I find it fascinating that there is so much pattern in our weather, and I find it frustrating when, sometimes, chaotically, one of them behaves slightly differently, as in this case producing wayward winds for Auckland.
If you were in New Zealand in the mid '70s you may remember a particularly strong wind-storm that devastated many parts of the eastern South Island. It struck on 1 August 1975, doing a huge amount of damage to pine trees in the Eyrewell and Balmoral forests in particular.
To give you an idea of the power of this storm, some of the peak recorded winds and gusts were:
From Wednesday 01 July 2009, MetService will provide a Severe Thunderstorm Warning Service. This blog entry explains why we're now able to do this, why warnings of thunderstorms are different from warnings of broad-scale weather events, which parts of New Zealand they will apply for, how you can receive them and what actions you can take to protect yourself.
MetService weather forecasters naturally spend a lot of time looking at satellite imagery and every so often are treated to some fascinating cloud patterns in the airflows around New Zealand. One pattern I've always liked seeing is the Kármán Vortex street, most frequently observed near our shores to the west of the North Island, generated by Mt Taranaki in a south to southeast flow.
MetService forecaster James Lunny (second from right) manning our trade display at last week’s National Fieldays.
MetService has been attending Fieldays for the past 15 years, and this year our display proved as popular as ever, attracting several thousand people.
A call for a new name for a variety of cloud.
In my previous blog post I wrote about how much the winds high in the sky differ from the winds that we are accustomed to nearer sea level. The winds aloft are usually much stronger than those near the earth's surface, this difference being especially true in New Zealand. Another difference (which I mentioned in the last blog post) is that the wind we experience every day is more variable, suggesting that the wind aloft is more unchanging.
Red sky at night, Shepherd’s delight. Red sky in the morning, Sailor’s warning. I'm not going to argue about shepherds and sailors; that’s not important here. The questions are: “Is it a useful saying? Does is work? If it works, why?” And, “Why is the sky blue?”
Today’s weather map shows how this cold southerly is being produced by a combination of a HIGH or anticyclone in the Tasman Sea, and a LOW or depression between Canterbury and the Chatham Islands. For want of a better phrase, we could call this an eggbeater southerly.