Predicting Winter More Gray Than Black And White
Sometimes in the months leading up to winter, people attempt to forecast how harsh or how long the upcoming season might be.
Sometimes those people are right and sometimes they’re wrong, but the prediction — much like winter itself — is typically more gray than it is black and white.
Dan Kelly, meteorologist at the National Weather Service in Buffalo, explained how the winter forecast is determined and how different this year is shaping out than last year.
“Usually, Jamestown picks up 4/10 of an inch in October,” Kelly said. “Our observer down there didn’t have anything (this year).”
This was due to how warm October was at 6.4 degrees above the normal temperature while last year October was 3.5 degrees above normal, Kelly said.
“It does change every year,” he said.
With the area’s first snowfall predicted to land today by the National Weather Service, Kelly said November normally receives 8.2 inches of snow on average.
“There are some longer range climatological outlooks,” Kelly said.
Available online are one month and three month outlooks at the probability of how the winter is shaping up. The categories are broken down into “above normal,” “near normal” and “below normal.”
The November outlook shows there is a 35 percent chance of being above normal temperatures. An equally distributed probability would have each category sitting at around 33 percent. While November is predicted to be above normal, it is only slightly more likely than being near normal and below normal.
“Just a very slight higher chance of above normal temperatures for the month of November,” Kelly said.
Kelly said for the three month outlook, including November, December and January, there is a 42-43 percent chance of being above normal temperatures. Kelly said there becomes a concern when the probability breaks the 50 percent threshold.
“Obviously we’re going to have warm days and cold days in there,” Kelly said. “But right now it’s hinting at a slightly higher probability of above normal temperatures.”
The same three categories are used when predicting precipitation as well. For the same three month outlook, there is an equal chance that precipitation will be above normal, near normal and below normal.
“There’s no strong signal that leads them to believe that there’d be above normal, below normal or near normal precipitation,” Kelly said.
For November, there is about a 43 percent chance Jamestown will receive above normal precipitation.
Visit cpc.ncep.noaa.gov to view predicted outlooks.