Hot Summer for Rockies, Plains; Great Lakes, Mid-Atlantic Stormy

May 10, 2012; 2:41 AM ET
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It will be a hot summer for the Rockies and Plains in 2012, while active severe weather targets portions of the Great Lakes to the mid-Atlantic. Meanwhile, the Northeast will have a lack of prolonged heat.

This summer will bring beneficial rain for drought-stricken and wildfire-ravaged areas of Florida in the form of showers and thunderstorms and perhaps tropical system impact.

Unlike the past two years, heavy monsoon downpours will target portions of the Southwest deserts. Monsoon downpours develop as moisture streams in from the eastern Pacific, typically setting in across the Southwest by the middle of July.

More detailed highlights of the Summer 2012 forecast can be found below.

Pattern for the Summer of 2012
The La Niña pattern, or cooler-than-normal water temperatures over the central and eastern equatorial Pacific, that has been in place for the past two years has ended.

This summer, the pattern is transitioning into an El Niño pattern, which is characterized by above-normal water temperatures in the central and eastern equatorial Pacific.

Heat Centered Over Rockies, Western and Central Plains
It will be a hot summer from the central and western Plains into the Rockies as a large dome of high pressure sets up residence across the region.

Temperature departures will be as much as four degrees above normal across western Nebraska, western Kansas and eastern Colorado for the entire summer.

"Western Nebraska, western Kansas and eastern Colorado have the potential to see temperatures in the upper 90s and more than 100 degrees for a long string of days," Pastelok, leader of the long-range forecasting team, said.

During June, the core of heat will be anchored over the central Plains with well above-normal temperatures stretching from West Texas to western Iowa. The large area of high pressure will shift farther west as the summer progresses, drawing the hottest air farther north and west. Wyoming and Colorado could be the hottest during the peak of summer in July and into August. Denver, Colo., is expected to have a hot summer.

Due to the high heat and dry conditions expected, the fire danger could be higher than normal for the Front Range of the Rockies from Colorado to Montana. In addition, the threat for isolated dry thunderstorms with plenty of lightning exists in the higher elevations underneath the dome of heat. The lightning could spark wildfires.

In this aerial photograph, smoke rises from the Lower North Fork Wildfire, burning near the foothills community of Conifer, Colo., southwest of Denver on Tuesday, March 27, 2012. (AP Photo/David Zalubowski)

As the interior Northwest dries out, it will become quite warm for the middle to latter part of the summer. Cities such as Spokane, Wash., Pendleton, Ore., Boise, Idaho, and Salt Lake City, Utah, are among the cities that will turn out rather warm.

Hot spells will also reach eastward into the Midwest at times during the summer. Chicago will have some heat surges, but rounds of wet weather and even severe weather will keep heat waves from lasting very long.

Active Severe Weather for Great Lakes to the Mid-Atlantic
An active severe weather season will extend into the summer. Storms will ride over the northeastern edge of heat with increased chances for severe weather from the Great Lakes to portions of the mid-Atlantic. This type of severe weather pattern is often referred to as "ring of fire" storms.

Michigan and Minnesota to portions of Kentucky, Virginia, Maryland and New Jersey will lie in the battlegrounds of severe storms at times. Cincinnati, Ohio, Lexington, Ky., Washington, D.C., and Philadelphia are among the cities at risk for active severe weather.

During the early and middle part of the summer, the threats may include damaging winds and the threat for tornadoes before the northern jet stream weakens and an El Niño pattern sets in. Later in the summer, there may be a shift to more heavy rain events in the unsettled zone.

Lack of Prolonged Heat for Eastern Ohio Valley, Northeast
While heat is centered over the northern and central portions of the Rockies and storms rattle the Great Lakes to the mid-Atlantic, it appears that there will be a lack of long-duration heat in the eastern Ohio Valley and the Northeast this summer.

A blocking pattern will set up at times, keeping long-lasting heat away from the eastern Ohio Valley and the Northeast.

"Blocking over Greenland or northern Canada forces systems to dive to the Ohio Valley," Pastelok explained.

"Temperatures will turn out near normal for the I-95 corridor from Boston to New York City and Philadelphia to Washington, D.C.," Pastelok said, since a lack of prolonged heat is expected this season.

Above-normal precipitation is forecast for the East during both June and August. The rain will be beneficial for communities that have endured a dry March and April and for some since the beginning of the winter. August may feature one or two big rain events, perhaps including a tropical system hit, that pushes rainfall totals over the norm.

Atlantic Hurricane Forecast: East Coast Vulnerable
Forecast Factors for the 2012 Atlantic Hurricane Season
Boston to Philly: Needed Northeast Rain May Come at a Cost
Southeast Summer Warmth, Some Rain Relief
Pacific Northwest Coast Will Have a Cool Start to Summer

The East Coast will be vulnerable to a tropical system impact, since steering currents will be up the East Coast.

Drought Gradually Eases in Florida
A pattern change will occur in Florida this summer with showers and thunderstorms returning to areas that greatly need rain.

The zone from Jacksonville and Daytona Beach to Orlando and Tampa need rain badly with extreme to exceptional drought conditions in place, according to the U.S. Drought Monitor.

"Near-normal rainfall will gradually cut into the drought this summer," Pastelok said.

Furthermore, tropical moisture may have an impact on Florida with storms expected to brew in the Gulf of Mexico and western Atlantic this hurricane season.

"If Florida remains dry through May and into June, then statistics would suggest a tropical hit in central or southern Florida," Expert Senior Meteorologist Dan Kottlowski added.

The track may become favorable for Florida to get hit by a tropical storm or hurricane as the Atlantic ridge of high pressure shifts.

Heavy Monsoon for the Southwest
Monsoon downpours will return to the Southwest this summer after remaining fairly weak the past two years.

Tropical activity in the eastern Pacific is expected to be more active than the last couple of years with a more conducive atmosphere for development. This will play a role in the monsoon season in the Southwest deserts.

"The number of tropical storms and hurricanes will be higher in the eastern Pacific," Kottlowski said. "This increases the probability of recurving tropical systems into Mexico, which could allow more moisture to reach into the Southwest."

A dust storm known as a "haboob" rolls into downtown Phoenix on Tuesday night, July 5, 2011, bringing strong winds and low visibility. Haboobs are part of Arizona's annual monsoon season. (AP Photo/Amanda Lee Myers)

The monsoon is expected to kick in around the typical time in the middle of July, mainly focused over Arizona. "The monsoon moisture will gradually spread from Arizona to Utah and Nevada," Pastelok said. "It will take some time for this to occur."

While the mountains of the Southwest will receive the most rainfall, there will be chances at locally heavy showers and thunderstorms for cities such as Phoenix and Tucson, Ariz.

Flash flooding often results monsoon thunderstorms, so these will be concerns to watch out for this summer. Strong outflow from storms can also stir up dust, resulting in blowing dust and dust storms.


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