WOCN31 CWHX 130000 POST-TROPICAL STORM FLORENCE INFORMATION STATEMENT ISSUED BY THE CANADIAN HURRICANE CENTRE OF ENVIRONMENT CANADA AT 9.30 PM NDT TUESDAY 12 SEPTEMBER 2006. THE NEXT STATEMENT WILL BE ISSUED BY 3.30 AM NDT ...RAIN AHEAD OF POST-TROPICAL STORM FLORENCE MOVING ACROSS AVALON AND BURIN PENINSULAS..WINDS TO FOLLOW OVERNIGHT... 1. CURRENT POSITION, STRENGTH, CENTRAL PRESSURE AND MOTION AT 9.30 PM NDT... POST-TROPICAL STORM FLORENCE WAS LOCATED NEAR LATITUDE 40.3 N AND LONGITUDE 58.5 W... ABOUT 225 NAUTICAL MILES OR 420 KM SOUTH SOUTHEAST OF SABLE ISLAND. MAXIMUM SUSTAINED WINDS ARE ESTIMATED AT 65 KNOTS... 120 KM/H... AND CENTRAL PRESSURE AT 980 MB. FLORENCE IS MOVING NORTHEAST AT 19 KNOTS... 35 KM/H. 2. FORECAST POSITION, CENTRAL PRESSURE AND STRENGTH DATE TIME LAT LON MSLP MAX WIND NDT MB KTS KMH SEP 12 9.30 PM 40.3N 58.5W 980 65 120 POST-TROPICAL SEP 13 3.30 AM 41.9N 57.1W 980 65 120 POST-TROPICAL SEP 13 9.30 AM 43.7N 55.1W 978 60 111 POST-TROPICAL SEP 13 3.30 PM 45.2N 53.0W 975 60 111 POST-TROPICAL SEP 13 9.30 PM 46.4N 50.2W 975 60 111 POST-TROPICAL SEP 14 3.30 AM 47.2N 47.4W 975 55 102 POST-TROPICAL SEP 14 9.30 AM 48.0N 43.9W 975 55 102 POST-TROPICAL SEP 14 3.30 PM 48.3N 40.8W 975 55 102 POST-TROPICAL SEP 15 9.30 PM 48.4N 37.2W 975 55 102 POST-TROPICAL 3. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY NEWFOUNDLAND: TROPICAL STORM WARNINGS ARE IN EFFECT FOR EASTERN AND SOUTHERN NEWFOUNDLAND AND A TROPICAL STORM WATCH FOR NORTHEASTERN SECTIONS OF THE ISLAND. WIND GUSTS NEAR 100 KM/H CAN BE EXPECTED IN THE WARNING AREA WITH LOCAL COASTAL GUSTS TO HURRICANE FORCE..120 KM/H..NOT OUT OF THE QUESTION. RAINFALL AMOUNTS OF 75 TO 125 MM (3 TO 5 INCHES) ARE POSSIBLE ACROSS THE EASTERN HALF OF NEWFOUNDLAND. WIND AND RAINFALL WARNINGS ARE ALSO IN EFFECT FOR PARTS OF EASTERN AND SOUTHERN NEWFOUNDLAND. DANGEROUS SURF FROM 10 METRE BREAKING SWELLS SHOULD BE EXPECTED ALONG THE SOUTH COAST OF NEWFOUNDLAND ON WEDNESDAY. HEAVY WAVE ACTION AND HIGHER THAN NORMAL WATERS LEVELS WILL LIKELY DEVELOP IN AREAS AROUND THE BURIN..AVALON AND BONAVISTA PENINSULAS ON WEDNESDAY. MARITIMES: ROUGH AND POTENTIALLY DANGEROUS SURF IS STILL EXPECTED ALONG THE ATLANTIC COAST OF NOVA SCOTIA TONIGHT AND WEDNESDAY AS 5-6 METRE SWELLS ROLL INTO THE COASTLINE AND BREAK ONSHORE. 4. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY GALES ARE BEING REPORTED AT THE CURRENT TIME FROM ALL SOUTHERN MARITIME WATERS WITH GALES REACHING 400 NAUTICAL MILES NORTHEAST OF THE STORM CENTRE. STORM FORCE WINDS HAVE MOVED INTO THE LAURENTIAN FAN AREA. A SWATH OF GALE AND STORM FORCE WIND WARNINGS HAVE BEEN ISSUED FOR SOUTHERN MARITIME WATERS AND OVER MANY NEWFOUNDLAND WATERS. VERY HIGH SEAS ARE ALSO PREDICTED OVER THE SOUTHERN GRAND BANKS ON WEDNESDAY WHERE HEIGHTS COULD REACH 15 METERS. 5. TECHNICAL DISCUSSION A. ANALYSIS SATELLITE FIX.... CENTRAL PRESSURE REMAINS DIFFICULT TO DETERMINE FROM THE PAUCITY OF DATA. HOWEVER STRONG TRANSITION SHOULD KEEP THE PRESSURE FROM FILLING TOO RAPIDLY. FSU CPS DIAGRAMS FOR GFS UKMET AND MM5 FROM FSU INDICATE THAT FLORENCE REMAINS WARM CORE UNTIL EARLY THURSDAY WHILE GOING THROUGH A PERIOD OF INCREASING AND THEN DECREASING ASYMMETRY. THE CMC MODEL SIMPLY COMPLETES TRANSITION IN A MORE TRADITIONAL SENSE BY THIS TIME. THE SATELLITE SIGNATURE OF DRY AIR ENTRAINMENT... FRONT-LIKE FEATURES... AND LOSS OF SIGNIFICANT CONVECTION LEAD US TO DECLARE FLORENCE AS A POST-TROPICAL CYCLONE AT THIS TIME. THIS WAS IN AGREEMENT WITH NHC FOLLOWING DISCUSSION. WATER VAPOUR IMAGERY SHOWS A TROUGH DIGGING SOUTHWARD OVER THE MARITIME PROVINCES. CONVECTION HAS JUST STARTED TO FORM NEAR THE CENTRE OF THE STORM WHICH COULD BE AN INDICATION OF ENHANCED VERTICAL MOTION FROM THE INTERACTING SHORTWAVE. B. PROGNOSTIC IN THE LAST TRACK OF THE NHC THEY FAVOURED THE EASTERN EDGE OF THE ENVELOPE OF MODELS. THIS CERTAINLY FITS THE MOTION OF THE STORM OVER THE LAST FEW HOURS BUT WE FEEL COMPELLED TO REMAIN WITH THE IDEA THAT NUMEROUS MODELS HAVE ALLUDED TO OVER THE LAST FEW DAYS WITH FLORENCE EXHIBITING AN'S-SHAPED TRACK BEFORE PASSING EAST OF NEWFOUNDLAND. THIS ALSO RESULTS IN US ERRING ON THE SIDE OF CAUTION WITH REGARD TO NEWFOUNDLAND. ALSO..THE 18Z RUN OF GFS MODEL SHOWS POST-TROPICAL FLORENCE MOVING WITH A MORE NORTHWARD COMPONENT OVERNIGHT AS THE SHORT WAVE TROUGH OBSERVED IN WATER VAPOUR IMAGERY THIS EVENING DIGS OVER THE MARITIMES. THIS COULD INDEED RESUT IN THE'S-SHAPED STORM TRAJECTORY WHICH WOULD BRING THE CENTRE CLOSER TO NEWFOUNDLAND. FLORENCE IS BEGINNING TO MOVE OVER COOLER SSTS BUT THE TROPICAL WEAKENING THAT WOULD OCCUR FROM THAT SHOULD BE OFFSET BY THE STRENGTHENING BAROCLINIC DEVELOPMENT AND TROUGH INTERACTION THAT IS ALREADY UNDERWAY. THE GALE RADII REFLECT BOTH THE STORM AND THE PRESSURE GRADIENT OUT AHEAD AND THE CMC MODEL SUGGESTS THAT THE FAR REACHING GALES OUT AHEAD OF THE STORM WILL SHIFT TO GALES THAT REACH FARTHER SOUTH ON WEDNESDAY. C. PUBLIC WEATHER SEE ABOVE. D. MARINE WEATHER ALTHOUGH THE WIND FIELD WILL NOT BE INDICATIVE OF A PURE TROPICAL CYCLONE..WE ARE CARRYING RADII DURING THE TRANSITION TO PROVIDE GUIDANCE TO MARINERS ON THE EXTENT OF THE EXPANDING WIND FIELD. PREDICTED WIND RADII (NM) TIME GALES STORMS HURRICANE NE SE SW NW NE SE SW NW NE SE SW NW 13/00Z 360 360 300 360 240 150 150 150 60 90 90 30 13/06Z 330 360 300 330 200 150 150 120 60 90 90 30 13/12Z 300 360 300 300 90 180 150 120 0 0 0 0 13/18Z 270 360 300 270 90 210 180 90 0 0 0 0 14/00Z 240 360 300 240 90 210 210 90 0 0 0 0 14/06Z 210 390 330 240 30 180 180 30 0 0 0 0 14/12Z 210 420 360 240 0 150 150 0 0 0 0 0 14/18Z 210 420 360 240 0 120 120 0 0 0 0 0 15/00Z 210 420 360 240 0 120 120 0 0 0 0 0 OUR TRAPPED FETCH WAVE MODEL INDICATES THE POTENTIAL FOR 14M WAVES OVER THE LAURENTIAN FAN AND SOUTHWESTERN GRAND BANKS BY ABOUT MIDDAY WEDNESDAY. SWELLS THAT BEGAN BUILDING WITH THE HURRICANE YESTERDAY SHOULD REACH THE ATLANTIC COAST OF NOVA SCOTIA WEDNESDAY AS 5-6M WHILE THOSE REACHING NEWFOUNDLAND WEDNESDAY AS STILL BUILDING AND COULD REACH SOUTHEASTERN NEWFOUNDLAND WATERS AS 10-12M BREAKERS. END BOWYER/FOGARTY