000 WTNT43 KNHC 130844 TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 4 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082007 500 AM EDT THU SEP 13 2007 SATELLITE IMAGES AND MICROWAVE DATA INDICATE THAT THE CLOUD PATTERN HAS NOT BECOME ANY BETTER ORGANIZED DURING THE PAST FEW HOURS AND THE LOW-LEVEL CENTER IS LOCATED TO THE NORTH OF A LARGE CIRCULAR AREA OF DEEP CONVECTION. INITIAL INTENSITY REMAINS AT 30 KNOTS. THE DEPRESSION STILL HAS THE OPPORTUNITY TO BECOME A TROPICAL STORM SINCE THE SHEAR IS EXPECTED TO DECREASE IN THE NEXT DAY OR SO. THEREAFTER...ALL GLOBAL MODELS FORECAST STRONG UPPER-LEVEL WESTERLIES OVER THE EASTERN CARIBBEAN AND THE ADJACENT ATLANTIC WATERS ASSOCIATED WITH A STRONGER THAN NORMAL UPPER-LEVEL TROUGH. THIS PATTERN IS LIKELY TO INHIBIT THE DEPRESSION FROM STRENGTHENING SIGNIFICANTLY. WEAKENING IS INDICATED BY THE END OF THE FORECAST PERIOD AS THE CYCLONE APPROACHES THE AREA WELL TO THE NORTHEAST OF THE LEEWARD ISLANDS WHERE THE SHEAR IS EXPECTED TO BE LARGE. THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 9 KNOTS AROUND A WEAK MID-LEVEL HIGH PRESSURE SYSTEM. SINCE STEERING CURRENTS ARE FORECAST TO FURTHER WEAKEN...THE DEPRESSION IS EXPECTED TO DECREASE IN FORWARD SPEED DURING THE NEXT 12 TO 24 HOURS. THE CYCLONE SHOULD THEN CONTINUE ON THIS GENERAL SLOW WEST-NORTHWEST TRACK THROUGH 5 DAYS. TRACK GUI DACE IS IN GOOD AGREEMENT BRINGING THE CYCLONE ON A SLOW WEST-NORTHWEST MOTION AND WEAKENING. THE UK AND ECMWF MODELS KEEP THE CYCLONE A LITTLE BIT LONGER BUT THIS IS NOT REALISTIC GIVEN THE ANTICIPATED HIGHLY UNFAVORABLE UPPER-LEVEL ENVIRONMENT AHEAD OF THE CYCLONE. FORECAST POSITIONS AND MAX WINDS INITIAL 13/0900Z 13.9N 47.5W 30 KT 12HR VT 13/1800Z 14.5N 48.8W 35 KT 24HR VT 14/0600Z 14.8N 49.6W 40 KT 36HR VT 14/1800Z 15.0N 50.5W 45 KT 48HR VT 15/0600Z 15.5N 51.5W 45 KT 72HR VT 16/0600Z 16.5N 54.0W 45 KT 96HR VT 17/0600Z 17.5N 57.0W 40 KT 120HR VT 18/0600Z 19.0N 60.0W 35 KT $$ FORECASTER AVILA