000 AXNT20 KNHC 181209 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON MAR 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL GUINEA NEAR 11N15W TO 8N17W AND 5N19W. THE ITCZ CONTINUES FROM 5N19W TO 2N30W... CROSSING THE EQUATOR ALONG 39W...TO 2S42W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO STRONG TO THE SOUTH OF 4N BETWEEN 14W AND 40W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE PASSES THROUGH THE ATLANTIC OCEAN NEAR 28N78W ACROSS THE NORTHERN PART OF FLORIDA...BEYOND THE FLORIDA PANHANDLE. MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW SPANS THE AREA. A MIDDLE LEVEL TO UPPER LEVEL TROUGH STILL IS INLAND...PASSING THROUGH NEBRASKA INTO WEST TEXAS. A MIDDLE LEVEL SHORTWAVE TROUGH WAS IN THE NORTHWESTERN CORNER OF THE GULF OF MEXICO AT 17/2115 UTC. IT MOVED NORTHEASTWARD WITH TIME AND IT HAS DISSIPATED SINCE THEN. ISOLATED MODERATE CONVECTIVE PRECIPITATION DEVELOPED ON THE EASTERN SIDE OF THE TROUGH...TO THE NORTH OF 25N TO THE EAST OF 88W. RAINSHOWERS ARE POSSIBLE ELSEWHERE TO THE EAST OF 90W...INCLUDING IN THE YUCATAN CHANNEL...AND POSSIBLY TO THE SOUTH OF 23N TO THE WEST OF 90W. THE OFFSHORE OIL PLATFORM SITES THAT ARE TO THE NORTH OF 27N TO THE WEST OF 88W...THE SKIES ARE CLEAR/FAIR FOR THE PLATFORMS THAT ARE TO THE EAST OF 90W. THE VISIBILITIES RANGE FROM 1 TO 2 MILES WITH HAZE AND FOG FOR THE STATIONS THAT ARE OFF THE TEXAS GULF COAST. THE VISIBILITIES RANGE FROM 5 MILES TO 6 MILES FROM ICAO STATION KECH AND SOUTHWARD ROUGHLY BETWEEN 92W AND 94W. THE ICAO STATIONS KCRH...KVNP...AND KVBS ARE REPORTING LOW CLOUD CEILINGS AND VISIBILITIES THAT ARE LESS THAN 2 MILES WITH FOG. THE ICAO STATIONS THAT ARE ALONG AND TO THE EAST OF 90W ARE REPORTING COMPARATIVELY BETTER VISIBILITIES SUCH AS 9 MILES AND 10 MILES. ONLY ICAO STATION KMYT IS REPORTING A VISIBILITY OF 3 MILES WITH FOG. THE REST OF THE PLATFORM SITES ARE REPORTING VISIBILITIES OF 4 MILES OR LESS WITH FOG. ICAO STATION KSPR REPORTS A VISIBILITY OF 1.5 MILES WITH FOG. LOW CLOUD CEILINGS COVER THE TEXAS GULF COASTAL PLAINS...TO THE NORTH OF THE DEEP SOUTH OF TEXAS. BEAUMONT/PORT ARTHUR IS REPORTING A VISIBILITY OF 2 MILES WITH FOG. LOW CLOUD CEILINGS AND SOME FOG COVER THE LOUISIANA COASTAL PLAINS. LOW CLOUD CEILINGS...SOME RAIN AND SOME FOG ARE OBSERVED IN THE FLORIDA PANHANDLE. LOW CLOUD CEILINGS ELSEWHERE TO THE WEST OF 83W. FAIR SKIES COVER THE REST OF THE FLORIDA GULF COAST TO THE SOUTH OF SARASOTA. CARIBBEAN SEA... BROAD MIDDLE LEVEL TO UPPER LEVEL ANTICYCLONIC WIND FLOW COVERS THE AREA. A RIDGE EXTENDS FROM THE COLOMBIA COAST THAT IS NEAR 10N75W TO 15N80W... BEYOND THE YUCATAN CHANNEL/WESTERN CUBA. RAINSHOWERS ARE POSSIBLE TO THE NORTH OF 15N TO THE EAST OF 80W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT 25 TO 30 KNOT WINDS AND 9 TO 12 FOOT SEA HEIGHTS FROM 13N TO 15N BETWEEN 73W AND 77W. EXPECT 20 TO 25 KNOT WINDS AND 8 TO 10 FOOT SEA HEIGHTS ELSEWHERE FROM 10N TO 15N BETWEEN 70W AND 78W. EXPECT 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS FROM 16N TO 18N BETWEEN 70W AND 76W. EXPECT 20 KNOT WINDS OR LESS AND 9 FOOT SEA HEIGHTS FOR THE REST OF THE AREA FROM 10N TO 16N BETWEEN 68W AND 80W. EXPECT 20 TO 25 KNOT WINDS AND SEA HEIGHTS LOWER THAN 8 FEET TO THE SOUTH OF 18N BETWEEN 85W AND 87W... INCLUDING IN THE GULF OF HONDURAS. ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N26W TO 26N33W TO 22N42W. A DISSIPATING COLD FRONT IS ALONG 31N27W TO 24N34W AND 22N42W. A SHEAR AXIS CONTINUES FROM 22N42W TO 21N50W AND 20N62W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE WITHIN 90 NM ON EITHER SIDE OF THE LINE THAT STARTS NEAR 31N24W 22N32W 20N51W AND 18N64W. RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF 13N41W 18N48W 19N51W 17N60W. A SURFACE RIDGE PASSES THROUGH 32N39W TO 27N48W...TO A 1024 MB HIGH PRESSURE CENTER THAT IS NEAR 28N60W...TO 28N78W...ACROSS THE NORTHERN PART OF FLORIDA...BEYOND THE FLORIDA PANHANDLE. A SURFACE RIDGE PASSES THROUGH THE CANARY ISLANDS TO 22N20W 17N32W AND 18N50W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS A SHEAR AXIS FROM 21N44W TO 20N55W AND 18N63W. EXPECT 20 KNOT WINDS OR LESS WITHIN 180 NM TO THE NORTH OF THE SHEAR AXIS AND 9 FOOT SEA HEIGHTS. ELSEWHERE TO THE NORTH AND NORTHEAST OF A LINE FROM 27N35W TO 22N43W TO 22N55W TO 28N53W TO 31N65W WINDS 20 KT OR LESS. SEAS TO 9 FT. EXPECT 20 KNOT WINDS OR LESS AND 8 FOOT SEA HEIGHTS TO THE SOUTH OF 10N BETWEEN 45W AND 58W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT