Summer is upon us! While astronomical summer begins on June 20th, June 1st starts the three month period meteorologists refer to as climatological summer. While the end of April through around mid-May were dominated by cloudy and cool conditions, we've recently gotten a brief taste of summer-like conditions a bit ahead of schedule. With that said, what can we expect over the next few months?
One of the major themes in the world of long range meteorology over the past year has been El Niño. However, El Niño is rapidly diminishing and confidence grows that La Niña, the opposite phase of ENSO (El Niño Southern Oscillation), will emerge in the Tropical Pacific. While El Niño is characterized by warmer than normal temperatures across much of the equatorial Pacific Ocean, La Niña correlates with anomalously cool sea surfaces temperatures (SSTs) across the Tropical Pacific.
Coming off one of the warmest winters on record, it's obvious ENSO has a large impact over our weather patterns during the colder months. With that said, La Niña’s influence can still be felt even as far as eastern North America during the warm season. We can assess the effect ENSO will have on the upcoming summer by looking at analog or “scenario” years. Simply put, analog years represent past seasons that compare favorably with the conditions we anticipate for the summer of 2016. Thus, we highly considered years that featured a transition from El Niño to La Niña. Also, given the fact that 2015-16 El Niño was one of the strongest on record, a majority of the scenario years we looked at were moderate or strong El Niño’s that switched to La Niña.
The majority of model guidance shows the transition from El Niño to La Niña during the upcoming summer
When reviewing the ENSO transition years, there were some very apparent trends. These summers were overwhelmingly warmer than normal across the Midwest and East Coast. This was especially true for the second half of summer, with the most anomalous warmth in August. While precipitation patterns were much more variable, the mid-Atlantic and Southeast were frequently drier than average for the June through August period.
With much of the heat staying west of the Rockies over the past couple of years, it has been a few years since the Midwest, Northeast and mid-Atlantic have endured a scorching summer. So despite a cool month of May, we expect a very warm summer for a good portion of the country. In addition, we anticipate the highest temperatures anomalies during the second half of summer, as folks in the eastern US will likely see some below average readings over the first couple weeks of June. As for precipitation, we anticipate drier than normal conditions along the Eastern Seaboard, with much of Central U.S favored to receive a good deal of rainfall.
So with hot weather expected from the Great Lakes to the East Coast, folks in the Eastern U.S will have to keep an eye out for a couple of heat waves and perhaps even some triple digits! For more information, be sure to Like our page on Facebook and follow us on Twitter.
