000 AXNT20 KNHC 220003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 21 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... WHAT REMAINS OF A SURFACE LOW PRESSURE CENTER THAT WAS OVER THE NORTHEASTERN CARIBBEAN SEA SIX HOURS AGO NOW IS INLAND IN CENTRAL AND WESTERN PUERTO RICO. THE DATA FROM THE AIR FORCE RECONNAISSANCE FLIGHT DO NOT SHOW A WELL-DEFINED SURFACE CIRCULATION CENTER YET. THE LOW CENTER IS EXPECTED TO MOVE GENERALLY NORTHWARD DURING THE NEXT DAY OR TWO...AND IT MAY BECOME A TROPICAL DEPRESSION AT ANY TIME. LOCALLY HEAVY RAINFALL WILL CONTINUE OVER PUERTO RICO AND THE U. S. AND BRITISH VIRGIN ISLANDS THROUGH MONDAY. THESE RAINS MAY CAUSE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES. EVERYONE IN PUERTO RICO...THE U.S. AND BRITISH VIRGIN ISLANDS...AND EASTERN HISPANIOLA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM AND ANY WATCHES OR WARNINGS ISSUED BY THE RESPECTIVE WEATHER FORECAST OFFICES. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE FROM 17N TO 19N BETWEEN 65W AND 67W AROUND AND ON TOP OF PUERTO RICO. OTHER SHOWERS AND THUNDERSTORMS ARE WITHIN A 30 NM RADIUS OF 20N60W... 18N62W...AND 15N67W. ISOLATED AND DISORGANIZED SHOWERS AND POSSIBLE THUNDERSTORMS ARE IN THE DOMINICAN REPUBLIC FROM 18N TO 19N BETWEEN 70W AND 72W. ISOLATED MODERATE SHOWERS ARE IN HAITI FROM THE NORTHEASTERN CORNER TO THE SOUTHWESTERN CORNER. WARMING CLOUD TOP TEMPERATURES AND DISSIPATING BUT LINGERING CONVECTIVE PRECIPITATION FROM 15N TO 16N BETWEEN 63W AND 65W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 25W/26W SOUTH OF 17N MOVING WEST 10 TO 15 KT. ISOLATED DISORGANIZED SHOWERS AND THUNDERSTORMS ARE FROM 10N TO 14N BETWEEN 24W AND 30W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 40W/41W SOUTH OF 20N MOVING WEST 10 TO 15 KT. LOW CLOUDS ARE AROUND THE WAVE FROM 10N TO 20N BETWEEN 37W AND 42W. A TROPICAL WAVE IS ENTERING THE EASTERN CARIBBEAN SEA ALONG 60W/61W SOUTH OF 20N MOVING WEST 10 TO 15 KT. SHOWERS AND THUNDERSTORMS ARE WITHIN A 15 NM TO 30 NM RADIUS OF 20N60W... 18N62W...AND FROM 16N TO 17N BETWEEN 61W AND 62W. A TROPICAL WAVE IS ALONG 86W/87W SOUTH OF 21N MOVING WEST 10 TO 15 KT PASSING THROUGH HONDURAS AND NICARAGUA. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE IN THE YUCATAN PENINSULA NORTH OF 20N. ...THE ITCZ... ALONG 10N/11N BETWEEN 15W AT THE AFRICA COAST AND 25W...10N29W 7N40W 7N50W 8N59W. STRONG SHOWERS AND THUNDERSTORMS FROM 3N TO 4N BETWEEN 36W AND 40W...AND FROM 6N TO 8N BETWEEN 44W AND 48W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE TO UPPER LEVEL SURFACE TROUGH IS INLAND THROUGH CENTRAL LOUISIANA TO CENTRAL TEXAS. AN UPPER LEVEL RIDGE COVERS THE GULF OF MEXICO FROM THE SOUTHWESTERN CORNER OF THE AREA NORTHEASTWARD BEYOND NORTH FLORIDA. A SURFACE TROUGH IS ALONG 19N93W 24N94W 27N94W. DISORGANIZED SHOWERS ARE SOUTH OF 22N BETWEEN THE YUCATAN PENINSULA AND MEXICO. OTHER SHOWERS AND POSSIBLE THUNDERSTORMS ARE IN BROAD SURFACE LOW PRESSURE UNDER THE RIDGE FROM 25N TO 28N BETWEEN 85W AND 86W. FROM THE ATLANTIC OCEAN INTO THE NORTHWESTERN CARIBBEAN SEA... AND THE CARIBBEAN SEA WEST OF 70W... A MIDDLE TO UPPER LEVEL TROUGH IS ALONG 31N75W TO 27N76W ACROSS THE BAHAMAS TO 23N78W. THE TROUGH CONTINUES ACROSS CUBA INTO THE NORTHWESTERN CARIBBEAN SEA TO 19N82W 17N86W THROUGH CENTRAL HONDURAS TO THE EL SALVADOR/NICARAGUA BORDER. A SURFACE TROUGH PASSES THROUGH 32N74W TO THE FLORIDA COAST NEAR 29N81W. ISOLATED MODERATE SHOWERS ARE WEST OF 74W. UPPER LEVEL ANTICYCLONIC FLOW COVERS THE CARIBBEAN SEA BETWEEN 70W AND 80W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS COVER THE AREA FROM 13N IN NICARAGUA TO 15N IN HONDURAS BETWEEN 87W AND 88W IN EASTERN EL SALVADOR. THE 31N75W-TO-17N86W TROUGH ALSO EXTENDS INTO THE EASTERN PACIFIC OCEAN NEAR 8N87W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS EXTEND FROM WESTERN PANAMA TO NORTHERN COSTA RICA...INTO WESTERN NICARAGUA...AND SPREAD OUT ACROSS HONDURAS. CONVECTIVE DEBRIS CLOUDS COVER THE CARIBBEAN SEA WATERS AND CENTRAL AMERICA SOUTH OF 15N WEST OF 81W. ISOLATED MODERATE SHOWERS IN UPPER LEVEL DIFFLUENT FLOW ARE FROM 14N TO 17N BETWEEN 79W AND 83W. STRONG SHOWERS AND THUNDERSTORMS IN SOUTHERN GUATEMALA ARE IN ALSO IN AN AREA OF UPPER LEVEL DIFFLUENT FLOW. THE REST OF THE CARIBBEAN SEA EAST OF 70W... THE SPECIAL FEATURE LOW PRESSURE CENTER IS INLAND IN PUERTO RICO. OVERCAST HIGH CLOUDS COVER PRACTICALLY THE ENTIRE AREA NORTH OF 10N EAST OF 70W. MIDDLE TO UPPER LEVEL EASTERLY FLOW APPROACHES THE EASTERN CARIBBEAN SEA FROM THE ATLANTIC OCEAN. THE REST OF THE ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 26N63W. A MIDDLE TO UPPER LEVEL CENTRAL ATLANTIC OCEAN TROUGH GOES FROM 28N42W TO A CYCLONIC CIRCULATION CENTER NEAR 23N47W TO 16N48W. AN EASTERN ATLANTIC OCEAN MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N13W TO A CYCLONIC CIRCULATION CENTER NEAR 29N23W TO 22N24W. ISOLATED MODERATE SHOWERS ARE NORTH OF 29N BETWEEN 30W AND 40W. $$ MT