ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION JOHN DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102012 800 PM PDT MON SEP 03 2012 THE CENTER OF JOHN REMAINS DEVOID OF DEEP CONVECTION...AND WHAT DEEP CONVECTION REMAINS HAS BEEN SHUNTED TO THE SOUTHWEST BY STRONG NORTHEASTERLY WIND SHEAR. A BLEND OF THE LATEST SATELLITE INTENSITY ESTIMATES WITH RECENT UW-CIMSS ADT VALUES IS THE BASIS FOR LOWERING THE INITIAL INTENSITY TO 30 KT. JOHN IS NEARING THE 26C-ISOTHERM...AND SHOULD REACH A SHARP GRADIENT OF DECREASING SEA SURFACE TEMPERATURES IN 12-24 HOURS. AN INCREASINGLY STABLE THERMODYNAMIC ENVIRONMENT AND A CONTINUATION OF AT LEAST MODERATE NORTHEASTERLY SHEAR SHOULD MEAN A QUICK DEMISE OF JOHN. THE NEW NHC INTENSITY FORECAST SHOWS STEADY WEAKENING IN BASIC AGREEMENT WITH THE LATEST SHIPS AND LGEM GUIDANCE. JOHN IS FORECAST TO BECOME A REMNANT LOW IN 36 HOURS...IF NOT SOONER. THE INITIAL MOTION ESTIMATE IS 305/11...THOUGH RECENT CENTER FIXES SUGGEST A SOMEWHAT SLOWER FORWARD SPEED. THE LARGE-SCALE MODELS SHOW JOHN DECELERATING ON A WEST-NORTHWESTWARD TO NORTHWESTWARD COURSE OVER THE NEXT COUPLE OF DAYS...AROUND THE SOUTHWESTERN PERIPHERY OF A MID-LEVEL RIDGE OVER THE SOUTHWESTERN UNITED STATES. ONCE THE CYCLONE DECOUPLES AND BECOMES SHALLOW...ITS FORWARD MOTION SHOULD SLOW FURTHER AND THE TRACK SHOULD BEND TOWARD THE NORTH OR POSSIBLY THE NORTHEAST. THE NHC TRACK FORECAST IS A HAIR TO THE RIGHT OF THE PREVIOUS ONE FOR THE FIRST COUPLE OF DAYS...AND THEN MORE SO BEYOND 72 HOURS. THIS IS IN GOOD AGREEMENT WITH THE MULTI-MODEL CONSENSUS TVCE. FORECAST POSITIONS AND MAX WINDS INIT 04/0300Z 21.7N 114.6W 30 KT 35 MPH 12H 04/1200Z 22.7N 116.0W 30 KT 35 MPH 24H 05/0000Z 23.9N 117.6W 25 KT 30 MPH 36H 05/1200Z 25.0N 119.2W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 06/0000Z 25.8N 120.4W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 07/0000Z 27.0N 121.0W 15 KT 15 MPH...POST-TROP/REMNT LOW 96H 08/0000Z...DISSIPATED $$ FORECASTER KIMBERLAIN NNNN
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Page last modified: Monday, 31-Dec-2012 12:10:29 UTC