Early Season Storm Dumps On California

Winter is on the way, and that means Americans have to get ready for the threat of the white stuff.

Snowfall forecasting is among the most challenging tasks meteorologists face as many factors can determine if you will see a winter wonderland, a slushy mix or no snow at all.

Here's why you should keep this in mind next time snow is in your forecast.

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1. Nailing down snow totals is difficult more than a couple of days out: You might be frustrated when meteorologists say "this snow forecast is highly uncertain" or "it's too soon to tell how much snow will fall."

We understand that frustration. But meteorologists aren't holding back information.

Let's say meteorologists are watching a potential snowmaker several days out. Well, that system may still be over 1,000 miles away.

A lot can change as it approaches, and each run of models can call for tweaks in a forecast. For example, models can bring a variety of potential strength to a storm system and locations that could see its impacts. So, if computer forecast models call for feet of snowfall several days out, you may not want to cancel all plans or panic just yet.

A small change in the amount of moisture translates into a much bigger change in the amount of snowfall. If you expect a quarter-inch of rain and get an inch, you may not see that as a bad forecast. But if you expect three inches of snow and end up with a foot, that's a different story.

So meteorologists frequently can see the potential for a snowstorm, say, somewhere in the Plains or Northeast up to a week in advance, and specify generally what time period it may occur. But it's just too soon to pinpoint exact snowfall totals for a specific city or town.

2. Take with a grain of salt those model snowfall graphics you see on social media: Those maps often show one single forecast from a computer model that sends local communities into a frenzy about a potential storm coming, sometimes more than a week away.

These maps will always be on the internet, but you can do your part by not sharing them. We previously wrote extensively about this topic.

An example of this happened in early December 2023, when one forecast of a particular model painted a significant snowstorm over Arkansas and other parts of the central U.S. more than five days in advance. Just 12 hours later, a new forecast from that same model showed a much less snowy forecast, including no accumulation over Arkansas.

That caused the National Weather Service in Little Rock, Arkansas, to hammer home this point in one of their forecast discussions

There are many computer forecast models, and while some might have a good handle on the forecast, others may not. These models also show there's a range of possibilities with an upcoming snow event, rather than what any single model depicts.

Professional, experienced meteorologists learn what those computer models do best and what they struggle with, as well as follow their trends over multiple days in order to produce a forecast.

So next time, make sure your source of weather information, particularly on social media, is a trusted source, such as your local National Weather Service office, a private forecasting company such as The Weather Channel, or a local TV or radio meteorologist.

3. The first snowfall forecast you hear a few days out will probably change: Don't assume the first snowfall forecast you heard several days ago is gospel. Check your forecast frequently leading up to the storm for important changes.

As stated earlier, forecasts are updated many times a day and often evolve. Computer forecast models typically drawing closer to each other as the event nears. But sometimes, even when we're close enough to begin issuing specific snowfall forecasts, there can be considerable remaining question marks.

In general, snow falls to the north and northwest of the track of the surface low-pressure center – the red "L" you see on weather maps.

Changes in the track of this low, even 50 miles or less, can shift the area of snow, ice and rain.

One example of this is shown in the maps above. At left, the track of a low would have favored heavy snow four days in advance of its arrival. At right, by the time the storm has nearly arrived a day in advance, the forecasts steadily trended the low's track westward to bring rain to areas where snow was originally expected.

4. Tens of miles can make a big difference in snow totals: Pay attention to areas around your location on a snowfall forecast map. If totals are much higher or lower, there's boom or bust potential in your snowfall forecast.

Larger areas of snow often have embedded, smaller bands of much heavier snow. These bands may only be five to 10 miles wide and can produce snowfall rates of over an inch per hour, sometimes accompanied by lightning.

(MORE: What is a Snow Squall?)

One example below was from a March 2017 Northeast snowstorm, indicated in the radar loop by the thin band of darkest green.

Except for lake-effect snow situations, it's not possible to forecast exactly where these heavier bands will set up in a snowstorm. However, meteorologists will typically spell out the potential for these heavy bands in their overall storm forecast.

On the other end of the spectrum, sometimes there's a sharp cutoff to snowfall on the northern edge as dry air intrudes into the storm. Such was the case in March 2018 over Indiana, where parts of the Indianapolis metro area picked up eight inches of snow, but areas just north of the city picked up little or nothing.

In a case like this, the National Weather Service may issue a winter storm warning out of an abundance of caution, but you may just miss out on either heavy snow, or any snow at all.

5. A storm's timing, temperatures and winds also matter: It's not all about amounts. There are other key items to keep in mind with any snow forecast.

Timing can be as important as snowfall totals.

When will the snow start and end? Will it fall during rush hour on a weekday or on a weekend? That could mean the difference between a nightmare commute and a relaxing Saturday morning at home, hot chocolate in hand, watching the storm outside.

Also, pay attention to temperatures during and after the storm.

Will temperatures be warm enough to melt the snow as it falls on roads? This is often a consideration in more southern locations and also early in the fall or later in spring. In this case, there may be more "snowfall," but the actual amount on the ground may be much less on pavement as opposed to grassy areas or the tops of vehicles.

Will colder air eventually turn that slush or melted snow to stretches of ice the following night or morning? Meteorologists call this a flash freeze.

And in more northern locations where road salt and brine are used heavily, will the cold plunge behind the storm be so cold to render them ineffective? In general, once temperatures dip into the teens or colder, road salt can't melt much ice.

Finally, check your wind forecast during the storm, especially if you have plans to drive.

Wind-driven snow can reduce visibility, particularly in rural areas and open country, leaving you disoriented, even if you're only a few miles from home. Drifting snow can make roads impassable, stranding drivers.

When heavy, wet snow causes tree limbs and power lines to sag, strong winds can be the final straw that triggers more widespread power outages and tree damage.

6. You should pay close attention to light snowfall forecasts too: It's human nature to focus on the snow forecasts with high amounts, or just the highest total in, say, a "three to six-inch" forecast.

But don't underestimate the hazard from light snow.

According to a study released in 2019, 54% of deadly snow-related traffic accidents in the U.S. occurred where snowfall was too light or didn't last long enough to prompt the National Weather Service to issue a winter storm warning or winter weather advisory.

This is particularly hazardous when road temperatures are below freezing, allowing a thin film of slush or ice to form on untreated roads.

It can also happen with a brief burst of snow known as a snow squall, when only an inch or so of snow falls, but happens within an hour or so. The abrupt change in visibility and suddenly slick road from a fast-moving snow squall can lead to multi-vehicle chain-reaction accidents.

In general, checking frequently with a trusted meteorologist for forecast updates should keep you in the know the next time snow is in the forecast.