 65W, fresh to strong southwest winds east of Florida will shift eastward today ahead of a cold front that will move off the southeastern U.S. coast this morning. The front will reach from near 31N75W to east-central Florida by late this morning and from near 31N70W to the central Bahamas to east-central Cuba this evening. The front will move east of 65W on Wed as weak high pressure builds in behind it over the western Atlantic. Another cold front is expected to cross the waters to the north and northeast of the Bahamas on Tue. Fresh to strong southwest winds are expected to precede this front. Farther east, a surface trough extends from 26N45W to 23N57W, with isolated showers near its axis. Another surface trough extends from 27N30W to 16N52W. Upper-level diffluence is sparking scattered moderate showers and tstorms along and east of this surface trough axis, mainly east of 42W from 20N-29N. A recent ASCAT pass shows fresh to strong W winds north of 29N between 30W-42W associated with a low pressure system north of our discussion area. Seas are 10-12 ft in this area. Northerly swell over the central Atlantic will diminish today as the low moves NE and weakens. A 1020 mb high is located over the Canary Islands. A surface ridge with light to gentle winds extends from this high to 18N47W to 22N59W. $$ Hagen