How this winter is expected to be different from last winter

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

The most important drivers that influence the pattern in the United States are set up differently than last year.

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

• Warmer than normal temperatures
• Around normal precipitation
• Lower than normal snowfall
• Snow on the ground for Christmas
• Stormy and cold bookends (December and March)
• One quick, extremely cold shot in January or early February
• Large temperature fluctuations in February lead to an early start to the maple sugar season
• Winter release slowly in early spring

It is important to note that seasonal forecasts go a step further than educational guesses.

That said, 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’s El Nino Southern Oscillation, or ENSO.

This winter will be a weak La Nina, or possibly near neutral.

That means the water temperature in the Equatorial Pacific Ocean is cooler than normal.

Just as important is what’s 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 ocean water temperature anomaly tends to promote an active storm track through the Northern Plains, Rockies, Midwest and Great Lakes.

The coldest temperatures relative to normal tend to occur in the west.

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

I expect this to start in December this year, and we’ll see snow sooner than we did last winter.

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

These are the winters that best match this winter.

Weak La Nina winters similar to this winter

Temperature deviations for these winters look like this:

Precipitation anomalies for these winters look like this:

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

Some had major snowstorms, including the 2013 and 2018 snowstorms.

The winter of 1996 is a personal favorite for me and there were many snow storms.

The average of all these winters shows that 58 percent had more snowfall than normal.

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

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

Eighty-three percent of the La Nina years analyzed had a cold March. Seventy-five percent of those Marches had major snowfall.

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

I limited the study to the negative Pacific Decadal Oscillation (PDO), which showed similarly warm ocean temperature anomalies in the North Pacific. They are:

The first thing I thought of was cold snaps caused by polar vortex disruptions. We will ensure that this happens again this winter.

In two-thirds of these winters, southern and central Maine quickly got cold from -10 to -25 degrees.

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

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

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 degrees lower.

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

Let’s introduce some prediction models.

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

The same seasonal precipitation models look like this from December through February:

I suspect that precipitation will be normal in the months of December, January and February.

How that translates to snow is probably the trickiest 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.

Here you can always find our forecast updated several times a day.

Thanks for reading.

Charlie Lopresti, chief meteorologist