WTNT44 KNHC 130849 TCDAT4 HURRICANE HUMBERTO DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 AM AST FRI SEP 13 2013 HUMBERTO IS ON A WEAKENING TREND...AND IT IS BARELY HANGING ON TO HURRICANE STATUS. LATEST GEOSTATIONARY SATELLITE IMAGES INDICATE THAT THE ASSOCIATED DEEP CONVECTION IS LOSING ORGANIZATION...AND MICROWAVE IMAGES REVEAL THAT THE LOW-LEVEL CENTER IS LOCATED NEAR THE SOUTHWESTERN EDGE OF THE DEEP CLOUDINESS. THIS ASYMMETRIC CLOUD PATTERN IS DUE TO 20-25 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR. THE INITIAL WIND SPEED IS LOWERED TO 65 KT...IN ACCORDANCE WITH AN AVERAGE OF THE LATEST DVORAK CI-NUMBERS FROM TAFB...SAB...AND UW-CIMSS ADT...AND THIS ESTIMATE COULD BE GENEROUS. THE TROPICAL CYCLONE IS GRADUALLY TURNING TO THE LEFT AS THE STEERING FLOW IS BECOMING MORE DOMINATED BY A DEEP-LAYER RIDGE TO ITS NORTH-NORTHWEST. THE LATEST INITIAL MOTION ESTIMATE IS 335/10. A TURN TO THE WEST-NORTHWEST IS EXPECTED TO BEGIN LATER TODAY AND CONTINUE THROUGH MUCH OF THE WEEKEND WHILE HUMBERTO MOVES ON THE SOUTH SIDE OF THE RIDGE. A TURN BACK TO THE NORTH IS FORECAST TO OCCUR IN 4 TO 5 DAYS WHEN HUMBERTO MOVES INTO A PRONOUNCED WEAKNESS IN THE RIDGE CAUSED BY AN APPROACHING TROUGH. THE NHC TRACK FORECAST IS CLOSE TO THE GFS AND ECMWF MODELS. ADDITIONAL WEAKENING IS EXPECTED DURING THE NEXT 48 HOURS WHILE HUMBERTO REMAINS OVER 25-26C WATERS AND MOVES INTO EVEN STRONGER SHEAR AND A DRIER AIRMASS. BEYOND THAT TIME...THE SHEAR IS EXPECTED TO LESSEN WHILE HUMBERTO MOVES OVER WARMER WATER. THESE MORE FAVORABLE CONDITIONS COULD ALLOW THE CYCLONE TO RE-INTENSIFY. IN ADDITION...MOST OF THE GLOBAL MODELS SHOW HUMBERTO DEEPENING IN 3 TO 5 DAYS WHEN IT INTERACTS WITH A COUPLE OF UPPER-LEVEL TROUGHS. THE NHC WIND SPEED PREDICTION FOLLOWS THE INTENSITY MODEL CONSENSUS AND IS NOT TOO DIFFERENT FROM THE PREVIOUS ADVISORY. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 24.4N 30.2W 65 KT 75 MPH 12H 13/1800Z 25.2N 31.4W 55 KT 65 MPH 24H 14/0600Z 26.0N 33.5W 50 KT 60 MPH 36H 14/1800Z 27.1N 36.0W 45 KT 50 MPH 48H 15/0600Z 28.2N 38.2W 40 KT 45 MPH 72H 16/0600Z 30.3N 41.5W 45 KT 50 MPH 96H 17/0600Z 32.5N 44.5W 50 KT 60 MPH 120H 18/0600Z 35.5N 45.0W 55 KT 65 MPH $$ FORECASTER CANGIALOSI
Posted on: Fri, 13 Sep 2013 13:37:44 +0000
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