000 AXNT20 KNHC 201804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sun Aug 20 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 1740 UTC. ...SPECIAL FEATURES... Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details on these special features. ...in the Eastern Tropical Atlantic Ocean (AL98): Shower and thunderstorm activity continues in association with a tropical wave, and a 1006 mb broad area of low pressure center, that is near 16N35W. This position is several hundred miles to the west of the Cabo Verde Islands. The environmental conditions appear to be generally favorable for more development of this system. It is likely for a short-lived tropical depression to form this weekend. It will move west-northwestward or northwestward 10 mph across the eastern tropical Atlantic Ocean. The upper level winds that will be over the system are forecast to increase by early next week. More development is not expected. The chance of formation into a tropical cyclone during the next 48 hours is high. Please, refer to the latest NHC Tropical Weather Outlook, at www.hurricanes.gov, for more details. ...TROPICAL STORM EMILY... The center of Tropical Storm Emily, at 20/1500 UTC, is near 19.5N 38.8W. Emily is moving WNW, or about 300 degrees, 09 knots. The estimated minimum central pressure is 1001 mb. The maximum sustained wind speeds are 45 knots with gusts to 55 knots. Tropical storm force winds are within 160 nm of the center in the NE quadrant; within 0 nm of the center in the SE quadrant; within 0 nm of the center in the SW quadrant; and within 100 nm of the center in the NW quadrant. The sea heights of 12 feet or greater are within 180 nm of the center in the NE quadrant; within 0 nm of the center in the SE quadrant; within 0 nm of the center in the SW quadrant; and within 150 nm of the center in the NW quadrant. Precipitation: scattered to numerous strong is within 250 nm of the center in the N quadrant. Please, refer to the following website, www.hurricanes.gov, for more information. ...TROPICAL DEPRESSION SIX... The center of TROPICAL DEPRESSION SIX, at 20/1500 UTC, is near 16.8N 53.7W. T.D. SIX is moving westward, or 280 degrees, 10 knots. The estimated minimum central pressure is 1008 mb. The maximum sustained wind speeds are 30 knots with gusts to 40 knots. The sea heights range from 7 feet to 11 feet within 300 nm of the center in the N semicircle. The sea heights range from 5 feet to 8 feet within 400 nm of the center in the S semicircle. Expect the wind speeds to range from 20 knots to 30 knots from 16N to 19N between 52W and 54W. Precipitation: numerous strong is from 15N to 18N between 51W and 55W. Please, refer to the following website, www.hurricanes.gov, for more information. ...INVEST AL90 IN THE EASTERN CARIBBEAN SEA... A 1004 mb low pressure center is near 14N65W, along a tropical wave. Precipitation: numerous strong is from 12N to 15N between 65W and 67W. Scattered moderate to strong is from 11N to 18N between 54W and 64W. The sea heights are reaching 10 feet in most of the eastern one-third of the Caribbean Sea, except for 4 feet in the coastal waters of Venezuela. The sea heights are ranging from 5 feet to 7 feet in the central Caribbean Sea, between 70W and Jamaica. The precipitation pattern continues to show signs of organization. More development of this weather system is expected. It is likely for a tropical depression to form during the next couple of days. The movement will be westward to west-northwestward 10 to 15 mph in the eastern and the central Caribbean Sea. The weather system is forecast to turn northward, and move into the southwestern Atlantic Ocean by midweek. Heavy rainfall is possible in parts of the Lesser Antilles during the next couple of days. Anyone who has interests in the eastern and the central Caribbean Sea should monitor the progress of this system. A NOAA Hurricane Reconnaissance mission is scheduled to investigate the system later today. The chance of formation into a tropical cyclone during the next 48 hours is high. Please, refer to the following website, www.hurricanes.gov, for more information. ...INVEST 91L IN THE WESTERN GULF OF MEXICO... A far eastern Gulf of Mexico area of disturbed weather is expected to lead to the formation of a broad area of low pressure early this week. It is possible that some slow development of this weather system may occur. The weather system is forecast to move westward 15 to 20 mph. It is possible that a tropical depression may form, as it the weather system approaches the western Gulf of Mexico coastline by Tuesday. The chance of formation into a tropical cyclone during the next 48 hours is medium. Please, refer to the following website, www.hurricanes.gov, for more information. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 22W/23W, from 22N southward, moving westward 10 knots to 15 knots. Precipitation: widely scattered to scattered moderate and isolated strong is from 07N to 19N between Africa and 31W. The environmental conditions appear to be conducive for gradual development of this weather system. It is possible that a tropical depression may form later this week. The weather system is forecast to move west-northwestward through the eastern tropical Atlantic Ocean. Please, refer to the following website, www.hurricanes.gov, for more information. A Caribbean Sea tropical wave is along 86W/87W, from 22N southward, moving westward 10 knots to 15 knots. Precipitation: widely scattered moderate to isolated strong is from 15N northward from 80W westward, especially along the coast of the Yucatan Peninsula and Belize. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the SW coastal areas of Senegal, 12N23W, and 17N35W. Precipitation: isolated moderate to locally strong is elsewhere from 20N southward from 60W eastward. ...GULF OF MEXICO... Please, read the SPECIAL FEATURES section, for details about the INVEST 91L, and the GULF OF MEXICO developing low pressure center. A north-to-south oriented surface trough extends from the Florida Big Bend toward the Yucatan Channel. Precipitation: scattered moderate to widely scattered strong is in the eastern half of the area. Fresh cyclonic wind flow is to the east of the surface trough, and within 75 nm of the tropical wave to the west. Moderate NE winds are elsewhere from 90W eastward. Gentle to moderate winds cover the western half of the area. The sea heights are: reaching 3 feet off the NW coast of the Yucatan Peninsula, and in the SE Gulf/Straits of Florida; and they are ranging from 1 foot to 2 feet elsewhere. Broad upper level cyclonic wind flow, and isolated moderate to locally strong precipitation, are in the western half of the Gulf of Mexico. A surface ridge over the Gulf waters will support mostly gentle to moderate winds and slight seas across most of the basin today. Moderate to fresh winds are noted in the eastern Gulf due to a trough extending across the region. Looking ahead, an area of disturbed weather located in the far eastern Gulf of Mexico is expected to lead to the formation of a broad area of low pressure early this week. Some slow development of this system could occur thereafter as it moves westward at about 15 to 20 mph, and a tropical depression could form as it approaches the western Gulf of Mexico coastline by Tuesday. This system has a low chance of development in 48 hours and a medium chance in 7 days. ...CARIBBEAN SEA... Please, refer to the SPECIAL FEATURES section, for details about the INVEST AL90. Please, refer to the TROPICAL WAVES section, for details about the 86W/87W tropical wave. Some sea height information is in the SPECIAL FEATURES section, regarding the AL90 INVEST. The sea heights are reaching 4 feet in the SW corner of the area, and they are ranging from 1 foot to 2 feet elsewhere. Strong NE winds are within 240 nm off the coast of Colombia between 74W and 78W. Fresh NE winds are elsewhere in the central one-third of the area. Moderate or slower wind speeds cover the rest of the area. The monsoon trough is along 10N74W, southwestward beyond eastern Panama, and into the Pacific Ocean. Precipitation: scattered moderate to strong is from 16N southward from 74W westward. The 24-hour rainfall totals in inches, according to the Pan American Temperature and Precipitation Tables, MIATPTPAN, for the period that ended at 20/1200 UTC, are: 1.76 in Guadeloupe; 0.89 in Freeport in the Bahamas, 0.66 in Trinidad; 0.60 in Curacao; and 0.13 in Montego Bay in Jamaica. A tropical wave/low pressure is over the eastern Caribbean. Showers and thunderstorms continue to show signs of organization in association with this area of low pressure. Additional development of this system is expected, and a tropical depression is likely to form during the next couple of days as it moves W to WNW at 10 to 15 kt over the eastern and central Caribbean, before turning northward and moving into the southwestern Atlantic Ocean by midweek. Regardless of development, heavy rainfall is possible over portions of the Lesser Antilles during the next couple of days. Interests in the eastern and central Caribbean should monitor the progress of this system. A NOAA Hurricane Reconnaissance mission is scheduled to investigate the system later today. This system has a high chance of evelopment in 48 hours. Regardless of development, strong winds and moderate to rough seas can be expected through midweek. ...ATLANTIC OCEAN... Please, refer to the SPECIAL FEATURES section, for details about TROPICAL STORM EMILY and TROPICAL DEPRESSION SIX. Upper level cyclonic wind flow is from 20N northward between 50W and 66W. Precipitation: widely scattered moderate to isolated strong is from 25N northward between 48W and 65W. The GFS model for 500 mb and for 700 mb shows that broad cyclonic wind flow is to the east of the Gulf of Mexico surface trough, reaching 74W in the Atlantic Ocean. Precipitation: widely scattered moderate to isolated strong is to the northwest of the line that runs from 30N70W to the Straits of Florida. The subtropical ridge covers the rest of the Atlantic Ocean. Fresh winds are elsewhere to the south of the line 28N32W 24N48W 23N60W 27N73W. Moderate or slower wind speeds are in the remainder of the Atlantic Ocean. The sea heights range from 4 feet to 7 feet in the remainder of the area. Tropical Depression Six is near 16.8N 53.7W at 11 AM EDT, and is moving west at 10 kt. Maximum sustained winds are 30 kt with gusts to 40 kt, and the minimum central pressure is 1008 mb. Six will move to 16.9N 55.1W this evening, become a remnant low and move to 17.2N 57.0W Mon morning, and dissipate Mon evening. Fresh to strong tradewinds will pulse off Hispaniola and the Windward Passage each evening through Tue night. Fresh tradewinds south of 25N will persist through Tue. $$ MT