000 AXNT20 KNHC 132300 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUN 13 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 2245 UTC. ...TROPICAL WAVES... E ATLC TROPICAL WAVE IS ALONG 20W/21W MOVING W 10-15 KT. SATELLITE IMAGES AND DERIVED WINDS SHOW LOW-MID LEVEL TURNING AND A FAINT INVERTED V-SHAPE ASSOCIATED WITH THIS FEATURE. CONVECTION IS MINIMAL AND MORE ASSOCIATED WITH THE ITCZ. SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 20W-24W. W ATLC TROPICAL WAVE IS ALONG 56W/57W FROM 7N TO 22N MOVING QUICKLY TO THE W NEAR 20-25 KT. THIS LARGE WAVE CONTINUES TO BE EASY TO TRACK SINCE IT EMERGED OFF THE AFRICAN COAST SEVERAL DAYS AGO. LOW LEVEL...SHARP AMPLITUDE INVERTED-V SIGNATURE IS OBSERVED ON VISIBLE SATELLITE IMAGERY. SCATTERED SHOWERS ARE FROM 19N-22N BETWEEN 54W-57W...OTHERWISE THE SYSTEM REMAINS ABSENT OF ANY DEEP CLOUDINESS OR SIGNIFICANT SHOWER ACTIVITY. A LOW AMPLITUDE TROPICAL WAVE HAS MOVED MOSTLY INLAND OVER SOUTH AMERICA AND IS ALONG 62W/63W S OF 12N MOVING W 10-15 KT. WITH MOST OF THE WAVE INLAND THERE IS NO SATELLITE INDICATION OF THE WAVE AXIS. SHOWER AND THUNDERSTORM ACTIVITY CONTINUES S OF 12N FROM 60W-65W BUT IS MOSTLY ASSOCIATED WITH THE ITCZ. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N15W 7N23W 3N41W 6N54W. BESIDES FOR CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ...SCATTERED THUNDERSTORMS ARE WITHIN 150 NM OF THE AXIS FROM 28W-34W...FROM 40W-45W...AND S OF 12N TO INLAND OVER SOUTH AMERICA BETWEEN 48W-60W. NUMEROUS THUNDERSTORMS HAVE DEVELOPED INLAND OVER SW AFRICA WITH SCATTERED SHOWERS MOVING OFF THE COAST S OF 14N W OF 5W. ...DISCUSSION... GULF OF MEXICO... LARGE ELONGATED UPPER TROUGH EXTENDS FROM THE W ATLC INTO THE NE GULF WITH AN EMBEDDED UPPER LOW ALONG THE COAST NEAR THE FL/GA BORDER. THE UPPER LOW IN THE E BAY OF CAMPECHE NEAR 20N91W HAS BEEN CUT-OFF FROM THE LARGE UPPER TROUGH OVER THE NE GULF. A SURFACE TROUGH EXTENDS ALONG THE BASE OF THE UPPER TROUGH ACROSS S FLORIDA INTO THE GULF NEAR NAPLES NW TO A 1010 MB SURFACE LOW NEAR NEW ORLEANS. THIS BOUNDARY...ALONG WITH ENERGY FROM AN UPPER JET...IS PRODUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 28N FROM MISSISSIPPI TO E TEXAS E OF HOUSTON AND OVER THE FLORIDA PENINSULA. UPPER RIDGING COVERS THE W GULF ANCHORED BY AN UPPER HIGH CENTER OVER N CENTRAL MEXICO NEAR MONTERREY. A 1014 MB SURFACE HIGH IS LOCATED IN THE W GULF NEAR 25N92W. THIS PATTERN IS MAINTAINING FAIR WEATHER AND LIGHT WINDS ACROSS THE REMAINDER OF THE W GULF. CARIBBEAN SEA... THE MOST ACTIVE WEATHER OF THE REGION REMAINS ACROSS THE W CARIBBEAN WHERE CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE GENERALLY W OF 80W N OF 12N TO OVER CUBA AND THE YUCATAN CHANNEL. THIS ACTIVITY APPEARS TO BE INDUCED BY SEVERAL FACTORS. THE MOST PERSISTENT HAS BEEN DIFFLUENCE ALOFT BETWEEN AN UPPER LOW SPINNING OVER THE E BAY OF CAMPECHE AND A BROAD RIDGE/UPPER HIGH CENTERED NEAR 12N81W. THE TROPICAL WAVE THAT IS INLAND OVER NICARAGUA AND A SURFACE TROUGH ANALYZED FROM THE HONDURAS COAST TO THE W TIP OF CUBA ALONG 16N86W 20N86W TO 22N83W ARE SUPPLYING LOW-LEVEL LIFT AIDING IN THE CONVECTIVE DEVELOPMENT. ELSEWHERE...A PLUME OF MID-HIGH LEVEL CLOUDINESS WITH SIMILAR CONVECTION ARE STREAMING ACROSS THE GREATER ANTILLES FROM CUBA TO HISPANIOLA. THE REMAINDER OF THE AREA IS FREE OF SIGNIFICANT MOISTURE...ALTHOUGH TYPICAL TRADE WIND SHOWERS ARE POSSIBLE AT ANY GIVEN LOCATION...ESPECIALLY ACROSS THE SE CARIB WHERE THE ENVIRONMENT IS MOISTENED FROM THE NEARBY TROPICAL WAVE AND ITCZ AXIS IN THE E PACIFIC REGION. STRONG EASTERLY TRADE WINDS REMAIN ACROSS THE S/CENTRAL CARIBBEAN...BUT BELOW GALE FORCE. ATLANTIC OCEAN... EXTENSIVE STRONG SW FLOW ALOFT TO THE E/SE OF A LARGE ELONGATED UPPER TROUGH IS PROVIDING PLENTY OF MOISTURE FOR SHOWERS AND THUNDERSTORMS. THIS UPPER SYSTEM IS SUPPORTING A 1009 MB LOW CENTERED ABOUT 150 NM NE OF THE GREAT ABACO ISLAND IN THE N BAHAMAS NEAR 28N75W. A WARM FRONT EXTENDS E FROM THE LOW ALONG 29N72W TO 29N64W. SATELLITE IMAGERY AND LIGHTNING DATA DETECT CLUSTERS OF SCATTERED SHOWERS AND THUNDERSTORMS ALONG THE E COAST OF THE US N OF 25N W OF 77W WITH SIMILAR ACTIVITY IN A DIFFLUENT ZONE BETWEEN THE EXTENSIVE TROUGHING AND RIDGING TO THE E...S OF THE FRONT BETWEEN 65W-72W AND S OF 24N FROM 72W-81W. FARTHER E...WV IMAGERY SHOWS A WEAK UPPER LEVEL SHORTWAVE RIDGE EXTENDING NE FROM PUERTO RICO TO 32N51W. DIFFLUENCE TO THE W IS GENERATING A LARGE AREA OF SCATTERED SHOWERS/THUNDERSTORMS WITHIN AN UPPER TROUGH EXTENDS FROM 28N26W TO A SMALL UPPER LOW NEAR 23N40W TO A LARGER UPPER LOW NEAR 18N56W TO THE LESSER ANTILLES NEAR 14N61W. BROAD SURFACE RIDGE COVERS MUCH OF THE ATLC W OF 60W ANCHORED BY A 1024 MB HIGH CENTERED NEAR 29N39W. THIS HIGH IS AIDING IN THE MOSTLY FAIR WEATHER AND PRODUCING A LARGE AREA OF MODERATE TRADES ACROSS THE TROPICAL ATLC...ESPECIALLY BETWEEN THE HIGH ITSELF AND THE LARGE TROPICAL WAVE NOTED ALONG 56W/57W. $$ WALLACE