WOCN31 CWHX 131800 TROPICAL STORM ALBERTO INFORMATION STATEMENT ISSUED BY THE CANADIAN HURRICANE CENTRE OF ENVIRONMENT CANADA AT 3.00 PM ADT TUESDAY 13 JUNE 2006. THE NEXT STATEMENT WILL BE ISSUED BY 9.00 PM ADT ... ALBERTO EXPECTED TO APPROACH ATLANTIC CANADA AS A POST-TROPICAL STORM LATER THIS WEEK... 1. CURRENT POSITION, STRENGTH, CENTRAL PRESSURE AND MOTION AT 3.00 PM ADT... TROPICAL STORM ALBERTO WAS LOCATED NEAR LATITUDE 30.3 N AND LONGITUDE 83.5 W... ABOUT 30 NAUTICAL MILES OR 55 KM SOUTH SOUTHWEST OF VALDOSTA GEORGIA. MAXIMUM SUSTAINED WINDS ARE ESTIMATED AT 40 KNOTS... 74 KM/H... AND CENTRAL PRESSURE AT 997 MB. ALBERTO IS MOVING NORTHEAST AT 12 KNOTS... 22 KM/H. 2. FORECAST POSITION, CENTRAL PRESSURE AND STRENGTH DATE TIME LAT LON MSLP MAX WIND ADT MB KTS KMH JUN 13 3.00 PM 30.3N 83.5W 997 40 74 JUN 14 3.00 AM 32.2N 81.7W 997 35 65 JUN 14 3.00 PM 34.5N 78.4W 1000 30 56 POST-TROPICAL JUN 15 3.00 AM 37.2N 73.4W 1002 35 65 POST-TROPICAL JUN 15 3.00 PM 40.7N 66.9W 1002 40 74 POST-TROPICAL JUN 16 3.00 AM 44.5N 59.6W 999 40 74 POST-TROPICAL JUN 16 3.00 PM 48.2N 51.8W 996 40 74 POST-TROPICAL JUN 17 3.00 AM 51.2N 43.5W 995 40 74 POST-TROPICAL JUN 17 3.00 PM 53.7N 34.5W 995 40 74 POST-TROPICAL 3. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY NO INLAND WARNINGS HAVE BEEN ISSUED. HEAVY RAIN IS A POSSIBILITY FOR PORTIONS OF NOVA SCOTIA AND NEWFOUNDLAND LATE THURSDAY AND FRIDAY AS ALBERTO APPROACHES ATLANTIC CANADA AS A POST-TROPICAL STORM. THE CURRENT FORECAST TRACK WOULD KEEP STRONG WINDS AWAY FROM NOVA SCOTIA HOWEVER SOUTHERN NEWFOUNDLAND MIGHT SEE GALES THURSDAY NIGHT OR FRIDAY. 4. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY EVEN THOUGH ALBERTO IS EXPECTED TO HAVE LOST MUCH OF ITS TROPICAL CHARACTERISTICS BY THE TIME IT REACHES SOUTHWESTERN CANADIAN WATERS ON THURSDAY GALES ARE STILL EXPECTED AS THE SYSTEM TRANSFORMS INTO A STRONG FRONTAL LOW PRESSURE SYSTEM. WHEN THIS TYPE OF TRANSFORMATION HAPPENS IT IS EXPECTED THAT THE RANGE OF GALE FORCE WINDS SHOULD EXPAND SIGNIFICANTLY TO THE RIGHT OF THE STORMS TRACK . . . MEANING THAT SOUTHERN MARITIME AND NEWFOUNDLAND WATERS ARE EXPECTED TO EXPERIENCE GALES WHEN POST-TROPICAL ALBERTO PASSES ON THURSDAY AND FRIDAY. NO GALES HAVE BEEN ISSUED YET. 5. TECHNICAL DISCUSSION A. ANALYSIS ALBERTO IS NOW INLAND IN FLORIDA AND SHOULD BE WEAKENING AT THE TYPICAL RATE EVEN THOUGH WIND SHEAR HAS LESSENED OVER THE CENTRE SINCE LAST NIGHT. A CLOSE-IN VISUAL IMAGE MAKES ALBERTO LOOK QUITE TROPICAL BUT A ZOOMED-OUT VIEW OF AN IR PERSPECTIVE GIVES THE SENSE OF A BAROCLINIC DEVELOPMENT. TRANSITION IS POSSIBLY ALREADY UNDERWAY. B. PROGNOSTIC BASED ON HOW ALBERTO APPEARS ON THE IR AND HOW IT IS DEVELOPED ON MOST DYNAMICAL MODELS WE CONCUR WITH THE NHC ASSESSMENT THAT IT WONT BE A PURELY TROPICAL ENTITY FOR VERY LONG . . . IF IT EVEN IS STILL NOW. THE LATEST SUITE OF DYNAMICAL MODELS GIVE A CLEAR PATH FOR ALBERTO ...TOWARDS THE NORTHEAST OVER THE NEXT 3 DAYS. THE GEM GLOBAL AND GFS ARE SIMILAR AND LEAD US TO INCREASE THE FORWARD SPEED OF THE STORM OVER THE NEXT 2-3 DAYS. THIS IS WHAT NHC DOES AND AGAIN SEEMS PRUDENT. THE GEM REGIONAL IS OFFERING A VERY DIFFERENT SOLUTION AS IT DEVELOPS A MORE SIGNIFICANT BAROCOLINIC CYCLONE EARLIER IN THE PACKAGE. WE SUSPECT THAT IT IS OVERDOING THE CONVECTIVE INPUT SINCE OTHER MODELS DONT SHOW THIS. BUT IT IS A CAUTIONARY POINT TO KEEP IN MIND OVER THE NEXT COUPLE DAYS. OUR TRACK IS SIMILAR TO WHAT WE ISSUED EARLIER AS IT REMAINS IN THE MIDDLE OF THE SOLUTION ENVELOPE. C. PUBLIC WEATHER HEAVY RAIN SEEMS TO BE A LIKELY SCENARIO FOR PORTIONS OF NOVA SCOTIA AND SOUTHERN NEWFOUNDLAND AS PT ALBERTO PASSES. THE STORM SPEED SHOULD BE SUFFICIENTLY HIGH ENOUGH TO KEEP AMOUNTS FROM BEING TOO GREAT AND OF COURSE THE DEGREE TO WHICH ALBERTO HAS TRANSITIONED WILL ALSO DETERMINE HOW FAR LEFT OF TRACK THE RAIN SWATH WILL BE. AT THIS POINT IT WOULD SEEM THAT RAINFALL WARNINGS WOULD BE A GOOD BET FOR THOSE AREAS LATER IN THE WEEK . . . BASED ON THIS TRACK. D. MARINE WEATHER THE CHC TRAPPED FETCH WAVE MODEL INDICATES THAT WAVE DEVELOPMENT SHOULD BE SIGNIFICANTLY HAMPERED BY THE FAST FORWARD SPEED OF THE STORM. IT COULD BE DIFFICULT TO BUILD EVEN 6 METRE WAVES FOR A SYSTEM THAT IS EXPECTED TO MOVE THIS QUICKLY . . . ALTHOUGH THE SPATIAL EXTENT OF THE STORM WILL PLAY A BIG FACTOR. AS EARLIER WE HAVE INCLUDED A WIND RADII TABLE EVEN THOUGH WE ARE EXPECTING IT TO BE EXTRATROPICAL BY THE TIME IT REACHES CANADIAN WATERS . . . HENCE THE GALE RADII AT THAT TIME WILL BE QUITE LARGE . . . MUCH LARGER THAN WITH A TYPICAL TROPICAL STORM. PREDICTED WIND RADII (NM) TIME GALES STORMS HURRICANE NE SE SW NW NE SE SW NW NE SE SW NW 13/18Z 60 90 40 30 0 0 0 0 0 0 0 0 14/06Z 60 90 25 10 0 0 0 0 0 0 0 0 14/18Z 0 0 0 0 0 0 0 0 0 0 0 0 15/06Z 60 90 15 0 0 0 0 0 0 0 0 0 15/18Z 160 215 45 15 0 0 0 0 0 0 0 0 16/06Z 225 300 75 60 0 0 0 0 0 0 0 0 16/18Z 250 375 90 105 0 0 0 0 0 0 0 0 17/06Z 250 425 90 120 0 0 0 0 0 0 0 0 17/18Z 250 500 120 120 0 0 0 0 0 0 0 0 END (BOWYER)