396 AXNT20 KNHC 260044 AAA TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 844 PM EDT Tue Sep 25 2018 Updatec Special Features section 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...Special Features...Updated A 1014 mb low is centered about 175 nm south of Cape Hatteras, North Carolina. A surface trough extends southwestward from the low to near 29N77W. According to reports from an Ar Force Reserve Hurricane Hunter aircraft the circulation associated with this low pressure area has become better defined. Latest satellite imagery shows that associated shower and thunderstorm activity is rather disorganized, and the low has not yet developed into a tropical depression. Only scattered moderate convection is seen removed to the NE and E of the center within 30 nm of line from 32N74W to 33N74W to 34N74W and 34N75W. Some additional development is possible tonight as the low moves northward near or over portions of extreme eastern North Carolina. After tonight, development appears unlikely due to strong upper-level winds while the system moves generally north-northeastward near the eastern United States coast. Regardless of development, this system is likely to bring scattered showers and thunderstorms across portions of eastern South Carolina and eastern North Carolina tonight. In addition, dangerous surf conditions and rip currents are expected along portions of the North Carolina coast tonight. There is a medium chance of of this system becoming a tropical cyclone during the next 48 hours. For more information, please see products from your local National Weather Service office. The remnant of Kirk is analyzed as a 1007 mb low near 12N48.5W or about 650 nm east of the Windward Islands. A tropical wave extends from the low to near 17N, and south of the low to near 04N. This system is moving westward at about 22 kt. The associated shower and thunderstorm activity has become a little better organized during the last several hours, however, the system still appears to lack a closed circulation.Scattered moderate convection is within 120 nm of the low in the SE and NW quadrants, and within 90 nm of the low in the NE and SW quadrants. This system continues to produce winds to near gale force on its north side. This disturbance is likely to redevelop into a tropical cyclone during the next day or two before it moves into an area of highly unfavorable upper-level winds as it approaches the Caribbean Sea. Interests in the Windward and Leeward Islands should monitor the progress of this disturbance as gusty winds and locally heavy rains are likely over the next couple of days even if the system does not redevelop into a tropical cyclone. There is a high chance of redevelopment of this system within the next 48 hours. For more information on this system, see High Seas Forecasts issued by the National Weather Service. ...TROPICAL WAVES... A far eastern Atlantic tropical wave has its axis along 21W from 03N to 17N, moving westward at 10 to 15 kt. A 700 mb trough associated with this wave is well depicted in model guidance. Saharan air is not as prevalent near the wave as it was yesterday. The SAL has moved out ahead of the wave and is not as dense, as suggested by GOES-16 Geo-color imagery and split-window imagery. Isolated showers and thunderstorms are within 150 nm west and 120 nm east of the wave axis from 11N to 14N. A tropical wave has its axis along 59W south of 19N, moving westward at 15 kt. The wave corresponds with a moisture maximum in TPW imagery. In addition, satellite imagery depicts ample deep moisture in the form of multilayer clouds surrounding the wave south of 17N. Scattered showers and thunderstorms are underneath these clouds from 08N to 15N between 57W and 62W, including the Windward Islands Gusty winds are possible with some of this activity. This activity is likely to continue through Wed morning. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the African coast near the border of Senegal/Guinea-Bissau border to 07N21W and to 07N25W. The ITCZ begins at 06N27W and continues to 07N36W to 10N44W, then resumes west of the remnants of Kirk near 08N48W to near the coast of Suriname near 06N57W. Outside of the convection mentioned with the two tropical waves and the remnants of Kirk, scattered moderate isolated strong convection is within 60 nm north of the ITCZ between 25W-30W and between 31W-36W. Similar activity is within 30 nm south of the ITCZ between 30W-32W. Scattered moderate convection is within 30 nm north of the trough between 18W-20W, and along the coast of Africa from 14N to 17N. ...DISCUSSION... GULF OF MEXICO... Upper-level diffluence over the north-central Gulf Coast is enhancing scattered showers and isolated thunderstorms north of 27N between 84W-90W. A thermal trough over the east-central Bay of Campeche is weakening and is no longer producing any significant shower activity. A surface trough will develop over the Yucatan peninsula each evening, shift W over the SW Gulf each night, then dissipate each morning. Elsewhere across the Gulf, gentle to moderate winds will increase to between moderate and fresh during the second half of this week as high pressure builds N of the region. CARIBBEAN SEA... Scattered showers and thunderstorms ahead of a tropical wave that is approaching the Windward Islands have moved into the far eastern Caribbean, and are south of 17N east of 64W to across the Windward Islands. Isolated showers and thunderstorms are elsewhere over the eastern Caribbean. The eastern Pacific monsoon trough combined with diffluence aloft earlier enhanced scattered moderate to isolated strong convection in the SW Caribbean. Over the past few hours, this activity has diminished to scattered showers and isolated thunderstorms. Scattered moderate convection over the interior sections of Honduras and Nicaragua are gradually diminishing, with the heaviest of this activity now having shifted to the western sections of those countries. Expect fresh to strong winds over the central Caribbean through midweek, with moderate to fresh winds thereafter through Friday. ATLANTIC OCEAN... Currently, there are three tropical waves in the tropical Atlantic between Africa and the Lesser Antilles. There is also a low with development potential off the southeast coast of the U.S. For information on those features, please read the Special Features and Tropical Waves sections above. A cold front is analyzed from near 32N52W to near 30N60W, where it becomes a dissipating stationary front to 31N64W. Little to no shower activity is observed with the front at this time. A surface trough is analyzed from just north of the area at 33N41W to 26N45W to 23N53W and to near 21N62W. Scattered moderate isolated strong convection is within 90 to 120 nm east of the trough north of 25N. Elsewhere, ridging over the northeast Atlantic is helping to create fair weather north of 20N and east of 35W. For additional information please visit http://www.hurricanes.gov/marine $$ MT/Aguirre