Show Selection: |
#113248 (Received by flhurricane at: 4:40 PM 27.Sep.2006) TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092006 500 PM EDT WED SEP 27 2006 VISIBLE SATELLITE IMAGERY INDICATES THAT THE LOW-LEVEL CIRCULATION HAS CONTINUED TO GRADUALLY BECOME BETTER-DEFINED IN THE LOW PRESSURE AREA OVER THE CENTRAL ATLANTIC. ALTHOUGH THE DEEP CONVECTION DOES NOT WRAP MUCH AROUND THE CENTER...THE SYSTEM HAS SUFFICIENT ORGANIZATION TO BE DESIGNATED AS A 30 KT TROPICAL DEPRESSION AT THIS TIME. AN 1800 UTC SHIP REPORT ABOUT 60 MILES TO THE NORTHWEST OF THE CENTER REPORTED A RATHER HIGH CENTRAL PRESSURE OF 1016.5 MB...A 21 KT SUSTAINED WIND...AND 13 FT SEAS. BASED ON THIS SHIP REPORT...12 FT SEA RADII HAVE BEEN INCLUDED IN THE ADVISORY. THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 315/12...SINCE THE LOW- LEVEL CENTER HAS REFORMED AT LEAST ONCE DURING THE PAST 12 TO 24 HOURS. THE DEPRESSION IS CURRENTLY SITUATED BETWEEN AN UPPER-LEVEL CYCLONE TO ITS WEST AND A LOW- TO MID-LEVEL RIDGE TO ITS EAST. THE GFS...UKMET... AND NOGAPS MODELS ALL TAKE THE CYCLONE AROUND THE WESTERN PERIPHERY OF THE RIDGE...THEN ACCELERATE THE SYSTEM AT DAYS THREE THROUGH FIVE NORTHEASTWARD AHEAD OF A DEEP-LAYER TROUGH FROM THE WEST. THE OFFICIAL TRACK FORECAST FOLLOWS CLOSELY WITH A CONSENSUS OF THE AFOREMENTIONED GUIDANCE. THE CURRENT POOR ORGANIZATION OF THE DEEP CONVECTION AND THE PRESENCE OF THE UPPER LOW JUST TO THE WEST OF THE TROPICAL CYCLONE ARGUES AGAINST ANY RAPID STRENGTHENING. HOWEVER...THE VERTICAL SHEAR IS NOT EXPECTED TO BE STRONG ENOUGH TO PROHIBIT SOME GRADUAL INTENSIFICATION. THE OFFICIAL INTENSITY FORECAST IS IN REASONABLE AGREEMENT WITH THE SHIPS GUIDANCE. FORECAST POSITIONS AND MAX WINDS INITIAL 27/2100Z 26.5N 53.1W 30 KT 12HR VT 28/0600Z 27.6N 54.5W 35 KT 24HR VT 28/1800Z 29.1N 56.0W 40 KT 36HR VT 29/0600Z 31.0N 57.5W 45 KT 48HR VT 29/1800Z 34.0N 58.0W 50 KT 72HR VT 30/1800Z 39.0N 56.0W 50 KT 96HR VT 01/1800Z 42.0N 50.0W 50 KT...EXTRATROPICAL 120HR VT 02/1800Z 46.0N 40.0W 50 KT...EXTRATROPICAL $$ FORECASTER MAINELLI/PASCH |