Jeff Callaghan

In the past we have discussed the desirability of issuing advices for
potential deep extra-tropical cyclones when all the models are in unison.
This has been suggested to stop yachties embarking on say, a
Auckland  Sydney voyage when it probably is prudent to wait a few days.
Most  models I have seen so far appear to suggest possible bomb development
in the 24 hours to 12Z Thursday west of Auckland.

Lets see what happens

jeff
 

Date: Tue, 18 Jun 2002 10:03:57 +1000
From: Jeff Callaghan <j.callaghan@bom.gov.au>
To: tropical-storms@tstorms.org
Subject: [Tropical-storms] Sub-tropical or intense extra-tropical development

Most models are now developing an intense cyclone west of Auckland by 12Z Thursday next. The EC forecast has 850hPa
50 to 60 knot winds (2.5 degrees  resolution)  around a small tight centre while the UK is similar with 850 winds to 75 knots.
The centre is forecast to be within the deep thermal  ridge  with a thermal trough and PV to the west and northwest. If the
forecasts are correct what will be the classification,  Sub or extra-tropical or do mariners really care?
Jeff

Alasdair Hainsworth

Hi Jeff,  (I'm sitting in Dave Thomas's job at present)

Looks like a very interesting situation and nice to see the progs so well in
line for such a sig development.

Many yachties I know would be MOST interested to know of any such
development if they were in or planning to move in to the area. Some advice
would be a good idea I feel.

Cheers,

Alasdair.
_____________________________
Alasdair Hainsworth
a/SRCO

Chip Guard (NOAA)
iJeff,

I would think you have to look at the satellite signature to make that
assessment--depth of convection and its relationship to the center.  It may
well be that the system transitions from one classification to the other
through its evolution.  Hope all is going well.  Take care and keep us posted
if you get any good verification data.

Chip

Jeff Callaghan
Date: Thu, 20 Jun 2002 13:46:04 +1000
From: Jeff Callaghan <j.callaghan@BoM.GOV.AU>
To: synoptic_discussion@BoM.GOV.AU
Subject: [synoptic_discussion] potential bomb west of Auckland

The models appear to have been spot on
Cape Reinga AWS (N tip of NZ) has dropped 7.3 hPa  over past 3 hours and
wind is now 050/42knots (was 070/25 knots 3 hours ago)
jeff

Ken Batt
Date: Fri, 21 Jun 2002 16:13:06 +1000
Hi Jeff
You are dead right yet again
Check out the article that appears on the following Kiwi web-site
Regards
kenn

http://cupviews.com/

Text here:

Weather "bomb" hits Auckland
        A severe storm hit Auckland and the Hauraki Gulf yesterday afternoon and overnight unleashing winds up to160kph (100mph) with torrential rain.

        Metservice spokesperson Bob McDavitt explained that a "weather bomb" was created when a sudden
        drop in pressure left a vaccum which became a deep low. It was called a bomb because it developed
        so suddenly.

        Strong variable winds hit Auckland, Northland and the Coromandel peninsula followed by torrential
        rain.
            
        The Coromandel town of Thames was hit worst as high tides backed by strong winds flooded
        residents homes. Power was cut to thousands of homes. The water supply has been disrupted and
        about 50 homes were evacuated.

        In Auckland the winds were variable ranging from 160kph (100mph) at Tiritiri Matangi Island in the
        Hauraki Gulf near the America's Cup course. The seas rose to 4m swells.

        At the top of the Sky Tower in central Auckland the wind speed hit 123kph (77mph). But the storm was
        variable with winds reaching only about 25kmph (15mph) in some pockets.

        Emergency services were kept busy with houses loosing their roofs, trees falling over and flooding.

        This morning the storm has moved south and the wind and rain in Auckland have subsided, although the Met Service is warning of a strong southerly
        sting in the tail of the storm around midday today.

Jeff Callaghan wrote:

> In the past we have discussed the desirability of issuing advices for
> potential deep extra-tropical cyclones when all the models are in unison.
> This has been suggested to stop yachties embarking on say, a
> Auckland  Sydney voyage when it probably is prudent to wait a few days.
> Most  models I have seen so far appear to suggest possible bomb development
> in the 24 hours to 12Z Thursday west of Auckland.
>
> Lets see what happens
>
> jeff