000 WTNT44 KNHC 120250 TCDAT4 HURRICANE HUMBERTO DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST WED SEP 11 2013 THE LARGE CENTRAL DENSE OVERCAST OF HUMBERTO IS EXHIBITING QUITE COLD CLOUD TOPS WITH A SMALL EYE INTERMITTENTLY APPEARING. DVORAK SUBJECTIVE INTENSITY ESTIMATES FROM TAFB AND SAB REMAIN AT ABOUT 75 KT...WHILE ADT IS SLIGHTLY HIGHER AND CIMSS AMSU SLIGHTLY LOWER. THE INTENSITY ANALYSIS REMAINS AT 75 KT. A DIRECT HIT BY AN ASCAT SCATTEROMETER SATELLITE AT 2250Z PROVIDED OBSERVATIONS SHOWING THAT HUMBERTO IS LARGER IN ITS TROPICAL STORM AND 50-KT WIND RADII THAN EARLIER ESTIMATED. THIS IS CONSISTENT WITH THE LARGE CDO AND INDEPENDENT ANALYSES FROM CIRA AMSU SIZE VALUES. CURRENTLY...HUMBERTO HAS BEEN TRAVERSING OVER WATERS OF 26C AND THROUGH AN ATMOSPHERE OF WEAK VERTICAL WIND SHEAR...AS WELL AS MOIST AND UNSTABLE AIR. IT APPEARS...HOWEVER...THAT HUMBERTO MAY BE AT ITS PEAK INTENSITY. AS HUMBERTO TRACKS NORTHWARD THEN WESTWARD DURING THE NEXT FEW DAYS...THE CYCLONE WILL APPROACH A STRONG TROPICAL UPPER TROPOSPHERIC TROUGH. THIS TROUGH WILL INDUCE MODERATE TO STRONG SOUTHWESTERLY VERTICAL SHEAR BEGINNING IN ABOUT A DAY AND CONTINUING THROUGH THE END OF THE FORECAST PERIOD. THE HOSTILE SHEAR AND COOLER SSTS SHOULD INDUCE SUBSTANTIAL WEAKENING. THE INTENSITY PREDICTION IS SLIGHTLY LOWER THAN THAT FROM THE PREVIOUS ADVISORY AND CLOSEST TO THE IVCN INTENSITY CONSENSUS THROUGH 48 HOURS AND CLOSEST TO THE DECAY-SHIPS STATISTICAL MODEL THEREAFTER. THERE ARE SUGGESTIONS BY THE GLOBAL MODELS THAT HUMBERTO MAY ATTEMPT A COMEBACK STARTING AROUND DAY 5...BUT IT IS QUITE UNCERTAIN HOW MUCH OF A TROPICAL CYCLONE WILL BE REMAINING AT THAT TIME AFTER EXPERIENCING SUBSTANTIAL VERTICAL SHEAR FOR NEARLY FOUR DAYS. HUMBERTO IS MOVING DUE NORTH AT 11 KT...PRIMARILY DUE TO THE STEERING INDUCED BY A MID-LEVEL RIDGE OVER WEST AFRICA TO ITS EAST. IN ABOUT TWO DAYS...A STRONG DEEP-LAYER RIDGE WILL DEVELOP NEAR THE AZORES AND FORCE HUMBERTO TOWARD THE WEST FOR THE NEXT FEW DAYS. THE TRACK GUIDANCE IS TIGHTLY CLUSTERED AND THE TRACK PREDICTION IS NEARLY UNCHANGED FROM THE PREVIOUS ADVISORY. FORECAST POSITIONS AND MAX WINDS INIT 12/0300Z 19.1N 29.0W 75 KT 85 MPH 12H 12/1200Z 20.7N 29.2W 75 KT 85 MPH 24H 13/0000Z 22.3N 29.9W 70 KT 80 MPH 36H 13/1200Z 23.5N 31.0W 60 KT 70 MPH 48H 14/0000Z 24.2N 32.8W 50 KT 60 MPH 72H 15/0000Z 25.2N 37.6W 40 KT 45 MPH 96H 16/0000Z 26.0N 42.0W 35 KT 40 MPH 120H 17/0000Z 27.5N 45.0W 30 KT 35 MPH $$ FORECASTER LANDSEA