000 WTNT42 KNHC 302042 TCDAT2 TROPICAL STORM PHILIPPE DISCUSSION NUMBER 27 NWS NATIONAL HURRICANE CENTER MIAMI FL AL172011 500 PM AST FRI SEP 30 2011 THE STRUCTURE OF PHILIPPE HAS CHANGED LITTLE THROUGH THE DAY EXCEPT THAT THE LOW-LEVEL CENTER HAS BEEN RE-COVERED BY DEEP CONVECTION SINCE THE LAST ADVISORY. THE INITIAL INTENSITY IS BEING HELD AT 45 KT BASED ON THE EARLIER ASCAT PASS...AND THIS IS SUPPORTED BY DVORAK ESTIMATES OF T3.0 FROM TAFB AND T2.9 FROM THE UW-CIMSS ADT. HILARY IS CURRENTLY LOCATED WITHIN A COL REGION BETWEEN AN UPPER-LEVEL LOW TO ITS SOUTH AND A LARGE DEEP-LAYER TROUGH COVERING THE EASTERN ATLANTIC. HOWEVER...THE CYCLONE WILL BE EXITING THE COL REGION WITHIN THE NEXT 12 HOURS OR SO AND IS FORECAST TO BE CONTINUOUSLY BLASTED BY STRONG NORTHERLY SHEAR FOR THE NEXT SEVERAL DAYS. IN FACT...THE SHIPS MODEL DIAGNOSTICS ARE INDICATING UP TO 40 KT OF SHEAR WITHIN ABOUT 24 HOURS. IT IS PARADOXICAL... HOWEVER...THAT NEARLY EVERY INTENSITY MODEL IS EITHER SHOWING PHILIPPE MAINTAINING ITS INTENSITY OR STRENGTHENING DURING THE FORECAST PERIOD. THIS IS HARD TO BELIEVE GIVEN THE HOSTILE CONDITIONS EXPECTED...AND THE OFFICIAL INTENSITY FORECAST IS CLOSEST TO THE LGEM MODEL...WHICH IS ALONG THE LOWER BOUND OF THE GUIDANCE ENVELOPE. PHILIPPE IS MOVING AT 320 DEGREES AT 11 KT AND IS FORECAST TO GRADUALLY TURN WESTWARD OVER THE NEXT COUPLE OF DAYS AS IT COMES UNDER THE INFLUENCE OF A BUILDING LOW- TO MID-LEVEL HIGH TO ITS NORTH. THE SPREAD IN THE TRACK GUIDANCE DOES NOT BECOME SIGNIFICANT UNTIL AFTER 72 HOURS. MOST OF THE GUIDANCE IS INDICATING THAT PHILIPPE WILL RECURVE BY DAY 4 OR 5 AS IT APPROACHES A DEEP-LAYER LONGWAVE TROUGH OVER THE WESTERN ATLANTIC. THE GFS IS A SOUTHERN OUTLIER AND KEEPS PHILIPPE ON A WESTWARD COURSE...MOST LIKELY BECAUSE IT APPEARS TO DE-AMPLIFY THE WESTERN ATLANTIC TROUGH SOONER THAN THE OTHER MODELS. THE OFFICIAL TRACK FORECAST SHOWS THE BEGINNING OF A SLOW RECURVATURE BY DAY 5 BUT IS TO THE SOUTHWEST OF THE TVCA CONSENSUS AND NOT AS FAST AS THE 12Z ECMWF AND UKMET MODELS AT THAT TIME. FORECAST POSITIONS AND MAX WINDS INIT 30/2100Z 23.5N 46.2W 45 KT 50 MPH 12H 01/0600Z 24.2N 47.6W 45 KT 50 MPH 24H 01/1800Z 25.0N 49.4W 40 KT 45 MPH 36H 02/0600Z 25.7N 51.2W 40 KT 45 MPH 48H 02/1800Z 26.1N 53.0W 40 KT 45 MPH 72H 03/1800Z 26.0N 57.0W 30 KT 35 MPH 96H 04/1800Z 26.5N 61.0W 30 KT 35 MPH 120H 05/1800Z 28.5N 61.5W 35 KT 40 MPH $$ FORECASTER BERG