RENO - Northern Nevada's unusual cool, wet weather in June could be related to an El Nino forming in the Pacific Ocean, regional climate experts said.
But whether the ocean condition will bring winter storms to build the Sierra snowpack and ease the drought remains to be seen.
An El Nino is evidenced by warming of surface water temperatures near the equator. Its opposite, La Nina, is characterized by cooler water temperatures. Both can influence weather patterns.
Kelly Redmond with the Western Regional Climate Center in Reno said the El Nino formed quickly.
"It kind of took me by surprise," he said.
The waters began to warm in May, with conditions shifting this month toward El Nino. The federal Climate Prediction Center forecast said the warming trend could continue into August.
Experts said El Ninos typically form later in the year, and the early arrival could signal a strong one.
"When you do have a quick summer season increase, those do have the potential to become strong, well-constructed El Ninos," said Jeff Underwood, Nevada's state climatologist.
June already is one of the wettest on record for Reno, with thunderstorms producing a string of eight consecutive days of measurable rain early in the month.
"This is very unusual," Underwood said. "This is probably coinciding with the warming of the Pacific."
Redmond agreed June's weather has been anything but normal.
"It may turn out that in retrospect, when we look back, there is some relationship," Redmond said.
"The month of June is usually completely quiet. This is a real unusual situation and it's unusual to see this any time in the summer. You have to go back 40 or 50 years."
But whether the condition brings hefty winter snows after three years of lackluster snowpack is unpredictable.
The Reno-Lake Tahoe region is near the dividing line of an El Nino's influence. It can cause heavy precipitation to areas south, and drier conditions to the north.
"We're kind of at the tipping point," Redmond said. "We've had El Ninos that have brought both wet and dry winters to Reno."
The last El Nino of any consequence was in 2002-2003, a dry year. A stronger El Nino occurred in 1998, when heavy rain and snow came to the region, producing an above-average snowpack.
A strong El Nino in 1983 caused widespread flooding and mudslides in the Reno-Tahoe area and for the first time alerted climate experts about how important the phenomenon can be in influencing weather.