000 WTNT44 KNHC 122034 TCDAT4 HURRICANE HUMBERTO DISCUSSION NUMBER 17 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 PM AST THU SEP 12 2013 THE EYE IS NO LONGER APPARENT ON SATELLITE IMAGES...AND THERE CONTINUES TO BE SOME EVIDENCE OF SOUTHWESTERLY SHEAR OVER THE HURRICANE. DVORAK-BASED CURRENT INTENSITY ESTIMATES FROM TAFB AND SAB HAVE NOT YET DECREASED...SO THE ADVISORY INTENSITY IS KEPT AT 75 KT. HUMBERTO SHOULD BE IN AN ENVIRONMENT OF MODERATE TO STRONG WEST-SOUTHWESTERLY SHEAR AND MARGINAL SEA SURFACE TEMPERATURES FOR THE NEXT COUPLE OF DAYS...AND WEAKENING SHOULD OCCUR DURING THAT TIME FRAME. LATER ON...THE TROPICAL CYCLONE IS LIKELY TO TRAVERSE WARMER WATERS WEST OF 40W LONGITUDE AND THE SHEAR IS FORECAST TO RELAX A LITTLE. THUS...THE OFFICIAL WIND SPEED FORECAST HINTS AT SOME RE-STRENGTHENING BY LATE IN PERIOD. THIS IS IN GOOD AGREEMENT WITH THE LATEST LGEM GUIDANCE. IT SHOULD BE NOTED THAT THE GLOBAL MODELS SUGGEST THAT HUMBERTO COULD BE EVEN STRONGER THAN INDICATED HERE AT DAYS 4-5. THE NORTHWARD MOTION CONTINUES...AT 350/12 KT. A LARGE MID- TROPOSPHERIC HIGH PRESSURE AREA CENTERED NORTH OF THE AZORES SHOULD CAUSE HUMBERTO TO TURN TOWARD THE NORTHWEST AND THEN THE WEST- NORTHWEST OVER THE NEXT SEVERAL DAYS. LATER IN THE FORECAST PERIOD...THE TROPICAL CYCLONE IS EXPECTED TO TURN BACK TO THE RIGHT WITHIN THE FLOW BETWEEN THE HIGH AND A MID-TROPOSPHERIC TROUGH MOVING EASTWARD FROM THE NORTHEASTERN U.S. AND ATLANTIC CANADA. THE NEW TRACK GUIDANCE...ESPECIALLY THE ECMWF...AND THE OFFICIAL FORECAST...ARE A LITTLE FASTER THAN THE PREVIOUS ONES. THE NHC TRACK FORECAST FOR THIS ADVISORY IS SIMILAR TO THE MODEL CONSENSUS AND ESSENTIALLY SPLITS THE DIFFERENCE BETWEEN THE GFS AND THE ECMWF. FORECAST POSITIONS AND MAX WINDS INIT 12/2100Z 23.1N 29.2W 75 KT 85 MPH 12H 13/0600Z 24.1N 30.3W 70 KT 80 MPH 24H 13/1800Z 25.2N 32.0W 65 KT 75 MPH 36H 14/0600Z 26.0N 34.2W 55 KT 65 MPH 48H 14/1800Z 26.8N 36.5W 45 KT 50 MPH 72H 15/1800Z 28.8N 40.8W 45 KT 50 MPH 96H 16/1800Z 30.5N 43.5W 45 KT 50 MPH 120H 17/1800Z 33.0N 45.0W 50 KT 60 MPH $$ FORECASTER PASCH