000 WTNT45 KNHC 161432 TCDAT5 TROPICAL DEPRESSION ERIN DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052013 1100 AM AST FRI AUG 16 2013 SATELLITE IMAGES INDICATE THAT ERIN HAS WEAKENED. THE STRUCTURE OF THE CYCLONE CONSISTS OF A LOW-LEVEL CLOUD SWIRL WITH A COUPLE OF SMALL AREAS OF CONVECTION SOUTH AND EAST OF THE CENTER. THE DVORAK CLASSIFICATIONS HAVE FALLEN...AND ERIN IS DOWNGRADED TO A 30-KT TROPICAL DEPRESSION FOR THIS ADVISORY. THE OBSERVED WEAKENING IS LIKELY THE RESULT OF COOL SEA SURFACE TEMPERATURES AND STABLE AIR... AS SEEN IN THE GOES-R PROVING GROUND AIRMASS PRODUCT. ALTHOUGH ERIN IS EXPECTED TO MOVE OVER WARMER WATER IN A FEW DAYS... SOUTHWESTERLY SHEAR IS ANTICIPATED TO INCREASE WHILE THE DEPRESSION REMAINS IN A STABLE ATMOSPHERE. THE NHC INTENSITY PREDICTION CALLS FOR LITTLE CHANGE IN STRENGTH THROUGHOUT THE FORECAST PERIOD. IT IS POSSIBLE THAT ERIN COULD DEGENERATE TO A REMNANT LOW OR AN OPEN TROUGH DURING THE NEXT FEW DAYS...AS SUGGESTED BY SOME OF THE MODEL GUIDANCE. THE DEPRESSION IS MOVING WEST-NORTHWESTWARD AT ABOUT 15 KT. THIS GENERAL MOTION WITH SOME DECREASE IN FORWARD IS EXPECTED DURING THE NEXT 36 HOURS WHILE THE CYCLONE FEELS SOME INFLUENCE FROM A WEAKNESS IN THE SUBTROPICAL RIDGE. BETWEEN 36 AND 72 HOURS...LOW- TO MID-LEVEL RIDGING IS FORECAST TO BECOME MORE PRONOUNCED TO THE NORTH OF THE SYSTEM...CAUSING A TURN TOWARD THE WEST. BEYOND THAT TIME...A GRADUAL TURN TO THE NORTHWEST IS PREDICTED WHEN THE WEAK CYCLONE MOVES TOWARD ANOTHER WEAKNESS IN THE RIDGE. THE NHC TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE AND CLOSE TO THE MULTI-MODEL CONSENSUS TVCA. FORECAST POSITIONS AND MAX WINDS INIT 16/1500Z 16.9N 32.1W 30 KT 35 MPH 12H 17/0000Z 17.9N 34.0W 30 KT 35 MPH 24H 17/1200Z 19.1N 36.2W 30 KT 35 MPH 36H 18/0000Z 19.9N 38.2W 30 KT 35 MPH 48H 18/1200Z 20.2N 40.2W 30 KT 35 MPH 72H 19/1200Z 21.1N 44.6W 30 KT 35 MPH 96H 20/1200Z 23.5N 49.5W 30 KT 35 MPH 120H 21/1200Z 25.5N 52.5W 30 KT 35 MPH $$ FORECASTER CANGIALOSI