Is Eastern Canada going to get a hurricane?
http://www.solar.ifa.hawaii.edu/Tropical/

How often does this happen?
Tim.

It won't be a hurricane, they only exist in tropical regions. They are known
as extratropical cyclones (with maybe hurricane force winds?) but the cold
water of the Grand Banks will likely ensure that it'll have long run out of
puff.

More likely it'll get caught up in the jetstream and get absorbed in some
depression or another in the Atlantic...

Les

--
Les Crossan,
Wallsend, Tyne & Wear 55N 01-30W,
Home of the Wallsend Stormcam - http://www.uksevereweather.org.uk

"tim harrison" wrote in message
...
Is Eastern Canada going to get a hurricane?
http://www.solar.ifa.hawaii.edu/Tropical/

How often does this happen?
Tim.




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On Fri, 26 Sep 2003 11:48:38 GMT, "Les Crossan"
wrote:

It won't be a hurricane, they only exist in tropical regions. They are known
as extratropical cyclones (with maybe hurricane force winds?) but the cold
water of the Grand Banks will likely ensure that it'll have long run out of
puff.

More likely it'll get caught up in the jetstream and get absorbed in some
depression or another in the Atlantic...

Looks like being declared ex-tropical *and* ex-hurricane before it
hits land. Still a bit breezy though! From NHC's Juan Discussion no. 4
this morning http://www.wunderground.com/tropical/at200315.disc.html :

"48hr VT 28/0600z 38.4n 63.8w 60 kt
72hr VT 29/0600z 46.0n 63.0w 55 kt...extratropical inland
96hr VT 30/0600z 50.5n 60.5w 50 kt...extratropical inland
120hr VT 01/0600z...absorbed by larger extratropical low"

--
Dave

In article , Les Crossan
writes
It won't be a hurricane, they only exist in tropical regions. They are known
as extratropical cyclones (with maybe hurricane force winds?) but the cold
water of the Grand Banks will likely ensure that it'll have long run out of
puff.

More likely it'll get caught up in the jetstream and get absorbed in some
depression or another in the Atlantic...

Warm-core tropical cyclones do make it all the way to the waters off the
east of Canada from time to time. "Fabian", for example, was still a
genuine hurricane when it crossed 45 deg N earlier this month. North
Atlantic hurricanes are often found outside of the tropics. Indeed, it's
not unusual for them to form outside of the tropics.

Norman
--
Norman Lynagh Weather Consultancy
Chalfont St. Giles
Buckinghamshire

I stand corrected Norman. I prefer the term "tropical cyclone" anyway.

Les

--
Les Crossan,
Wallsend, Tyne & Wear 55N 01-30W,
Home of the Wallsend Stormcam - http://www.uksevereweather.org.uk

"Norman Lynagh" wrote in
message ...
In article , Les Crossan
writes
It won't be a hurricane,


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Norman Lynagh wrote in message ...
In article , Les Crossan
writes

It won't be a hurricane, they only exist in tropical regions. They are known
as extratropical cyclones (with maybe hurricane force winds?)

Warm-core tropical cyclones do make it all the way to the waters off the
east of Canada from time to time. "Fabian", for example, was still a
genuine hurricane when it crossed 45 deg N earlier this month. North
Atlantic hurricanes are often found outside of the tropics. Indeed, it's
not unusual for them to form outside of the tropics.

Wasn't the term adopted for all winds of a certain power (that equated
to speeds over 75 mph) according to Beaufort? Darwinists here will
appreciate Linaean priority.

I always thought hurricane-force winds could come from extratropical
cyclones or mid-latitude depressions too?? Has the thinking changed on this
recently.... please correct me if I'm wrong..

the usw glossary has this: Hurricane Force: This term (in UK Met Office use)
is only used in shipping bulletins and associated Gale/Storm warnings. It is
strictly defined as a mean (10 minute) wind of 64 knots or more. (Gusts not
defined) (See also comments at Severe Gale).

The USW FAQ has a distinction in 2B.1 too between tropical cyclones and deep
depressions. I'm confused now. HELP!

(:

Les

--
Les Crossan,
Wallsend, Tyne & Wear 55N 01-30W,
Home of the Wallsend Stormcam - http://www.uksevereweather.org.uk


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On Fri, 26 Sep 2003 19:26:50 GMT, Les Crossan in
wrote:

I always thought hurricane-force winds could come from extratropical
cyclones or mid-latitude depressions too?? Has the thinking changed on this
recently.... please correct me if I'm wrong..

No - you are quite correct, Les. Luckily it is quite rare, but I do get
worried when I hear of F12 (hurricane force) being forecast for Rockall,
Malin and Hebrides - all close to here. Wind is the one element that gets
me edgy.

snip


The USW FAQ has a distinction in 2B.1 too between tropical cyclones and deep
depressions. I'm confused now. HELP!

I haven't checked in the FAQ but would suggest a "deep depression" is a
deep "Low" - "Deep Extratropical Cyclone" - different names for the same
feature in mid latitudes.

The tropical cyclone (hurricane) may well become a deep depression after
moving into higher latitudes, but may retain its hurricane status well
beyond where conditions are ideal for its formation. As Norman mentioned,
"Fabian" was still a hurricane north of 45 degrees even though it could not
have formed there.

--
Mike posted to uk.sci.weather 26/09/2003 19:57:49 UTC
Coleraine
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In article , Les
Crossan writes
I always thought hurricane-force winds could come from extratropical
cyclones or mid-latitude depressions too?? Has the thinking changed on this
recently.... please correct me if I'm wrong..

the usw glossary has this: Hurricane Force: This term (in UK Met Office use)
is only used in shipping bulletins and associated Gale/Storm warnings. It is
strictly defined as a mean (10 minute) wind of 64 knots or more. (Gusts not
defined) (See also comments at Severe Gale).

The USW FAQ has a distinction in 2B.1 too between tropical cyclones and deep
depressions. I'm confused now. HELP!

Hurricane force winds (Beaufort Force 12) can be produced by tropical
cyclones or mid-latitude depressions or even by katabatic effects in the
Antarctic. Hurricane force refers purely to the strength of the wind and
is not dependent on the nature of the weather system producing the wind.

Tropical cyclones (including regional names such as hurricanes and
typhoons) are warm-cored low pressure systems which are fuelled by large
quantities of water vapour evaporated from the sea surface. They develop
and persist in regions of low vertical wind shear. Increasing vertical
shear generally results in weakening.

Mid-latitude lows form in highly baroclinic areas. In maturity they are
cold-cored. During the developmental phase there is almost always
considerable vertical wind shear above the developing surface low.

When a tropical cyclone is said to be in transition to an extratropical
low this means that it is losing its warm core and the strong convection
immediately surrounding it. Typically, this happens when the centre
moves over colder water. A major hurricane/typhoon can take a
considerable time to completely lose its tropical characteristics.

Hope this helps!

Norman.
--
Norman Lynagh Weather Consultancy
Chalfont St. Giles
Buckinghamshire

In article , Les
Crossan writes
I always thought hurricane-force winds could come from extratropical
cyclones or mid-latitude depressions too?? Has the thinking changed
on this
recently.... please correct me if I'm wrong..

.... Norman covered this: the only times (few indeed) that I put
'Hurricane Force 12' in either the High Seas Forecast or the Shipping
Forecast, IIRC was solely due to baroclinic/rapidly deepening
disturbances forced by imbalance aloft (jetstreaks etc.), or perhaps
down the Denmark Strait area - if tropical elements were involved, they
were often diffuse and simply added to the baroclinicity (greater
thermal contrast .. enhanced jet stream vigour) and led to more
vigorous development. (We did though, before the responsibilities
between France and UK changed a few years back, put F12 in for *genuine*
tropical storms in the North Atlantic Bulletin, as its boundaries were
further south).


The USW FAQ has a distinction in 2B.1 too between tropical cyclones
and deep
depressions. I'm confused now. HELP!

.... This Q/A was written in the context of the October 1987 storm. I
need to add a short phrase which makes clear that once formed,
Hurricanes/Tropical Cyclones can move out of the defined tropics, and
indeed, there are a class of 'Sub-tropical Storms' which exhibit
characteristics of both Tropical Storms and mid-latitude disturbances.
For more see:.........

http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqHED.html

Martin.