000 AXNT20 KNHC 190518 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT SEP 19 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0000 UTC SURFACE ANALYSIS...AND GOES-12 SATELLITE IMAGERY THROUGH 0315 UTC...AND METEOSAT-8 IMAGERY THROUGH 0445 UTC. ...SPECIAL FEATURES... A 1008 MB LOW PRESSURE CENTER IS NEAR 13N40W. IT HAS BEEN MOVING WESTWARD 5 KT DURING THE LAST 24 HOURS. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 11N TO 14N BETWEEN 36W AND 39W...AND FROM 12N TO 14N BETWEEN 41W AND 43W. THE CHANCE THAT THIS SYSTEM MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM. AN UPPER LEVEL TROUGH THAT EXTENDS FROM 31N20W TO 24N29W TO 19N40W TO 16N44W IS ABOUT 300 NM TO THE NORTHWEST OF THE LOW CENTER. ...TROPICAL WAVES... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 26W/27W TO THE SOUTH OF 18N MOVING WESTWARD 10 TO 15 KT. SCATTERED STRONG SHOWERS AND THUNDERSTORMS ARE FROM 17N TO 19N BETWEEN 18W AND 22W...AND FROM 16N TO 17N BETWEEN 23W AND 25W. A TROPICAL WAVE HAS MOVED OUT OF THE CARIBBEAN SEA AND NOW IS ALONG 90W/91W TO THE SOUTH OF 20N MOVING WESTWARD 10 TO 15 KT. THIS WAVE COVERS THE AREA FROM THE WESTERN YUCATAN PENINSULA BEYOND WESTERN GUATEMALA INTO THE EASTERN PACIFIC OCEAN. THE SOUTHERN END OF AN UPPER LEVEL TROUGH THAT EXTENDS FROM THE EASTERN GULF OF MEXICO TO THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA TO THE ISTHMUS OF TEHUANTEPEC IS CLOSE TO THE NORTHERN END OF THIS WAVE. CLOUD TOP TEMPERATURES FROM EARLIER PRECIPITATION IN THE YUCATAN PENINSULA HAVE WARMED. A FEW CELLS OF SHOWERS REMAIN IN THE ISTHMUS OF TEHUANTEPEC. ADVANCING UPPER LEVEL CYCLONIC FLOW THAT IS MOVING AROUND THE 15N80W LARGE-SCALE UPPER LEVEL CYCLONIC CIRCULATION CENTER HAS REACHED CENTRAL AMERICA. ...THE ITCZ... 14N17W 15N25W 13N28W 13N38W 11N44W 10N56W INTO NORTHEASTERN VENEZUELA NEAR 10N63W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 7N TO 10N TO THE EAST OF 50W...AND FROM 10N TO 13N BETWEEN 49W AND 60W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL TROUGH PASSES THROUGH THE NORTHEASTERN GULF OF MEXICO INTO THE EASTERN GULF...TO THE NORTHWESTERN YUCATAN PENINSULA TO THE ISTHMUS OF TEHUANTEPEC. DISORGANIZED AND ISOLATED MODERATE SHOWERS ARE TO THE EAST OF 90W...AND ACROSS THE ISTHMUS OF TEHUANTEPEC. AN UPPER LEVEL RIDGE THAT STRETCHES FROM SOUTH CENTRAL MEXICO BEYOND THE LOWER VALLEY OF TEXAS IS PUSHING UPPER LEVEL MOISTURE FROM MEXICO AND TEXAS INTO THE GULF OF MEXICO TO THE WEST OF 92W. THE CARIBBEAN SEA... AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 15N80W... ABOUT 200 NM TO THE EAST OF THE BORDER OF EASTERN HONDURAS AND NORTHEASTERN NICARAGUA. CYCLONIC FLOW COVERS THE WHOLE AREA TO THE WEST OF 70W. STRONG SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ON TOP OF LAKE MARACAIBO AND ALONG THE NORTHEASTERN EDGE OF THE LAKE...IN NORTHWESTERN VENEZUELA. UPPER LEVEL CYCLONIC FLOW COVERS THE AREA TO THE NORTH OF 13N TO THE EAST OF 70W. THIS CYCLONIC FLOW IS RELATED TO THE ATLANTIC OCEAN UPPER LEVEL CYCLONIC CENTER THAT IS NEAR 22N60W. ISOLATED MODERATE SHOWERS ARE TO THE SOUTH OF 24N TO THE EAST OF 86W IN THE GULF OF MEXICO...AND IN THE CARIBBEAN SEA TO THE NORTH OF 20N TO THE WEST OF 79W IN UPPER LEVEL DIFFLUENT FLOW. THE ATLANTIC OCEAN... AN UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 22N60W. CYCLONIC FLOW AROUND THIS CENTER COVERS THE CARIBBEAN SEA AND THE ATLANTIC OCEAN TO THE NORTH OF 13N BETWEEN 50W AND 71W. THE 1012 MB LOW PRESSURE CENTER THAT IS NEAR 26N68W IS THE REMNANT OF HURRICANE FRED. A SURFACE TROUGH GOES FROM 30N67W TO THE 1012 MB REMNANT LOW CENTER TO 22N68W. ISOLATED MODERATE SHOWERS ARE WITHIN 30 NM ON EITHER SIDE OF THE TROUGH...AND FROM 16N TO 20N BETWEEN 58W AND 61W UNDER THE LARGE-SCALE CYCLONIC FLOW. A SURFACE TROUGH IS ALONG 31N73W 28N76W... ACROSS ABACO ISLAND IN THE BAHAMAS TO 24N79W. ISOLATED MODERATE SHOWERS COVER THE BAHAMAS FROM 24N TO 26N BETWEEN 77W AND 80W. $$ MT