000 AXNT20 KNHC 211746 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN OCT 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... THE TROPICAL WAVE THAT WAS PREVIOUSLY ANALYZED ALONG 52W/53W ON THE 06Z SURFACE MAP WAS RELOCATED ALONG 50W/51W BASED ON LATEST VIS SATELLITE IMAGERY THAT SHOWS A VERY WELL DEFINED INVERTED-V PATTERN ASSOCIATED WITH THIS FEATURE. THIS WAVE CONTINUES TO SHOW UP WELL IN LOW LEVEL SATELLITE DERIVED WINDS...AND THE UW-CIMSS TPW PRODUCT WITH A GOOD SURGE OF MOISTURE. SCATTERED MODERATE CONVECTION IS MAINLY EAST OF AXIS FROM 7N-16N BETWEEN 45W-51W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 6N30W 11N49W 11N53W 10N63W. BESIDES FOR THE ACTIVITY ASSOCIATED WITH THE TROPICAL SCATTERED MODERATE CONVECTION IS WITHIN 180 NM N OF AXIS WEST OF 26W. SIMILAR CONVECTION IS SEEN OVER THE WINDWARD ISLANDS AND NE VENEZUELA. DISCUSSION... GULF OF MEXICO... THE STATIONARY FRONT THAT WAS OVER THE CENTRAL GULF IS BEGINNING TO MOVE NWD AS A WARM FRONT. AS OF 1500 UTC...THE WARM FRONT EXTENDS ACROSS N-CENTRAL FLORIDA TO THE CENTRAL GULF NEAR 26N90W TO 25N96W. THIS FRONT AND ASSOCIATED MOISTURE/SHOWERS WILL CONTINUE TO LIFT N OVER THE NORTHERN GULF WATERS TONIGHT. A CLUSTER OF MODERATE CONVECTION IS ALONG THE FRONTAL BOUNDARY COVERING FROM 24N-27N BETWEEN 84W-87W. THIS CONVECTIVE ACTIVITY IS JUST AHEAD OF A SHORTWAVE TROUGH LOCATED OVER THE EASTERN GULF WHILE AN UPPER HIGH SITUATED NEAR 22N92W DOMINATES THE WESTERN HALF OF THE REGION. THE COMBINATION OF THE FRONT AND THE UPPER TROUGH IS ALSO SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS OVER NORTH FLORIDA. A SFC RIDGE ANCHORED ON A HIGH OVER NORTH CAROLINA IS IN CONTROL OF THE SE U.S. AND THE NORTHERN GULF WATERS. THIS HIGH IS EXPECTED TO MOVE E FAIRLY QUICKLY OVER THE NEXT COUPLE OF DAYS IN ADVANCE OF THE NEXT STRONGER COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST MONDAY MORNING. GALE CONDITIONS ARE STILL EXPECTED ACROSS THE WESTERN GULF...BEHIND THE COLD FRONT MONDAY NIGHT THROUGH TUE. CARIBBEAN SEA... SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THE NW CARIBBEAN MAINLY WEST OF 85W ASSOCIATED WITH A SFC TROUGH AND A WEAK 1008 MB LOW LOCATED NEAR 18N87W AT 21/1500 UTC. THESE SYSTEMS ARE FORECAST TO MOVE INLAND OVER THE YUCATAN PENINSULA/BELIZE LATE THIS AFTERNOON. THE TROUGH IS ANALYZED FROM 24N86W TO 14N89W CROSSING HONDURAS. UPPER DIFFLUENCE AROUND THE SE PERIPHERY OF AN UPPER HIGH OVER THE WESTERN GULF IS ENHANCING THIS CONVECTIVE ACTIVITY. AN UPPER-LEVEL LOW REMAINS OVER THE E CARIBBEAN AND NOW IS LOCATED JUST SOUTH OF DOMINICAN REPUBLIC. THIS UPPER SYSTEM HAS A TROUGH EXTENDING SW TOWARDS PANAMA AND NE THROUGH PUERTO RICO INTO THE CENTRAL ATLC. SWLY WINDS AHEAD OF THE TROUGH HAVE BEEN ADVECTING ABUNDANT TROPICAL MOISTURE FROM NORTHERN SOUTH AMERICA THROUGH THE EASTERN CARIBBEAN INTO THE TROPICAL NORTH ATLANTIC. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OVER THIS AREA. TRADES ARE MODERATE OVER THE CENTRAL AND ERN CARIBBEAN...AND BEND MORE SE IN THE WRN PORTION EAST OF THE TROUGH NEAR THE GULF OF HONDURAS. ATLANTIC OCEAN... A STATIONARY FRONT IS OVER THE WRN ATLC...ENTERING THE AREA NEAR 31N68W AND CONTINUING MAINLY WEST OVER N-CENTRAL FLORIDA. SCATTERED SHOWERS AND TSTMS ARE ALONG THE FRONTAL BOUNDARY. THE UPPER PATTERN OVER THE WRN ATLC IS STILL DOMINATED BY A LARGE ANTICYCLONE CENTERED NEAR 28N73W. NELY WINDS BETWEEN THIS HIGH AND AN ELONGATED UPPER TROUGH THAT EXTENDS SW ACROSS MUCH OF THE CENTRAL ATLC ARE TRANSPORTING VERY DRY AIR ACROSS THE CENTRAL AND SE BAHAMAS...EASTERN CUBA...HISPANIOLA AND JAMAICA. THE ELONGATED UPPER-LEVEL TROUGH IS SUPPORTING A SFC TROUGH ALONG 31N32W 25N40W 25N56W...WHICH EXTENDS SW FROM A 1015 MB LOW LOCATED NEAR THE AZORES. SCATTERED SHOWERS ARE GENERALLY WITHIN 120 NM EITHER SIDE OF THE SFC TROUGH. THE REMAINDER OF THE ATLC FORECAST AREA IS UNDER THE INFLUENCE OF A RIDGE AROUND A 1027 MB HIGH N OF THE AREA NEAR 38N42W AND ANOTHER WEAK 1024 MB HIGH CENTERED JUST E OF PORTUGAL. A WEAK UPPER-LEVEL LOW HAS DEVELOPED WITHIN 225 NM N OF THE CAPE VERDE ISLANDS AND IS GENERATING ISOLATED SHOWERS. $$ GR