000 AXNT20 KNHC 211752 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED SEP 21 2011 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... THE CENTER OF TROPICAL STORM OPHELIA AT 21/1500 UTC IS NEAR 13.0N 43.6W...OR ABOUT 1050 NM TO THE EAST OF THE EASTERN CARIBBEAN SEA ISLANDS. OPHELIA IS MOVING WEST 14 KT. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KT WITH GUSTS TO 60 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. PUBLIC ADVISORIES ABOUT OPHELIA ARE ISSUED UNDER WMO HEADER WTNT31 KNHC AND UNDER AWIPS HEADER MIATCPAT1. FORECAST/ADVISORIES ABOUT OPHELIA ARE ISSUED UNDER WMO HEADER WTNT21 KNHC AND UNDER AWIPS HEADER MIATCMAT1. NUMEROUS STRONG CONVECTIVE PRECIPITATION IS FROM 12N TO 14N BETWEEN 41W AND 43W. THIS PRECIPITATION RANGES FROM 90 NM TO 120 NM AWAY FROM THE SYSTEM CENTER IN THE EASTERN SEMICIRCLE. AN UPPER LEVEL TROUGH PASSES THROUGH 33N28W TO 29N34W 25N42W AND 26N51W. UPPER LEVEL CYCLONIC FLOW THAT IS MOVING AROUND THE TROUGH REACHES 19N46W...STILL ABOUT 385 NM TO THE NORTH-NORTHWEST OF OPHELIA. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 19N21W...ACROSS THE CAPE VERDE ISLANDS...TO 9N27W. ISOLATED MODERATE RAINSHOWERS TO POSSIBLE THUNDERSTORMS ARE FROM 4N TO 13N BETWEEN 22W AND 36W. SOME OF THIS PRECIPITATION ALSO IS RELATED TO THE MONSOON TROUGH. ...THE MONSOON TROUGH/THE ITCZ... THE MONSOON TROUGH REACHES THE AFRICAN COAST NEAR 19N16W TO 18N17W. IT CONTINUES EVENTUALLY FROM 10N25W TO 9N28W AND 12N36W. ISOLATED MODERATE RAINSHOWERS TO POSSIBLE THUNDERSTORMS ARE FROM 4N TO 13N BETWEEN 22W AND 36W...AND FROM 6N TO 12N BETWEEN 40W AND 52W. ...DISCUSSION... THE GULF OF MEXICO... THE SURFACE PRESSURE GRADIENT IS BROAD AND FLAT. A SURFACE TROUGH IS ALONG 83W/84W FROM 16N TO 24N. THIS TROUGH HAS BEEN MOVING WESTWARD FOR THE LAST FEW DAYS. AN UPPER LEVEL TROUGH PASSES THROUGH CENTRAL TEXAS INTO CENTRAL MEXICO. THIS TROUGH MAY BE THE TROUGH THAT WAS SUPPORTING A TEXAS GULF COASTAL PLAINS COLD FRONT 24 HOURS AGO. THAT FRONT EVENTUALLY DISSIPATED FROM 22/0000 UTC TO 22/0600 UTC. WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED STRONG THUNDERSTORMS COVER THE GULF WATERS TO THE NORTH OF 24N TO THE EAST OF 91W. RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 26N TO THE WEST OF 90W. THE CARIBBEAN SEA... A SURFACE TROUGH IS ALONG 83W/84W FROM 16N TO 24N. STRONG CONVECTIVE PRECIPITATION THAT HAD BEEN WITHIN 100 NM OF THE WESTERN SEMICIRCLE OF LA ISLA DE LA JUVENTUD OF CUBA ABOUT FIVE HOURS AGO HAS WEAKENED AND DISSIPATED. AN UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN NEAR 32N64W...ABOUT 60 NM TO THE EAST OF BERMUDA...TO 27N66W...TO 24N74W...TO SOUTHEASTERN CUBA NEAR 27N78W. AN UPPER LEVEL TROUGH IS ALONG 17N73W 13N78W...TO 9N80W ALONG THE PANAMA COAST. UPPER LEVEL CYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA TO THE WEST OF 70W. THE MONSOON TROUGH PASSES THROUGH COLOMBIA ALONG 10N76W TO 10N82W...AND THEN NORTHWESTWARD BEYOND NORTHWESTERN NICARAGUA. WIDELY SCATTERED MODERATE RAINSHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE TO THE SOUTH OF 13N BETWEEN 80W AND 83W. ISOLATED MODERATE RAINSHOWERS ARE FROM 13N TO THE SOUTHERN COASTS OF JAMAICA AND HISPANIOLA BETWEEN 70W AND 81W...AND FROM JAMAICA TO CUBA BETWEEN THE WINDWARD PASSAGE TO THE CAYMAN ISLANDS. A 1011 MB LOW PRESSURE CENTER IS NEAR 18N61W. THIS LOW PRESSURE CENTER IS NOT EXPECTED TO DEVELOP INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. IT WILL CONTINUE MOVING WESTWARD 15 TO 20 MILES PER HOUR. ANY DEEP CONVECTIVE PRECIPITATION THAT WAS ACCOMPANYING THIS LOW CENTER FIVE HOURS HAS DISSIPATED. A NEW CELL OF CONVECTIVE PRECIPITATION HAS DEVELOPED ALONG THE NORTHERN SHORES OF GUADELOUPE. THE ATLANTIC OCEAN... A SURFACE TROUGH IS ALONG THE U.S.A. COAST FROM 31N NEAR GEORGIA TO VIRGINIA. SCATTERED MODERATE RAINSHOWERS ARE WITHIN 90 NM OF THE U.S.A. COAST. AN UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN NEAR 32N64W...ABOUT 60 NM TO THE EAST OF BERMUDA...TO 27N66W...TO 24N74W...TO SOUTHEASTERN CUBA NEAR 27N78W. AN UPPER LEVEL TROUGH PASSES THROUGH 33N28W TO 29N34W 25N42W AND 26N51W. UPPER LEVEL CYCLONIC FLOW THAT IS MOVING AROUND THE TROUGH REACHES 19N46W...STILL ABOUT 385 NM TO THE NORTH-NORTHWEST OF OPHELIA. SCATTERED MODERATE TO STRONG CONVECTIVE PRECIPITATION IS FROM 22N TO 24N BETWEEN 65W AND 67W...AND FROM 27N TO 29N BETWEEN 60W AND 62W. ISOLATED MODERATE RAINSHOWERS ARE ELSEWHERE FROM 20N TO 27N BETWEEN 62W AND 74W. RAINSHOWERS ARE POSSIBLE ALSO ELSEWHERE TO THE NORTH OF 20N TO THE WEST OF 70W IN SURFACE CONFLUENT WIND FLOW AND AFTERNOON HEATING. RAINSHOWERS ARE POSSIBLE FROM 20N TO 30N BETWEEN 50W AND 60W...AND FROM 30N TO 34N BETWEEN 27W AND 30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT