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Summer 2017 Temperature Outlook: Hotter East, South, West as Northern Plains, Rockies Keep Their Cool
Published: May 19, 2017
The best chance for a hotter-than-average summer will be near the East and West coasts as well as in the southern tier or states, according to the latest outlook from The Weather Company, an IBM Business, as well as NOAA.
These warmer-than-average conditions include the Pacific Northwest, where a chilly pattern has been in place throughout much of the winter and spring.
Portions of the northern Rockies and northern Plains, however, may see a cooler-than-average summer.
One of the factors at play is the possibility of a weak El Niño's development.
"Any El Niño event that occurs in 2017 will likely be slower to develop, weaker, and center farther west in the equatorial Pacific, all of which resulted in warmer changes to our summer forecast in the major population centers of the eastern U.S. this summer," said Dr. Todd Crawford, chief meteorologist with The Weather Company.
Whether or not El Niño develops, the demise of La Niña will likely lead to warmer temperatures across the Pacific Northwest. Overall, El Niño summers have resulted in cooler conditions in the northern tier, with warmer temperatures across the South.
In the most recent outlook, NOAA placed the odds of El Niño's summer and fall development at slightly lower than 50 percent. El Niño is the warming of the equatorial eastern and central Pacific Ocean temperatures, which can have impacts on weather patterns across the globe.
Another factor to consider is the historically-low Arctic sea ice values, which also typically favors the greatest above-average temperatures to be across the southern tier with any below-average temperatures farther north, notes Crawford.
A third factor in the temperature forecast is the warmer sea surface temperatures in the North Atlantic, which indicate a higher chance of warmer temperatures in the East and South.
Below, we take a closer look at what to expect each month and also a look at NOAA's summer outlook.
The best chance for warmer-than-average temperatures this June will be from east Texas through much of the South and up the East Coast, as well as in the Pacific Northwest.
(MAPS: Average Monthly Temperatures)
Areas from the Southwest into the Midwest may experience temperatures near or slightly warmer than average. Farther north, in parts of the Rockies and northern Plains, temperatures may be near to slightly below average.
In July, temperatures are expected to be well above average from southern California into portions of the Desert Southwest. The rest of the West, with the exception of most of Montana and far northeastern Wyoming, will also see warmer-than-average temperatures.
A different story is expected in the northern Plains, where cooler-than-average temperatures are likely. Temperatures for the East will likely be near to slightly above average.
The expanse of hotter-than-average temperatures will grow in August, stretching from the West Coast through the Southwest and into the South and up the Northeast seaboard. Areas from southern California into southern Arizona, as well as from southeastern Louisiana into much of the Southeast, may see temperatures soar well above average.
Most of the northern Rockies, northern Plains and portions of the Upper Midwest, however, are expected to experience near to slightly below average temperatures.
NOAA's Summer Temperature Outlook
NOAA's temperature forecast shows probabilities of above, below or near-average temperatures.
The outlook from NOAA for June through August is similar to The Weather Company's forecast, showing areas along both coasts and through the South having a higher chance of above-average temperatures.
Areas of the northern Rockies into the northern and central Plains, as well as the upper and mid-Mississippi Valley, have equal chances of above-, below- and near-average temperatures.
Climate forecast models and the slight tilt toward El Niño were considered in the temperature forecast, as was soil moisture and snowpack anomalies.
For the Pacific Northwest, NOAA indicates the recent above-average snowpack and soil moisture reduces the probability of warmer-than-average temperatures. The above-average soil moisture in parts of the Rockies and Plains is also a factor in the equal chances for above- or below-average conditions in those regions.
Meanwhile, drought conditions in the Southeast are also expected to contribute to the likelihood of above-average temperatures.
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The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.