000 AXNT20 KNHC 181741 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Apr 18 2021 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 1200 UTC surface analysis and satellite imagery through 1720 UTC. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Guinea near 11N15W, to 08N20W, and to 05N24W. The ITCZ continues from 05N24W, 01N30W, crossing the Equator along 33W, to 03SN35W, and to 03S39W. Precipitation: isolated to widely scattered moderate, and locally strong, is from 08N southward from 52W eastward. Isolated moderate is elsewhere from 10N southward from 60W eastward. GULF OF MEXICO... A warm front passes through 30N80W in the Atlantic Ocean, to Cedar Key in Florida. The front becomes stationary from Cedar Key in Florida, to 27N90W in the north central Gulf of Mexico, and curving to 19N95W along the coast of Mexico. The stationary front continues northwestward in interior sections of Mexico. A surface trough is just to the west of the Yucatan Peninsula, along 90W/91W from 18N in Mexico to 25N. Precipitation: scattered moderate to isolated strong is within 125 nm to the south of the stationary front between 83W and 92W. Isolated moderate to locally strong is elsewhere, within 180 nm on the northern side of the stationary front, and in Florida and in the Atlantic Ocean from 27N northward between 76W and 83W. A nearly stationary front extends from near Cedar Key, Florida, to 25N92W, to just south of Veracruz in Mexico. Strong to near gale-force winds are occurring to the west of this boundary along the Mexican coast. This front will remain nearly stationary into mid week, before reinforcing cool and dry air pushes the front into the far southeastern Gulf of Mexico from Wednesday into Thursday. CARIBBEAN SEA... The GFS model for 250 mb shows: broad anticyclonic wind flow in the Caribbean Sea. A ridge is along 79W, between Jamaica and 80W. The GFS model for 500 mb shows: an anticyclonic circulation center that is in the northern coastal waters of Haiti. Anticyclonic wind flow covers the Caribbean Sea from 14N northward from 80W eastward. A NW-to-SE oriented trough extends from the Yucatan Channel to 13N76W. The GFS model for 700 mb shows: a ridge from an Atlantic Ocean anticyclonic circulation center that is near 23N68W, to eastern Honduras/NE Nicaragua. The monsoon trough is along 11N74W in northern Colombia, across Panama along 08N/09N, beyond southern Costa Rica, into the eastern Pacific Ocean. Precipitation: scattered moderate to strong is in a few clusters, from 13N southward from 75W westward, in general. One of the specific areas of precipitation is along the coast of Colombia between 75W and 77W. Another specific area of precipitation is from 10N to 12N between 80W and 83W. Broken to overcast low level clouds, and isolated moderate rainshowers, cover the rest of the Caribbean Sea. The clouds and isolated moderate precipitation are moving with the surface-to-low level wind flow. A ridge extends to the north of the basin, across the Atlantic Ocean, through the central Bahamas. Fresh to strong SE winds north of central Honduras will diminish this afternoon. The high pressure center will shift eastward, in advance of a weak front that is moving through the Gulf of Mexico, allowing the trade winds to increase in mainly the south central Caribbean Sea through mid week. ATLANTIC OCEAN... A cold front extends from a 1015 mb low pressure center that is near 32N59W, to 31N61W. The front is stationary from 31N61W to 31N73W. The front is warm from 31N73W to the NE coast of Florida near 30N. Precipitation: isolated moderate to locally strong is from 24N northward between 40W and 60W, and from 28N northward from 60W westward. A surface ridge extends from a 1025 mb high pressure center that is near 33N31W, to 29N42W to 22N59W, across the Bahamas to 24N80W in the Straits of Florida. Surface anticyclonic wind flow covers the Atlantic Ocean away from the 59W-to-NE Florida frontal boundary southward. An east-to-west-oriented frontal boundary will remain nearly stationary off the coast of northeastern Florida, through the early part of the week, as a ridge extends westward from the central Atlantic Ocean through the central Bahamas. Looking ahead: as the ridge shifts eastward by Wednesday, a slightly stronger frontal boundary will move off the southeastern U.S.A. coast by Thursday. $$ mt/ec