000 AXNT20 KNHC 251108 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT TUE SEP 25 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 VALID THROUGH 1015 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL STORM NADINE AT 25/0900 UTC IS NEAR 32.1N 29.6W. NADINE IS ABOUT 380 NM/695 KM TO THE SOUTH- SOUTHWEST OF THE AZORES. NADINE IS MOVING WESTWARD 5 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 996 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 40 KNOTS WITH GUSTS TO 50 KNOTS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 150 NM IN THE NORTHEASTERN QUADRANT...70 NM IN THE SOUTHEASTERN QUADRANT... 100 NM IN THE SOUTHWESTERN QUADRANT...AND 170 NM IN THE NORTHWESTERN QUADRANT. PLEASE READ THE FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC...AND THE PUBLIC ADVISORY...MIATCPAT4/WTNT34 KNHC... FOR MORE DETAILS. CONVECTIVE PRECIPITATION...SCATTERED MODERATE TO ISOLATED STRONG FROM 30N TO 32N BETWEEN 28W AND 32W. ...TROPICAL WAVE... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 60W/62W TO THE SOUTH OF 19N...MOVING WESTWARD 15 KNOTS DURING THE LAST 24 HOURS. RAINSHOWERS ARE POSSIBLE WITHIN 60 NM ON EITHER SIDE OF THE TROPICAL WAVE. IT IS NOT EASY TO FIND PRECIPITATION THAT ONLY ACCOMPANIES THE WAVE...BECAUSE OF THE MIDDLE LEVEL TO UPPER LEVEL TROUGH THAT IS ALONG 20N66W 14N72W 9N78W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SENEGAL NEAR 15N12W TO 14N23W AND 13N29W. THE ITCZ DOES NOT EXIST DUE TO THE PREVAILING WIND FLOW. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG FROM 2N TO 18N TO THE EAST OF 50W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE LEVEL TO UPPER LEVEL TROUGH CUTS THROUGH THE FLORIDA NEAR 30N84W...TO 24N90W TO 19N92W IN THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO. COMPARATIVELY DRIER IN SUBSIDENCE IS TO THE NORTHWEST AND WEST OF THE FLORIDA NEAR 30N84W-TO-24N90W-TO 24N97W LINE. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE TO THE EAST OF THE FLORIDA 30N84W-TO-24N97W LINE. A MIDDLE LEVEL TO UPPER LEVEL TROUGH PASSES THROUGH 32N73W IN THE ATLANTIC OCEAN TO 30N76W. A STATIONARY FRONT PASSES THROUGH 32N69W IN THE ATLANTIC OCEAN...TO A 1015 MB LOW PRESSURE CENTER THAT IS NEAR 28N75W. THE FRONT BECOMES DISSIPATING STATIONARY FROM THE 1015 MB LOW PRESSURE CENTER THAT IS NEAR 28N75W...ON TOP OF THE FLORIDA KEYS...TO 23N87W IN THE GULF OF MEXICO. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE RAINSHOWERS ARE TO THE WEST/NORTHWEST OF THE LINE THAT PASSES THROUGH 32N61W TO 29N62W TO 22N71W. THE CARIBBEAN SEA... SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS TO THE NORTHWEST OF THE LINE THAT PASSES THROUGH HONDURAS NEAR 16N86W...BEYOND 20N80W AT THE COAST OF CUBA. THIS PRECIPITATION IS RELATED TO THE UPPER LEVEL DIFFLUENT WIND FLOW FROM THE GULF OF MEXICO FLORIDA PANHANDLE TO 24N90W TO 19N92W MIDDLE TO UPPER LEVEL TROUGH. A MIDDLE LEVEL TO UPPER LEVEL TROUGH IS ALONG 20N65W 14N70W 10N79W. THIS CYCLONIC WIND FLOW HAS BEEN IN THE CARIBBEAN SEA FOR AT LEAST THE LAST 4 DAYS OR MORE. THE CYCLONIC CIRCULATION CENTER FROM 24 HOURS AGO HAS WEAKENED AND DISSIPATED. CONVECTIVE PRECIPITATION...NUMEROUS STRONG FROM 10N TO 12N BETWEEN 75W AND 77W IN THE COLOMBIA COASTAL WATERS AND FROM 11N TO 13N BETWEEN 67W AND 70W IN THE VENEZUELA COASTAL WATERS AND IN LAKE MARACAIBO...SCATTERED MODERATE TO STRONG FROM 14N TO 16N BETWEEN 65W AND 70W...ISOLATED MODERATE ELSEWHERE TO THE EAST OF THE LINE 20N64W 16N71W 14N71W 11N77W. THE MONSOON TROUGH IS ALONG 9N/10N BETWEEN 74W IN COLOMBIA AND 85W IN NORTHWESTERN COSTA RICA. RAINSHOWERS ARE POSSIBLE IN THE SOUTHWESTERN CORNER OF THE CARIBBEAN SEA TO THE SOUTH OF 12N TO THE WEST OF 77W. PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...AND THE OFFSHORE FORECAST...MIAOFFNT3...FOR DETAILS ABOUT 20 TO 25 KNOT WINDS AND 8 TO 9 FOOT SEA HEIGHTS FROM 12N TO 17N BETWEEN 70W AND 80W FOR AT LEAST THE FIRST 24 HOURS OF THE FORECAST PERIOD. THE ATLANTIC OCEAN... AN UPPER LEVEL TROUGH PASSES THROUGH 32N58W TO A 25N58W CYCLONIC CIRCULATION CENTER...TO 20N58W. ISOLATED MODERATE TO LOCALLY STRONG CONVECTIVE PRECIPITATION TO THE NORTH OF 23N BETWEEN 56W AND 60W. A SURFACE TROUGH IS ALONG 47W/48W FROM 15N TO 23N. SCATTERED MODERATE TO ISOLATED STRONG CONVECTIVE PRECIPITATION IS WITHIN A 30 NM RADIUS OF 21.5N49W. A DEEP LAYER TROUGH EXTENDS AWAY FROM THE AREA THAT IS NEAR TROPICAL STORM NADINE...TO 28N32W 21N35W 10N44W. COMPARATIVELY DRIER AIR IN SUBSIDENCE SPANS THE AREA OF THE TROUGH AND IT INCLUDES THE ATLANTIC OCEAN THAT IS WITHIN 90 T0 150 NM ON EITHER SIDE OF THE LINE THAT STARTS NEAR 30N24W TO 24N30W 19N38W 17N43W. A SURFACE RIDGE PASSES THROUGH 32N55W TO 22N68W. PLEASE READ THE HIGH SEAS FORECASTS...MIAHSFAT2...FOR DETAILS ABOUT 8 TO 12 FOOT SEA HEIGHTS TO THE NORTH OF 21N TO THE EAST OF 52W AT THE START OF THE FORECAST TIME. TROPICAL STORM NADINE BEGINS TO BE A FACTOR AT 24 HOURS INTO THE FORECAST PERIOD... NEAR 31.1N 30.7W...AND NEAR 29.0N 31.5W AT 48 HOURS INTO THE FORECAST PERIOD. EXPECT 20 TO 25 KNOT WINDS AND 8 FOOT SEA HEIGHTS TO THE NORTH OF 29N BETWEEN 75W AND 80W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT