By Steve Keating

VANCOUVER, British Columbia (Reuters) - The Vancouver Winter Games countdown shifts from months to days on Tuesday just as a "Pineapple Express" weather front has slammed into the Pacific Northwest dampening Olympic fever.

Weather fronts that bring warm, wet conditions from the Pacific ocean during the winter are often described as Pineapple Expresses by local forecasters.

With just one month to go until the February 12th opening ceremonies, the spring like conditions, which are expected to remain in the area through the weekend, could pose a threat to several Olympic venues.

Cypress Mountain, host for freestyle skiing and snowboard competitions, was closed on Monday due to heavy rain and snow making halted as temperatures in Vancouver climbed to a balmy 11 degrees Celsius (52 Fahrenheit).

Work crews at the popular resort, located just 12 kilometers outside of Vancouver, have been busy stockpiling snow at higher elevations and said snow making would resume as soon as temperatures dropped.

Whistler, about 125 km from Vancouver and venue for all alpine skiing, cross-country and sliding events, was also facing a soggy week with rain and temperatures well above freezing set to remain in place until Sunday.

"We're putting everything we've learned and planned for regarding weather contingency into practice at the outdoor venues in order to be ready for the Games," said Tim Gayda, VANOC's vice president of sport in a statement.

Crews have been preparing since the first snowfalls hit Whistler and Cypress mountains, according to Gayda.

"We're confident these courses will be in world-class shape when the athletes start to arrive to practice in our venues in the first week of February," he said.

Depending on weather conditions, VANOC said it may need to further restrict use or close competition venues to the public to protect and preserve the competition and training sites.

BIG BUCKS TO PREDICT THE WEATHER

While Olympic organizers cannot change the weather they have invested $13.5 million state-of-the-art tracking equipment and scientific expertise to monitor conditions.

"Weather is involved in just about every decision we make as Games organizers, from when to make and stockpile snow to transportation planning, and we're constantly monitoring it," explained Chris Doyle, an Environment Canada meteorologist and VANOC's manager of weather services.

"All of this provides an invaluable real-time snapshot of what's happening at the outdoor venues and what Mother Nature has in store in the near future so that we can plan and take action."

With the city under a heavy rainfall warning there is little buzz that Vancouver is about to host a Winter Games.

The picture postcard images of the snow capped Rocky Mountains that are suppose to provide the dramatic backdrop have disappeared into the thick fog and clouds while more people can been seen out jogging city streets in shorts than strolling in heavy winter coats.

There are, however, undeniable signs that the Olympics are on the way.

Security fencing has sprung up around downtown venues while local officials have cautioned residents to prepare for the implementation of driving restrictions what will be part of the Games transportation plan.