The Met Office has started to produce weather forecasts from the supercomputer at its Exeter headquarters.
The NEC SX-8 system doubles the computing power of each of the two existing 120-processor NEC SX-6 systems, which have been operational since April 2004.
NEC was awarded the contract to supply Met Office supercomputers in June 2002, following a tender worth £27.5m. The 128-processor NEX SX-8 will be used by the Met Office to improve the accuracy of weather forecasts and climate predictions.
The aim is to predict severe weather as early as possible and estimate the level of impact on affected areas. The NEC supercomputer has a theoretical peak power of 16 billion calculations per second per processor.