000 AXNT20 KNHC 122356 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Sep 13 2022 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis analyzed from near 20N19W to 13N20W to 05N21W. It is moving westward at 15 kt. Scattered moderate to isolated strong convection is increasing from 12N to 18N between 19W-22W. Scattered moderate convection is east of the wave from 09N to 12N between 16W-20W. Environmental conditions appear only marginally favorable, and any development of this wave should be slow to occur while it moves westward or west-northwestward across the eastern tropical Atlantic through the end of the week. A central Atlantic tropical wave has its axis extending from 21N42W to 13N44W to 04N44W. It is moving westward at 15-20 kt. Latest ASCAT data shows a rather sharp northeast to southeast wind shift across the wave axis consisting of mainly fresh wind speeds. Satellite imagery shows an increasing area of numerous moderate to strong convection east-northeast of the wave from 14N to 18N between 34W-44W. Scattered moderate convection is from 8N to 11N between 37W-44W. Some slow development of this system is possible over the next several days while it moves generally westward to west-northwestward over the central tropical Atlantic and approaches the Windward Islands by the end of the week. An eastern Caribbean tropical wave has its axis along 66W south of 21N moving westward near 20 kt. This position is extrapolated from a time series analysis of the latest available upper-air data from Barbados, St. Martin, San Juan and the Dominican Republic. This wave is void of deep convection, however, low- level clouds moving westward with possible isolated showers are noted north of 13N within 180 nm either side of the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough axis enters the Atlantic through the coast of Mauritania near 18N16W, and continues southwestward to 12N24W and to 13N30W to 14N40W and to 09N46W to 09N53W. Aside from convection associated with the tropical waves, an area of scattered moderate to isolated strong convection is south of the trough axis from 06N to 09N between 23W-31W. Scattered moderate convection is within 120 nm south of the trough axis between 34W-39W, and within 60 nm north of the trough axis between 51W-53W. GULF OF MEXICO... A cold front is analyzed from near New Orleans, Louisiana southwestward to 28N93W and to inland southern Texas just north of Brownsville. Noticeably drier air is following in behind it. To its east, a surface trough extends from southeastern Georgia southwestward to near Panama City, Florida and continues to 27N90W to 23N93W and to the Bay of Campeche near 18N95W. The base of a broad upper- level trough is noted on water vapor imagery to reach south to roughly along 28N and between 88W-99W. Scattered moderate convection is over the NE Gulf north of 27N and east of the surface trough to inland the Florida peninsula. Scattered showers and isolated thunderstorms are seen south of 27N and east of the surface trough. Skies west of the cold front are mostly clear, while between the cold front and surface trough there are pockets of scattered showers and thunderstorms. Per the latest ASCAT data pass, gentle to moderate north to northeast winds are between the surface trough and front, except for moderate to fresh north winds in the western Bay of Campeche south of 22N and west of 94W, including offshore Veracruz. Light and variable winds are east of the surface trough north of 24N, and gentle east to southeast winds are south of 24N. Seas relatively low throughout, in the 1-3 ft range except 2-4 ft in the southwestern Gulf area. For the forecast, the surface trough extending from near Panama City, Florida to 27N90W to 23N93W and to the Bay of Campeche near 18N95W will linger over the southwestern Gulf into mid-week, ahead of a cold front currently moving through across the northwest Gulf. The weak cold front will shift slowly south then stall from near Tampa, Florida to Corpus Christi, Texas by mid week then dissipate. Looking ahead to later in the week, high pressure will build over the southeast U.S. following the front, maintaining gentle to moderate easterly breezes and slight seas. CARIBBEAN SEA... An upper-level low is identified on water vapor to near near 21N68W, while a smaller one is over Cuba near 23N81W. With plenty of Atmospheric already in place, these features are helping to maintain active weather in the form of scattered to numerous showers and thunderstorms across Cuba, Hispaniola and over some sections of western Puerto Rico. Upper-level diffluent flow between the upper-level low near 21N68W and upper anticyclonic flow west of 79W is helping to sustain isolated to scattered showers and few thunderstorms over the central and western Caribbean waters. Scattered showers and thunderstorms are also over the southwestern Caribbean south of 13N between 76W-82W. This activity is being further aided by the eastern extension of the eastern Pacific monsoon trough that extends along 11N to low pressure of 1010 mb over northwestern Colombia near 11N75W. Isolated showers moving westward are over the eastern Caribbean moving. Some of this activity is associated to the tropical wave along 66W. Weak high pressure north of the basin is allowing for moderate to locally fresh trade winds in the south-central Caribbean, while moderate or weaker winds are found elsewhere. Seas of 3-5 ft are over the south-central Caribbean and also north of 15N between 64W-72W. Seas of 2-4 ft are 15N to 18N between 72W-85W, and lower seas of 1-3 ft are elsewhere over the basin. For the forecast, gentle to moderate winds and slight to moderate seas will continue into Tue over the Caribbean as a tropical wave moves across the eastern and central portions of the basin. Winds and seas will begin to increase from east to west starting late Wed over the central Caribbean as high pressure builds north of the area in the wake of the tropical wave. Northerly swell will propagate through the Atlantic passages early on Tue and will gradually subside late Wed. Looking ahead, another tropical wave will move into the eastern Caribbean Fri, and reach the central Caribbean by Sat. ATLANTIC OCEAN... A cold front enters the area through 31N46W and continues to 27N51W, where it transitions into a dissipating stationary front that extends to 24N65W to 25N70W and northwestward to 31N75W. Scattered showers and thunderstorms are seen along and within 120 nm south of the stationary front between 70W-75W and along and within 30 of the stationary front between 65W-70W. Scattered showers and thunderstorms are within 30-60 nm southeast of the cold front north of 26N. Fresh southerly winds are north of 29N and east of the cold front to near 40W. Northerly swell associated with the remnants of former Hurricane Earl are generating seas of 8-10 ft N of 22N and between 40W and 74W. In the central Atlantic, a surface trough extends from 25N59W to 21N53W and to 17N54W. Isolated showers are along and just west of the trough. In the eastern Atlantic, high pressure of 1020 mb is analyzed near 30N34W, with a ridge stretching west-southwestward to 24N50W and another ridge east-northeastward to 30N18W. This feature controls the wind regime over the eastern Atlantic waters north of 20N maintaining generally mostly fair skies there. The remnants of former Hurricane Danielle are located a couple hundred miles east of Portugal and are generating a large swell region that extends into the tropical Atlantic. Seas of 8-11 ft are present north of 27N and east of 31W. Moderate to locally fresh northerly winds are north of 15N and east of 31W. Seas of 5-8 ft are north of of 15N and east of 31W. Elsewhere, moderate or weaker winds and seas of 4-6 ft continue. For the forecast west of 55W, northerly swell of 8 to 12 ft spreading across the waters east of the Bahamas is expected to subside into Wed. Looking ahead, the northern end of a tropical wave will pass 55W south of 22N by early on Fri bringing fresh east winds and locally rough seas to the area northeast of the northern Leeward Islands. The wave may weaken as it continues westward toward the Turks and Caicos Islands and southern Bahamas through Sat. $$ Aguirre