295 AXNT20 KNHC 181741 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 141 PM EDT Tue Sep 18 2018 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...SPECIAL FEATURES Tropical Depression Joyce is centered near 31.6N 27.4W at 18/1500 UTC or 385 nm S of the Azores moving S at 7 kt. Joyce will gradually turn to the southwest and west over the next couple of days. Estimated minimum central pressure is 1009 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Gradual weakening is forecast during the next couple days, and Joyce is forecast to become a remnant low tomorrow. Scattered moderate convection is noted between 60-90 nm northeast of the center and between 45-75 nm south of the center. Scatterometer data shows that the strongest winds are located in the northwest semicircle of Joyce. See the latest NHC forecast/ advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC for more details. ...TROPICAL WAVES... A tropical wave is approaching the Lesser Antilles with axis along 57W/58W from Suriname to 18N, moving west at 20-25 kt. Model guidance indicates the wave is associated with a 700 mb trough and is well-defined on the TPW product. It is near the leading edge of an extensive area of dry Saharan air from 12N-24N between 37W-57W. Only isolated showers are near the wave axis at this time. Moisture associated with the tropical wave is expected to mainly affect the Windward Islands later today into early Wed. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Guinea-Bissau near 12N16W to 10N20W. The ITCZ extends from 10N20W to 07N30W to near the coast of Suriname. Scattered to numerous moderate and isolated strong convection is within 300 nm south of the ITCZ from 20W-42W. Scattered moderate convection extends to within 60 nm south and 300 nm north of the ITCZ, between 42W-50W. The ITCZ is much more convectively active than 24 hours ago, especially between 37W-43W. ...DISCUSSION... GULF OF MEXICO... A weak 1015 mb surface high is over the western Gulf near 27N94W. Another 1017 mb surface high is centered over northern FL near 30N82W. Light to gentle breezes and minimal seas will continue over most of the Gulf during the next few days. An upper-level low is near 26N94W with upper-level cyclonic flow covering the western Gulf. A surface trough, associated with the remnants of Isaac, is over the northwest Caribbean along 83W from western Cuba to near Cabo Gracias a Dios, Nicaragua. The trough will move across the Yucatan Channel through Wed, then across the Yucatan Peninsula into the eastern Bay of Campeche late Wed into Thu. CARIBBEAN SEA... A trough over the northwest Caribbean along 83W from western Cuba to near Cabo Gracias a Dios, Nicaragua is associated with the remnants of Isaac. Scattered moderate convection is within 60 nm west and 120 nm east of the trough axis from 17N-21N. The trough will move west of the area on Wednesday. A trough over the southeast Bahamas continues to enhance some shower and thunderstorm activity across eastern Cuba, Jamaica and Hispaniola. High pressure building from the central Atlantic into the central Bahamas will support moderate to fresh trade winds and building seas across the entire basin late Wed through Fri. Near the coast of Colombia, fresh to strong winds are expected along with 9 ft seas through Wed. ATLANTIC OCEAN... Please refer to the Special Features section for details on Tropical Depression Joyce. An upper-level low with a surface reflection is spinning just south of Bermuda. A surface trough extends from this feature southwestward to the southeastern Bahamas. Scattered showers and thunderstorms are located along and east of the trough axis west of 65W. This convective activity is affecting the southeast Bahamas and the Turks and Caicos Islands. Abundant cloudiness and showers extend elsewhere east of the trough from 20N-31N between 56W-65W. The surface trough will likely weaken over the next 24-48 hours. Another trough extends into the forecast area from T.D. Joyce southward to near 21N32W. A narrow band of mainly low clouds with showers is associated with the trough. A 1023 mb surface high is located in between the two aforementioned troughs near 31N47W. A trough just inland over the southeastern U.S. will move eastward across the waters east of north-central Florida tonight through Wed night while weakening. Hovemoller Diagrams and satellite imagery indicate that a new tropical wave is about to move off the coast of Africa. This wave will likely be added to the 18Z map. For additional information please visit http://www.hurricanes.gov/marine $$ Hagen/GR
------------------------------------------------------------------
No comments:
Post a Comment
Note: Only a member of this blog may post a comment.