| TROPICAL STORM HUMBERTO DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST MON SEP 09 2013 RECENT MICROWAVE IMAGES AND SCATTEROMETER DATA INDICATE THAT THE CENTER OF HUMBERTO REMAINS NEAR THE NORTHEASTERN EDGE OF A LARGE MASS OF DEEP CONVECTION. THIS SUGGESTS THAT SOME EAST- NORTHEASTERLY SHEAR REMAINS OVER THE CYCLONE...ALTHOUGH RECENT SATELLITE PICTURES SHOW THAT CIRRUS OUTFLOW IS BEGINNING TO EXPAND OUTWARD OVER THE EASTERN PORTION OF THE STORM. THE ASCAT DATA INDICATE THAT THE MAXIMUM WINDS HAVE INCREASED TO AROUND 50 KT...AND THAT THE AREA OF TROPICAL STORM FORCE WINDS HAS ALSO EXPANDED SINCE THIS MORNING. SATELLITE CENTER FIXES OVER THE PAST 12 HOURS SUGGEST THAT HUMBERTO IS MOVING A LITTLE SLOWER THAN EARLIER TODAY...WITH A MOTION OF 285/9 KT. THE MID-LEVEL RIDGE TO THE NORTH OF THE STORM IS EXPECTED TO WEAKEN VERY SOON AS A COUPLE OF MID- TO UPPER-LEVEL LOWS MOVE SOUTHWARD OVER THE EASTERN ATLANTIC. THIS SHOULD CAUSE HUMBERTO TO TURN NORTH-NORTHWESTWARD IN 24 TO 36 HOURS AND A GENERAL NORTHWARD MOTION IS FORECAST TO THEN CONTINUE THROUGH 72 HOURS. AFTER THAT TIME...THE GLOBAL MODELS INDICATE THAT THE RIDGE WILL REBUILD TO THE NORTHWEST OF THE AZORES AND THIS SHOULD TURN HUMBERTO BACK TO THE WEST-NORTHWEST BY THE END OF THE FORECAST PERIOD. THE VERTICAL SHEAR CURRENTLY OVER HUMBERTO SHOULD DECREASE SOON...AND THIS SHOULD ALLOW FOR STEADY STRENGTHENING DURING THE NEXT COUPLE OF DAYS WHILE THE CYCLONE REMAINS OVER WARM WATER. THE MAJORITY OF THE INTENSITY GUIDANCE BRINGS HUMBERTO TO HURRICANE STRENGTH WITHIN 24 HOURS...AND SO DOES THE OFFICIAL FORECAST. THE NHC INTENSITY FORECAST SHOWS A SLIGHTLY HIGHER PEAK INTENSITY THAN THE PREVIOUS ADVISORY...BUT STILL IT IS NOT AS AGGRESSIVE AS THE SHIPS GUIDANCE. AFTER 72 HOURS...THE SHEAR IS FORECAST TO BECOME QUITE STRONG OUT OF THE SOUTHWEST...AND THIS IS EXPECTED TO INDUCE SIGNIFICANT WEAKENING. FORECAST POSITIONS AND MAX WINDS INIT 10/0300Z 13.9N 25.9W 50 KT 60 MPH 12H 10/1200Z 14.4N 27.1W 60 KT 70 MPH 24H 11/0000Z 15.4N 28.1W 70 KT 80 MPH 36H 11/1200Z 16.9N 28.7W 80 KT 90 MPH 48H 12/0000Z 19.1N 29.1W 85 KT 100 MPH 72H 13/0000Z 23.0N 30.0W 75 KT 85 MPH 96H 14/0000Z 25.2N 32.3W 55 KT 65 MPH 120H 15/0000Z 26.0N 36.0W 45 KT 50 MPH $$ FORECASTER BROWN |