AccuWeather's winter outlook: How much snow can we expect in the Philadelphia region?

PHILADELPHIA (WPVI) -- This winter in the Delaware Valley, we know that El Niño will be the big player and that temperatures will likely be above average when you look at the three months as a whole.

However, the big question becomes can we, at times, get some blocking to set up, allowing for enough colder air and a favorable East Coast storm track to get us near or above normal snowfall?

If we never see or take advantage of that blocking, it will be another dud winter. But if we can get two or three storms that drop 4-6" each, then we are right there near our average snowfall. As with most of these outlooks, it's not a clear-cut solution.

We've been in a bit of a snow drought lately, with below-average snowfall in four of the past five winters.

And it's been warm.

There have been above-average temperatures in three of the past five winters. Last year ranked our fifth warmest on record. Why? In a big part because of La Niña.

But this winter will be different.

Instead of La Niña, we'll be dealing with the opposite -- a moderate to strong El Niño. This is a warming of the Equatorial Pacific waters off the coast of South America.

But, all El Niño are not the same. When the warmest water is located just off the coast of South America, it's eastern-based. When the warmest waters are farther offshore, towards the central Pacific, it's called central based.

This is important because the location of the El Niño can lead to different atmospheric patterns across the U.S.

In an eastern-based El Niño, which we currently have, you typically see a lot of mild Pacific air quickly moving across the country.

When you have a more central-based El Niño, the jet stream is able to slow down allowing larger storms to form. It is possible to transition from one type of El Niño to another over the course of a winter, and that's something we'll be watching.

Based on the current setup, we expect the Pacific jet to dominate early winter, bringing storms and mild temperatures to a large part of the U.S., while the polar jet is under lock and key to our north.

Come late January and February, we may see more of a blocking pattern develop, increasing the chances of the polar and tropical jets meeting up, leading to the threat of nor'easters.

Here are the key points

While we will have some cold snaps, we expect milder air to win out. And with an active storm track nearby, precipitation will be above normal.

The early part of winter looks to be mild and wet. Late winter will give us our best chance of a wintry mix or snow.

Trying to use history as a guide for the future, we looked at several other strong El Niño winters. Snowfall totals range from our snowiest to the least snowiest winters. Just a trace in 1972-1973 to over six feet in 2009-2010. It was a wildcard pattern thanks to El Niño.

Honestly, this gives us relatively low confidence in our snowfall forecast. The majority of these totals would fall in two or three larger storms, which could make for a near-average winter.

Snow forecast

Here in Philadelphia, we expect 18-24" of snow and 30-36" in the Lehigh Valley. And right along the coast, we expect around 12-18" of snow.

No matter what Mother Nature brings our way this winter, the AccuWeather Team will be here to keep you safe and prepared.