Saturday, September 06, 2008

Tropical Storm Hanna Update 3





WOCN31 CWHX 061800
TROPICAL STORM HANNA INFORMATION STATEMENT ISSUED BY THE
CANADIAN HURRICANE CENTRE OF ENVIRONMENT CANADA AT 3.00 PM ADT
SATURDAY 06 SEPTEMBER 2008.

THE NEXT STATEMENT WILL BE ISSUED BY 9.00 PM ADT

... REMNANTS OF TROPICAL STORM HANNA TO CROSS THE MARITIMES
ON SUNDAY...

1. CURRENT POSITION, STRENGTH, CENTRAL PRESSURE AND MOTION

AT 3.00 PM ADT... TROPICAL STORM HANNA WAS LOCATED NEAR LATITUDE
37.6 N AND LONGITUDE 76.6 W... ABOUT 45 NAUTICAL MILES OR 80 KM
NORTH-NORTHWEST OF NORFOLK VIRGINIA. MAXIMUM SUSTAINED WINDS ARE
ESTIMATED AT 45 KNOTS... 83 KM/H... AND CENTRAL PRESSURE AT 993 MB.
HANNA IS MOVING NORTHEAST AT 22 KNOTS... 41 KM/H.

2. FORECAST POSITION, CENTRAL PRESSURE AND STRENGTH

DATE TIME LAT LON MSLP MAX WIND
ADT MB KTS KMH
SEP 06 3.00 PM 37.6N 76.6W 993 45 83 INLAND
SEP 06 9.00 PM 39.7N 74.7W 993 45 83 TRANSITIONING
SEP 07 3.00 AM 41.5N 71.9W 993 45 83 TRANSITIONING
SEP 07 9.00 AM 43.6N 68.4W 1000 45 83 POST-TROPICAL
SEP 07 3.00 PM 45.2N 64.4W 1002 40 74 POST-TROPICAL
SEP 07 9.00 PM 46.8N 60.0W 1002 40 74 POST-TROPICAL
SEP 08 3.00 AM 48.2N 55.3W 1002 40 74 POST-TROPICAL
SEP 08 9.00 AM 49.1N 50.3W 995 40 74 POST-TROPICAL
SEP 08 3.00 PM 49.8N 45.1W 994 40 74 POST-TROPICAL
SEP 08 9.00 PM 50.4N 39.7W 994 40 74 POST-TROPICAL
SEP 09 3.00 AM 51.1N 34.0W 994 40 74 POST-TROPICAL

3. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY
THE REMNANTS OF TROPICAL STORM HANNA WILL BRING PERIODS OF HEAVY
RAIN TO THE MARITIMES ON SUNDAY. RAINFALL WARNINGS WERE ISSUED BY
THE ATLANTIC STORM PREDICTION CENTRE EARLIER THIS MORNING
FOR SOUTHERN NEW BRUNSWICK..PEI AND NORTHERN NOVA SCOTIA WITH 40 TO
80 MM LIKELY.. WITH SOME COMPUTER GUIDANCE SUGGESTING NEAR 100 MM
POSSIBLE IN SOME AREAS. SOME GUSTY WINDS CAN BE EXPECTED OVER NOVA
SCOTIA..GUSTING TO AROUND 70 KM/H. WINDS SHOULD NOT BE MUCH OF A
FACTOR OVER NEW BRUNSWICK.

COMPLICATING MATTERS SOMEWHAT IS A LEADING AREA OF MOISTURE WELL
AHEAD OF HANNA..BUT NOT RELATED TO THE STORM..GIVING SOME HEAVY RAIN
TO PARTS OF NOVA SCOTIA TODAY WITH LOCAL AMOUNTS OF 30 TO 40 MM
POSSIBLE.

THE HEAVY RAINS FROM HANNA EXPECTED ON SUNDAY WILL GIVE THE
POSSIBILITY OF SOME LOCAL FLOODING IN PRONE AREAS AND POSSIBLE ROAD
OR SHOULDER WASHOUTS..ESPECIALLY COMBINED WITH THE RAINFALL
OCCURRING TODAY AND THE LARGE AMOUNT OF MOISTURE ALREADY IN THE
GROUND OVER MANY PARTS OF THE REGION.

4. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY
POST-TROPICAL STORM HANNA IS FORECAST TO BRING GALES TO SOUTHERN
MARITIME WATERS ON SUNDAY AND TO NEWFOUNDLAND WATERS ON MONDAY.
WAVE HEIGHTS ASSOCIATED WITH THESE WINDS SHOULD REACH NEAR 5
METRES IN THE OFFSHORE REGIONS BY LATE SUNDAY.

5. TECHNICAL DISCUSSION FOR METEOROLOGISTS

A. ANALYSIS
HANNA MADE LANDFALL AT APPROXIMATELY 420 AM ADT SATURDAY NEAR THE
BORDER BETWEEN SOUTH CAROLINA AND NORTH CAROLINA. LATEST POSITION
IS BASED ON SURFACE OBSERVATIONS AS WELL AS RADAR AND SATELLITE
IMAGERY.

B. PROGNOSTIC
IT STILL APPEARS THE GREATEST CONCERN WITH THE REMNANTS OF HANNA
WILL BE RAINFALL. COMPUTER MODELS HAVE BEEN AMAZINGLY CONSISTENT
WITH REGARDS TO THE TRACK OF HANNA..WITH THE CONSENSUS TAKING THE
CENTRE OF THE REMNANT LOW ALONG A PATH IN THE VICINITY OF THE BAY OF
FUNDY AROUND NOON SUNDAY. THE LATEST CHC TRACK REMAINS CONSISTENT
WITH THIS GUIDANCE..AS WELL AS THE NHC TRACK..AND TAKES THE CENTRE
OF THE REMNANT LOW ON AN EAST-NORTHEASTERLY TRACK ACROSS THE FUNDY
COASTLINE OF NOVA SCOTIA. THE STRONGEST WINDS WOULD BE SOUTH OF
WHERE THE CENTRE TRACKS..BUT WE DO NOT EXPECT WINDS TO BE OVERLY
SIGNIFICANT AT THIS TIME. HIGHEST RAINFALL AMOUNTS WILL LIKELY BE
ALONG AND JUST NORTH OF THE TRACK. THE GEM REGIONAL MODEL STILL
SERVES AS THE PRIMARY GUIDANCE FOR RAINFALL AND WIND..ALTHOUGH THE
12Z RUN BACKED OFF SLIGHTLY ON QPF FROM THE 00Z RUN. THE AMOUNTS
STILL LOOK REASONABLE AND IS APPROPRIATELY SKEWED LEFT OF THE LOW'S
TRACK WITH A 50 MM TO 100 MM SWATH ACROSS THE CENTRAL MARITIMES.
LATEST NAM AND GFS ARE ALSO VERY SIMILAR TO THE GEM REG WITH REGARD
TO THE RAINFALL AMOUNTS AND LOCATION..ALTHOUGH ARE HINTING AT JUST
SLIGHTLY HIGHER POSSIBLE TOTALS.

CYCLONE PHASE SPACE DIAGRAMS CONTINUE SUGGESTING EXTRATROPICAL
TRANSITION WILL BE COMPLETE PRIOR TO IT REACHING CANADIAN WATERS.
THIS INDICATES THAT THE WIND FIELD SHOULD BEHAVE GENERALLY LIKE A
TRADITIONAL BAROCLINIC CYCLONE AS IT CROSSES THE MARITIMES.

C. PUBLIC WEATHER
SEE ABOVE.

D. MARINE WEATHER
THESE WIND RADII REPRESENT BOTH HANNA AND THE LARGE SCALE CIRCULATION
AT THE OUTER EDGES OF THE STORM.

PREDICTED WIND RADII (NM)
TIME GALES STORMS HURRICANE
NE SE SW NW NE SE SW NW NE SE SW NW
06/18Z 200 200 40 0 0 0 0 0 0 0 0 0
07/00Z 200 200 40 0 0 0 0 0 0 0 0 0
07/06Z 150 220 40 20 0 0 0 0 0 0 0 0
07/12Z 150 240 100 40 0 0 0 0 0 0 0 0
07/18Z 150 250 150 40 0 0 0 0 0 0 0 0
08/00Z 150 250 150 40 0 0 0 0 0 0 0 0
08/06Z 150 250 150 40 0 0 0 0 0 0 0 0
08/12Z 150 250 150 40 0 0 0 0 0 0 0 0
08/18Z 170 250 150 60 0 0 0 0 0 0 0 0
09/00Z 180 250 150 90 0 0 0 0 0 0 0 0
09/06Z 190 250 150 90 0 0 0 0 0 0 0 0


END BORGEL/CAMPBELL

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