000 AXNT20 KNHC 181103 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST TUE DEC 18 2012 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. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH LIBERIA AND IT REACHES THE COAST OF LIBERIA NEAR 5N9W. THE ITCZ CONTINUES FROM 5N19W TO 5N35W AND 3N46W. CONVECTIVE PRECIPITATION... SCATTERED MODERATE TO STRONG WITHIN 120 NM ON EITHER SIDE OF 4N11W 4N22W 4N31W 5N40W 10N50W. ...DISCUSSION... THE GULF OF MEXICO... A DEEP LAYER TROUGH IS DIGGING THROUGH THE SOUTHEASTERN U.S.A....PASSING THROUGH THE NORTHEASTERN CORNER OF THE GULF OF MEXICO...INTO THE CENTRAL GULF WATERS...TO THE MEXICO GULF COAST NEAR 22N98W. BROKEN LOW TO MIDDLE LEVEL CLOUDS AND POSSIBLE RAINSHOWERS ARE IN THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA...MOVING THROUGH THE YUCATAN CHANNEL...AND TO THE SOUTHEAST OF THE LINE THAT EXTENDS FROM THE SOUTHWESTERN FLORIDA COAST NEAR 26N81W TO 23N91W. SIMILAR CLOUDS AND POSSIBLE PRECIPITATION ARE IN THE SOUTHWESTERN CORNER OF THE AREA TO THE SOUTH OF 23N TO THE WEST OF 94W. BROKEN TO OVERCAST HIGH LEVEL CLOUDS ARE FROM 23N TO 29N TO THE EAST OF 89W. A SURFACE RIDGE ORIGINATES IN THE ATLANTIC OCEAN...PASSING THROUGH 26N71W AND ACROSS THE BAHAMAS...THROUGH THE FLORIDA STRAITS...TO 25N90W IN THE CENTRAL GULF OF MEXICO. THE CARIBBEAN SEA... MIDDLE LEVEL NORTHEASTERLY WIND FLOW COVERS THE AREA TO THE EAST OF 70W...BECOMING MIDDLE LEVEL EASTERLY WIND FLOW BETWEEN 70W AND 80W...AND MIDDLE LEVEL SOUTHEASTERLY-TO-SOUTHERLY WIND FLOW TO THE WEST OF 80W TO THE NORTH OF 16N. MIDDLE LEVEL TO UPPER LEVEL SOUTHWESTERLY WIND FLOW MOVES FROM THE EASTERN PACIFIC OCEAN...CROSSING COSTA RICA...PANAMA AND COLOMBIA...INTO THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA. COMPARATIVELY DRIER AIR IN SUBSIDENCE IS EVIDENT ACROSS THE ENTIRE AREA ON WATER VAPOR SATELLITE IMAGERY. BROKEN LOW TO MIDDLE LEVEL CLOUDS AND POSSIBLE RAINSHOWERS ARE TO THE NORTH OF 12N TO THE WEST OF 78W IN THE WESTERN SECTIONS AND IN THE NORTHWESTERN CORNER OF THE AREA. SIMILAR CLOUDS AND PRECIPITATION ARE IN THE EASTERN CARIBBEAN SEA...FROM 16N TO 18N BETWEEN 62W AND 65W. THE 24-HOUR RAINFALL TOTAL FOR THE TIME PERIOD THAT ENDED AT 18/0000 UTC FOR GUADELOUPE WAS 0.57 INCHES. THE SURFACE PRESSURE GRADIENT IS WEAK ACROSS THE AREA. THE MONSOON TROUGH PASSES THROUGH 6N73W IN COLOMBIA...TO 6N79W IN THE EASTERN PACIFIC OCEAN...THROUGH 8N81W IN SOUTHERN PANAMA...THROUGH WESTERN PANAMA INTO SOUTHERN COSTA RICA... BEYOND 10N86W INTO THE EASTERN PACIFIC OCEAN. RAINSHOWERS ARE POSSIBLE TO THE SOUTH OF 11N TO THE WEST OF 80W IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND SCATTERED MODERATE CONVECTIVE PRECIPITATION ARE TO THE NORTH OF 2N TO THE EAST OF 90W IN THE EASTERN PACIFIC OCEAN. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR MORE DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS IN 48 HOURS TO THE SOUTH OF 18N BETWEEN 70W AND 80W. THE ATLANTIC OCEAN... A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N35W TO 27N40W 24N43W 20N47W AND 16N54W. AN UPPER LEVEL SHEAR AXIS CONTINUES FROM 16N54W TO 12N62W IN THE SOUTHEASTERN CORNER OF THE CARIBBEAN SEA. THIS TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 32N33W TO 31N35W. A SURFACE TROUGH CONTINUES FROM 31N35W TO 27N40W 24N44W 19N46W. CONVECTIVE PRECIPITATION... SCATTERED MODERATE TO ISOLATED STRONG WITHIN 120 NM ON EITHER SIDE OF 28N32W BEYOND 32N29W...BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION WITHIN 120 NM TO 180 NM ON EITHER SIDE OF 28N32W 24N34W 20N38W...AND WITHIN 30 NM TO 60 NM ON EITHER SIDE OF 20N38W 17N43W 13N50W...SCATTERED STRONG FROM 9N TO 12N BETWEEN 59W AND 61W...BROKEN MULTILAYERED CLOUDS AND POSSIBLE PRECIPITATION ARE ELSEWHERE FROM 6N TO 14N BETWEEN 50W AND 60W...SCATTERED MODERATE TO ISOLATED STRONG FROM 23N TO 27N BETWEEN 37W AND 42W. A MIDDLE LEVEL TO UPPER LEVEL RIDGE IS ALONG 20N70W BEYOND 32N65W. A SURFACE RIDGE EXTENDS FROM A 1021 MB HIGH PRESSURE CENTER THAT IS NEAR 32N51W...TO 27N60W 26N71W...ACROSS THE BAHAMAS BEYOND THE FLORIDA STRAITS. AN UPPER LEVEL TROUGH PASSES THROUGH 18N16W ALONG THE COAST OF MAURITANIA TO 10N26W. NO SIGNIFICANT CONVECTIVE PRECIPITATION BASED SOLELY ON SATELLITE IMAGERY. A SURFACE RIDGE PASSES OVER THE MADEIRA ARCHIPELAGO TO 28N24W AND 18N35W. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2...FOR MORE DETAILS ABOUT...GALE WIND CONDITIONS IN 48 HOURS TO THE NORTH OF 30N BETWEEN 52W AND 60W WITH A 31N50W 23N63W COLD FRONT... AND SEA HEIGHTS REACHING 22 FEET. EXPECT 20 KNOT WINDS AND 8 TO 9 FOOT SEA HEIGHTS TO THE EAST OF THE 30N35W 20N45W SURFACE TROUGH AS AN INITIAL CONDITION. EXPECT ALSO 20 TO 25 KNOT WINDS AND SEAS LESS THAN 8 FEET TO THE NORTH OF 30N TO THE WEST OF 65W AS AN INITIAL CONDITION WITH A COLD FRONT THAT WILL BE TO THE WEST OF THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT