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A power shortage in Japan's biggest city, Tokyo, will be eased by a warmingtrend starting Friday, local time.The shortage has been triggered by the loss of power generation at stations innortheastern Japan following the great 9.0-magnitude earthquake and resultingtsunami. It was then made worse by a growing crisis at one of the generatingstations, the stricken Fukushima Daiichi nuclear power station, located about150 miles north-northeast of Tokyo.

In greater Tokyo, the government had warned of unpredictable blackouts onThursday night owing to electrical heating demand amid unusual cold.

Temperatures at the time were diving into the upper 20s to the middle 30s, orabout 10 degrees below normal.

The flow of cold across the Tokyo area will shut off Friday as high pressuresettles nearby, then a warming flow will hike temperatures well above normalSaturday through Sunday. This warm-up will significantly lower the heatingdemand on the electric grid.

There being a shortage of power, brought about by the off-lining of powerplants in the quake areas, utility managers for area power providers initiated,as of Monday, a load shedding regimen requiring rotating blackouts.

TEPCO, a key supplier to the Tokyo area, had stated that about 10 millionhouseholds would be subject to the power rationing on Thursday. TEPCO is theoperator of the stricken Fukushima Daiichi nuclear power plant.

Along with direct impact to households, fallout from the rationing regimenextended to the electrified railways, which are a mainstay for transportationthroughout Japan. At least two operators in greater Tokyo reportedly cut thenumber of trains effective 5 p.m., local time.

Reports on Thursday said that power saving measures are expected to lastthrough April.

Story by Jim Andrews, AccuWeather.com Meteorologist