Floridians are getting ready for Isaac, and this currency trade will have you prepared too.

Republican party poobahs have their eyes trained on Tropical Storm Isaac as it crawls toward convention headquarters in Tampa - and so does Rebecca Patterson, chief investment officer at Bessemer Trust.

Patterson isn't worrying about a confetti drop, though. She told CNBC's Melissa Leethat when storms like Isaac hit Florida's west coast, that can cause currencies of oil-producing countries to rise, so she has a trading plan to ride out the storm.

"If you have a big hit to refineries on the coast," she says, countries that export oil gain from rising prices and diminished supply. And Norway, she says, "is benefiting through trade flows and growth."

So Patterson wants to buy the Norwegian krone against the dollar. The krone has been strengthening lately, she says, but she still thinks it has room to rise further. In addition to a potential lift from Isaac, Norway's central bank has a meeting coming up. The central bank has been cutting interest rates recently, but Patterson says, "I think they are turning a bit more hawkish" in the face of rising housing prices.

She wants to enter the trade at around 5.8330, setting a target of 5.6500.

Amelia Bourdeau, director of foreign exchange at Westpac Institutional Bank, likes the trade, and agrees that an interest rate change is unlikely. She is also eyeing the Canadian dollar against the Australian dollar, since Canada is also an oil exporter and Bank of Canada officials have been sounding hawkish.

You can watch the discussion on the video clip.

Learn more: The essential vocabulary for currency trading is on Key Terms Dictionary. Top currency strategies are broken down for you in Currency Class.

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