How this winter is expected to be different from last winter

On By Littum

PORTLAND (WGME) — It’s time to start thinking about winter.

The main driving forces influencing the pattern in the US are set up differently than last year.

Here’s what we expect in Maine and New Hampshire:

  • Warmer than normal temperatures
  • About normal rainfall
  • During normal snowfall
  • Snow on the ground for Christmas
  • Stormy and Cold Book Ends (December and March)
  • A quick blow in extreme cold in January or early February
  • Large temperature swings in February, leading to an early start to the maple sugar season
  • Winter slow to drop in early spring

It is important to note that seasonal forecasting is a step above educated guesswork.

That said, though, you can usually get a general idea of ​​how the pattern will develop.

The first place we look for this is the Pacific Ocean.

Most important is the state of El Nino Southern Oscillation, or ENSO.

This winter is shaping up to be a weak La Nina, or possibly close to neutral.

This means that the water temperature in the Equatorial Pacific Ocean is running cooler than normal.

Equally important is what is happening in the North Pacific.

Note that the water temperature is warmer than normal, this is the negative phase of the Pacific Decadal Oscillation.

This sea water temperature anomaly tends to favor an active storm track through the Northern Plains, Rockies, Midwest, and Great Lakes.

The coldest temperatures compared to normal usually set up towards our west.

Sometimes late developing nor’easters can produce large storms in the Northeast.

I expect it to start in December this year and we will see snow earlier than last winter.

I analyzed weak La Ninas and ENSO near neutral, -0.3 to -0.9, over the past 41 years.

Here are the winters that are best suited for this winter.

Weak La Nina winters are similar to this winter

Temperature anomalies for these winters look like this:

Precipitation anomalies for these winters look like this:

For Portland, 67 percent of those winters were warmer than normal.

Some had major blizzards, including blizzards in 2013 and 2018.

The winter of 1996 is a personal favorite of mine and included many blizzards.

An average of all these winters shows that 58 percent were above normal in snowfall.

There is a clear signal of cold and snow in December and March.

The December analyzed was 75 percent colder than normal and 67 percent snowier than normal.

83 percent of the La Nina years analyzed had a cold March. 75 percent of these Marches had heavy snowfall.

67 percent of Christmases surveyed showed at least 1 inch of snow on the ground in Portland. Let’s walk with snow on the ground on Christmas morning.

I narrowed the research to include the negative Pacific Decadal Oscillation (PDO), which showed similar warm anomalies in sea water temperature in the North Pacific. They are:

The first thing that came to my mind was cold snaps caused by polar vortex disturbances. We will make sure that it happens again this winter.

Two-thirds of those winters had a brisk cold of -10 to -25 below in southern and central Maine.

Most recently, you may remember February 2023, when Mount Washington recorded the US record wind chill of -108.

Who remembers New Year’s morning 2018? My backyard thermometer that morning read -27 degrees.

The Big Black River, a USGS site in northern Maine, broke the all-time Maine record on the morning of January 16, 2009. The mercury dropped to 50 below.

It seems appropriate to include a quick cold snap in January or early February.

Let’s introduce some forecast modeling.

The temperature anomaly is warm for 5 out of 6 of these seasonal models from December to February.

The same seasonal patterns of precipitation appear from December to February:

My guess is that we will be around normal for rainfall in the months of December, January and February.

How that translates to snow is probably the hardest part of forecasting.

Using the combination of analog years outlined above and computer guidance, I see no sign of a major snow winter in the Northeast.

You can always find our weather forecast updated several times a day here.

Thanks for reading along.

Charlie Lopresti, Chief Meteorologist