WOCN31 CWHX 291800 TROPICAL STORM ISAAC INFORMATION STATEMENT ISSUED BY THE CANADIAN HURRICANE CENTRE OF ENVIRONMENT CANADA AT 3.30 PM NDT FRIDAY 29 SEPTEMBER 2006. THE NEXT STATEMENT WILL BE ISSUED BY 9.30 PM NDT ... ISAAC POSSIBLY TO AFFECT SOUTHEASTERN MARINE AREAS AND SOUTHEASTERN NEWFOUNDLAND EARLY NEXT WEEK... 1. CURRENT POSITION, STRENGTH, CENTRAL PRESSURE AND MOTION AT 3.30 PM NDT... TROPICAL STORM ISAAC WAS LOCATED NEAR LATITUDE 29.6 N AND LONGITUDE 56.5 W... ABOUT 450 NAUTICAL MILES OR 835 KM EAST SOUTHEAST OF BERMUDA . MAXIMUM SUSTAINED WINDS ARE ESTIMATED AT 40 KNOTS... 74 KM/H... AND CENTRAL PRESSURE AT 1006 MB. ISAAC IS MOVING WEST AT 5 KNOTS... 9 KM/H. 2. FORECAST POSITION, CENTRAL PRESSURE AND STRENGTH DATE TIME LAT LON MSLP MAX WIND NDT MB KTS KMH SEP 29 3.30 PM 29.6N 56.5W 1006 40 74 SEP 30 3.30 AM 30.3N 57.7W 1003 45 83 SEP 30 3.30 PM 31.3N 59.0W 999 50 93 OCT 01 3.30 AM 32.9N 60.2W 999 50 93 OCT 01 3.30 PM 35.8N 60.7W 999 50 93 BECOMING POST-TROPICAL OCT 02 3.30 AM 39.8N 59.7W 999 50 93 BECOMING POST-TROPICAL OCT 02 3.30 PM 43.3N 56.6W 999 50 93 BECOMING POST-TROPICAL OCT 03 3.30 AM 46.1N 51.7W 999 50 93 BECOMING POST-TROPICAL OCT 03 3.30 PM 47.7N 46.3W 999 50 93 POST-TROPICAL OCT 04 3.30 AM 48.7N 40.2W 999 50 93 POST-TROPICAL OCT 04 3.30 PM 49.0N 33.9W 999 50 93 POST-TROPICAL 3. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY RAIN ASSOCIATED WITH ISAAC MAY AFFECT SOUTHEASTERN NEWFOUNDLAND MONDAY OR TUESDAY BUT IT IS TOO EARLY TO PROVIDE DETAILS. 4. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY SOUTHEASTERN WATERS... NAMELY LAURENTIAN FAN AND THE GRAND BANKS... WILL LIKELY EXPERIENCE GALES AND POSSIBLY STORM FORCE WINDS AS ISAAC TRACKS THROUGH THOSE AREAS MONDAY OR TUESDAY. IT IS TOO EARLY FOR WARNINGS TO BE ISSUED. 5. TECHNICAL DISCUSSION A. ANALYSIS FOLLOWING NHC LEAD ON INTENSITY. POSITION BASED ON VISIBLE IMAGERY WHICH SHOWS OPEN AREA IN CIRCULATION. B. PROGNOSTIC WE HAVE FOLLOWED THE NHC TRACK AND INTENSITY ALMOST VERBATIM AT THIS POINT. THE UKMET NOGAPS AND FSU MM5 ARE BEGINNING TO OFFER CONVERGING SOLUTIONS... ALBEIT WITH INTERESTING DIFFERENCES. IT IS THE VARIOUS DIFFERENCES AND UNCERTAINTIES THAT CONCERN US. ISAAC HAS BEEN MOVING ALMOST DUE WEST FOR THE LAST FEW HOURS. THIS TREND MAY CONTINUE AS THE RIDGING TO THE NORTH IS FORECAST TO STRENGTHEN OUT TO AT LEAST 36-48 HOURS. CMC REPORTS ISAAC INITIALIZED 1 DEGREE TOO FAR SW IN TRIAL FIELD. FOR THE MOST PART THE SMALL SIZE OF ISAAC IS PROBLEMATIC FOR THE INITIALIZATION ON MANY OF THE DYNAMICAL MODELS. THERE IS AGREEMENT IN THE MODELS THAT BAROCLINIC CYCLOGENESIS TAKES PLACE OFF THE EAST COAST AS THE LARGE UPPER TROUGH PUSHES THROUGH ATLANTIC CANADA BEYOND 60 HOURS. THE GFS INITIATES CYCLOGENESIS AFTER 60 HOURS WHICH THEN DEVELOPS SO SIGNIFICANTLY THAT THE STORM SIZE SWAMPS THE DOMAIN AND ISAAC IS EITHER LOST OR ABSORBED. THE UKMET HOWEVER KEEPS ISAAC AS AN IDENTIFIABLE SURFACE LOW IN AN ELONGATED SURFACE FEATURE FOLLOWING THE CYCLOGENESIS AND HAS A TRACK THAT IS SLIGHTLY NORTH OF THE NHC TRACK AT 72 HRS... BEYOND WHICH IT MOVES FASTER AND EVEN FARTHER NORTH. THE NOGAPS AND FSU MM5 MODELS HAVE A SIMILAR SOLUTION TO THE UKMET BUT KEEP IT FARTHER SOUTH ONCE IT PASSES NEWFOUNDLAND. MEANWHILE THE VORTICITY AND QPF OUTPUT ON THE CANADIAN MODEL INDICATES THAT ISAAC NEVER GETS SUFFICIENTLY CLOSE TO THE TROUGH FOR MARKED INTERACTION. IT IS ALSO WORTH MENTIONING THAT IF THE APPROACHING TROUGH IS NOT AS LARGE AND IF ISAAC RETARDS ITS MOTION TO THE NORTHWEST FOR TOO LONG IT COULD ACTUALLY BECOME ORPHANED IN THE SUBTROPICS... RESULTING IN HUGE TRACK ERRORS FOR DAYS 3-5. HENCE WE REFRAIN FROM BEING TOO DEFINITIVE AT THIS POINT BUT SIMPLY WATCH FOR A GREATER CONCENSUS OF MODELS... WHICH WE DOUBT WILL OCCUR UNTIL AT LEAST 48 HOURS FROM NOW. C. PUBLIC WEATHER NONE. D. MARINE WEATHER PREDICTED WIND RADII (NM) TIME GALES STORMS HURRICANE NE SE SW NW NE SE SW NW NE SE SW NW 29/18Z 120 90 45 60 0 0 0 0 0 0 0 0 30/06Z 120 120 60 75 0 0 0 0 0 0 0 0 30/18Z 120 120 60 75 40 30 0 0 0 0 0 0 01/06Z 120 120 60 90 40 30 0 0 0 0 0 0 01/18Z 120 120 60 90 40 30 0 0 0 0 0 0 02/06Z 120 120 110 90 50 40 0 0 0 0 0 0 02/18Z 150 150 140 90 90 90 0 0 0 0 0 0 03/06Z 210 240 150 90 90 90 0 0 0 0 0 0 03/18Z 240 360 150 120 90 90 0 0 0 0 0 0 04/06Z 240 400 150 120 90 90 0 0 0 0 0 0 04/18Z 240 400 150 120 90 90 0 0 0 0 0 0 THESE RADII REFLECT THE TRANSITION OF ISAAC IN THE LONGER RANGE AND ARE ONLY INTENDED TO SHOW A CONCEPTUAL RATHER THAN DETERMINISTIC TREND. END BOWYER