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| #288913 (Received by flhurricane at: 5:02 AM 17.Aug.2009) TCDAT2 TROPICAL DEPRESSION ANA DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022009 500 AM AST MON AUG 17 2009 IT IS UNCLEAR IF ANA STILL HAS A CLOSED LOW-LEVEL WIND FIELD. A MID-LEVEL CIRCULATION IS NOTED IN RADAR IMAGERY FROM GUADELOUPE AND SAN JUAN PUERTO RICO...BUT NO SURFACE OBSERVATIONS FROM THE NORTHERN LEEWARD ISLANDS HAVE SHOWN A WESTERLY WIND COMPONENT. IN ADDITION...AN ASCAT PASS AROUND 0140 UTC STRONGLY SUGGESTED THAT THE SYSTEM IS A SHARP TROPICAL WAVE. BECAUSE OF THE RECENT CONVECTIVE DEVELOPMENT...ADVISORIES ARE BEING CONTINUED FOR THE DEPRESSION AT THIS TIME UNTIL VISIBLE SATELLITE IMAGERY CAN CONFIRM OR DENY THE EXISTENCE OF A WELL-DEFINED LOW-LEVEL CENTER LATER THIS MORNING. ANA IS MOVING AT AN UNCERTAIN BUT FAST 285/24. THE MODEL GUIDANCE IS TIGHTLY CLUSTERED FOR THE NEXT 36 HOURS OR SO AND INDICATES THAT ANA WILL MOVE OVER HISPANIOLA LATER TODAY. THEREAFTER...MOST OF THE DYNAMICAL GUIDANCE WEAKEN THE VORTEX AND BRING THE REMNANTS TOWARD THE EASTERN GULF OF MEXICO OR FLORIDA BY DAYS 3 THROUGH 5...SIMILAR TO THE SHALLOW LAYER BAM TRACK. THE OFFICIAL FORECAST IS CLOSE TO THE MODEL CONSENSUS THROUGH 36 HOURS AND THEN SHOWS A SLIGHT NORTHEASTWARD SHIFT THEREAFTER TOWARDS BAM SHALLOW SINCE THE REST OF THE GUIDANCE LOSES THE VORTEX. THIS FORECAST IS HIGHLY UNCERTAIN AS IT IS ENTIRELY POSSIBLE THAT THE CIRCULATION MAY NOT MAKE IT ACROSS HISPANIOLA INTACT. FORECAST POSITIONS AND MAX WINDS INITIAL 17/0900Z 16.6N 63.9W 30 KT 12HR VT 17/1800Z 17.6N 67.2W 30 KT 24HR VT 18/0600Z 19.3N 71.5W 25 KT...REMNANT LOW 36HR VT 18/1800Z 21.2N 75.2W 25 KT...REMNANT LOW 48HR VT 19/0600Z 22.8N 78.0W 25 KT...REMNANT LOW 72HR VT 20/0600Z 25.5N 82.0W 25 KT...REMNANT LOW 96HR VT 21/0600Z 28.0N 84.0W 25 KT...REMNANT LOW 120HR VT 22/0600Z 30.0N 84.5W 25 KT...REMNANT LOW $$ FORECASTER BERG |
