000 AXNT20 KNHC 050603 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT MAY 05 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 1N20W 3N30W 2N50W. ISOLATED CLUSTERS OF MODERATE CONVECTION GENERALLY DOT THE ENTIRE ATLC AREA WITHIN 90NM EITHER SIDE OF THE AXIS BETWEEN SOUTH AMERICA AND AFRICA. HOWEVER...THE MODERATE CONVECTION IS MORE NUMEROUS IN NATURE WITH POCKETS OF ISOLATED STRONG CONVECTION FROM EQ-4N BETWEEN 20W-30W. ...DISCUSSION... GULF OF MEXICO... MODERATE RETURN FLOW DOMINATES THE GULF AROUND A WEAK 1016MB HIGH IN THE NE PORTION NEAR 29N85W. THE BLOW UP OF CONVECTION IN THE NRN GULF/S OF MISSISSIPPI AND ALABAMA HAS CONTINUED TO DIMINISH OVER THE LAST FEW HOURS. UPPER RIDGING IS BUILDING INTO THE WRN GULF BEHIND THE TROUGHING DOMINATING THE ERN GULF. AN EMBEDDED UPPER LOW IS NOTED IN WV IMAGERY OVER THE SE GULF NEAR 24N84W. THIS...IN ADDITION TO SEA BREEZES COLLIDING AND DAYTIME HEATING EFFECTS...LIKELY AIDED THE CONVECTION OVER FLORIDA DURING FRI WHICH HAS NOW DIMINISHED. LIGHT TO MODERATE E TO SE WINDS EXPECTED E OF 90W THROUGH THE WEEKEND...AROUND THE PERIPHERY OF SFC RIDGING. STRONGER RETURN FLOW DEVELOPS W OF 90W WHERE A STRONGER GRADIENT IS EXPECTED IN RESPONSE TO LOWER PRESSURE OVER MEXICO. THIS WILL ALLOW SE WIND WAVES TO BUILD THROUGH SUN FOR THE WRN GULF...WITH WW3 GUIDANCE SHOWING SEAS NEARING 10' BY SUNDAY AFTERNOON AT BUOY 42020. CARIBBEAN SEA... MODERATE TRADES DOMINATE MUCH OF THE BASIN EXCEPT FOR THE NORTH CENTRAL PORTION...N OF 16N BETWEEN 67W-82W...WHERE LIGHTER AND MORE VARIABLE WINDS EXIST. TRADE FLOW HAS BEEN DISRUPTED HERE DUE TO THE TROUGHING IN THE SW NORTH ATLC. THE TRADES ARE ADVECTING THEIR TYPICAL PATCHES OF LOW LEVEL MOISTURE WWD THIS EVENING...THOUGH THE MAIN THING NOTED IN TONIGHTS SATELLITE PICTURES IS THE ABUNDANT UPPER MOISTURE/HIGH CLOUDINESS STREAMING NE ESPECIALLY E OF 80W...DOWNSTREAM FROM ITCZ CONVECTION. AN UPPER TROUGH IS BUILDING INTO THE WRN GULF WHILE BROAD RIDGING FROM SOUTH AMERICA GENERALLY DOMINATES THE ERN PORTION. LIGHT TO MODERATE TRADES EXPECTED ACROSS THE CARIB THROUGH THE WEEKEND...ALTHOUGH TROUGHING FROM THE ATLC EXPECTED TO CONTINUE TO AFFECT THE WINDS/WEATHER IN THE NRN PORTION. ATLANTIC... MAIN FEATURE IN THE WRN ATLC CONTINUES TO BE THE SFC TROUGH EXTENDING NE FROM THE TURKS AND CAICOS. THIS...ALONG WITH UPPER DIFFLUENCE BETWEEN AN UPPER TROUGH OVER THE WRN ATLC AND AND UPPER RIDGE OVER THE CENTRAL ATLC...IS SUPPORTING THE OVERCAST CLOUDINESS WITH SCATTERED SHOWERS/ISOLD TSTMS N OF 20N BETWEEN 57W-72W. MODEL GUIDANCE HAS NOT BEEN HANDLING THIS SITUATION PARTICULARLY WELL. FOR WHAT ITS WORTH...GFS LIFTS ONE LOW LEVEL VORT MAX NE OVER THE WEEKEND WITH TROUGHING TRAILING SW TOWARDS HISPANIOLA. GUIDANCE HAS ALSO BEEN DIVERGENT ON THE DEVELOPMENT OF ANOTHER LOW OFF THE SE US COAST LATE SUN/EARLY NEXT WEEK...THOUGH THE 00Z GFS SEEMS A LITTLE MORE IN LINE WITH THE OTHER GLOBAL MODELS THAN THE 04/18Z GFS RUN WAS. OTHERWISE MUCH OF THE REMAINDER OF THE ATLC DISCUSSION AREA IS DOMINATED BY THE SRN PERIPHERY OF A 1030MB SFC HIGH S OF THE AZORES NEAR 36N29W. THERE IS AN UPPER TROUGH EXTENDING S THROUGH THE ERN ATLC ALONG 35W...BUT DOES NOT APPEAR TO BE GENERATING ANY SIGNIFICANT WEATHER. $$ WILLIS