A Royal Navy officer from West Devon is giving Michael Fish a run for his money by forecasting the weather on board the nation's strike carrier HMS Ark Royal as she takes part in exercises off the east coast of America.

Lieutenant Comm-ander Andy Jacob, head of the meteorological sub-department, works with his team to check conditions for aircraft flying on and off the Portsmouth-based carrier.

A highly-technical job, the role is key to 'Exercise Auriga 2010,' which is mainly an aviation and submarine exercise that involves forces from America, Canada and France.

Lt Cdr Jacob, from Okehampton, said: 'It is the type of job that you aspire to as an RN forecaster because you can prove your worth in one of the most challenging forecasting environments — a strike carrier on an aviation exercise.'

For the forecasters there is a significant difference between checking conditions for helicopters, which fly mainly at low altitude and subsurface missions, and jets, which fly a variety of missions from high-level reconn-aissance to low-level bombing sorties.

With the arrival of the jets the operational tempo for the Met Office increases dramatically as the staff must look at conditions from sea-level up to 40,000 feet and vary the details from large scale planning charts to highly focussed cross sections of the weather around both the ship and a selected target.

As well as weather patterns the Met Office look at pressure readings as just one megabyte of pressure can mean a 30ft difference in height for pilots, making the distinction between a safe or unsafe landing.

Lt Cdr Jacob added: 'The watch must work together seamlessly to ensure that all products and briefs are delivered in a timely, accurate and above all, safe manner, ensuring the safety of our crew in the air and that their mission can be achieved.'

Ark Royal is heading an international task group for Exercise Auriga 2010 — a string of exercises between May and August. Joining her in the task group are Type 42 destroyer HMS Liverpool, Devonport-based Type 23 frigate HMS Sutherland, Royal Fleet Auxiliary vessel Fort George, French submarine FS Perle and US destroyer USS Barry.

They are supported by an amphibious force comprising Devonport-based HMS Ocean and RFA Largs Bay, together with Royal Marines from 3 Commando Brigade and RN helicopters.