Late-Spring Outlook Calls For Mild Conditions Across South and East, Which Could Lead to Hot Summer Start

Chris Dolce
Published: March 17,2017
Mild conditions are expected overall in late-spring across the southern and eastern states and that could be followed by a hot start to summer, according to the latest three-month outlook from The Weather Company, an IBM Business.
La Niña has gone away, but its impact on the atmosphere may continue to linger later into spring, namely, the best odds for cooler-than-average temperatures will remain anchored in the Northwest and northern Plains through April and May. Conversely, the greatest chance of near- or above-average temperatures continues to be in the South and East.
(MORE: The U.S. Saw a Mild, Wet Winter)

April 2017 temperature outlook.

"Anomalously warm sea-surface temperatures near and east of the Indonesia/Maritime Continent are still persisting, and since they drive the anomalous convection that has produced the La-Niña-like pattern this winter, we don’t see any clear reason why the atmospheric response to La Nina won’t hang around for a while," said Dr. Todd Crawford, chief meteorologist with The Weather Company.
(MORE: When is the Last Freeze, Typically?)

May 2017 temperature outlook.

The start of summer in June could then usher in an intensification of the warmer-than-average conditions east of the Rockies given the transition from the La Niña event we just saw to the potential development of El Niño conditions later this year.
NOAA has placed the odds of El Niño developing at 50 to 55 percent in the July-December timeframe, though it mentions there is some chance it could begin to emerge earlier. El Niño is the warming of the equatorial central and eastern Pacific Ocean temperatures, which can have wide-reaching impacts on weather patterns across the globe depending on its strength.
"Typical transitions from La Niña to El Niño conditions result in cooler summers overall, especially late; our forecast reflects this warmest-early, coolest-late idea, but is not particularly cool given the recent pronounced global-scale warming after the last historically-strong El Nino event along with the expected negative NAO conditions driven by historically-low Arctic sea ice levels," said Crawford.
(MORE: El Niño Could Return During Hurricane Season)
June's forecast map reflects the potential for a hot start to summer with the potential for much above average warmth overall along the East Coast. Above-average temperatures are also favored throughout a large swath of the nation's southern tier plus the Ohio Valley and Great Lakes.
"We think any big eastern heat will be more likely to occur earlier in the summer," Crawford added.

June 2017 temperature outlook.

The only area where the start of summer may be near or slightly below average is in the northern Rockies and northern Plains.
(MAPS: Average Highs and Lows By Month)
This outlook is an overall trend for the three-month period April-June. An individual cold front or an upper ridge of high pressure could lead to a brief period of colder or warmer weather, respectively.

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