000 AXNT20 KNHC 131807 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU APR 13 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS... RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1745 UTC. ...ITCZ... ITCZ 7N10W 1N20W...TO THE EQUATOR AT 30W...TO 1S40W AND 1S48W. STRONG SHOWERS AND THUNDERSTORMS IN INDIVIDUAL CELLS ARE FOUND WITHIN 30 NM ON EITHER SIDE OF 3N BETWEEN 29W AND 32W. ISOLATED MODERATE SHOWERS AND LOCALLY STRONG THUNDERSTORMS ARE WITHIN 30 NM TO 60 NM ON EITHER SIDE OF 1N15W 1N19W 3N23W...AND 4N36W 4N44W 4N46W 1N50W. ...DISCUSSION... THE GULF OF MEXICO SOUTH OF 25N EAST OF 85W...THE CARIBBEAN SEA...AND THE ATLANTIC OCEAN NORTH OF 20N WEST OF 56W... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM AN ATLANTIC OCEAN LOW CENTER NEAR 26N73W TO A SECOND LOW CENTER NEAR 19N77W OFF THE SOUTHEASTERN COAST OF CUBA IN THE CARIBBEAN SEA...TO NORTHEASTERN NICARAGUA NEAR 15N84W. CYCLONIC FLOW AS SEEN ON WATER VAPOR IMAGERY IS FOUND IN MIDDLE TO UPPER LEVEL DRY AIR...WITHIN 360 NM ON EITHER SIDE OF THE TROUGH. THE UPPER LEVEL SOUTHWESTERLY WIND FLOW...WHICH HAS BEEN SO PROMINENT FOR MORE THAN ONE WEEK...CONTINUES TO STREAM INTO THE SOUTHWESTERN CARIBBEAN SEA ACROSS COSTA RICA AND PANAMA. THIS SOUTHWESTERLY FLOW MERGES WITH THE SOUTHWESTERLY FLOW AROUND THE SOUTHERN SIDE OF THE ATLANTIC OCEAN-TO-CARIBBEAN SEA TROUGH. A SURFACE 1009 MB LOW PRESSURE CENTER WAS ANALYZED NEAR 21N70W. A COLD FRONT PASSES THROUGH 32N56W TO 29N60W TO 26N68W TO THE 1009 MB LOW CENTER. IT IS POSSIBLE THAT PUERTO RICO AND LAND AREAS TO THE EAST OF THE TROUGH MAY EXPERIENCE ENHANCED AMOUNTS OF RAINFALL UNDER THESE ATMOSPHERIC CONDITIONS. A FLASH FLOOD WATCH IS IN EFFECT UNTIL 5 PM TODAY FOR PUERTO RICO. OVERCAST HIGH CLOUDS ARE STREAMING NORTHEASTWARD...AND COVER THE AREAS FROM 20N TO 31N BETWEEN 52W AND 74W IN THE ATLANTIC WATERS. HIGH CLOUDS ARE STREAMING NORTHEASTWARD FROM NORTHWESTERN VENEZUELA INTO THE CENTRAL CARIBBEAN SEA...TOWARD THE AREA BETWEEN 62W AND 72W IN THE NORTHERN CARIBBEAN SEA. THE SURFACE WIND FLOW IS NORTHERLY TO THE WEST OF THE MIDDLE TO UPPER LEVEL TROUGH. THE SURFACE WIND FLOW IS SOUTHEASTERLY ON THE EASTERN SIDE OF THE TROUGH. SHOWERS ARE POSSIBLE IN CONFLUENT LINES OF LOW CLOUDS ELSEWHERE. THE REST OF THE GULF OF MEXICO... THE SURFACE WIND FLOW IS FROM THE NORTHEAST. SHOWERS ARE POSSIBLE IN CONFLUENT LINES OF LOW CLOUDS. THE SOUTHERN END OF AN EAST COAST U.S.A. MIDDLE TO UPPER LEVEL TROUGH REACHES CENTRAL FLORIDA FROM GEORGIA AND THE ATLANTIC WATERS JUST OFF THE GEORGIA COAST. MIDDLE TO UPPER LEVEL DRY AIR IS NORTH OF 31N77W 26N84W 28N94W AS THE NOSE OF THE THIS TROUGH PUSHES SOUTHWARD. UPPER LEVEL NORTHWESTERLY FLOW MOVES FROM TEXAS AND MEXICO INTO THE OPEN GULF WATERS. THE REST OF THE ATLANTIC OCEAN... AN UPPER LEVEL RIDGE RUNS FROM A HIGH CENTER NEAR 12N61W TO 30N60W. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE EASTERN CARIBBEAN SEA AND THE ATLANTIC WATERS FROM THE EQUATOR TO 30N BETWEEN 45W AND THE CYCLONIC FLOW AROUND THE CUBA/BAHAMAS LOW CENTER AND TROUGH. A SEPARATE TROUGH IS ALONG 30N48W BEYOND 35N52W. THE NEXT LARGE-SCALE TROUGH IS EAST OF THE ANTICYCLONIC FLOW WHICH IS AROUND THE 60W/61W RIDGE. THIS TROUGH IS ALONG 12N34W 18N32W 25N29W BEYOND 31N24W. A 1015 MB LOW PRESSURE CENTER IS NEAR 30N27W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE FOUND FROM 30N TO 29N TO 35N BETWEEN 20W AND 32W. $$ MT