Tropical Storm Dolphin, that is -- a western Pacific tempest that peaked as a Category 5 typhoon Saturday on the Saffir-Simpson wind-speed scale and is now fading in power, heading toward the northern part of the ocean.

While that may seem like a long way from the continental U.S., such storms can provide a dollop of energy that help amplify whatever eastbound weather system happens to be in the area, said Dan Petersen, a meteorologist at the Weather Prediction Center in College Park, Maryland.

“We will see that sequence happen a couple of times a year,” he said.

Last October, Hurricane Ana in the eastern Pacific lent its strength to another system bringing heavy rains and high winds to western Canada and the U.S. Northwest.

That scenario isn’t likely this time.

The heat Dolphin drags into the mid-latitudes will help develop a high-pressure ridge over the North Pacific, said Todd Crawford, chief meteorologist at WSI in Andover, Massachusetts.

“When ridges build in the North Pacific, they tap cooler air masses from the Arctic and send them toward the U.S.,” he said.

Midwest Chill

Typhoon Noul struck the Philippines earlier this month and then swept into the North Pacific after grazing the coast of Japan. This week, temperatures in Minneapolis-St. Paul peaked at 48 degrees Fahrenheit (9 Celsius)), 22 lower than normal.

Frost advisories and freeze warnings stretched from Minnesota to Michigan on Tuesday, according to the National Weather Service. The low in Chicago, outside of the warning area, was forecast to be 42 overnight.

Computer models “missed the big cool-down this week in the Midwest,” said Matt Rogers, president of the Commodity Weather Group LLC in Bethesda, Maryland. “My main concern is that Dolphin could surprise the models again for cooler impacts behind the next cold from mid-to-late next week.”

Rogers said neither Noul nor Dolphin was strong enough to throw the whole U.S. weather pattern out of whack. “But they put the brakes on this warmer weather for a handful of days.”

El Nino

Crawford said all this is a reminder of the importance of an even larger weather disrupter: El Nino.

The phenomenon, which has begun, occurs when the sea- surface temperatures of the equatorial Pacific warm above normal levels. The ocean heat provides a fertile breeding ground for typhoons west of the International Dateline and hurricanes to the east.

More storms mean more chances for the remnants of tropical systems to end up in the northern Pacific.

“One of the main reasons El Nino summers are cooler in the U.S. is due to enhanced typhoon activity in these years,” Crawford said.