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#632653 (Received by flhurricane at: 10:35 PM 16.Sep.2013) TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST MON SEP 16 2013 HUMBERTO HAS WEAKENED A LITTLE THIS EVENING. THE LOW-LEVEL CENTER HAS SEPARATED FROM THE DEEP CONVECTION AND IS NOW LOCATED ABOUT 60 NMI TO THE SOUTH-SOUTHWEST OF THE ASSOCIATED THUNDERSTORM ACTIVITY. AN ASCAT PASS AROUND 0000 UTC SHOWED MAXIMUM WINDS OF AROUND 25 KT...WHICH IS CONSIDERABLY LOWER THAN THE PREVIOUS PASS FROM EARLIER TODAY. THE INITIAL WIND SPEED IS CONSERVATIVELY LOWERED TO 35 KT...ASSUMING THAT STRONGER WINDS COULD BE OCCURRING IN THE NORTHEASTERN QUADRANT...WHICH WAS NOT CAPTURED BY THE ASCAT DATA. THE TROPICAL STORM HAS BEEN MEANDERING DURING THE PAST FEW HOURS AS IT IS CURRENTLY ENTANGLED WITH A MID- TO UPPER-LEVEL LOW. THE CYCLONE IS EXPECTED TO BEGIN MOVING NORTH-NORTHWESTWARD OVERNIGHT OR EARLY TUESDAY...HOWEVER...AND THEN TURN NORTHWARD ON WEDNESDAY WHEN IT MOVES ON THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. AFTER THAT TIME...A FASTER NORTHEASTWARD MOTION IS FORECAST WHEN THE STORM BECOMES EMBEDDED IN THE STRONG SOUTHWESTERLY FLOW ON THE EAST SIDE OF AN APPROACHING TROUGH. THE LATEST NHC TRACK FORECAST REMAINS CLOSE TO THE MULTI-MODEL CONSENSUS TVCA. STRONG SHEAR AND DRY AIR...PARTIALLY ASSOCIATED WITH THE AFOREMENTIONED UPPER-LEVEL LOW...ARE CURRENTLY AFFECTING HUMBERTO. THIS UPPER-LEVEL FEATURE IS EXPECTED TO MOVE SOUTHEASTWARD AND WEAKEN DURING THE NEXT COUPLE OF DAYS...CREATING A MORE FAVORABLE ATMOSPHERIC PATTERN FOR HUMBERTO TO STRENGTHEN. THE NHC INTENSITY FORECAST IS A LITTLE LOWER THAN THE PREVIOUS ONE TO ACCOUNT FOR THE RECENT WEAKENING AND TO COME INTO BETTER AGREEMENT WITH THE LATEST GUIDANCE. HUMBERTO IS FORECAST TO BECOME AN EXTRATROPICAL CYCLONE OVER THE NORTHEASTERN ATLANTIC OCEAN IN 4 TO 5 DAYS. FORECAST POSITIONS AND MAX WINDS INIT 17/0300Z 27.0N 43.3W 35 KT 40 MPH 12H 17/1200Z 28.0N 44.0W 35 KT 40 MPH 24H 18/0000Z 29.0N 44.7W 35 KT 40 MPH 36H 18/1200Z 30.0N 45.1W 40 KT 45 MPH 48H 19/0000Z 30.9N 45.0W 45 KT 50 MPH 72H 20/0000Z 33.7N 43.1W 50 KT 60 MPH 96H 21/0000Z 40.0N 37.5W 60 KT 70 MPH 120H 22/0000Z 52.0N 26.0W 55 KT 65 MPH...POST-TROP/EXTRATROP $$ FORECASTER CANGIALOSI |