000 AXNT20 KNHC 081754 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU NOV 08 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 56W S OF 13N MOVING W 10-15 KT. WHILE AT FIRST GLANCE THERE DOES NOT APPEAR TO BE MUCH OF A WAVE IN THIS VICINITY...A WAVE PASSAGE WAS EVIDENT VIA THE CAYENNE FRENCH GUINNA RAOB DATA AROUND 1800 UTC YESTERDAY. A SMALL...LOW AMPLITUDE MOISTURE SURGE WITH THIS WAVE IS ALSO NOTED IN THE UW-CIMSS TPW PRODUCT. REGARDLESS...THE FEATURE IS NOT GENERATING MUCH SHOWER ACTIVITY AT THE MOMENT AND IS POORLY DEFINED IN SATELLITE IMAGERY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N12W 6N23W 7N36W 8N60W. THE AXIS IS A LITTLE MORE ACTIVE TODAY WITH SCATTERED CLUSTERS OF MODERATE CONVECTION NOTED WITHIN 180 NM S OF THE AXIS E OF 35W THROUGH THE AFRICAN COAST. SIMILAR ACTIVITY IS WITHIN 180 NM N OF THE AXIS BETWEEN 35W-47W. SOME OF THIS APPEARS TO BE ASSOCIATED WITH A LOW AMPLITUDE TROPICAL WAVE IN THE VICINITY...BUT WILL HOLD OFF ADDING TO THE MAP AT THIS POINT DUE TO THE RATHER LINEAR E-W NATURE OF THE ITCZ. THIS MAY NEED TO BE REEVALUATED ON FUTURE MAPS...AS MODEL GUIDANCE SUGGESTS THE ASSOCIATED SHOWER ACTIVITY WILL AFFECT THE LESSER ANTILLES OVER THE WEEKEND. DISCUSSION... GULF OF MEXICO... WINDS AND SEAS ARE MOSTLY RELAXING ACROSS THE GULF THIS AFTERNOON IN WAKE OF THE FRONT THAT TRAVERSED THE AREA YESTERDAY AND LAST NIGHT. WINDS ARE MOSTLY 15 KT OR BELOW...EXCEPT FOR A BIT STRONGER NNE FLOW NEAR THE YUCATAN CHANNEL S OF 25N. A PIECE OF YESTERDAYS FRONT STILL REMAINS OVER THE SW/W GULF...BETWEEN THE NW YUCATAN PENINSULA AND BROWNSVILLE TEXAS. THIS LINGERING QUASI-STATIONARY BOUNDARY IS CHARACTERIZED BY A LINE OF LOW TO MID CLOUDS AND ISOLATED SHOWERS WITHIN 30 NM OF THE FRONT. LIGHT ONSHORE SE WINDS HAVE DEVELOPED NEAR THE TEXAS AND WRN LOUISIANA COAST AS HIGH PRES N OF THE AREA HAS MOVED E...THIS IS HELPING TO SUPPORT THE BROKEN TO OVERCAST STRATUS NOTED NEAR THE NW GULF COAST AND INLAND OVER ERN TEXAS. RECENT VIS IMAGERY SHOWS THESE LOW CEILINGS THINNING A BIT THOUGH AS WE MOVE INTO THE AFTERNOON HOURS. OTHERWISE FAIR WEATHER AND PLENTIFUL SUNSHINE IS AFFECTING THE GULF. ALOFT...FAIRLY UNIFORM NW FLOW AND DRY AIR IS OVER THE GULF...AIDING IN THE PLEASANT CONDITIONS. CARIBBEAN SEA... A COLD FRONT IS MOVING THROUGH THE NW CARIBBEAN...EXTENDING BETWEEN WRN CUBA NEAR 22N80W AND THE YUCATAN NEAR 19N88W AS OF 08/1500 UTC. THE FRONT IS DIFFICULT TO FIND SOLELY WITH WINDS...AS MODERATE TO FRESH NLY WINDS ARE BLOWING ON BOTH SIDES OF THE BOUNDARY. HOWEVER...THE UW-CIMSS TPW PRODUCT HAS BEEN EXTREMELY HELPFUL IN TRACKING THIS BOUNDARY. CONVENTIONAL SATELLITE IMAGERY ALSO SHOWS A SMALL CONCENTRATION OF SHOWER ACTIVITY ASSOCIATED WITH THE FRONT JUST OFFSHORE THE YUCATAN PENINSULA AND BELIZE...WITHIN 60 NM OF 18N87W. A SEPARATE SFC TROUGH IS BEING ANALYZED AHEAD OF THE FRONT...GENERALLY BETWEEN SE JAMAICA TO JUST OFFSHORE THE COSTA RICA/PANAMA BORDER. THIS IS GENERATING SCATTERED TSTMS JUST OFFSHORE NICARAGUA AND COSTA RICA W OF 78W. A TYPICAL 1008 MB LOW IS OVER THE COLOMBIAN COAST NEAR 10N76W...WHICH IS GENERATING ISOLATED TSTMS WITHIN 120 NM OF THE COLOMBIAN COAST. ISOLATED TSTMS ARE ALSO AFFECTING THE FAR NE CARIBBEAN NEAR PUERTO RICO AND VIRGIN ISLANDS...AS LIGHT TO MODERATE TRADES OVER THE E CARIB CONVERGE WITH THE CYCLONIC FLOW AROUND THE TROUGHING TO THE N IN THE ATLC. ATLANTIC OCEAN... A COLD FRONT ENTERS THE WRN ATLC AREA NEAR BERMUDA AND CONTINUES SW THROUGH THE CENTRAL BAHAMAS. THE FRONT IS GENERATING ISOLATED TSTMS WITHIN 60 NM OF THE BOUNDARY MOSTLY N OF 27N...AND ALSO PARTLY RESPONSIBLE FOR THE FEW CELLS NOTED NEAR THE NW BAHAMAS. MODERATE NLY WINDS ARE BEHIND THE FRONT...BUT HAVE GENERALLY RELAXED SOME SINCE YESTERDAY AFTERNOON AND LAST NIGHT. THESE WINDS EXPECTED TO RELAX FURTHER THROUGH FRI AS HIGH PRES BUILDS OVER THE NE GULF. A LITTLE FURTHER E...A 1007 MB LOW IS NEAR 28N63W THAT HAS A TROUGH EXTENDING S TO HISPANIOLA...AND A SEPARATE TROUGH EXTENDING ENE TO 31N57W. THE TROUGHING IS GENERATING ISOLATED TSTMS S OF 25N TO THE COAST OF HISPANIOLA BETWEEN 65W-71W...AND ALSO N OF 29N BETWEEN 54W-58W. A 1009 MB SFC LOW IS NOW N OF THE AREA NEAR 34N29W...BUT AN ELONGATED TRAILING TROUGH EXTENDS THROUGH THE AREA ALONG 32N25W 25N28W 20N42W 13N49W. THIS BOUNDARY IS NOT AS WELL DEFINED AS IT WAS IN DAYS PAST WITH ONLY ISOLATED SHOWERS NEAR THE TROUGH...AND WILL THUS LIKELY BE READJUSTED SOME AT 1800 UTC. THE REMAINDER OF THE E ATLC IS DOMINATED BY FAIR WEATHER AND MODEST SFC RIDGING...WITH THE UW-CIMSS SAL PRODUCT AND VISIBLE IMAGERY SHOWING A FAIRLY DENSE AREA OF AFRICAN DUST AHEAD OF THE AFOREMENTIONED ELONGATED SFC TROUGH. $$ WILLIS