000 AXNT20 KNHC 041805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED SEP 04 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. ...SPECIAL FEATURE... A CARIBBEAN SEA 1009 MB LOW PRESSURE CENTER IS NEAR 16N65W...ABOUT 140 NM TO THE SOUTH-SOUTHEAST OF PUERTO RICO. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 15N TO 19N BETWEEN 65W AND 67W. THIS PRECIPITATION COVERS PARTS OF PUERTO RICO AND THE VIRGIN ISLANDS AND THE WATERS THAT ARE TO THE SOUTH OF THIS AREA. THE 24-HOUR RAINFALL TOTALS IN INCHES FOR THE PERIOD ENDING AT 04/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN...ARE 1.04 IN GUADELOUPE...0.28 IN SAN JUAN PUERTO RICO...AND 0.18 IN TRINIDAD. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. LOCALLY HEAVY RAINFALL AND GUSTY WINDS ARE EXPECTED TO SPREAD OVER PARTS OF THE LEEWARD ISLANDS...THE VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA DURING THE NEXT DAY OR TWO. A RECONNAISSANCE PLANE IS INVESTIGATING THIS SYSTEM CURRENTLY. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W TO THE SOUTH OF 18N...MOVING WESTWARD 20 KNOTS. A 1012 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 12N. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 24N46W 17N45W 11N44W... MOVING WESTWARD 15 KNOTS. CONVECTIVE PRECIPITATION...RAINSHOWERS ARE POSSIBLE FROM 23N TO 27N BETWEEN 40W AND 44W...AND FROM 11N TO 17N BETWEEN 40W AND 50W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 22N60W 11N59W MOVING WESTWARD 10 TO 15 KNOTS. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 10N TO 11N BETWEEN 56W AND 57W...FROM 14N TO 20N BETWEEN 56W AND 61W...AND FROM 21N TO 22N BETWEEN 56W AND 58W. IT IS EASILY POSSIBLE THAT SOME OF THE ISLANDS OF THE EASTERN CARIBBEAN SEA MAY EXPERIENCE SOME OF THIS PRECIPITATION DURING THE NEXT 12 TO 24 HOURS IF THE PRECIPITATION PATTERN REMAINS INTACT DURING THE WESTWARD MOTION OF THE TROPICAL WAVE. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 21N74W NEAR THE SOUTHERN BAHAMAS...THROUGH THE WINDWARD PASSAGE...TO 16N75W AND 10N76W... MOVING WESTWARD 15 KNOTS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 14N17W TO 12N23W 12N26W 9N30W AND 6N39W. THE ITCZ CONTINUES FROM 6N39W TO 5N47W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG FROM 16N TO 18N BETWEEN 20W AND 24W. SCATTERED STRONG FROM 15N TO 16N BETWEEN 26W AND 27W. SCATTERED MODERATE TO ISOLATED STRONG FROM 8N TO 14N BETWEEN 26W AND 30W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N77W IN THE ATLANTIC OCEAN...ACROSS NORTH FLORIDA...TO 28N84W IN THE GULF OF MEXICO...TO 28N91W...TO A 26N92W CYCLONIC CIRCULATION CENTER. A SECOND MIDDLE LEVEL TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 24N101W IN MEXICO. THIS CYCLONIC CENTER HAS MOVED SOUTHWESTWARD FROM THE UPPER TEXAS GULF COAST TO ITS PRESENT POSITION SINCE 01/2315 UTC. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG FROM 24N TO 26N BETWEEN SOUTH FLORIDA AND 90W. WIDELY SCATTERED TO SCATTERED MODERATE TO ISOLATED STRONG COVERS THE REST OF THE AREA THAT IS TO THE WEST OF 90W. ISOLATED MODERATE COVERS THE REST OF THE AREA THAT IS TO THE EAST OF 90W. A SURFACE TROUGH IS ALONG 26N91W TO A 1011 MB LOW PRESSURE CENTER THAT IS NEAR 19N91W IN THE WESTERN YUCATAN PENINSULA OF MEXICO. THIS SYSTEM HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS...AND A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. A SURFACE RIDGE EXTENDS FROM A 1026 MB HIGH PRESSURE CENTER THAT IS NEAR 33N52W TO 31N66W...ACROSS FLORIDA FROM 29N TO 30N...INTO SOUTHEASTERN LOUISIANA. FOR THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N TO THE WEST OF 88W... VISIBILITIES OF ONE MILE OR LESS AND HAZE ARE BEING OBSERVED AT THE ICAO STATION KEMK. FAIR SKIES/CLEAR SKIES AT OR LOWER THAN 12000 FEET ARE BEING REPORTED ELSEWHERE ACROSS THE AREA. FROM THE EASTERN ATLANTIC OCEAN...ACROSS THE CENTRAL ATLANTIC OCEAN...THROUGH THE WINDWARD PASSAGE...INTO THE CARIBBEAN SEA... A MIDDLE LEVEL TO UPPER LEVEL TROUGH/SHEAR AXIS IN SOME LOCATIONS...PASSES THROUGH 32N18W TO 28N21W AND 28N38W...TO A 24N44W CYCLONIC CIRCULATION CENTER...TO A SECOND CYCLONIC CENTER THAT IS NEAR 26N61W...TO 23N68W...CURVING TO 23N75W...THROUGH THE WINDWARD PASSAGE...TO A 17N78W CYCLONIC CIRCULATION CENTER IN THE CARIBBEAN SEA...BEYOND THE COASTAL BORDERS OF SOUTHEASTERN NICARAGUA AND NORTHEASTERN COSTA RICA. CONVECTIVE PRECIPITATION IN THE ATLANTIC OCEAN...RAINSHOWERS ARE POSSIBLE FROM 23N TO 27N BETWEEN 40W AND 44W...AND TO THE NORTH OF 22N BETWEEN 54W AND 61W. CONVECTIVE PRECIPITATION IN THE CARIBBEAN SEA...ISOLATED TO WIDELY SCATTERED MODERATE BETWEEN 70W AND THE LINE THAT RUNS FROM THE WINDWARD PASSAGE AND SOUTHEASTERN NICARAGUA/NORTHEASTERN COSTA RICA. THE 24-HOUR RAINFALL TOTAL IN INCHES FOR THE PERIOD ENDING AT 04/1200 UTC...ACCORDING TO THE PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES... MIATPTPAN...IS 0.42 IN MONTEGO BAY IN JAMAICA...AND 0.34 IN CURACAO. THE REST OF THE CARIBBEAN SEA... MIDDLE LEVEL TO UPPER LEVEL RIDGE ANTICYCLONIC WIND FLOW COVERS THE WESTERN/NORTHWESTERN CORNER OF THE AREA...BETWEEN THE CYCLONIC WIND FLOW THAT IS MOVING AROUND THE 17N76W CYCLONIC CIRCULATION CENTER AND ASSOCIATED TROUGH... AND THE WIND FLOW THAT IS MOVING AROUND THE 24N101W MEXICO CYCLONIC CENTER. BROAD SURFACE LOW PRESSURE COVERS THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO. CONVECTIVE PRECIPITATION...SCATTERED TO NUMEROUS STRONG IS ALONG THE EASTERN COASTAL PLAINS/IN THE COASTAL WATERS OF THE YUCATAN PENINSULA FROM NORTHERN BELIZE NORTHWARD. BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE CARIBBEAN SEA THAT IS TO THE EAST OF THE WINDWARD PASSAGE-TO- SOUTHWESTERN CARIBBEAN SEA TROUGH. THE MONSOON TROUGH IS ALONG 9N73W IN COLOMBIA TO 9N80W IN PANAMA...BEYOND 10N85W IN COSTA RICA. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG TO THE SOUTH OF 11N TO THE WEST OF 76W IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. PLEASE READ THE HIGHS SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT THE 1009 MB LOW PRESSURE CENTER THAT STARTS NEAR 16.5N 65W. EXPECT WINDS 20 TO 25 KNOTS AND SEA HEIGHTS LOWER THAN 8 FEET WITHIN 90 NM IN THE NORTHERN SEMICIRCLE OF THE LOW CENTER. EXPECT ALSO SCATTERED STRONG THUNDERSTORMS WITHIN 120 NM IN THE EASTERN SEMICIRCLE OF THE LOW CENTER. HISPANIOLA... THE NUMEROUS STRONG CONVECTIVE PRECIPITATION THAT ACCOMPANIES THE 1009 MB LOW PRESSURE THAT IS NEAR 16N65W MAY REACH HISPANIOLA...AS IT IS NOW...DURING THE NEXT 24 HOURS OR SO. THIS AMOUNT AND INTENSITY MAY RESULT IN SIGNIFICANT AMOUNTS OF RAINFALL...AND IT MAY LEAD TO FLOODING IN SOME AREAS. A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 23N75W IN THE BAHAMAS...ACROSS SOUTHEASTERN CUBA AND JAMAICA...TO A 17N78W CYCLONIC CIRCULATION CENTER THAT IS IN THE CARIBBEAN SEA... BEYOND THE COASTAL BORDERS OF SOUTHEASTERN NICARAGUA AND NORTHEASTERN COSTA RICA. CONVECTIVE PRECIPITATION IN THE CARIBBEAN SEA...ISOLATED TO WIDELY SCATTERED MODERATE BETWEEN 70W AND THE LINE THAT RUNS FROM THE WINDWARD PASSAGE AND SOUTHEASTERN NICARAGUA/NORTHEASTERN COSTA RICA. THE GFS FORECAST FOR 700 MB SHOWS THAT EASTERLY WIND FLOW...THAT IS ON THE NORTHWESTERN SIDE OF AN INVERTED TROUGH...WILL COVER THE AREA FOR THE FIRST HALF OF THE FIRST 24 HOURS OF THE FORECAST PERIOD. AN INVERTED TROUGH WILL MOVE ACROSS THE AREA AND REMAIN THERE UNTIL THE END OF 48-HOUR FORECAST PERIOD. THE GFS FORECAST FOR 500 MB SHOWS THAT A RIDGE WILL COVER THE AREA FOR THE FIRST 24 HOURS OF THE FORECAST...WHILE AN INVERTED TROUGH APPROACHES HISPANIOLA FROM THE EAST. THE INVERTED TROUGH WILL COVER THE AREA FOR THE REST OF THE 48 HOUR FORECAST PERIOD. THE GFS FORECAST FOR 250 MB SHOWS THAT AN EAST-TO-WEST ORIENTED RIDGE WILL COVER THE AREA FOR THE ENTIRE TIME. THE REST OF THE ATLANTIC OCEAN... AN UPPER LEVEL INVERTED TROUGH IS ALONG 40W FROM 10N TO 18N. NO SIGNIFICANT DEEP CONVECTIVE PRECIPITATION IS APPARENT. BROAD SURFACE ANTICYCLONIC WIND FLOW COVERS THE ATLANTIC OCEAN TO THE NORTH OF 20N TO THE EAST OF 42W. A 1025 MB HIGH PRESSURE CENTER IS NEAR 33N33W. A SURFACE RIDGE EXTENDS FROM A 1026 MB HIGH PRESSURE CENTER THAT IS NEAR 33N52W TO 31N66W...ACROSS FLORIDA FROM 29N TO 30N...INTO SOUTHEASTERN LOUISIANA. THROUGH 32N34W TO 30N49W TO 28N61W...TO ANDROS ISLAND IN THE BAHAMAS...SOUTHWESTWARD BEYOND WESTERN CUBA. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS ABOUT THE SURFACE TROUGH FROM 24N61W TO A CARIBBEAN SEA 1009 MB LOW PRESSURE CENTER THAT IS NEAR 16.5N 65W. EXPECT NORTHEAST TO EAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS TO 9 FEET FROM 18N TO 23N TO THE WEST OF THE TROUGH TO 65W. EXPECT EAST TO SOUTHEAST WINDS 20 TO 25 KNOTS EXCEPT 25 TO 30 KNOTS FROM 18N TO 21N. SEA HEIGHTS WILL RANGE FROM 8 TO 11 FEET FROM 17N TO 24N TO THE EAST OF THE TROUGH TO 55W. EXPECT ALSO EAST TO SOUTHEAST WINDS 20 TO 25 KNOTS AND SEA HEIGHTS TO 8 FEET FROM 13N TO 17N BETWEEN 52W AND 56W. EXPECT SCATTERED STRONG THUNDERSTORMS FROM 15N TO 19N BETWEEN 57W AND 60W. THE ATLANTIC OCEAN 12-HOUR FORECAST INCLUDES WINDS 20 KNOTS OR LESS AND SEA HEIGHTS TO 8 FEET. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT