WOCN31 CWHX 111145
TROPICAL CYCLONE INFORMATION STATEMENT UPDATED BY THE CANADIAN
HURRICANE CENTRE OF ENVIRONMENT CANADA
AT 8:44 AM ADT WEDNESDAY 11 SEPTEMBER 2013
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TROPICAL CYCLONE INFORMATION STATEMENT FOR:
NEWFOUNDLAND
NOVA SCOTIA
PRINCE EDWARD ISLAND
QUEBEC MARITIME.
FOR TROPICAL STORM GABRIELLE.
THE NEXT STATEMENT WILL BE ISSUED BY 3:00 PM ADT.
TROPICAL STORM GABRIELLE NEAR BERMUDA - DIRECT OR
REMNANT EFFECTS EXPECTED DURING THE PERIOD FRIDAY TO
SATURDAY.
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==DISCUSSION==
1. SUMMARY OF BASIC INFORMATION AT 9.00 AM ADT.
LOCATION: 32.7 NORTH 65.9 WEST ABOUT 120 KILOMETRES WEST-NORTHWEST OF
BERMUDA.
MAXIMUM SUSTAINED WINDS: 83 KM/H.
PRESENT MOVEMENT: NORTHWEST AT 13 KM/H.
MINIMUM CENTRAL PRESSURE: 1008 MB.
2. PUBLIC WEATHER IMPACTS AND WARNINGS SUMMARY.
TROPICAL STORM GABRIELLE REDEVELOPED TUESDAY AFTER SPENDING
A FEW DAYS DRIFTING NORTHWARD AS A WEAK TROPICAL LOW.
THE STORM IS EXPECTED TO REMAIN IN A MODERATE 'WIND SHEAR'
ENVIRONMENT WHICH SHOULD LIMIT OR EVEN SUPPRESS ANY SIGNIFICANT
INTENSIFICATION. SOMETIMES 'SHEARED' STORMS CAN DISSIPATE QUICKLY OR
EVEN INTENSIFY RAPIDLY - THERE IS LOW SCIENTIFIC SKILL IN PREDICTING
INTENSITY CHANGE IN SYSTEMS LIKE THIS. MOST COMPUTER MODELS KEEP IT
GOING AS A MODERATE-INTENSITY TROPICAL STORM FOR THE NEXT TWO DAYS
AND THEN PUSH IT OR ITS REMNANTS TOWARD EASTERN NOVA SCOTIA AND
NEWFOUNDLAND ON FRIDAY. MODELS ARE UNANIMOUS IN THEIR PREDICTION OF
A COLD FRONT MOVING INTO THE MARITIME PROVINCES FRIDAY MORNING. THE
MERGING OF FRONTS WITH TROPICAL MOISTURE OR TROPICAL STORMS, IN
GENERAL, OFTEN RESULTS IN A HEAVY RAINFALL EVENT.
GIVEN THE CURRENT EXPECTATION OF A TRACK JUST EAST OF CAPE BRETON,
HEAVY RAIN COULD BE AN ISSUE OVER NOVA SCOTIA, PRINCE EDWARD ISLAND
AND ÎLES-DE-LA-MADELEINE. NEWFOUNDLAND IS CURRENTLY EXPECTED TO BE ON
THE 'WARMER' AND 'WINDIER' SIDE OF THE TRACK, BUT THIS PREDICTED
PICTURE COULD EASILY SHIFT, SO PLEASE STAY TUNED TO FORECAST UPDATES
TO ESTABLISH A SENSE OF HOW THE FORECAST IS CHANGING.
NEW BRUNSWICK WILL LIKELY RECEIVE HEAVY RAINFALL TODAY AND THURSDAY
BUT IT IS NOT ASSOCIATED WITH MOISTURE FROM GABRIELLE.
A. WIND.
MUCH TOO EARLY TO QUOTE WIND SPEEDS. BY THURSDAY MORNING WE WILL HAVE
AN IDEA OF WHAT TO EXPECT IN TERMS OF WIND. AT THIS POINT IT APPEARS
THAT NEWFOUNDLAND WOULD HAVE A HIGHER CHANCE OF WINDY CONDITIONS.
B. RAINFALL.
MUCH TOO EARLY TO QUOTE RAINFALL AMOUNTS. BY THURSDAY MORNING WE WILL
HAVE AN IDEA OF WHAT TO EXPECT IN TERMS OF AMOUNTS. FRONTS MERGING
WITH TROPICAL MOISTURE/STORMS CAN CERTAINLY LEAD TO FLOODING
RAINFALLS. THIS MUST BE KEPT IN MIND ESPECIALLY FOR AREAS WEST OF THE
TRACK (WHICH AT THIS TIME INCLUDES NOVA SCOTIA, PEI,
ÎLES-DE-LA-MADELEINE AND WESTERN NEWFOUNDLAND).
C. SURGE/WAVES.
TOO EARLY TO ESTIMATE MAGNITUDE. WE WILL HAVE AN IDEA OF WAVE HEIGHTS
LATE WEDNESDAY OR THURSDAY MORNING.
3. MARINE WEATHER IMPACTS AND WARNINGS SUMMARY.
IF THE STORM PERSISTS AND DEVELOPS FURTHER, HIGHEST WAVES AND WINDS
WOULD BE OVER SOUTHEASTERN MARITIME AND MOST NEWFOUNDLAND WATERS.
TOO EARLY TO PREDICT DETAILS THOUGH.
VISIT WEATHER.GC.CA/HURRICANE (ALL IN LOWER CASE) FOR THE LATEST
HURRICANE TRACK INFORMATION MAP.
PLEASE ALSO REFER TO THE PUBLIC AND MARINE FORECASTS AND WARNINGS
ISSUED BY ENVIRONMENT CANADA FOR YOUR AREA.
VISIT WEATHEROFFICE.GC.CA/HURRICANE (ALL IN LOWER CASE) FOR THE
LATEST:
- FORECAST POSITION, CENTRAL PRESSURE TABLE.
- STRENGTH AND PREDICTED WIND RADII TABLE.
- HURRICANE TRACK INFORMATION MAP.
- TECHNICAL DISCUSSION.
PLEASE ALSO REFER TO THE PUBLIC AND MARINE FORECASTS AND WARNINGS
ISSUED BY ENVIRONMENT CANADA FOR YOUR AREA.
END/COUTURIER/BORGEL/HARTT
000
WTNT42 KNHC 111436
TCDAT2
TROPICAL STORM GABRIELLE DISCUSSION NUMBER 13
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072013
1100 AM AST WED SEP 11 2013
GABRIELLE IS BARELY HANGING ON AS A TROPICAL CYCLONE...WITH A SMALL
AREA OF DEEP CONVECTION TO THE EAST OF THE EXPOSED LOW-LEVEL
CENTER. THIS IS LIKELY DUE TO THE 15-20 KT OF SOUTHWESTERLY SHEAR
OVER THE CYCLONE. THE INTITAL INTENSITY HAS BEEN CONSERVATIVELY
LOWERED TO 40 KT FOR THIS ADVISORY. LITTLE CHANGE IN STRENGTH IS
FORECAST DURING THE NEXT 36 HOURS OR SO AS MODERATE SHEAR
CONTINUES...BUT SOME INTENSIFICATION IS SHOWN AT 48 HOURS AS AN
UPPER-LEVEL TROUGH MAY PROVIDE SOME BAROCLINIC SUPPORT FOR
INTENSIFICATION. BY 72 HOURS...GABRIELLE SHOULD BE EXTRATROPICAL
AND BE ABSORBED OR DISSIPATE SHORTLY THEREAFTER. ALTERNATIVELY...IF
DEEP CONVECTION DISSIPATES ENTIRELY...GABRIELLE COULD BECOME A
POST-TROPICAL CYCLONE AT ANY TIME DURING THE FORECAST PERIOD.
THE CYCLONE HAS BEEN MOVING LITTLE OVER THE PAST FEW HOURS...AND IS
NOW DRIFTING WESTWARD AT ABOUT 3 KT. HOWEVER THE MODEL GUIDANCE IS
IN GOOD AGREEMENT ON A SLOW NORTHWESTWARD MOTION DEVELOPING DURING
THE NEXT 12 TO 24 HOURS DUE TO AN UPPER-LEVEL LOW TO THE SOUTHWEST
OF GABRIELLE AND A LOW/MID-LEVEL RIDGE TO THE NORTH AND NORTHEAST.
RECURVATURE IS EXPECTED BY 48 HOURS AS THE CYCLONE ACCELERATES
NORTH-NORTHEASTWARD AHEAD OF AN ADVANCING MID/UPPER-LEVEL TROUGH.
THE TRACK MODEL GUIDANCE HAS TRENDED A LITTLE SLOWER AND TO THE
LEFT THIS CYCLE AND SO HAS THE NHC TRACK WHICH NOW LIES ALONG...BUT
IS A LITTLE FASTER THAN...THE TVCA MULTI-MODEL CONSENSUS.
FORECAST POSITIONS AND MAX WINDS
INIT 11/1500Z 32.5N 65.9W 40 KT 45 MPH
12H 12/0000Z 33.1N 66.5W 40 KT 45 MPH
24H 12/1200Z 33.8N 67.1W 40 KT 45 MPH
36H 13/0000Z 35.5N 67.2W 40 KT 45 MPH
48H 13/1200Z 38.6N 65.9W 45 KT 50 MPH
72H 14/1200Z 48.5N 58.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 15/1200Z...DISSIPATED
$$
FORECASTER BRENNAN
