Severe Thunderstorm Warning Service

From Wednesday 01 July 2009, MetService has been providing a Severe Thunderstorm Warning Service. This blog entry explains why we are 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.

Red sky at night...

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?”

An eggbeater southerly

Written by Bob McDavitt, Meteorologist

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.

Variable 10 knots

Several years ago, while on a trip to the UK, I noticed something of meteorological interest that was not in the sky. I was outside Westminster Abbey, one of the worlds greatest landmarks, and the burial place of many famous people. Sir Isaac Newton, a man who had a profound influence on all branches of science (including atmospheric science) being one such esteemed individual. As I walked around the Abbey, I noticed a plaque that nicely describes what mariners might call "variable 10 knots"...

Canterbury Snow, 10 May 2009

With clear skies over most of Canterbury on Monday May 11th 2009, there was  a good look at the fresh snow that fell the previous day, Sunday (10th May).  Here's the view late Monday morning  (around 10:30am) from NASA's Earth Observing System Terra Satellite,

2009-05-10-2225Fresh snow on the Alps and Canterbury foothills - as @ Monday 11 May 2009. (Image courtesy of MODIS Rapid Response Project at NASA/GSFC.)