000 WTNT41 KNHC 110843 TCDAT1 TROPICAL DEPRESSION ONE DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012006 500 AM EDT SUN JUN 11 2006 QUIKSCAT DATA...NIGHT-VIS SATELLITE IMAGERY...AND A SHIP REPORT FROM WCY8453 INDICATE THAT THE CENTER OF THE DEPRESSION IS A LITTLE WEST OF OUR PREVIOUS TRACK...INDEED PROBABLY FARTHER WEST THAN THE CURRENT ADVISORY POSITION...AND INCREASINGLY REMOVED FROM THE DEEP CONVECTION. NEVERTHELESS...THE PULASKI SHOAL LIGHT CMAN STATION...NEAR THE DRY TORTUGAS...REPORTED A 10-MINUTE MEAN WIND OF 36 KT SHORTLY BEFORE 06Z IN A NARROW BAND OF CONVECTION THAT HAS SINCE DISSIPATED. IT IS QUITE POSSIBLE THAT THERE ARE STILL A FEW SPOTS OF TROPICAL STORM FORCE WINDS AROUND...BUT I AM LOATH TO UPGRADE THE DEPRESSION GIVEN THE SATELLITE PRESENTATION AND THE RECENT CONVECTIVE TRENDS. THE INITIAL MOTION ESTIMATE IS 325/8. THE DEPRESSION IS SOUTH OF A MID-LEVEL RIDGE OVER THE NORTHERN GULF THAT EXTENDS EASTWARD INTO THE WESTERN ATLANTIC...WHILE STRONG SOUTHWESTERLY FLOW CONTINUES OVER THE CYCLONE CENTER. THIS SHEARING FLOW LEADS TO TWO VERY DIFFERENT FORECAST SCENARIOS. THE GFS...NOGAPS...CANADIAN...AND GFDL MODELS MAINTAIN OR STRENGTHEN THE DEPRESSION AND LIFT IT NORTHEASTWARD WITH A MID-LATITUDE TROUGH IN 36-48 HOURS. THIS IS THE SCENARIO THAT THE LAST FEW OFFICIAL FORECASTS HAVE FOLLOWED... AND WHICH I WILL MAINTAIN FOR THIS ADVISORY PACKAGE. HOWEVER...A SECOND SCENARIO IS BECOMING INCREASINGLY LIKELY...IN WHICH THE DEPRESSION IS SEPARATED FROM ITS DEEP CONVECTION BY THE SOUTHWESTERLY SHEAR...LEAVING A WEAK VORTEX TO LINGER AND DEGENERATE IN THE WESTERN GULF OF MEXICO. IF DAYLIGHT IMAGERY AND/OR RECONNAISSANCE DATA CONFIRM THAT THE WESTERN CENTER IS THE ONLY CENTER...THEN SOME SIGNIFICANT ADJUSTMENTS IN THE TRACK AND INTENSITY FORECASTS WILL LIKELY BE NECESSARY LATER TODAY. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 11/0900Z 23.5N 87.0W 30 KT 12HR VT 11/1800Z 24.7N 87.4W 35 KT 24HR VT 12/0600Z 26.0N 87.0W 35 KT 36HR VT 12/1800Z 27.5N 85.3W 40 KT 48HR VT 13/0600Z 29.2N 83.0W 40 KT 72HR VT 14/0600Z 32.0N 77.0W 40 KT...EXTRATROPICAL 96HR VT 15/0600Z 39.0N 68.0W 40 KT...EXTRATROPICAL 120HR VT 16/0600Z 46.0N 56.0W 40 KT...EXTRATROPICAL $$ 000 WTNT41 KNHC 110843 TCDAT1 TROPICAL DEPRESSION ONE DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL012006 500 AM EDT SUN JUN 11 2006 QUIKSCAT DATA...NIGHT-VIS SATELLITE IMAGERY...AND A SHIP REPORT FROM WCY8453 INDICATE THAT THE CENTER OF THE DEPRESSION IS A LITTLE WEST OF OUR PREVIOUS TRACK...INDEED PROBABLY FARTHER WEST THAN THE CURRENT ADVISORY POSITION...AND INCREASINGLY REMOVED FROM THE DEEP CONVECTION. NEVERTHELESS...THE PULASKI SHOAL LIGHT CMAN STATION...NEAR THE DRY TORTUGAS...REPORTED A 10-MINUTE MEAN WIND OF 36 KT SHORTLY BEFORE 06Z IN A NARROW BAND OF CONVECTION THAT HAS SINCE DISSIPATED. IT IS QUITE POSSIBLE THAT THERE ARE STILL A FEW SPOTS OF TROPICAL STORM FORCE WINDS AROUND...BUT I AM LOATH TO UPGRADE THE DEPRESSION GIVEN THE SATELLITE PRESENTATION AND THE RECENT CONVECTIVE TRENDS. THE INITIAL MOTION ESTIMATE IS 325/8. THE DEPRESSION IS SOUTH OF A MID-LEVEL RIDGE OVER THE NORTHERN GULF THAT EXTENDS EASTWARD INTO THE WESTERN ATLANTIC...WHILE STRONG SOUTHWESTERLY FLOW CONTINUES OVER THE CYCLONE CENTER. THIS SHEARING FLOW LEADS TO TWO VERY DIFFERENT FORECAST SCENARIOS. THE GFS...NOGAPS...CANADIAN...AND GFDL MODELS MAINTAIN OR STRENGTHEN THE DEPRESSION AND LIFT IT NORTHEASTWARD WITH A MID-LATITUDE TROUGH IN 36-48 HOURS. THIS IS THE SCENARIO THAT THE LAST FEW OFFICIAL FORECASTS HAVE FOLLOWED... AND WHICH I WILL MAINTAIN FOR THIS ADVISORY PACKAGE. HOWEVER...A SECOND SCENARIO IS BECOMING INCREASINGLY LIKELY...IN WHICH THE DEPRESSION IS SEPARATED FROM ITS DEEP CONVECTION BY THE SOUTHWESTERLY SHEAR...LEAVING A WEAK VORTEX TO LINGER AND DEGENERATE IN THE WESTERN GULF OF MEXICO. IF DAYLIGHT IMAGERY AND/OR RECONNAISSANCE DATA CONFIRM THAT THE WESTERN CENTER IS THE ONLY CENTER...THEN SOME SIGNIFICANT ADJUSTMENTS IN THE TRACK AND INTENSITY FORECASTS WILL LIKELY BE NECESSARY LATER TODAY. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 11/0900Z 23.5N 87.0W 30 KT 12HR VT 11/1800Z 24.7N 87.4W 35 KT 24HR VT 12/0600Z 26.0N 87.0W 35 KT 36HR VT 12/1800Z 27.5N 85.3W 40 KT 48HR VT 13/0600Z 29.2N 83.0W 40 KT 72HR VT 14/0600Z 32.0N 77.0W 40 KT...EXTRATROPICAL 96HR VT 15/0600Z 39.0N 68.0W 40 KT...EXTRATROPICAL 120HR VT 16/0600Z 46.0N 56.0W 40 KT...EXTRATROPICAL $$