000 AXNT20 KNHC 131644 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Fri Oct 13 2023 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 1200 UTC surface analysis and satellite imagery through 1600 UTC. ...SPECIAL FEATURES... Tropical Storm Sean is centered near 14.6N 41.7W at 13/1500 UTC or 1030 nm W of the Cabo Verde Islands, moving WNW at 10 kt. Estimated minimum central pressure is 1006 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Peak seas are currently around 15 ft. Sean is a sheared tropical storm and scattered moderate isolated strong convection is evident within 60 nm in the N semicircle. Additional scattered moderate convection is evident within 360 nm in the NE semicircle. A turn toward the northwest at a similar forward speed is expected today. Sean is then expected to gradually slow down, turning back toward the west- northwest by Sunday. Additional weakening is anticipated. Sean will likely become a post-tropical remnant low over the weekend. Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website - https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest Sean NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. West Atlantic Gale Warning: A gale force 993 mb low pressure is centered just N of the area near 32N65W. A cold front extends SW from the low to 28N73W to 29N78W then continuing as a stationary front to 1008 mb low pressure near Jacksonville, Florida at 30.5N81.5W. A warm front extends from 25N54W to 31N59W to the low. Scattered moderate convection is evident within 250 nm ENE of the front. Gale force winds are occurring N of 28N ahead of the front as confirmed by a recent ASCAT scatterometer pass which showed 30-40 kt winds. Peak seas are 10-13 ft. Scattered moderate convection is noted from 23N to 29N between 60W and 74W, and from 26N to 29N between 74W and 80W continuing across S Florida. The gale force winds will continue ahead of the front as it moves SE across the northern Atlantic waters through the weekend. Continued scattered showers and thunderstorms as well as rough seas are expected with this frontal system. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...TROPICAL WAVES... An eastern Atlantic tropical wave has an axis along 27W/28W just SW of the Cabo Verde Islands, from 15N southward, moving W at around 10 kt. A 1010 mb low pressure area (AL94) is along the wave near 08.5N27W. Scattered moderate isolated strong convection is evident within 240 nm in the NW semicircle of the low. Winds are currently 20-25 kt with the low with seas of 5-7 ft. Only gradual development of this disturbance is expected during the next couple of days. Environmental conditions are expected to become more conducive for development by the end of the weekend while the disturbance begins to move westward across the central tropical Atlantic. Additional development is expected after that, and a tropical depression is likely to form during the early to middle portion of next week as the system moves steadily westward across the central and western tropical Atlantic. This system has a low chance of development within the next 48 hours and a high chance within the next 7 days. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through The Gambia near 13N17.5W to 1010 mb low pressure (AL94) near 08.5N27W to 06N33W. No ITCZ is evident to the W of the monsoon trough due to Tropical Storm Sean off to the NW-N. In addition to the convection associated with AL94 as described above, scattered moderate isolated strong is evident S of the monsoon trough to 04N between the coast of Africa and the tropical wave along 27W/28W. ...GULF OF MEXICO... A pair of 1008 mb lows are located over the northern Florida Panhandle, one near Jacksonville and the other near Destin. A trough, which is the remnants of an old front, extends from across Lake Okeechobee to the central Gulf near 25N92W. Scattered thunderstorms are S of the trough to 25N to the E of 86W across portions of S Florida. Moderate to locally fresh S winds are S of the trough to the E of 87W including through the Yucatan Channel. Light to gentle winds are elsewhere in the basin. For the forecast, the remnants of a stationary front will gradually dissipate over the northeast Gulf through tonight. Scattered showers and thunderstorms in the SE Gulf will also move E of the area today also. High pressure across the Atlantic will build modestly westward into the eastern Gulf through early Sat, before the next cold front moves into the NW Gulf Sat morning and across the entire basin by Sun evening. ...CARIBBEAN SEA... A weak ridge extends from N of Puerto Rico and Hispaniola to across central Cuba. Mainly moderate E-SE winds are found across the Caribbean basin E of 83W, with moderate to fresh SE-S winds W of 83W including through the Yucatan Channel. Seas are 2-4 ft in the eastern Caribbean and 3-6 ft elsewhere, highest offshore northern Colombia and in the NW Caribbean. Other than a few spotty, isolated showers and thunderstorms, the basin is quite fair and dry. For the forecast, moderate to fresh trade winds across the eastern and central Caribbean will diminish to gentle to moderate today and prevail through Tue. Fresh SE to S winds in the Gulf of Honduras will continue through tonight. A cold front will sink S-SE across the western Atlantic over the weekend maintaining the weak trade wind flow across the basin and support moderate to fresh northerly winds in the NW Caribbean Mon and Tue. ...ATLANTIC OCEAN... Please read the Special Features section for details on a Gale Warning over the western Atlantic and on Tropical Storm Sean. Please read the Tropical Waves section for details on AL94. A ridge extends along 20N/21N to the S of the gale force cold frontal system. Mainly gentle to moderate winds are under the influence of this ridge across the waters S of 23N/24N away from Sean and AL94, along with seas of 3-6 ft, higher closer to Sean. An old cold front is dying from 31N37W to 27N50W with a pair of pre-frontal troughs noted about 300 nm SE of the parent front. Moderate to locally fresh winds are within the same area ahead of the front, as well as N of 29N between 43W and 48W. Seas are 5-7 ft N of 27N between 30W and 50W, locally 8 ft near 31N47W. For the forecast W of 55W, see the Special Features section above. Looking ahead, another cold front will move off the northeast Florida coast by early Sun, stall from near Bermuda to central Cuba by late Mon. $$ Lewitsky