How is this winter expected to be different than last winter?

PORTLAND (WGME) – It's time to think about winter.

The key drivers influencing the pattern in the United States are different in nature than last year.

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

• Warmer than normal temperatures
• About normal precipitation
• Below normal snowfall
• There is snow on the ground at Christmas
• Stormy and cold book ends (December and March)
• A quick hit of extreme cold in January or early February
• Large temperature swings in February lead to an early start to the maple sugar season
• Winter slowly subsides in early spring

It's important to note that seasonal forecasts go a step beyond educational guesswork.

However, with that said, you can usually get a general idea of ​​how the pattern will develop.

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

The most important thing is the state of the El Nino Southern Oscillation, or ENSO for short.

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

This means that the water temperature in the equatorial Pacific is 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 seawater temperature anomaly tends to favor an active storm track through the Northern Plains, Rocky Mountains, Midwest, and Great Lakes.

The coldest temperatures compared to normal are usually in our west.

Sometimes late developing northeasterly winds can produce large storms in the Northeast.

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

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

Here are the winters that best suit this winter.

Weak winters in La Nina, similar to this winter

Temperature anomalies for these winters are as follows:

Precipitation anomalies for these winters are as follows:

In Portland, 67 percent of these winters have been warmer than normal.

Some have had major snowstorms, including the blizzards of 2013 and 2018.

The winter of 1996 is one of my personal favorites and included many snowstorms.

The average of all of these winters shows that 58 percent of snowfall was above normal.

In December and March there is a clear signal of cold and snow.

The Decembers analyzed were 75 percent colder than normal and 67 percent snowier than normal.

83 percent of the La Nina years analyzed had a cold March. There was heavy snowfall in 75 percent of these brands.

There was at least an inch of snow on the ground in Portland during 67 percent of the Christmases surveyed. Let's go Christmas morning with snow on the ground.

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

The first thing that came to mind was cold snaps caused by polar vortex disturbances. We'll watch for that to happen again this winter.

Two-thirds of these winters experienced rapid onset cold temperatures of -10 to -25°C in southern and central Maine.

Most recently, you may remember February 2023, when Mount Washington recorded a U.S. record wind chill of -108.

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

Big Black River, a USGS site in northern Maine, broke the previous Maine record on the morning of January 16, 2009. The temperature dropped to 50 degrees below zero.

It seems reasonable to plan for a sudden cold snap this January or early February.

Let's introduce some forecast models.

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

The same seasonal precipitation models look from December to February:

I expect rainfall to be about normal in the months of December, January and February.

How this affects snow is probably the hardest part of the forecast.

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

You can always find our forecast, which is updated several times a day, here.

Thank you for reading.

Charlie Lopresti – Chief Meteorologist