DENVER -- Much colder weather has now moved into Colorado as a cold front slices southward.

Temperatures by late afternoon were running 25 to 30 degrees colder than 24 hours ago, with readings in Denver, Greeley, Fort Collins and Boulder dropping into the low 40s.

Overnight, the lows will dip to near freezing in the Denver metro area. Along with the colder weather, an upper level storm system will spin across Colorado Tuesday night and early Wednesday.

This storm will produce a mix of rain and snow in the metro area, with heavy snow possible in the foothills and in the mountains along and east of the Continental Divide. The heaviest snowfall will be over the Wet Mountains and the Sangre de Cristo Mountains -- up to a foot of snow will fall at elevations above 10,000 feet.

In the Denver area, rain will mix with and change to snow later tonight. One to three inches of snow will fall by 9 a.m. Wednesday -- mainly accumulating on the grass.

To the west and south of Denver, a WINTER WEATHER ADVISORY is in effect for elevations above 6,000 feet for Tuesday night and Wednesday morning. Three to six inches of snow will be possible in those areas.

If you have to drive in the foothills or to the south of Denver (Lakewood, Highlands Ranch) late Tuesday night or early Wednesday, allow extra time. Road conditions will be slushy and slow in Mount Vernon Canyon, along Highway 285 west of Denver and from Interstate 25 and Lincoln, south to Colorado Springs.

The weather was still warm over the southeast corner of the state, as highs hit the 80 mark at Springfield in the afternoon. But as the cold front moved through, temperatures quickly dropped into the low 50s by evening and will dip to the mid-30s by morning.

The storm will move out by Wednesday afternoon, with gradually clearing skies. The weather will then slowly warm up as we head to the weekend.

For a look at the weather watches and warnings, click our Severe Weather Page.

Stay with Denver’s 7 as we fine-tune this wintry forecast during the next 24 hours.

El Niño's Impact On Colorado Weather

Some folks are thinking about El Niño as we head into the winter. According to the National Oceanic and Atmospheric Administration, El Nino is strengthening.

What does this mean for Colorado? Generally, a strong El Niño means more moisture and milder temperatures for our state.

In past El Niño years, we have seen some heavy snowfalls. Keep in mind, however, that El Niño affects global or large-scale weather patterns. There are many other factors that influence Denver's weather specifically, such as our terrain and continental location. While we may feel some impacts from El Niño on our average weather, remember that each weather event has very specific origins and effects. This is the difference between weather and climate.

When we get to the end of the coming winter, we can assess the impacts of El Niño. However, we caution against pinning individual weather events on global patterns.