341 AXNT20 KNHC 101632 CCA TWDAT Tropical Weather Discussion...Corrected NWS National Hurricane Center Miami FL 805 AM EDT Mon Sep 10 2018 Corrected Caribbean Sea section to include Hurricane Isaac information 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 0600| UTC surface analysis and satellite imagery through 1145 UTC. ...SPECIAL FEATURES... Hurricane Florence is centered near 24.9N 58.9W at 10/0900 UTC or 545 nm SE of Bermuda and about 465 nm NNE of the northern Leeward Island moving WNW or 285 degrees at 8 kt The estimated minimum central pressure is 969 mb. The maximum sustained wind speeds have increased to 90 kt with gusts to 110 kt. Florence is rapidly strengthening. Latest satellite imagery shows an apparent 10 nm wide eye feature with Florence. Scattered moderate convection is within 90 nm of the eye in the NE quadrant, within 60 nm of the eye in the NW quadrant and within 30 nm in the semicircle. Scattered moderate isolated strong convection is elsewhere within 180 nm of the eye in the NE quadrant and within 150 nm of the eye in the SW quadrant. Scattered moderate convection is within 120 nm of the eye in the N and NW quadrants and within 60 nm of the eye in the S quadrants. Scattered moderate convection is seen well away from Florence from 21N to 24N between 56W and 63W, and from 24N to 27N between 61W and 64W. Latest NHC advisory has Florence continuing to strengthen as it tracks in a west-northwest motion during the next couple of days, before an expected turn to the northwest occurs Wed night or on Thu. Public Advisories for Florence are issued under WMO header WTNT31 KNHC and under AWIPS header MIATCPAT1. Forecast/Advisories for Florence are issued under WMO header WTNT21 KNHC and under AWIPS header MIATCMAT1. Hurricane Isaac is centered near 14.7N 42.7W at 10/0900 UTC, which is about 1070 nm E of the Windward Islands, moving or 275 degrees at 12 kt. The estimated minimum central pressure is 993 mb. The maximum sustained wind speeds are 65 kt with gusts to 80 kt. Issac has changed little during the past several hours. Isaac remains a small hurricane, with scattered moderate to numerous strong convection within about 75 nm of the center, except 60 nm in the N and S quadrants. Scattered moderate convection denotes an outer rainband within 30 nm of a line from 12.5N44W to 14N45W. Scattered moderate convection is within 30 nm of 13N46W and within 30 nm of 14N47W. Latest NHC advisory forecasts a westward motion, with a slight increase in forward speed the end of the week. Public Advisories for Isaac are issued under WMO header WTNT34 KNHC and under AWIPS header MIATCPAT4. Forecast/Advisories for Isaac are issued under WMO header WTNT24 KNHC and under AWIPS header MIATCMAT4. Hurricane Helene is centered near 14.3N 28.9W at 10/0900 UTC, which is about 265 nm W of the southernmost Cabo Verde Islands, It is moving WNW or 285 degrees at 15 kt. The estimated minimum central pressure is 984 mb. The maximum sustained wind speeds are 75 knots with gusts to 90 kt. Latest satellite imagery shows scattered moderate to numerous strong convection within 120 nm of the center in the NE, SE and S quadrants, and within 90 mm elsewhere of the center. Latest NHC advisory forecasts Helene to continue its present motion through the next couple of days, before a turn to the NW occurs on Wed. Scattered moderate convection is seen from 15N to 17N between 27W and 31W, and from 11N to 12.5N between 29W and 32W. Public Advisories for Helene are issued under WMO header WTNT33 KNHC and under AWIPS header MIATCPAT3. Forecast/Advisories for Helene are issued under WMO header WTNT23 KNHC and under AWIPS header MIATCMAT3. ...TROPICAL WAVES... The northern portion of a tropical wave with is axis along 92W reaches northward to the eastern Bay of Campeche at 21N. Isolated weakening convection is seen over far eastern Mexico from 17N to 19N between 91W and 93W. Isolated showers and thunderstorms are over the Pacific waters near Guatemala and the Isthmus of the Gulf of Tehuantepec of southern Mexico between 92W and 95W. ...MONSOON TROUGH/ITCZ... The monsoon trough is analyzed over inland Africa. The ITCZ extends from 07.5N47W to 07N58W. Isolated moderate convection is within 60 nm S of the ITCZ between 47W and 53W and within 60 nm N of the ITCZ between 54W and 58W. ...DISCUSSION... GULF OF MEXICO... An upper-level trough extends from the NE corner of the Gulf of Mexico, to an elongated upper-level low at 25N87W and southwestward to the Yucatan Peninsula. Upper-level cyclonic flow covers the Gulf of Mexico and surrounding coastal plains to the east of the line that runs from coastal Alabama, to 26N92W, to the coast of Mexico near 20N92W. Isolated showers and thunderstorms are noted over just about the entire basin, with the exception of scattered moderate isolated strong convection from 24N to 28N west of 94W. The gradient associated with a weak high pressure over the southeastern United States will maintain light to moderate winds over the basin through Fri night. A surface trough will move westward, off the coast of the Yucatan Peninsula each evening, and it will dissipate in the SW Gulf of Mexico each morning. The trough will be accompanied by moderate to fresh winds. CARIBBEAN SEA...Corrected Upper level cyclonic flow covers the Caribbean Sea to the NW of the line that runs from NW Cuba to the Gulf of Honduras. Scattered mdoerate to strong convection is seen from 14N to 22N between 80W and 84W associated mainly with with a weak surface trough. The disturbance is forecast to move slowly northwestward across the northwestern Caribbean Sea and the Yucatan Peninsula over the next couple of days with only slow development expected during that time. Isolated showers and thunderstorms are elsewhere to the NW of the line that runs from the Mona Passage to the east central coast of Nicaragua. The monsoon trough is along 09N74W in northern Colombia, beyond 10N in NW Costa Rica. Scattered mdoerate to strong convection in clusters are observed from 09N to 11N between Colombia and 77W. Hurricane Isaac well east of the basin near 14.7N 42.7W 993 mb at 5 AM EDT is moving W at 11 kt. Maximum sustained winds 65 kt with gusts to 80 kt. Isaac is forecast by the 09 UTC NHC advisory to reach near 15.3N 58.0W Wed night and weaken to a tropical storm near 15.5N 64.0W Thu night. Isaac is forecast to continue to weaken as it moves to the central Caribbean near 15.6N 69.2W Fri night. Otherwise, relatively weak ridging over the western Atlantic will maintain moderate to fresh trade winds over most of the region through tonight. A relatively weak surface ridge in the western Atlantic Ocean will maintain moderate to fresh trade winds in most of the region through Monday night. ATLANTIC OCEAN... Please read the Special Features section for details about Hurricane Florence, Hurricane Isaac, and Hurricane Helene. An upper level cyclonic circulation center is near 29N70W. A surface trough extends from 32N63W to near 28N66W. Upper-level cyclonic wind flow also is from 30N northward from 77W westward. Isolated showers and thunderstorms are north of 22N and west of 70W. Hurricane Isaac near 14.7N 42.7W 993 mb at 5 AM EDT moving W at 11 kt. Maximum sustained winds 65 kt gusts 80 kt. Isaac will move to 14.8N 44.6W this afternoon, 15.0N 47.4W tonight, 15.0N 50.3W Tue afternoon, 15.0N 53.0W Tue night and to 15.3N 58.0W Wed night. Isaac will weaken to a tropical storm near 15.5N 64.0W Thu night, and continue to weaken as it moves to the central Caribbean near 15.6N 69.2W Fri night. Otherwise, relatively weak ridging over the western Atlantic will maintain moderate to fresh trade winds over most of the region through tonight. Hurricane Florence near 24.9N 58.9W 969 mb at 5 am EDT this morning moving WNW at 8 kt. Maximum sustained winds are 90 kt with gusts to 110 kt. Florence will move to near 25.4N 60.5W this afternoon, 26.1N 63.1W near tonight, 27.3N 66.2W near Tue afternoon, near 28.8N 69.3W Tue night, and 32.2N 74.8W Wed night. Florence is forecast to become a major hurricane this morning, and is expected to remain an extremely dangerous major hurricane through Thursday. Florence will continue to 34.5N 78.1W Thu night, and weaken to a tropical storm while moving inland to near 35.8N 79.6W Fri night. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre