000 AXNT20 KNHC 130001 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI OCT 12 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL DEPRESSION FIFTEEN AT 12/2100 UTC IS NEAR 30.8N 49.5W MOVING NORTH 3 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1012 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 25 KT WITH GUSTS TO 35 KT. PLEASE READ THE NATIONAL HURRICANE CENTER FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC OR THE PUBLIC ADVISORY UNDER MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. THE DEPRESSION HAS BECOME A TIGHT SWIRL OF LOW CLOUDS WITH NO DEEP CONVECTION. IT APPEARS THAT IT IS WEAKENING RAPIDLY TO A REMNANT LOW. THE SHEAR IS FORECAST TO INCREASE SIGNIFICANTLY AND REGENERATION IS NOT ANTICIPATED. THE SYSTEM STILL MAY PRODUCE INTERMITTENT BURSTS OF SHOWERS/THUNDERSTORMS BEFORE DISSIPATION. THE DEPRESSION HAS BEEN MEANDERING AND ONLY A SMALL NORTHWARD DRIFT IS ANTICIPATED DURING THE NEXT 12 TO 24 HOURS. ...TROPICAL WAVES... A CARIBBEAN SEA TROPICAL WAVE IS ALONG 69W/70W SOUTH OF THE EASTERN SECTION OF THE DOMINICAN REPUBLIC. A MIDDLE TO UPPER LEVEL INVERTED TROUGH HAS BEEN MOVING NEARLY IN PHASE WITH THIS WAVE FOR THE LAST FEW DAYS. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS FROM 11N TO 17N BETWEEN 62W AND 72W. THE COMPARATIVELY COLDEST CLOUD TOP TEMPERATURES RANGED FROM -70C TO -60C FROM 14N TO 15N BETWEEN 68W AND 69W. ...THE ITCZ... 12N16W 7N23W 7N40W 9N50W 11N69W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS IN THE WESTERN TWO-THIRDS OF SIERRA LEONE IN AFRICA. ISOLATED MODERATE SHOWERS FROM 3N TO 12N BETWEEN 10W AND 30W...AND FROM 3N TO 10N BETWEEN 30W AND 57W. DISCUSSION... THE GULF OF MEXICO... BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW COVERS THE GULF OF MEXICO. THE TROUGH THAT IS RESPONSIBLE FOR THIS FLOW PASSES THROUGH THE WESTERN FLORIDA PANHANDLE TO THE WEST CENTRAL GULF WATERS TO THE SOUTHWESTERN CORNER OF THE AREA. DRY AIR/SUBSIDENCE IS EVERYWHERE. HIGH CLOUDS HAVE ENCROACHED INTO THE SOUTHEASTERN CORNER OF THE AREA FROM THE NORTHWESTERN CARIBBEAN SEA...FROM THE SURFACE TROUGH THERE AND THE TWO SURFACE LOW PRESSURE CENTERS ALONG THE TROUGH. THE SURFACE PRESSURE GRADIENT IN THE GULF OF MEXICO IS WEAK. THE 1008 MB ISOBAR IS AROUND THE NORTHWESTERN CARIBBEAN SEA LOW PRESSURE CENTERS IN THE SOUTHEASTERN CORNER OF THE AREA. THE 1012 MB ISOBAR MOVES FROM FLORIDA JUST EAST OF THE FLORIDA BIG BEND INTO THE NORTH CENTRAL GULF WATERS TO NORTHEASTERN MEXICO JUST SOUTH OF THE DEEP SOUTH OF TEXAS. THE CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION CENTER IS NEAR JAMAICA. ANTICYCLONIC FLOW IS EVERYWHERE...EXCEPT FOR THE MIDDLE TO UPPER LEVEL INVERTED TROUGH ON TOP OF THE 69W/70W TROPICAL WAVE. A SURFACE TROUGH EXTENDS NORTHEASTWARD FROM A 1005 MB NORTH CENTRAL GUATEMALA LOW PRESSURE CENTER TO A 1004 MB LOW PRESSURE CENTER NEAR 19N87W AT THE NORTHERN EDGE OF THE BANCO CHINCHORRO...TO CUBA NEAR 22N80W AND BEYOND INTO THE ATLANTIC OCEAN. STRONG SHOWERS/THUNDERSTORMS ARE SOUTH OF 17N WEST OF 86W INCLUDING IN THE GULF OF HONDURAS...FROM 20N TO 21.5N BETWEEN 83W AND 84W...OFF THE NORTHWESTERN JAMAICA COAST FROM 18N TO 19.5N BETWEEN 78.5W AND 79.5W...OFF THE SOUTHEASTERN CUBA COAST FROM 19N TO 20N BETWEEN 75.5W AND 77W...AND ALONG THE HAITI/ DOMINICAN REPUBLIC BORDER NEAR 19N71.5W. THIS PRECIPITATION ALSO IS OCCURRING IN THE AREA OF UPPER LEVEL DIFFLUENT FLOW...IN RELATION TO THE MIDDLE TO UPPER LEVEL SOUTHWESTERLY FLOW THAT IS ALONG AND NORTHWEST OF 31N68W 26N75W 22N86W. MIDDLE TO UPPER LEVEL CYCLONIC FLOW RIGHT NOW IS IN THE ATLANTIC OCEAN FROM 10N TO 16N BETWEEN 53W AND 60W...THAT MAY OR MAY NOT MOVE INTO THE EASTERN CARIBBEAN SEA DURING THE NEXT FEW DAYS. THE ATLANTIC OCEAN... THE SOUTHERN END OF A COLD FRONT PASSES THROUGH 32N69W TO 30N71W TO 27N77W TO THE SOUTHEASTERN FLORIDA COAST NEAR 26N80W. THE DEEP LAYER TROUGH THAT SUPPORTS THIS TROUGH IS NORTH OF THE AREA. DRY AIR/SUBSIDENCE IS NORTHWEST OF 32N67W TO 27N72W 26N80W. MIDDLE TO UPPER LEVEL SOUTHWESTERLY WIND FLOW IS IN THIS AREA OF DRY AIR/SUBSIDENCE. THE SURFACE TROUGH THAT ORIGINATES FROM THE 1005 MB GUATEMALA LOW PRESSURE CENTER PASSES THROUGH CUBA NEAR 22N80W TO THE BAHAMAS NEAR 23N75W TO 26N70W TO 31N66W. SOME CLUSTERS OF STRONG SHOWERS/THUNDERSTORMS ARE FROM 23N TO 24N BETWEEN 73W AND 75W...FROM GRAND INAGUA TO THE TURKS AND CAICOS AND FROM 22N TO 23.5N BETWEEN 70.5W AND 71.5W...FROM 23N TO 26N BETWEEN 67W AND 69W...FROM 28N TO 30N BETWEEN 65.5W AND 67W...AND WITHIN A 15 TO 30 NM RADIUS OF 29N61.5W. A MIDDLE TO UPPER LEVEL TROUGH STARTS NEAR 31N48W AND STRETCHES TO A CYCLONIC CIRCULATION CENTER NEAR 24N52W...TO 17N57W TO 9N59W. NO DEEP CONVECTIVE PRECIPITATION IS NEAR THIS TROUGH. UPPER LEVEL NORTHERLY FLOW MOVES FROM 32N SOUTHWARD TO 17N BETWEEN AT LEAST 40W AND 50W AS PART OF UPPER LEVEL ANTICYCLONIC FLOW AROUND A RIDGE ROUGHLY ALONG 50W FROM 10N BEYOND 32N. A SURFACE FRONTAL BOUNDARY IS ALONG 31N/32N BETWEEN 32W AND 45W. A RIDGE STRETCHES FROM A 1019 MB HIGH PRESSURE CENTER NEAR 29N35W TO 23N47W TO THE NORTHEASTERN CARIBBEAN SEA NEAR 19N64W. A 1010 MB LOW PRESSURE CENTER STILL IS JUST OFF THE WESTERN EDGE OF THE CANARY ISLANDS. ITS MIDDLE TO UPPER LEVEL SUPPORT IS A CYCLONIC CIRCULATION CENTER OVER THE WATERS ABOUT 60 NM TO THE NORTH OF THE CANARY ISLANDS. SCATTERED MODERATE SHOWERS FROM 30N TO 32N BETWEEN 7W AND 11W FROM MOROCCO TO THE COASTAL WATERS. ISOLATED MODERATE SHOWERS FROM 29N TO 30N BETWEEN 14W AND 16W. $$ MT