The Northern Shenandoah Valley could have a wetter than normal winter, according to a seasonal forecast released Thursday by the National Oceanic and Atmospheric Administration.
Precipitation is projected to be slightly above normal, said Kyle Pallozzi, a meteorologist for the National Weather Service in the Sterling office, which provides weather forecasts for NOAA.
Whether that precipitation would be rain or snow, he said, would depend on temperatures at the time of the storm. Temperatures are projected to be about normal with standard periods of cold normal to any winter season, he added.
The NOAA forecast is for the weather in December, January and February.
“It is hard to predict this far out,” Pallozzi said. “In the span of a winter, one storm can make a difference of whether we are above, below or average.”
The definition of normal is based on a 30-year-look back, he said.
Pallozzi said a normal winter for this region appears to be average precipitation of 7.56 inches and an average combined daytime and a nighttime temperature of 34.9 degrees.
The forecast could change if a weak El Nino appears by late fall or early winter, an event NOAA estimates to have a 70-75 percent likelihood, Pallozzi said. NOAA forecasters say an El Nino could result in wetter weather in the south and a warmer, drier winter in the North.
NOAA’ s website describes an El Nino as “an ocean-atmosphere climate interaction that is linked to periodic warming in sea surface temperatures in the central and eastern equatorial Pacific.”