The National Weather Service said confidence was increasing on the potential for “impactful” winter weather across Alabama next week.

It will come in the form of snow chances for the southern half of the state and dangerously cold temperatures for the entire area.

The weather service cautioned that the forecast was still evolving and that changes were likely, so be sure to keep up with the latest updates through the weekend.

The key points as of Saturday:

• Very cold temperatures are expected statewide starting on Sunday, especially Sunday night into Monday morning, with wind chills making it feel even colder. Expect bitterly cold temperatures to last through much of the week. Take measures now to protect people, pets, pipes and plants from the coldest temperatures of the winter.
• Snow flurries will be possible across the northern part of the state on Sunday, but no accumulations are expected.
• Chances for snow on Tuesday across the southern part of the state, roughly from Interstate 20 southward, were increasing. The primary window for snow or other winter precipitation will be Tuesday into Wednesday. No accumulations are expected for north Alabama, but parts of central and southern Alabama could see several inches of snow.
• Hazardous or impossible travel will be a concern, especially for south Alabama, starting on Tuesday and potentially lasting a day or two. But even areas that get only a little precipitation could have travel issues because of the very cold temperatures.
• Snow/ice amounts are still uncertain.
• An extreme cold watch has been issued for south Alabama, and there will likely be more cold weather advisories coming for other parts of the state in the coming days.
• Expect the forecast to change from now until Tuesday, especially snow or ice amounts.

More forecast details:

The National Weather Service expects rain to move out from Alabama through the day today.

A blast of arctic air will arrive on Sunday, sending temperatures plummeting into the teens and 20s statewide with a bitterly cold north wind.

Wind chills on Monday morning will range from the single digits to lower teens on Monday morning in north Alabama to the teens and 20s in south Alabama.

Here are the forecast low temperatures (air temperatures, not wind chills) from Sunday night into Monday morning:

Monday will not provide much relief from the cold, with highs only expected in the 20s in north Alabama, the low to mid-30s in central Alabama and the 40s in south Alabama.

Monday’s expected high temperatures:

Another bitterly cold night is forecast for Monday night into Tuesday morning, with more wind chills in the single digits and teens expected across the state.

Here are the low temperatures (not wind chills) from Monday night into Tuesday morning:

The threat for winter precipitation will begin on Tuesday as an area of low pressure develops in the Gulf of Mexico and tracks eastward, spreading precipitation into parts of Alabama.

The National Weather Service’s precipitation forecast amounts have increased overnight, although forecasters noted that those are likely to change as the forecast evolves.

Because it will be so cold, it will only take a little precipitation to cause travel issues, according to forecasters.

Here’s what the weather service expects for Alabama by region:

SOUTH ALABAMA

The National Weather Service in Mobile said there will be a high chance (60-70 percent) of a least a half-inch of snow areawide and a medium chance (40 percent) of reaching winter storm warning levels, which are 2 inches or more.

Computer model forecasts for the Mobile area on Saturday (which will likely change) ranged from 2 inches to as much as 5 inches.

The weather service said the precipitation type for coastal areas is still murky, but a mixture of freezing rain, sleet and snow will be possible.

Forecasters added that as of Saturday the chance for accumulating freezing rain is low, with about 20 percent chance for areas south of Interstate 10. Areas to the north have even lower chances of accumulating ice.

An extreme cold watch has been issued for southwest Alabama and will be in effect from Sunday night through Monday morning.

The counties affected are Choctaw, Washington, Clarke, Wilcox, Monroe, Conecuh, Butler, Crenshaw, Escambia, Covington, Mobile and Baldwin.

The weather service said wind chills as low as 8 degrees will be possible.

CENTRAL ALABAMA

The National Weather Service in Birmingham said areas generally south of Interstate 20 and north of I-85 are currently forecast to receive a quarter inch to 2 inches of snow, with amounts increasing to as high as 3-4 inches near Troy and Eufaula.

“We’re still 4 days out on this threat, so the forecast is certainly going to change, including exact snowfall amounts and their extent,” the weather service said in its forecast discussion on Saturday.

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“It does appear increasingly likely we’ll have winter impacts to deal with Tuesday into Wednesday morning.”

Arctic air is forecast to arrive in Central Alabama Sunday night into Monday morning.

This will correspond with gusty winds to produce wind chill values in the single digits to lower 10s during the morning commute Monday.

Similar conditions are forecast Tuesday morning with wind chills in the single digits to upper 10s.

NORTH ALABAMA

The National Weather Service in Huntsville said there will be a low chance for a few snow flurries tonight into Sunday morning across north Alabama, but accumulations are not expected.

As of Tuesday, chances for accumulating snow were on the low side for north Alabama, with the bulk of the precipitation, as for now, expected to stay south of the region.

However, forecasters added they will be watching trends very closely in case that changes.

Forecasters said cold weather advisories will likely be issued Sunday night into Monday morning, as wind chill values drop below 5 degrees.

Temperatures may stay below freezing through Thursday for many areas.