Friday, August 26, 2011

Hurricane Irene Update Eleven






WOCN31 CWHX 262345

Tropical cyclone information statement updated by the Canadian
Hurricane Centre of Environment Canada at 8:36 PM ADT Friday
26 August 2011.
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Tropical cyclone information statement for:
Atlantic provinces
Southern Quebec.
For hurricane Irene.
The next statement will be issued by 3:00 AM ADT.
Hurricane Irene forecast to make landfall near Long Island new
York Sunday afternoon affecting Eastern Canada late Sunday into
Monday as it becomes post-tropical.
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==discussion==

1. Summary of basic information at 3.00 PM ADT.

Location: 32.2 north 77.1 west.
About 370 kilometers south-southwest of Cape Hatteras, North
Carolina.
Maximum sustained winds: 157 km/h.
Present movement: north at 22 km/h.
Minimum central pressure: 952 MB.

2. Public weather impacts and warnings summary.

Irene will affect eastern Canadian territory starting Sunday and into
early next week. The storm will be undergoing transition to
post-tropical with wind and rainfall spreading far from the storm
center. It is expected that the heaviest rainfall will occur to the
left of the track and highest winds to the right. Computer models
are suggesting this sort of pattern and it is consistent with a storm
that will be transforming to a post-tropical low. Over the weekend
we will be able to be more geographically specific about where these
effects will be felt. Although the official forecast track goes
through Maine, it is equally possible that Irene could track close to
the Bay of Fundy.

A. Wind.

It is still a bit too early to know what the wind speeds are likely
to be when Irene arrives. It is quite likely that sustained tropical
storm force winds (60+ km/h) will spread over much of the maritime
provinces and the eastern portions of Quebec. We will have a better
understanding over the weekend as to how strong the gusts may be.

B. Rainfall.

Heavy rain potentially exceeding 100 millimetres is likely over some
areas left of Irene's track. Additionally, a large band of heavy
rain is anticipated to spread out well ahead and to the right of the
storm centre which would be followed by the strongest winds. It is
worth noting that many parts of Eastern Canada have received above
normal rainfall this summer which could raise the risk of flooding.
This risk will be primarily left of the storm track. Details will
become available over the weekend.

C. Surge/waves.

The potential for high winds pushing storm surge and waves from the
southwest into the Bay of Fundy exists with this storm. It is
important to note that spring tides around midnight Sunday night and
midday Monday in that region could exacerbate surge/wave effects if
the storm were to arrive precisely coincident with those tides.
Note that as of now, there is a timing uncertainty of +/- 12 hours
with this storm. Storm surge and wave threats will also exist
throughout the maritime provinces and eastern portions of Quebec and
the St Lawrence river/gulf region with the arrival of the storm.
Details will become available over the weekend.

3. Marine impacts and warnings summary.

Gale force winds in advance of Irene will likely move into portions
of the southwestern maritime marine district late on Sunday.
These gales would spread to portions of the gulf of st.
Lawrence thereafter. Just right of the storm track, storm force or
even hurricane-force winds are possible. Wave heights up to 5 metres
are possible over southwestern maritime waters into the Bay of Fundy
late Sunday and/or Monday. Large waves could occur over portions of
the Gulf of St. Lawrence and the entrance to the St Lawrence river
when Irene approaches and passes through.

Please also refer to the public and marine forecasts and warnings
issued by Environment Canada for your area.

END/HATT/March

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