000 AXNT20 KNHC 211016 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Dec 21 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... .GULF OF MEXICO GALE WARNING... An extratropical low pressure of 1008 mb located near 26N86W is strengthening it moves NE through the NE Gulf. Overnight scatterometer data indicated a wide area of strong cyclonic winds in the vicinity of the low, with a smaller area of gale force winds to 40 kt within about 90 nm of the center in the N semicircle. These gales will progress as the low moves toward the Florida coast, and will end around midday as the low moves inland and away from the area. Seas through the day will be 8 to 11 ft. Conditions will begin to improve late today. Please refer to the latest High Seas Forecast, issued by the National Hurricane Centered the following website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. .ATLANTIC GALE WARNING... Low pressure will track across Florida later today and then northeastward into the Atlantic this evening. As it does, westerly winds will increase over Atlantic waters, with gales developing N of 28N and W of 71W this evening and continuing into at least early Wed. As the low accelerates northeast, farther away from the area, Wed, conditions will slowly improve. Seas in and near the gale area will increase to 10 to 14 ft Tue night and continue through Wed. Please refer to the latest High Seas Forecast issued by the National Hurricane Center, at the following website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the Prime Meridian at 02N and continues to around 02N02W. The ITCZ continues from 02N02W to 03N07W to 03N22W to 01N47W. Scattered moderate convection is noted from 03N to 14N between 13W and 27W as well as within 270 nm N of the ITCZ between 35W and 41W. ...GULF OF MEXICO... Please see the Special Features section above for details about a low pressure in the NE Gulf producing gale conditions this morning. A large area of numerous moderate to scattered strong convection is noted in association with this low pressure, from 26N to 31N between 83W and 86W. In addition, a cold front trails southward from the low, stretching from 26N86W to the Yucatan Channel. Scattered moderate to isolated strong convection is also present in advance of this cold front, extending as far east as 82W. Finally, a slow-moving warm front extends east from the low to near Fort Myers, Florida. As the low and cold front progress east and northeast this morning, the potential for strong to severe thunderstorms exists over the far eastern Gulf of Mexico. Farther west, high pressure of 1022 mb, centered offshore Tampico, Mexico, is building SE into the Gulf. Outside of the winds in direct association with the low pressure, fresh NW winds dominate the basin, with an area of strong NW occurring just offshore Veracruz, Mexico. Ahead of the cold front in the far SE basin, including the Florida Straits, winds are moderate to fresh out of the SW. Seas of 8 to 11 ft extent across a broad area of the Gulf, stretching from the Bay of Campeche and SW Gulf, through the central Gulf, and into the NE Gulf. Seas are likely higher near the most robust convection in the NE basin. In the NW Gulf, seas of 5 to 7 ft are present, with seas of 4 to 6 ft occurring to the east of the cold front in the far SE Gulf. For the forecast, the aforementioned low pressure will track NE and move inland into Florida by midday, ending gales for the NE Gulf of Mexico, with the cold front moving SE of the Gulf by this evening. Fresh to strong winds and seas of 8 to 10 ft behind the front will gradually subside Wed. High pressure crossing the northern Gulf will lead to tranquil conditions Wed night through Thu, but by Fri and into the weekend, fresh to possibly locally strong return S flow will develop in the western Gulf. ...CARIBBEAN SEA... Most of the basin is void of convection, but a band of scattered moderate thunderstorms extents within about 60 nm of a cold front that is crossing the Yucatan Channel and extends SW along the coast of the Yucatan Peninsula. Convection previously associated with the eastern extension of the East Pacific monsoon trough in the far SW Caribbean has diminished and moved inland over Panama and portions of Colombia. With the cold front approaching the basin, the pressure gradient between higher pressure to the north and lower pressure over South American has been disrupted and relaxed. This has allowed for trades to diminish some overnight, and now moderate trades dominate the central and eastern basin, with light to gentle winds in the west. Seas range from 3 to 6 ft in the central, east, and southwest, with heights averaging 1 to 3 ft in the NW. For the forecast, a cold front will move into the NW Caribbean today, then gradually stall from the Windward Passage to offshore Nicaragua for the latter part the week. Fresh N winds can be expected behind the front. Otherwise, a relatively weak pressure gradient will lead to diminished trades much of the week, with generally moderate E wind expected. ...ATLANTIC OCEAN... Please see Special Features section above for information on gales that will occurring later today and tonight in association with a low pressure that will move NE off the NE Florida coast. A cold front stretches from 31N50W to 27N70W, then transitions to a slow moving warm front that continues to near West Palm Beach, Florida. Scattered convection has developed N of this warm front, offshore within about 120 nm of the Florida coast. Otherwise, most precipitation associated with this frontal boundary is well N of 31N, E of 50W. N of 28N, ahead of the front to the E of 50W, fresh to strong SW winds are occurring, with fresh to locally strong NE winds to the N and W of the boundary, also N of 28N. Seas of 8 to 10 ft are also occurring in and near this area of higher winds, although most of the wave height is deriving from long period northerly swell. Most of the rest of the basin is dry, dominated by a weakening 1020 mb high pressure center near 25N48W. To the south of this high, the gradient between it and the ITCZ is inducing fresh to strong trades, leading to seas of 8 to 11 ft. Along and to the north of the high, to near 28N, winds are moderate or less and seas are 6 ft or less. For the forecast, in advance of low pressure, a warm front will lift northward out of the region today. The low will then move NE to the north of the area late today and tonight, with gale force winds developing on both sides of it for areas N of 28N and W of 71W. A trailing cold front will cross the region Wed through Thu, bringing scattered showers and thunderstorms with it. Building high pressure behind the low should lead toward tranquil conditions Thu night through Fri. $$ KONARIK