000 AXNT20 KNHC 031751 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED OCT 03 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. ...SPECIAL FEATURES... AS OF 1500 UTC...A 1005 MB SFC LOW IS ANALYZED IN THE GULF OF MEXICO NEAR 25N87W. SHOWER ACTIVITY ASSOCIATED WITH THIS NON-TROPICAL AREA OF LOW PRESSURE HAS BECOME LESS ORGANIZED TODAY...AND THE RECONNAISSANCE AIRCRAFT MISSION SCHEDULED FOR THIS AFTERNOON HAS BEEN CANCELLED. HOWEVER...THIS SYSTEM STILL HAS SOME POTENTIAL TO EVOLVE INTO A TROPICAL OR SUBTROPICAL DEPRESSION DURING THE NEXT DAY OR TWO AS IT MOVES TO THE WEST-NORTHWEST OR NORTHWEST AT ABOUT 10 MPH. A SWIRL OF LOW CLOUDS DEFINES THE PRESENCE OF THE LOW WITH SCATTERED SHOWERS AND TSTMS WITHIN 150 NM NW OF CENTER. SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT A BROAD AREA OF LOW PRESSURE IS FORMING A COUPLE HUNDRED MILES EAST OF THE NORTHWESTERN BAHAMAS. UPPER-LEVEL WINDS HAVE BECOME FAVORABLE FOR FURTHER DEVELOPMENT OF THIS SYSTEM...AND A TROPICAL DEPRESSION COULD FORM IN THIS AREA DURING THE NEXT DAY OR TWO. THIS SYSTEM IS EXPECTED TO MOVE LITTLE TODAY...BUT BEGIN A SLOW WESTWARD MOTION ON THURSDAY OR FRIDAY. A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF 22N69.5W. AN AREA OF LOW PRESSURE ANALYZED 1012 MB...ASSOCIATED WITH A TROPICAL WAVE IS LOCATED ABOUT 1130 NM EAST OF THE SOUTHERN WINDWARD ISLANDS. ALTHOUGH THIS SYSTEM IS SHOWING SIGNS OF ORGANIZATION...UPPER-LEVEL WINDS ARE EXPECTED TO GRADUALLY BECOME LESS FAVORABLE FOR DEVELOPMENT OVER THE NEXT COUPLE OF DAYS. THE WAVE AXIS IS ALONG 40W/41W. SCATTERED MODERATE CONVECTION IS FROM 7N-11N BETWEEN 37W-43W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 40W/41W S OF 15N MOVING W 15 KT. SEE SPECIAL FEATURES ABOVE. TROPICAL WAVE IS ALONG 48W S OF 14N MOVING W 10-15 KT. WEAK LOW LEVEL INVERTED-V CURVATURE IS NOTED ON SATELLITE IMAGERY WITH NO ASSOCIATED DEEP CONVECTION. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 8N25W 9N38W 8N47W 8N62W. MOST OF THE CONVECTION ALONG THE ITCZ IS FOUND NEAR THE INTERSECTION OF THE TROPICAL WAVE ALONG 40W/41W WITH A LOW NEAR 9N40W. SCATTERED MODERATE CONVECTION IS 130 NM S OF THE AXIS BETWEEN 17W-21W. CLUSTERS OF MODERATE TO ISOLATED STRONG CONVECTION ARE INLAND OVER WEST AFRICA FROM 9N-14N BETWEEN 7W-14W. DISCUSSION... GULF OF MEXICO... THE MAIN SHOWER ACTIVITY IN THE GULF OF MEXICO IS ASSOCIATED WITH THE NON-TROPICAL AREA OF LOW PRES LOCATED NEAR 25N87W. SEE SPECIAL FEATURES FOR MORE DETAILS. A WEAK SFC RIDGE DOMINATES THE FAR WEST GULF AND EASTERN MEXICO. THE SFC PRES GRADIENT IS WEAKER IN THE WRN GULF WITH WINDS MOSTLY 15 KT OR LESS. ALOFT... AN UPPER-LEVEL LOW DOMINATES ALMOST THE ENTIRE GULF WITH AN UPPER HIGH LOCATED OVER NE MEXICO. STRONG SW WINDS ON THE EAST SIDE OF THE UPPER LOW IS KEEPING THE CONVECTION SHEARED FROM THE LOW LOCATED OVER THE SE GULF. VERY DRY MID TO UPPER AIR IS ROTATING AROUND THE PERIPHERY OF THE UPPER-LEVEL LOW ANCHORED OVER THE BAY OF CAMPECHE/SOUTH MEXICO. WV IMAGERY SHOWS ANOTHER UPPER-LOW SPINNING OVER THE NE CORNER OF THE GULF. CARIBBEAN SEA... SCATTERED MODERATE TO ISOLATED STRONG CONVECTION PERSISTS SOUTH OF CUBA THIS AFTERNOON...MOST CONCENTRATED BETWEEN JAMAICA AND EASTERN CUBA. A DIFFLUENT PATTERN ALOFT ASSOCIATED WITH A STRONG UPPER HIGH SITUATED OVER THE CENTRAL BAHAMAS IS ENHANCING THIS CONVECTIVE ACTIVITY. THIS UPPER FEATURE COVERS MOST OF THE BASIN. THE FAR NW PORTION OF THE AREA AND THE YUCATAN CHANNEL HAS VERY LITTLE CLOUD COVER/SHOWER ACTIVITY DUE TO A SWATH OF DRY AIR ROTATING THROUGH THE AREA AROUND THE UPPER LOW FROM THE GULF. UPPER LEVEL MOISTURE AND A FEW SHOWERS ARE OVER THE FAR SE CARIBBEAN ASSOCIATED WITH AN UPPER LOW LOCATED JUST E OF BARBADOS. SCATTERED MODERATE CONVECTION IS FOUND OVER THE SW CARIBBEAN...PANAMA AND COSTA RICA RELATED TO THE ITCZ AND UPPER DIFFLUENCE. SLY LOW LEVEL FLOW IS OBSERVED OVER THE WESTERN CARIBBEAN AND CUBA DUE TO THE LOW OVER THE GULF OF MEXICO. THESE WINDS ARE EXPECTED TO BECOME LIGHT AND VARIABLE DUE TO A WEAK PRES GRADIENT PATTERN OVER THE REGION. LIGHT TO MODERATE E TO SE WINDS DOMINATES THE REMAINDER OF THE AREA. ATLANTIC OCEAN... MESSY WEATHER PERSISTS OVER THE WRN ATLC ASSOCIATED WITH A VERY DIFFLUENT PATTERN ALOFT...BETWEEN THE UPPER LOW OVER THE ERN GULF AND AN UPPER HIGH OVER THE CENTRAL BAHAMAS. CURRENTLY... SATELLITE IMAGERY AND SURFACE OBSERVATIONS INDICATE THAT A BROAD AREA OF LOW PRESSURE IS FORMING IN THIS REGION. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. THIS ACTIVITY IS AFFECTING PARTS OF THE BAHAMAS PARTICULARLY THE SE ISLANDS. FARTHER EAST...SATELLITE IMAGERY SHOWS AN INCREASE IN CONVECTIVE ACTIVITY ASSOCIATED WITH THE REMNANTS OF TROPICAL STORM MELISSA..ANALYZED AS A WEAK 1015 MB LOW NEAR 21N47W. UPPER-LEVEL WINDS ARE UNFAVORABLE FOR SIGNIFICANT REDEVELOPMENT OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS. A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N37W THEN CONTINUES MAINLY WEST ALONG 29N TO 58W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 125 NM MAINLY S OF THE FRONT BETWEEN 50W-58W. AN UPPER-LEVEL LOW IS PRODUCING A FEW SHOWERS AND TSTMS NEAR BARBADOS. THE REMAINDER OF THE E ATLC SFC PATTERN IS DOMINATED BY A 1020MB HIGH NEAR 26N29W AND MOSTLY STABLE CONDITIONS. BROAD UPPER RIDGE EXTENDS FROM OFF AFRICA TO NEAR 50W WITH THE AXIS ALONG 14W/15N. $$ GR