000 AXNT20 KNHC 172348 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT JUN 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE ADDED ALONG 16W S OF 14N MOVING W 15 KT. WAVE HAS GOOD CONTINUITY ON LONG-TERM SATELLITE LOOPS AND IS WELL REPRESENTED BY RADIOSONDE DATA AND MODEL FIELDS. MID-LEVEL CIRCULATION SEEN ALONG THE WAVE NEAR 9N. ISOLATED MODERATE CONVECTION FROM 7N-11N E OF 21W. TROPICAL WAVE IS ALONG 44W S OF 19N MOVING W 20 KT. WAVE HAS A WELL-DEFINED CYCLONIC SIGNATURE IN INFRARED SATELLITE IMAGERY AND IS PRODUCING SOME ISOLATED TSTMS FROM 8N-12N BETWEEN 42W-47W. COMPUTER MODELS HAVE MOISTURE FROM THIS WAVE BEGINNING TO AFFECT THE LESSER ANTILLES LATE MON. AN ACTIVE TROPICAL WAVE IS ALONG 62W S OF 20N MOVING W 10-15 KT. THIS WAVE IS ALREADY AFFECTING THE LESSER ANTILLES...MAINLY GUADALOUPE AND DOMINICA WITH ISOLATED SHOWERS AND TSTMS. THE WAVE IS INTERACTING WITH AN UPPER TROUGH PRODUCING AN AREA OF WIDELY SCATTERED MODERATE/STRONG CONVECTION FROM 19N-22N BETWEEN 54W-60W. MODELS SUGGEST THE LEEWARD ISLANDS AND PUERTO RICO HAS THE BEST CHANCE OF RAIN FROM THE WAVE THOUGH MOST OF THE RAIN WILL LIKELY BE OVER THE OPEN OCEAN. TROPICAL WAVE IS ALONG 90W S OF 19N MOVING W 10 KT. WAVE IS MOSTLY OVER CENTRAL AMERICA THUS DIMINISHING THE WAVE SIGNATURE. NO ASSOCIATED CONVECTION. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N14W 4N23W 9N40W 6N55W. WIDELY SCATTERED MODERATE WITHIN 60 NM OF AXIS BETWEEN 26W-31W. A FEW TSTMS ARE WITHIN 90 NM OF AXIS BETWEEN 32W-40W AND W OF 50W. ...DISCUSSION... GULF OF MEXICO... SQUALL LINE IS MOVING THRU LOUISIANA THOUGH IT IS BREAKING UP AS IT HEADS EASTWARD. DIGGING TROUGH THRU THE GREAT PLAINS IS THE CULPRIT FOR THE INCREASE IN WEATHER THOUGH IT IS CONFINED TO THE COASTAL AREAS AND INLAND. MID/UPPER HIGH NEAR 26N89W DOMINATES THE REST OF THE GULF WITH PLENTY OF DRY AIR ALOFT. RIDGE AXIS AT THE SURFACE HAS SHIFTED N OF THE AREA WITH LIGHT/MODERATE SLY WINDS BRINGING LOW-LEVEL MOISTURE BACK THROUGH THE AREA. WEAK TROUGH E OF FLORIDA SHOULD INCREASE RAIN CHANCES IN S FLORIDA OVERNIGHT AND TOMORROW WITH A FAIR CHANCE OF RAIN ESPECIALLY ALONG THE SEABREEZES AROUND THE NORTHERN GULF COAST SUN. CARIBBEAN SEA... RIDGING FROM THE GULF COVERS THE NW CARIBBEAN WITH JUST A FEW DIURNAL TSTMS OVER CUBA. OTHERWISE MID/UPPER SUBSIDENCE OVER A GOOD PORTION OF THE AREA W OF 70W IS KEEPING CONDITIONS RELATIVELY DRY. UPPER TROUGH HAS MOVED SOUTHWARD FROM YESTERDAY AND EXTENDS SOUTHWARD ROM NEAR PUERTO RICO TO THE NW PORTION OF COLOMBIA. THIS TROUGH IS ENHANCED TSTMS OVER NORTHERN S AMERICA AND ALONG A TROPICAL WAVE BUT MOST OF THE ACTIVITY IS RATHER LIMITED OVER THE CARIBBEAN ISLANDS AND ADJACENT WATERS. TOMORROW SHOULD DRY OUT A LITTLE IN THE E CARIBBEAN WITH INCREASING MOISTURE ON MON AS A TROPICAL WAVE APPROACHES. THE GFS SUGGESTS TSTMS WILL INCREASE TO MORE TYPICAL LEVELS IN THE SW CARIBBEAN W OF 80W NEAR AND S OF NICARAGUA ON MON. ATLANTIC OCEAN... BASICALLY THE ATLANTIC HAS A TROUGH/RIDGE/TROUGH/RIDGE PATTERN OF FAIRLY HIGH AMPLITUDE. WESTERNMOST TROUGH IS JUST W OF BERMUDA SOUTHWARD THRU THE SE BAHAMAS WITH ISOLATED TSTMS N OF 25N BETWEEN 59W-65W. HIGH CLOUDS FORM A SHIELD OVER A GOOD PORTION OF THE SUBTROPICAL ATLC N OF 20N BETWEEN 40W-60W MOVING NORTHWARD AROUND A HIGH NEAR 18N49W RIDGING UP BEYOND 31N50W. DIFFLUENT FLOW BETWEEN THE HIGH AND TROUGHING TO THE W IS LEADING TO ACTIVE CONVECTION NE OF THE LEEWARD ISLANDS. FARTHER E... MID/UPPER LOW IS NEAR 30N34W TROUGHING S TO 20N36W WITH A FEW TSTMS ENHANCED WITHIN 90 NM OF 24N30W. OTHERWISE RIDGING IS FAR TO THE N CENTERED NEAR 22N20W WITH MOSTLY ELY WINDS ALOFT OVER A GOOD PORTION OF THE TROPICAL ATLC. THIS IS CONTRIBUTING TO THE RECENT ACTIVE CONDITIONS IN THE ATLC ITCZ AND THE RATHER HIGH AMPLITUDE WAVES OF THE PAST WEEK. SUBTROPICAL RIDGE HAS BUILT UP N OF THE AREA BRINGING NEAR OR ABOVE AVERAGE TRADES IN THE TROPICAL ATLC. $$ BLAKE