We had an enquiry from an astute member of the public asking about the comings and goings of rain. They had noticed that in southerly weather the rain has a tendency to "come in bands (e.g., 20 minutes rain, 20 mins dry, 20 mins rain etc.) rather than as a more constant rain that comes with northerlies". They were wondering why this was. This is a good question and I will try to answer it here.
All the best for researching your school assignment about weather and climate during the school holidays :)
There was a lot of rain in many parts of New Zealand over the last two weeks of May 2010. One of the few places to escape this was the sunny West Coast of South Island - the days are clear and stunning there when the flow is southeasterly. If you had been following the surface weather maps during May you would have noticed a lot of low pressure over the Tasman Sea and northern NZ, and periods of relatively high pressure farther south.
MetService issues severe weather warnings to New Zealanders whenever widespread heavy rain, heavy snow or damaging winds are expected. There are formal criteria that events have to meet or exceed for the forecast to be called a success; the wind criteria are in a previous post, while the rain and snow criteria relate to the total falls required within set periods.
When there is an ash cloud, you have to take extra precautions
WMO TURNED SIXTY
The last week in January 2010 will be remembered by many over the central North Island for the frequent thunderstorms that developed in the afternoon, often lasting well into the evening. Conditions changed little during the week with a slack pressure gradient over the North Island allowing afternoon sea breezes to combine with abundant low level moisture, triggering heavy showers and thunderstorms inland. Many of these storms were slow moving, prompting a number of Severe Thunderstorm Warnings as radar detected torrential rain and hail in some cells.
It must have been an insightful man who decided to build the new meteorological office on the end of the ridge above the Botanical Gardens. If you are lucky you can observe some beautiful meteorology from the roof of the building. The Director at the time, Dr John Gabities, probably had a big say in the matter. Being a meteorologist himself, he would have appreciated the value of that siting. At lunch time on Friday (22 January 2010), I was on the roof and noticed a little drama unfolding on the harbour and took a photo with my cell phone.
Feels like temperature, to the nearest degree, gives an idea of how cool or warm the air feels to us.