000 WTNT43 KNHC 270249 TCDAT3 TROPICAL DEPRESSION THIRTEEN DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL132007 1100 PM EDT WED SEP 26 2007 THE SATELLITE PRESENTATION OF THE DEPRESSION HAS DEGRADED THIS EVENING...WITH A PARTIALLY EXPOSED CENTER TO THE NORTHEAST OF A SMALL BAND OF MODEST CONVECTION. DVORAK T-NUMBERS FROM BOTH TAFB AND SAB HAVE DECREASED. THE INITIAL INTENSITY WILL BE HELD AT 30 KT PENDING THE ARRIVAL OF THE NEXT RECONNAISSANCE AIRCRAFT AT 06Z. THE DEPRESSION APPEARS TO HAVE COMPLETED A SMALL LOOP...AND THE INITIAL MOTION IS ESTIMATED TO BE 260/3...BASED MAINLY ON A 2315Z MICROWAVE PASS. THERE HAS BEEN A BIT OF A NORTHWARD SHIFT IN THE MODEL GUIDANCE THIS EVENING. THE MID-LEVEL RIDGE THAT IS FORECAST TO BUILD EASTWARD FROM NORTHERN MEXICO HAS SHIFTED A LITTLE FARTHER EASTWARD IN THE MODEL RUNS...WHICH ALLOWS THE DEPRESSION TO ACQUIRE SOME NORTHWARD COMPONENT OF MOTION AS IT APPROACHES THE COAST. THE OFFICIAL FORECAST HAS BEEN SHIFTED NORTHWARD...AND IS IN BEST AGREEMENT WITH THE GFS. NEARLY ALL THE OTHER GUIDANCE MODELS ARE EVEN FARTHER NORTH. THE UPPER-LEVEL FLOW OVER THE DEPRESSION IS ANTICYCLONIC AND DIFLUENT...AND IT IS A LITTLE SURPRISING THAT THE SYSTEM HAS NOT STRENGTHENED YET. THE UPPER-FLOW IS FORECAST TO REMAIN FAVORABLE FOR DEVELOPMENT...SO PERHAPS IT IS JUST A MATTER OF TIME. THE OFFICIAL FORECAST REMAINS CLOSE TO THE SHIPS GUIDANCE...WITH THE GFDL AND HWRF FORECASTING A LITTLE LESS DEVELOPMENT BUT STILL MAKING THE SYSTEM A TROPICAL STORM. THE NEW FORECAST BRINGS TROPICAL STORM FORCE WINDS VERY CLOSE TO THE MEXICAN COAST IN 36 HOURS...NECESSITATING A TROPICAL STORM WATCH AT THIS TIME. FORECAST POSITIONS AND MAX WINDS INITIAL 27/0300Z 21.2N 94.8W 30 KT 12HR VT 27/1200Z 21.1N 95.0W 35 KT 24HR VT 28/0000Z 20.9N 95.5W 45 KT 36HR VT 28/1200Z 20.9N 96.3W 50 KT 48HR VT 29/0000Z 21.0N 97.5W 55 KT...INLAND 72HR VT 30/0000Z 21.5N 99.5W 20 KT...INLAND 96HR VT 01/0000Z...DISSIPATED $$ FORECASTER FRANKLIN