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| #110130 (Received by flhurricane at: 6:43 AM 11.Sep.2006) TCDAT2 TROPICAL DEPRESSION SEVEN DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072006 500 AM EDT MON SEP 11 2006 CONVENTIONAL SATELLITE IMAGERY DEPICTS SOME IMPROVED ORGANIZATION IN THE CONVECTIVE BANDING THIS MORNING...PARTICULARLY OVER THE SOUTHEAST PORTION OF THE SYSTEM. DVORAK INTENSITY ESTIMATES HAVE INCREASED TO 30 KT FROM ALL AGENCIES WITH THE INITIAL INTENSITY FOLLOWING SUIT. THE INTENSITY FORECAST CONTINUES TO BE A BIT OF A MYSTERY. THE LATEST GFDL RUN NOW INDICATES THAT THE DEPRESSION WILL BECOME A HURRICANE IN 48 HOURS...SIMILAR TO THE SHIPS MODEL. THIS SEEMS SOMEWHAT AGGRESSIVE CONSIDERING THE CURRENT NORTHWESTERLY SHEAR...AND THE POTENTIAL FOR STRONG UPPER-LEVEL SOUTHEASTERLY FLOW IN AROUND 36-48 HOURS...AS THE LARGE SCALE MODELS INDICATE. IN FACT...THE GLOBAL MODELS UNANIMOUSLY DISSIPATE THE SYSTEM. THE OFFICIAL INTENSITY FORECAST IS QUITE SIMILAR TO THE PREVIOUS FORECAST... SUGGESTING LITTLE CHANGE IN STRENGTH DURING THE NEXT 48 HOURS. AFTERWARD...IF THE DEPRESSION SURVIVES...THE DYNAMICAL MODELS INDICATE SOME WEAKENING OF THE UPPER EASTERLIES AND IMPROVED OUTFLOW WHICH COULD PROVIDE AN OPPORTUNITY FOR SOME STRENGTHENING...WHICH IS REFLECTED IN THE OFFICIAL FORECAST. INITIAL MOTION IS ESTIMATED AT 290/6...WITHIN THE SOUTHWESTERN PERIPHERY OF A LOW- TO MID-LEVEL HIGH TO THE NORTHEAST. THE GLOBAL MODELS ALL INDICATE A WEAK STEERING CURRENT THAT WOULD EVENTUALLY TURN THE THE CYCLONE NORTHWESTWARD INTO A BREAK IN THE SUBTROPICAL RIDGE. THE BAM MODELS SHOW RECURVATURE INTO THE MID-LATITUDE WESTERLIES BY DAY 4. THE GFDL AND THE GLOBAL MODELS SUGGEST AN ABRUPT NORTHWESTWARD TURN...THEN A MORE NORTHWARD MOTION AFTER 48 HOURS. THE OFFICIAL FORECAST IS BASED ON BLEND OF THE BAMS... THOUGH SLIGHTLY SLOWER...AND CLOSELY FOLLOWS THE PREVIOUS FORECAST. FORECAST POSITIONS AND MAX WINDS INITIAL 11/0900Z 20.5N 55.1W 30 KT 12HR VT 11/1800Z 20.7N 55.9W 30 KT 24HR VT 12/0600Z 21.3N 57.2W 35 KT 36HR VT 12/1800Z 22.1N 58.4W 35 KT 48HR VT 13/0600Z 23.1N 59.6W 40 KT 72HR VT 14/0600Z 25.5N 61.5W 45 KT 96HR VT 15/0600Z 28.0N 62.5W 50 KT 120HR VT 16/0600Z 31.0N 62.0W 50 KT $$ FORECASTER ROBERTS/FRANKLIN |
