A string of record-warm months continued in March, and the Northeast and other population centers can expect more unusually high temperatures in May, according to forecasters at the National Oceanic and Atmospheric Administration (NOAA).
"We're favoring above-average temperatures for the far West, Alaska, along the northern tier of the United States and for the eastern third of the country as well," said Jon Gottschalck, chief of NOAA's Operational Prediction Branch. The only area expected to see below-average temperatures in May is a section of the Southwest and southern Plains, he said.
NOAA issued a similar temperature forecast for the three-month period beginning in May, favoring above-average temperatures for much of the West, the northern tier of the country and much of the East.
El Nino conditions remain in place in the Pacific Ocean, according to Gottschalck, but like other forecasters, NOAA sees a strong possibility for changes there that could affect weather across the United States.
"We continue to have an El Nino advisory in place," he said. "Although El Nino is weakening, we still have conditions both in the ocean and in the atmosphere that are consistent with El Nino conditions.' NOAA expects a transition to ENSO-neutral conditions by spring or early summer, he said. Moving through the summer and into autumn, there's a growing likelihood of La Nina conditions.
MDA Weather Services recently said that it, too, believes a transition from a Pacific El Nino to a La Nina event could lead to hotter-than-normal summer weather (see Daily GPI, April 7).
Average global surface temperature in March was 1.22 degrees Celsius above the 20th century average, the largest monthly departure from average on record, making it the warmest March on record.
"I might sound like a broken record at this point, but this was the 11th consecutive record warm month for the global surface," said NOAA Climate Scientist Jake Crouch. "This 11-month streak is the longest such streak in the 137 years that we've been keeping data at NOAA."
And it was an exceptionally warm March for the Lower 48 as well, Crouch said.
"The contiguous U.S. average temperature was 6 degrees Fahrenheit above the 20th century average, and this ranked as the fourth warmest March on record," he said. Every state's temperatures were above average for the month.
The western snowpack, which has a direct impact on hydro energy through the rest of the year, "is in much better shape this year throughout the west," according to Nina Oakly, an assistant research climatologist at NOAA. Most areas are experiencing near- to slightly-above-normal snowpack, she said.
"The improvement from 2015 to 2016 is especially notable for California and Nevada, the regions that have been experiencing persistent drought in the West," she said. Snowpack peaked in March, earlier than usual, and quickly declined during the first half of April. "The early snowmelt raises concerns for water resources, especially in basins that do not have storage, as well as environmental concerns."
Some forecasters have said the transition from El Nino to La Nina could pump up tropical storm activity in the Atlantic Basin (see Daily GPI, April 6). Colorado State University forecasters, on the other hand, have forecast average tropical activity this year (see Daily GPI, April 15).