000 AXNT20 KNHC 061759 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAY 06 2007 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 4N20W 1N30W EQ40W 1S48W. A CLUSTER OF MODERATE TO STRONG CONVECTION CAME OFF THE AFRICAN COAST EARLY THIS MORNING...BUT DURING THE LAST FEW HOURS THE STRONGEST CONVECTION HAS DIMINISHED A BIT. IT COVERS FROM 2N-6N BETWEEN 12W-16W. SCATTERED MODERATE CONVECTION IS WITHIN 30-45 NM EITHER SIDE OF THE AXIS WEST OF 39W. ...DISCUSSION... GULF OF MEXICO... MODERATE TO STRONG RETURN FLOW CONTINUES TO DOMINATE THE GULF MAINLY W OF 90W WHERE A TIGHTER PRES GRADIENT EXISTS DUE TO LOWER PRESSURE OVER MEXICO. EARLIER QUIKSCAT PASS SHOWED SLY WINDS OF 15 TO 25 KT. AN UPPER RIDGE IS BUILDING ACROSS THE GULF AND IS SPREADING UPPER LEVEL MOISTURE/HIGH CLOUDS EWD INTO THE GULF ESPECIALLY W OF 90W. MOSTLY DRY MID TO UPPER AIR IS OVER THE ERN PORTION WITH NW FLOW ASSOCIATED WITH A STRONG UPPER TROUGH DIGGING OFF THE EASTERN SEABOARD. BACKDOOR FRONT ASSOCIATED WITH THIS TROUGH WILL AFFECT THE MIDDLE AND ERN GULF LATE TONIGHT INTO MON. STRONG HIGH PRES WILL FOLLOW THE FRONTAL BOUNDARY GIVING THE AREA MODERATE TO STRONG NE-E FLOW. THIS WINDS ARE EXPECTED TO INCREASE TO 20-25 KT LATE TONIGHT. CARIBBEAN SEA... LIGHT TO MODERATE TRADES ARE BLOWING ACROSS MUCH OF THE BASIN DUE TO WEAK PRES GRADIENT OVER THE REGION. ALOFT...AN UPPER TROUGH IS DIGGING INTO THE WESTERN CARIBBEAN...WHILE AN UPPER HIGH CENTERED OFF NE SOUTH AMERICA EXTENDS A BROAD RIDGE OVER THE REMAINDER OF THE BASIN. THE RIDGE ALSO EXTENDS WWD FROM VENEZUELA TO COSTA RICA. SWLY WINDS ON THE WESTERN PERIPHERY OF THE RIDGE ARE TRANSPORTING ABUNDANT UPPER LEVEL MOISTURE/HIGH CLOUDS FROM THE EPAC ITCZ LOCATED JUST SOUTH OF PANAMA/COSTA RICA NEWD THROUGH THE CENTRAL AND NE CARIBBEAN. UPPER DIFFLUENCE AND THE CLOSE PROXIMITY OF THE EPAC ITCZ ARE ENHANCING CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION OVER PANAMA...COSTA RICA AND THE SW CARIBBEAN. FAIRLY WEAK PRES GRADIENT WILL KEEP TRADES IN THE LIGHT TO MODERATE CATEGORY OVER THE NEXT COUPLE OF DAYS. ATLANTIC... GLOBAL MODELS HAVE CONTINUED TO COME INTO BETTER AGREEMENT REGARDING THE DEVELOPMENT AND ASSOCIATED FRONTAL STRUCTURE OF A STRONG LOW PRESSURE CENTER OFF OF THE SE COAST OF UNITED STATES LATER TODAY THROUGH TUESDAY. THIS IS EXPECTED TO BRING SIGNIFICANT MARINE IMPACTS TO THE NW PORTION OF THE AREA INTO EARLY NEXT WEEK...INCLUDING GALE FORCE WINDS AND LARGE NLY SWELLS. SEVERAL MARINE ADVISORIES/WARNINGS ARE ALREADY IN EFFECT ALONG THE EASTERN COAST OF U.S FROM SOUTH FLORIDA TO BEYOND THE CAROLINAS. SHOWERS AND TSTMS HAVE INCREASED AHEAD OF THE BACKDOOR FRONT CURRENTLY EXTENDING FROM A 1012 MB SFC LOW NEAR THE OUTER BANK TO SOUTH GEORGIA. THIS CONVECTIVE ACTIVITY IS MOVING SOUTH CLIPPING NE FLORIDA. A SFC TROUGH REMAINS OVER THE W ATLC AND EXTENDS FROM 29N60W TO THE REGIONAL WATERS OF PUERTO RICO. THIS TROUGH HAS A 1012 MB LOW ATTACHED NEAR 28N60W. LATEST VIS SAT IMAGERY IS SHOWING A COUPLE OF LOW LEVEL SWIRLS ALONG THE TROUGH AXIS. MOST OF THE SHOWER ACTIVITY REMAINS WITHIN 80 NM E OF THE TROUGH WHERE MORE UPPER SUPPORT EXISTS...WITH DIFFLUENCE BETWEEN THE TROUGHING IN THE WRN ATLC AND RIDGING IN THE CENTRAL ATLC. MUCH OF THE REMAINDER OF THE ATLC DISCUSSION AREA IS DOMINATED BY THE SRN PERIPHERY OF A QUASI-STATIONARY 1033MB SFC HIGH S OF THE AZORES NEAR 35N28W. THIS IS GIVING THE AREA MODERATE TO FRESH TRADES AND MOSTLY FAIR WEATHER WITH ONLY PATCHES OF LOW LEVEL CLOUDS. THERE IS AN UPPER LOW NEAR 28N25W BUT IT DOES NOT APPEAR TO BE GENERATING ANY SIGNIFICANT WEATHER. $$ GR