000 AXNT20 KNHC 151747 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON OCT 15 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... TROPICAL WAVE IS ALONG 31W/32W S OF 19N MOVING W 10-15 KT. VISIBLE IMAGERY REVEALS A FAIR AMOUNT OF LOW-LEVEL TURNING IN THE CLOUD FIELD. HOWEVER...VERY STRONG UPPER LEVEL SOUTHWESTERLY WINDS ARE LIMITING ORGANIZING SHEARING MUCH OF THE DENSER CLOUDINESS TO THE E OF THE ANALYZED AXIS. SCATTERED SHOWERS AND TSTMS ARE VERY DISORGANIZED WITHIN 300 NM E OF THE AXIS N OF 12N AND WITHIN 150 NM EITHER SIDE NEAR THE INTERSECTION OF THE ITCZ FROM 9N-11N. LOW AMPLITUDE TROPICAL WAVE IS ALONG 51W S OF 14N MOVING W 10-15 KT. THIS WAVE WAS VERY CONVECTIVE A COUPLE OF DAYS AGO WHEN INTERACTING WITH ENERGY FROM AN UPPER JET BRANCH. HOWEVER ..SINCE THEN THE WAVE HAS MOVED INTO A MORE STABLE ENVIRONMENT. CONSEQUENTLY...CONVECTION HAS DIMINISHED WITH ONLY A SWIRL OF LOW CLOUDS LEFT OVER. TROPICAL WAVE IS IN THE WESTERN CARIBBEAN ALONG 80W S OF 19N MOVING W 10-15 KT. A 1007 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 13.5N. THIS LOW HAS BECOME INCREASINGLY DISORGANIZED THIS AFTERNOON AND IS NOW TOUGH TO LOCATE THE CENTER ON THE LATEST VIS IMAGES. ASSOCIATED SCATTERED SHOWERS AND TSTMS ARE SHEARED OFF TO THE W OF THE WAVE BY STRONG UPPER NELY WINDS ON THE BACK SIDE OF AN UPPER LOW. WHILE FURTHER DEVELOPMENT IS NOT ANTICIPATED THIS SYSTEM COULD STILL CAUSE LOCALLY HEAVY RAINS OVER PORTIONS OF CENTRAL AMERICA TODAY AND TOMORROW. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 5N21W 10N34W 8N44W 9N61W. BESIDES FOR THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...A SMALL AREA OF SCATTERED MODERATE IS WITHIN 60 NM OF THE AXIS E OF 14W. DISCUSSION... GULF OF MEXICO... THE MAIN WEATHER PRODUCING FEATURE IN THE AREA IS A 1006 MB LOW CENTERED JUST OFF THE W COAST OF THE YUCATAN PENINSULA NEAR 21N91W. THIS LOW LIES AT THE BASE OF A SFC TROUGH WHICH EXTENDS NE INTO THE CENTRAL GULF REACHING 26N87W. IR IMAGERY AND LIGHTNING DATA SUGGEST THAT THE MORE ORGANIZED SHOWER AND TSTM ACTIVITY IS TO THE N OF THE LOW WITHIN 60 NM EITHER SIDE OF THE TROUGH. SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING THE NEXT DAY OR TWO AS IT MOVES GENERALLY NORTHWESTWARD. THE REMAINDER OF THE GULF IS EXPERIENCING A FAIRLY NICE DAY UNDER MODERATE TO STRONG SUBSIDENCE EMBEDDED WITHIN AN UPPER HIGH CENTERED OVER THE SW GULF. SFC WINDS ARE ON THE STRONG SIDE...20-25 KT...E OF THE SFC TROUGH AS THE GRADIENT IS TIGHTENED BETWEEN IT AND HIGH PRES OVER THE MID-ATLANTIC STATES. CARIBBEAN SEA... THE AREA OF LOW PRES ASSOCIATED WITH A TROPICAL WAVE ALONG 80W HAS BECOME ILL-DEFINED TODAY LIKELY FEELING THE EFFECTS OF NELY SHEAR. FOR MORE INFORMATION REFER TO THE TROPICAL WAVES SECTION ABOVE. ELSEWHERE...A WWD MOVING UPPER LOW IS CURRENTLY CENTERED OFF THE N COAST OF COLOMBIA NEAR 13N73W. S TO SELY FLOW ON THE E SIDE OF THIS UPPER SYSTEM IS DRAWING MOISTURE NWD FROM THE DEEP TROPICS BASICALLY COVERING THE AREA E OF 70W. MOST OF THIS MOISTURE IS IN THE FORM OF MID-HIGH LEVEL CLOUDINESS...THOUGH AN AREA OF SCATTERED SHOWERS AND TSTMS HAVE FORMED OVER THE PAST FEW HOURS FROM 13N-16N BETWEEN 62W-68W. THE WRN CARIB...MAINLY W OF THE TROPICAL WAVE...IS EXPERIENCING SIMILAR WEATHER THOUGH MOST OF THE SHOWERS AND TSTMS ARE NOW INLAND OVER PORTIONS OF CENTRAL AMERICA. THE ATMOSPHERE IS SLIGHTLY DRIER IN THE CENTRAL CARIB...BETWEEN 70W-76W...UNDERNEATH THE UPPER LOW. TRADE WINDS ARE MAINLY MODERATE AND ARE EXPECTED TO REMAIN THAT WAY OVER THE NEXT COUPLE OF DAYS. ATLANTIC OCEAN... A STALLED FRONTAL BOUNDARY ENTERS THE REGION NEAR 32N58W AND EXTENDS SW TOWARD THE CENTRAL BAHAMAS WHERE IT IS BEGINNING TO DISSIPATE. SCATTERED SHOWERS AND ISOLATED TSTMS ARE GENERALLY WITHIN 75 NM OF THE BOUNDARY. DIFFLUENT FLOW ALOFT BETWEEN TROUGHING OFF THE U.S. EAST COAST AND AN UPPER HIGH NEAR 24N53W IS ALSO SUPPORTING THIS ACTIVITY. WIDESPREAD STRONG SUBSIDENCE DOMINATES ALONG AND TO THE W OF THE TROUGH OVER FLORIDA...THE NW BAHAMAS AND THE NEARBY ATLANTIC WATERS LIMITING SIGNIFICANT SHOWER ACTIVITY. THE TIGHTENED PRES GRADIENT BETWEEN THE FRONT...LOW PRES IN THE CARIB AND HIGH PRES OVER THE MID-ATLANTIC STATES IS PRODUCING MODERATE TO FRESH NE-E WINDS ACROSS PORTIONS OF THE SW NORTH ATLC. THESE WINDS ARE EXPECTED TO DECREASE SLIGHTLY OVER THE NEXT DAY OR TWO. CONDITIONS ARE FAIRLY TRANQUIL ACROSS MUCH OF THE REMAINDER OF THE CENTRAL AND E ATLC. THE SFC PATTERN IS MOSTLY CONTROLLED BY RIDGING EXTENDING S/SW FROM A 1022 MB HIGH SITUATED OVER THE AZORES NEAR 38N25W. THIS IS PRODUCING MAINLY LIGHT WINDS OVER THE SUBTROPICAL E AND CENTRAL ATLC...WHILE MODERATE TRADES PERSIST IN THE TROPICS. THE UPPER PATTERN OVER THE E ATLC CONSISTS OF A LARGE SCALE HIGHLY AMPLIFIED UPPER RIDGE/TROUGH PATTERN. A SWLY JET BRANCH ORIGINATES JUST AHEAD OF THE BASE OF THE TROUGH OVER THE TROPICAL ATLC AND EXTENDS NE TO AFRICA NEAR 23N16W. THIS JET IS SHEARING THE TROPICAL WAVE ALONG 31W AND SPREADING HIGH LEVEL CLOUDINESS ACROSS THE TROPICAL E ATLC. $$ CANGIALOSI