Thursday, July 20, 2006

BERYL WEAKENING BUT STILL EXPECTED TO BRING HEAVY RAIN

WOCN31 CWHX 210000
TROPICAL STORM BERYL INFORMATION STATEMENT ISSUED BY THE
CANADIAN HURRICANE CENTRE OF ENVIRONMENT CANADA AT 9.00 PM ADT
THURSDAY 20 JULY 2006.

THE NEXT STATEMENT WILL BE ISSUED BY 3.00 AM ADT

... BERYL WEAKENING BUT STILL EXPECTED TO BRING HEAVY RAIN...

1. CURRENT POSITION, STRENGTH, CENTRAL PRESSURE AND MOTION

AT 9.00 PM ADT... TROPICAL STORM BERYL WAS LOCATED NEAR LATITUDE
40.1 N AND LONGITUDE 71.3 W... ABOUT 85 NAUTICAL MILES OR 165 KM
SOUTHWEST OF CAPE COD . MAXIMUM SUSTAINED WINDS ARE ESTIMATED
AT 45 KNOTS... 83 KM/H... AND CENTRAL PRESSURE AT 1002 MB. BERYL 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
JUL 20 9.00 PM 40.1N 71.3W 1002 45 83
JUL 21 9.00 AM 41.9N 68.5W 1002 40 74 BECOMING POST-TROPICAL
JUL 21 9.00 PM 44.1N 63.7W 1004 35 65 POST-TROPICAL
JUL 22 9.00 AM 46.1N 57.2W 1004 35 65 POST-TROPICAL
JUL 22 9.00 PM 47.8N 51.0W 1004 35 65 POST-TROPICAL
JUL 23 9.00 AM 49.3N 46.8W 1004 35 65 POST-TROPICAL
JUL 23 9.00 PM 51.3N 43.5W 1004 35 65 POST-TROPICAL
JUL 24 9.00 AM 54.4N 41.3W 1004 35 65 POST-TROPICAL
JUL 24 9.00 PM 58.3N 40.2W 1004 35 65 POST-TROPICAL

3. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY
RAINFALL WARNINGS ARE IN EFFECT FOR WESTERN NOVA SCOTIA. IT IS
LOOKING LESS LIKELY NOW THAT WIND WARNINGS WILL BE REQUIRED FOR
NOVA SCOTIA. ROUGH SURF SHOULD STILL BE EXPECTED ALONG THE ATLANTIC
FACING COAST OF SOUTHWESTERN NOVA SCOTIA LATE FRIDAY AS BERYL PASSES.

4. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY
GALE WARNINGS ARE MAINTAINED IN SOUTHWESTERN MARITIME WATERS AND
ARE CARRIED FORWARD IN THE EXTENDED MARINE FORECASTS THROUGH CENTRAL
MARITIME AND NEWFOUNDLAND WATERS AROUND THE AVALON PENINSULA.

5. TECHNICAL DISCUSSION

A. ANALYSIS
SATELLITE IMAGERY INDICATED THAT BERYL WEAKENED THURSDAY AFTERNOON
AND DEVOLVED TO A SWIRL OF LOW CLOUDS AROUND A TIGHT CENTRE. THIS
COUPLED WITH LATE AFTERNOON US RECON SUGGESTS THAT THE CENTRAL
PRESSURE REMAINS ABOVE 1000 MB AND THAT MAXIMUM SUSTAINED WINDS HAVE
DROPPED BELOW 50 KTS. VISUAL SATELLITE LOOPS ALSO SUGGESTED THAT
BERYL BEGAN HEADING MORE TOWARD THE ENE BETWEEN 19 AND 20Z. WE STILL
EXPECT BERYL TO TRACK OVER COOLER WATER TONIGHT WHICH WILL FAVOUR
WEAKENING.

B. PROGNOSTIC
WE ARE IN
COMPLETE ACCORD WITH NHC WITH REGARD TO THE STORM SPEED AND MAX WINDS
BUT DIFFER ONLY OVER THE TRACK DIRECTION OVER NOVA SCOTIA. WE ARE
RELUCTANT TO TAKE IT INLAND AND THIS IS BASED ON TWO FACTORS.
FIRSTLY..THE INITIAL MOTION APPEARS MORE ENE THAN NE. SECONDLY..OUR
EXPERIENCE WITH THESE TYPES OF STORMS TELLS US THAT THEY TEND TO
TRACK TO THE RIGHT OF NUMERICAL MODEL TRACKS..WHICH INDICATE THE
CENTER TRACKING FARTHER NORTH. ACCORDINGLY..WE FAVOUR BERYL PASSING
JUST SOUTH OF NOVA SCOTIA'S ATLANTIC COASTLINE.

CANADIAN MODELS CONTINUE STRUGGLING WITH HANDLING THIS SYSTEM AND
THE PARALLEL GLOBAL DOES NOT HAVE A MARKEDLY IMPROVED SOLUTION OVER
THE OPERATIONAL RUN..AN ASSESSMENT BASED ON ITS INITIAL HANDLING
OF THE STORM. ALL MODELS EXCEPT THE 18Z RUN OF THE UKMET TAKE THE
STORM FARTHER NORTH..MANY THROUGH THE BAY OF FUNDY. AS A RESULT
THEY MERGE WITH THE APPROACHING FRONT. WE ARE HARD-PRESSED TO SEE WHY
THE STORM WOULD TURN MORE NORTHWARD AT THIS POINT..SOMETHING REQUIRED
FOR THOSE SOLUTIONS TO WORK..SO WE ARE STICKING WITH OUR PREVIOUS
THINKING. REGARDING THE 18Z UKMET RUN..IT NOW HAS A MORE IDENTIFIABLE
FEATURE THAN THE 12Z RUN AND ITS VERSION OF BERYL REMAINS INTACT
THROUGH MARITIME WATERS AND HAS SIMILAR POSITION FOR 22/00Z AS OUR
CURRENT FORECAST..THAT IS..JUST SOUTH OF HALIFAX.

NO CHANGE IN PREVIOUS THINKING REGARD EXTRATROPICAL TRANSITION..WE
CONTINUE SEEING TRANSITION BEING COMPLETED BY THE TIME IT NEARS NOVA
SCOTIA WITH WEAKENING OF THE WARM CORE. WE ARE NOT EXPECTING ANY
INTERACTION WITH THE APPROACHING FRONTAL SYSTEM SINCE BERYL SHOULD BE
SUFFICIENTLY SHEARED-OUT AHEAD BY THE TIME THE FRONT REACHES THE
MARITIMES.

C. PUBLIC WEATHER
WE HAVE NO REASON TO CHANGE THE CURRENT FORECAST WITH REGARD TO THE
RAIN WARNINGS AND WIND SPEEDS. DETAILED FORECASTS ARE FOUND UNDER
FORECAST HEADERS FPCN11/14/15 CWHX FOR THE MARITIME PROVINCES. MORE
DETAILS FOR NEWFOUNDLAND'S SATURDAY FORECAST WILL BE ISSUED EARLY
FRIDAY MORNING.

D. MARINE WEATHER
IN LIGHT OF THE WEAKER WINDS WITH THE STORM..THE CHC WAVE MODEL
NOW GENERATES ONLY MAX SIG WAVES OF NEART 6 METRES.


PREDICTED WIND RADII (NM)
TIME GALES STORMS HURRICANE
NE SE SW NW NE SE SW NW NE SE SW NW
21/00Z 120 90 60 50 0 0 0 0 0 0 0 0
21/12Z 125 90 60 50 0 0 0 0 0 0 0 0
22/00Z 140 95 65 55 0 0 0 0 0 0 0 0
22/12Z 150 105 70 65 0 0 0 0 0 0 0 0
23/00Z 160 115 70 75 0 0 0 0 0 0 0 0
23/12Z 175 120 70 85 0 0 0 0 0 0 0 0
24/00Z 180 120 70 90 0 0 0 0 0 0 0 0
24/12Z 180 120 70 90 0 0 0 0 0 0 0 0
25/00Z 180 120 70 90 0 0 0 0 0 0 0 0


END BOWYER/FOGARTY

0 Comments:

Post a Comment

<< Home