Topline
Most of the U.S. could see above-average temperatures this summer, according to aNational Weather Serviceclimate outlook published Thursday, as experts predict a weather pattern dubbed La Niña will hit in the coming months—and contribute to potentially record-breaking heat.
The National Weather Service predicts the entire continental U.S. could see hotter-than-average... [+]
Key Facts
The NWSestimatesmost contiguous U.S. states could see above-average temperatures beginning in June and into August—with the exception of North Dakota and parts of Minnesota, South Dakota and Iowa—though the risk is highest in the Northeast and a stretch from Texas up into the Pacific Northwest.
The chance of above-average temperatures extends to all 48 contiguous states in the NWS’three month climate outlookfor July through September.
La Niñais a weather pattern marked by cooler-than-average sea surface temperatures in parts of the Pacific Ocean, according to the National Oceanic and Atmospheric Administration, and is the opposite ofEl Niño,which brings warmer-than-average temperatures across the same areas.
Both patterns are part of the El Niño Southern Oscillation (ENSO) phenomenon, according toNOAA,and the National Weather Service has anEl Niño advisoryin effect—as well as a simultaneousLa Niña watch—as the weather pattern is expected to shift to aneutral conditionwithin the next month before likely turning into a La Niña pattern.
Transitions from El Niño to La Niña have been shown to increase temperatures during the summer in the U.S., according toAxios,which alsoreportedsummer conditions associated with La Niña are often warm and dry, particularly in the Southwest.
La Niña could also bring amore severe hurricane season—which happens from June 1 until November—since the cooling of the Pacific also drops air temperatures and makes it easier for such temperatures to rise in the Atlantic, according toThe Washington Post.
What To Watch For
There’s a50% chanceLa Niña could come between June and August—and a69% chanceit will develop between July and September and persist through the winter, according to theClimate Prediction Center.
Surprising Fact
La Niña is also sometimes dubbed “El Viejo” or “anti-El Niño,” according to theNational Ocean Service.It also typically lasts longer than El Niño weather events, theNWSsays. El Niño patterns typically last9.5 monthswhile the average duration of La Niña is15.4 months.
Big Number
37. That's the number of months the longest La Niña pattern was observed, according to theNOAA’s forecast office in La Crosse, Wis, between spring 1973 and spring 1976.
Key Background
La Niña and El Niño occurdue to interactionsbetween ocean surfaces and the overarching atmosphere in the Pacific, according to the NOAA and NWS, and both typically hit everythree to five years.La Niña patternsdo not always followbouts of El Niño. La Niña is typically characterized by warmer winters and drier conditions in the Southwest, Southeast and Central Plains at different points throughout the year, according to thePacific Marine Environmental Laboratory.It can also lead towetter-than-averageconditions in the Pacific Northwest.
Tangent
South Florida has beenexperiencingrecord-breaking heat this week, with hot temperatures expected to persist into this weekend. The NWS predicts that the region could experience feels-like temperatures of between 103 and 109 degrees.
Further Reading
Developing La Nina to bring summer scorcher to millions with soaking storms in eastern US(Fox Weather)
Key West Hits 115 Degree Heat Index In May— As U.S. Prepares For Another Extremely Hot Summer(Forbes)
La Niña Weather Pattern May Bring More Volatile Hurricane Season(Forbes)
An El Niño-less summer is coming. Here’s what that could mean for the US(CNN)
La Nina is on its way back. An atmospheric scientist explains what to expect(PBS)
