The lingering effects of a recent La Nina event “mean no summer for the Great Lakes” this year, according to AccuWeather.com forecasters, who also expect drought conditions to expand out of the southern Plains and flooding in the Midwest this summer.

“The weather pattern that produced a wild winter for the Northeast and parts of the Midwest, then extreme flooding and devastating killer tornadoes this spring, is changing to one that may not be as volatile this summer,” AccuWeather.com said Tuesday. “However, given the national economic impacts of the tornadoes and floods this spring, all it would take is one hit by a major hurricane to stress the economy even more.”

The end of the La Nina — a cooling of ocean surface temperatures off the western coast of South America — could deliver a “year without a summer” to the nation’s midsection, with “repeated intrusions of cool air from Canada, along with showers and thunderstorms” keeping temperatures below normal in many areas, the forecasters said. “Temperatures topping 90 degrees may be rare,” they said.

WSI Corp. recently said it too expects temperatures to average cooler than normal in the Great Lakes and Ohio Valley areas over the next three months (see Daily GPI, May 24). The rest of the country will have a warmer-than-normal summer, according to WSI forecasters. And MDA EarthSat Weather has said a faster-than-expected transition to El Nino/Southern Oscillation-neutral conditions this spring suggests that the summer “will be approximately 14.5% cooler than last summer” (see Daily GPI, May 18).

Cloudy and damp conditions that have plagued the Northeast this spring will give way to fairly typical summer conditions, including temperatures close to long-term averages, the AccuWeather.com forecasters said. There is always the threat of a tropical storm sneaking up the coast from the south as hurricane season ramps up beginning in June, according to AccuWeather.com hurricane forecaster Paul Pastelok.

The Southeast will remain hot and dry into the early summer, but increasing numbers of thunderstorms and the likelihood for tropical systems could bring with them the threat of flooding across the region. The chance for tropical storm development in June is possible along the entire Southeast coast, Pastelok said.

It may also be a more active tropical season in the eastern Pacific, especially in late summer, according to the forecasters, who said weakening Pacific tropical systems could send tropical moisture into the Southwest and trigger thunderstorm activity there.

Although the La Nina event is weakening, Pacific Ocean waters will still be colder than normal, giving the extreme West Coast, including beach areas, a persistent chill.

“The West Coast will have near- or below-normal temperatures as the cold [ocean temperatures] hangs on through the summer, while the interior West heats up,” Pastelok said.

AccuWeather.com forecasters, who have also predicted a higher-than-normal number of tropical systems with more direct impacts on the United States than last year, have said any effects of hurricanes on the energy industry — including spiking prices for gasoline — aren’t likely to last long.

The consensus forecast is for an active hurricane season this year, with WSI (see Daily GPI, May 25), the National Oceanic and Atmospheric Association (see Daily GPI, May 20) and MDA EarthSat all calling for above-average numbers of named storms and hurricanes.

The 2011 Atlantic hurricane season — which officially begins Wednesday — isn’t likely to produce as many hurricanes as 2010, but is likely to send at least one tropical storm into the North American coastline, according to most forecasts.

AccuWeather.com forecasters have also predicted a higher-than-normal number of tropical systems with more direct impacts on the United States than last year, but have said any effects of hurricanes on the energy industry aren’t likely to last long (see Daily GPI, April 26; April 1).

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