The summer of 2000 was a mild summer, with adequate rain, and only a few occasions of oppressive heat. July was one of the mildest mid-summer months in recent memory. Many areas, including Williamsport and Harrisburg had average high temperatures for July of nearly 3-1/2 degrees below normal.
La Nina, marked by cool waters in the Pacific Ocean, was pretty much out of business by early summer. Storms tended to continue a fast track from the Pacific northwest, east across the northern U.S. into our region, providing fairly frequent delivery of fresh air into our area from central and eastern Canada.
The above illustration shows a typical winter weather pattern associated with neutral years, or years with no significant El Nino or La Nina. An active polar jet competes with the subtropical jet for dominance across the eastern U.S. It reflects a pattern of the past season, dominated by frequent outbreaks of cool air from Canada, and ample wet weather across our region.
In the absence of either of the strong oceanic influences, most people are looking for a return to a more normal winter in this part of the country. That means a considerably colder, snowier winter than either of the past two. Of course, that would be true even if temperatures and snowfall are close to what is considered an average winter here.
Above, a new long-range prediction map compares temperatures and precipitation to normals from 1961-1990. Warmer than normal temperatures are expected from the Pacific Coast, east across the southern plains to the south Atlantic coast. Across the northern U.S., temperatures are up for grabs, with the best bet being near normal.
Precipitation is predicted to be wetter than normal for our region. This seems to indicate a fairly active winter for us, and certainly more typical of mid-latitude winters than we have experienced in the past two years. For most people, even a normal winter will seem harsh in comparison to the past two mild winters we’ve had in central Pennsylvania.