000 AXNT20 KNHC 181803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU APR 18 2013 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. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SIERRA LEONE NEAR 8N13W TO 6N15W. THE ITCZ CONTINUES FROM 6N15W TO 3N22W AND 2N28W. CONVECTIVE PRECIPITATION...SCATTERED STRONG FROM 2N TO 4N BETWEEN 2W AND 4W...AND FROM 4N TO 5N BETWEEN 33W AND 42W. SCATTERED MODERATE TO ISOLATED STRONG FROM 2N TO 4N BETWEEN 23W AND 26W. ISOLATED MODERATE ELSEWHERE TO THE SOUTH OF 7N TO THE EAST OF 50W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL RIDGE EXTENDS FROM THE SOUTHWESTERN CORNER OF THE AREA TO THE SOUTH CENTRAL LOUISIANA COASTAL PLAINS. A DEEP LAYER TROUGH STILL IS IN THE CENTRAL U.S.A. THE DEEP LAYER TROUGH SUPPORTS A STILL-INLAND COLD FRONT THAT PASSES THROUGH NORTHEASTERN TEXAS TO SOUTH CENTRAL TEXAS... BEYOND 28N100W INTO NORTHERN MEXICO. THE 85W-TO YUCATAN CHANNEL RIDGE FROM 24 HOURS AGO HAS BEEN PUSHED EASTWARD. THE WIND FLOW THAT WAS MOVING AROUND THE RIDGE HAS MERGED WITH THE MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW THAT IS ON THE WESTERN SIDE OF THE 32N44W TO 16N60W ATLANTIC OCEAN TROUGH. SCATTERED LOW CLOUDS COVER THE DEEP SOUTH OF TEXAS. LIGHT RAIN HAS BEEN REPORTED IN PORT ISABEL FOR THE LAST FEW HOURS. LOW CLOUD CEILINGS COVER THE U.S.A. GULF COASTAL PLAINS FROM THE MIDDLE TEXAS COAST TO THE FLORIDA PANHANDLE. SCATTERED TO BROKEN LOW CLOUDS WITH MIDDLE LEVEL AND HIGH LEVEL CLOUDS COVER THE REST OF THE FLORIDA GULF COAST. FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N TO THE WEST OF 88W... SCATTERED LOW CLOUDS COVER THE OIL PLATFORM SITES THAT ARE OFFSHORE ALONG THE TEXAS GULF COAST. VISIBILITIES OF 3 MILES OR LOWER ARE AT THE ICAO STATIONS...KHQI...KVNP...KATP...KGUL...AND MYT. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2... AND THE OFFSHORE FORECAST...MIAOFFNT4...FOR MORE INFORMATION ABOUT THE GALE WARNING. GALE-FORCE WINDS ARE FORECAST 24 HOURS INTO THE FORECAST TIME PERIOD. A COLD FRONT WILL BE ALONG 30N88W 24N95W 20.5N97W AT 24 HOURS. EXPECT NORTH TO NORTHEAST 30 TO 35 KNOT WINDS AND 8 TO 13 FOOT SEA HEIGHTS TO THE SOUTH OF 27N TO THE WEST OF THE FRONT. EXPECT 20 TO 30 KNOT NORTH WINDS AND 11 FOOT SEA HEIGHTS ELSEWHERE TO THE WEST OF THE FRONT. EXPECT NORTHWESTERLY 20 TO 25 KNOT WINDS AND SEA HEIGHTS LOWER THAN 8 FEET TO THE SOUTH OF 21N TO THE EAST OF THE FRONT TO 95W. THE CARIBBEAN SEA... BROAD MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW COVERS THE CARIBBEAN SEA TO THE NORTH OF 14N. THE AREA THAT IS TO THE SOUTH 14N IS COVERED BY THE MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY-TO-WESTERLY WIND FLOW. THE NORTHWESTERLY WIND FLOW IS FLOWING TOWARD THE BASE OF AN ATLANTIC OCEAN-TO-16N60W TROUGH. A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N44W IN THE ATLANTIC OCEAN...TO 16N60W JUST TO THE EAST OF THE EASTERN CARIBBEAN SEA ISLANDS. RAINSHOWERS ARE POSSIBLE WITHIN 150 NM ON EITHER SIDE OF 15N61W 19N52W. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE EAST OF 75W. THE SOUTHWESTERLY WIND FLOW FROM SOUTH AMERICA AND CENTRAL AMERICA HAS BEEN PUSHING HIGH CLOUDS INTO THE CARIBBEAN SEA...TO THE SOUTH OF 17N TO THE EAST OF 83W. THE TOTAL PRECIPITATION AMOUNT FOR THE 24-HOUR TIME PERIOD ENDING AT 18/1200 UTC IS 0.30 OF AN INCH FOR SAN JUAN PUERTO RICO...ACCORDING TO THE PAN AMERICAN TEMPERTATURE AND PRECIPITATION TABLE...MIATPTPAN. THE MONSOON TROUGH IS ALONG 7N73W IN COLOMBIA... TO 7N71W IN COLOMBIA...TO 8N80W IN PANAMA... AND BEYOND 9N84W IN SOUTHERN COSTA RICA... INTO THE EASTERN PACIFIC OCEAN. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 3N TO 6N BETWEEN 80W AND 84W. NUMEROUS STRONG FROM 6N TO 9N BETWEEN 82W AND 87W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2... AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE NORTHEAST TO EAST 20 TO 25 KNOT WINDS AND SEA HEIGHTS REACHING 9 FEET FROM 11N TO 13N BETWEEN 70W AND 78W. ALSO EXPECT EAST TO SOUTHEAST 20 TO 25 KNOT WINDS AND SEA HEIGHTS REACHING 8 FEET TO THE SOUTH OF 19N TO THE WEST OF 84.5W INCLUDING IN THE GULF OF HONDURAS. THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N44W AND 28N48W...TO A CYCLONIC CIRCULATION CENTER THAT IS NEAR 26N50W... TO 24N54W AND 20N60W...TO 16N60W JUST TO THE EAST OF THE EASTERN CARIBBEAN SEA ISLANDS. RAINSHOWERS ARE POSSIBLE WITHIN 150 NM ON EITHER SIDE OF 15N61W 19N52W 23N45W 25N41W. A SEPARATE CYCLONIC CIRCULATION CENTER IS NEAR 27N69W. THAT CENTER HAS A RADIUS OF 60 NM OR SO. MIDDLE LEVEL TO UPPER LEVEL NORTHWESTERLY WIND FLOW COVERS THE ATLANTIC OCEAN TO THE WEST OF THE TROUGH. BROAD MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE ATLANTIC OCEAN TO THE EAST OF THE TROUGH. A DISSIPATING STATIONARY FRONT TRAILS FROM A 1022 MB LOW PRESSURE CENTER THAT IS NEAR 33N40W...TO 29N45W AND 26N53W. RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 25N BETWEEN 40W AND 60W...AND TO THE NORTH OF 30N BETWEEN 38W AND 41W. A SURFACE TROUGH IS ALONG 33N71W 30N72W. THIS FEATURE REMAINS FROM THE TWO WESTERN ATLANTIC OCEAN LOW PRESSURE CENTERS OF THE LAST FEW DAYS. RAINSHOWERS ARE POSSIBLE WITH THE REMNANT CLOUDINESS THAT IS TO THE NORTH AND NORTHWEST OF THE LINE THAT PASSES THROUGH 32N64W 26N67W 26N74W 25N80W. A SURFACE RIDGE IS ALONG 32N31W 27N35W 25N40W AND 23N50W ON THE EASTERN SIDE OF THE DISSIPATING STATIONARY FRONT. A SURFACE RIDGE EXTENDS FROM A 1027 MB HIGH PRESSURE CENTER THAT IS NEAR 34N53W TO 28N61W AND 22N67W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2... FOR MORE DETAILS ABOUT THE WINDS 20 KNOTS OR LESS AND THE 10 FOOT SEA HEIGHTS TO THE NORTH OF 26N BETWEEN 40W AND 59W. ALSO EXPECT WINDS 20 KNOTS OR LESS AND 8 FOOT SEA HEIGHTS FROM 18.5N TO 23N BETWEEN 53W AND 66W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT