Extratropical Storm Danny Pounding New England and the Maritimes

WOCN31 CWHX 300000 CCA
Post tropical Danny information statement issued by the canadian
hurricane centre of Environment Canada at 9.00 PM ADT Saturday
29 August 2009.

The next statement will be issued by 3.00 AM ADT

... Post-tropical storm moving towards the Atlantic coast
Of Nova Scotia ...

1. Current position, strength, central pressure and motion

At 9.00 PM ADT... Hurricane Danny was located near latitude
40.6 N and longitude 68.6 W... About 75 nautical miles or 140 km
East southeast of Nantucket . Maximum sustained winds are
Estimated at 40 knots... 74 km/h... And central pressure at 1002
MB. Danny is moving northeast at 24 knots... 44 km/h.

2. Forecast position, central pressure and strength

Date time lat lon MSLP Max wind
ADT MB kts kmh
Aug 29 9.00 PM 40.6N 68.6W 1002 40 74 post-tropical
Aug 30 3.00 AM 42.2N 66.3W 1002 40 74 post-tropical
Aug 30 9.00 AM 43.6N 63.8W 1002 40 74 post-tropical
Aug 30 3.00 PM 45.4N 59.6W 1002 40 74 post-tropical
Aug 30 9.00 PM 46.7N 55.7W 1002 40 74 post-tropical
Aug 31 3.00 AM 48.5N 50.8W 1003 40 74 post-tropical
Aug 31 9.00 AM 49.4N 45.6W 1003 40 74 post-tropical

3. Public weather impacts and warnings summary
Rainfall warnings are in effect for pei and Southern New Brunswick
for amounts of 50 mm with local amounts to 80. For northern new
Brunswick.. Rainfall amounts of 20 to 30 mm can be expected.
Rainfall warnings are continued for Nova Scotia for amounts of
50 to 70 mm with local amounts up to 100 mm.
Rainfall warnings are in effect for the Southwestern Newfoundland
regions for amounts near 50 mm.

Rain at times heavy will reduce visibilities..Present driving
Hazards for motorists..And overflow catch basins and ditches.

Wind warnings are not anticipated. However warnings for Les Suetes
over the Cape Breton Highlands of 110 km/h and Wreckhouse winds near
Port aux Basques of 100 km/h are predicted.

Heavy swell associated with the storm may cause significant surf
And rip tides along the Atlantic coast of Nova Scotia. Caution
Should be observed by people near the coast.

4. Marine weather impacts and warnings summary
Gale warnings are continued for all maritime marine waters
Except the Laurentian fan. Gale warnings are in effect for all
The Newfoundland waters except the Grand Banks.

5. Technical discussion for meteorologists

A. Analysis
Post-tropical storm Danny is located over warm water and
Lots of convection is associated with it causing heavy rain
From numerous thundershowers in the northeast and southeast
quadrants. We locate Danny near the cluster of lightning strokes
indicates by the lighnting detectors. Radar echoes are strong
Which indicates heavy rain. Some land stations are reporting
Heavy rainfall amounts as well.


B. Prognostic
Canadian hurricane centre forecasters will maintain Danny as
A post-tropical entity until it moves out of the response
Zone on Monday. Dynamic support from the upper flow is driving
The system which at this time continues to feed from the warm
Sea surface.

Canadian hurricane centre forecasters will maintain Danny as
A post-tropical entity until it moves out of the response
Zone on Monday. Dynamic support from the upper flow is driving
The system which at this time continues to feed from the warm
Sea surface.

Post-tropical storm Danny will move over colder water
Tonight as it passes near the Atlantic coast of Nova Scotia
Then track near Cape Breton Sunday afternoon.
It will pass over Southeastern Newfoundland late Sunday then
Move away over the Atlantic Sunday night and on Monday.
Canadian and us models indicate upper support over the tropical
airmass associated with Danny which moves ahead of low
Pressure system coming from the Great Lakes and the low pressure
centre currently near Cape Cod. Past experience indicates that
post-tropical storm Danny has the potential to remain as an entity
during the forecast period under those conditions.

Note that Danny will track further south than indicated in previous
messages based in keeping Danny separate from the vorticity
Support centre of the Cape Cod low.

C. Public weather
The tropical nature of this system will produce rain at
Times heavy giving significant rainfall in a short period
Of time. Rainfall amounts of 50 mm and up to 100 mm are
Likely to fall over Nova Scotia..Pei and
Southern New Brunswick. Rainfall of 50 mm plus are predicted
For Southwestern Newfoundland.

D. Marine weather
Storm surge should not be an issue due to neap tides this
Weekend and insufficient winds. Waves should be less
Than 6 metres offshore of Nova Scotia and less than 5 metres
Into Newfoundland waters.

Predicted wind radii (NM)
Time gales storms hurricane
Ne se sw nw ne se sw nw ne se sw nw
30/00Z 260 180 120 10 0 0 0 0 0 0 0 0
30/06Z 260 220 120 10 0 0 0 0 0 0 0 0
30/12Z 260 220 120 10 0 0 0 0 0 0 0 0
30/18Z 220 160 120 10 0 0 0 0 0 0 0 0
31/00Z 220 150 120 10 0 0 0 0 0 0 0 0
31/06Z 200 150 100 10 0 0 0 0 0 0 0 0
31/12Z 180 150 60 10 0 0 0 0 0 0 0 0

End campbell