Wildfire outbreak and major winter storm possible Wednesday

A weather whiplash type of day is in store as a major snowstorm is taking shape over the Rockies, severe thunderstorms across the Plains and there's an extreme risk for wildfires for parts of Texas and Oklahoma.

On Wednesday morning, winter storm warnings were up for 5 million people, ahead of what could be Denver’s biggest snowstorm of the season so far.

Denver will see rain with embedded thunderstorms and temperatures near 50 degrees through the midday, before crashing into the low 30s with that rain changing to snow around the evening rush hour.

Once the snow starts across the Interstate 25 corridor, it will last through Friday morning, with snowfall rates of 1 to 3 inches per hour at times. The heavy snow combined with wind gusts up to 40 mph will make travel almost impossible. Heavy mountain snow will also impact northern Arizona, northern New Mexico, Utah and Wyoming.

The I-25 corridor could divide the more blockbuster snow totals of 2 to 4 feet to the west from 4 to 12 inches to the east.

• West of I-25: Total snow accumulations of 1-2 feet, with localized totals up to 4 feet especially for the eastern slopes of the Front Range.

• East of I-25: Lesser amounts will be possible here, with generally 4 to 10 inches the most likely scenario, with locally higher amounts of up to 8 to 16 inches especially along the Palmer Divide, which is just east of the Denver metro area.

This is a complex forecast for the Denver metro area, specifically, when it comes to how much snow residents will see. Regardless of the amounts, the snow beginning around the evening rush hour Wednesday night and continuing through the morning rush hour Thursday will likely cause major travel issues.

Denver Airport urged travelers to check with their airline for up-to-date information and to arrive at least two hours before their flight. Southwest Airlines posted a travel advisory for passengers traveling to, from or through Denver and the surrounding area.

Denver's largest snowstorm of the season was back in late October, when it picked up 7.5 inches. If it picks up snowfall totals in the double digits, it could be the city's biggest snowstorm in three years.

Significant snowstorms in March are common for this part of the country. Two of the four heaviest snowstorms on record in Denver happened in mid-March.

As the snow is picking up in intensity across the Rockies, severe storms will be igniting at the same time across portions of the central Plains.

As many as 6 million people are under the risk of severe storms Wednesday into Wednesday night across parts of northeastern Kansas, northern Missouri and extreme southern Nebraska.

Very large hail, up to the size of tennis balls, will be the main risk, followed by isolated tornadoes. Kansas City and Topeka are the main metro areas at risk.

On Thursday, as the storm system shifts east, 21 million people will be at risk along an 850-mile stretch from northern Illinois down to northeast Texas.

Very large hail will be the main risk, especially across eastern Oklahoma and western Arkansas. Isolated tornadoes and damaging winds will also be possible. Cities to watch include St. Louis, Little Rock and Dallas.

South of where the severe storms are expected to occur, wildfires will be a major threat Wednesday for the southern Plains.

The Storm Prediction Center used strong language in its fire weather outlook Wednesday, indicating a critical to extreme fire danger may lead to a ‘wildfire outbreak,’ with several wildfires sparking during the day.

The ingredients leading to the high wildfire concern Wednesday include:

• Sustained winds of 30 mph, with gusts to 50 mph or higher.

• Relative humidity in the single digits.

• Very dry fuel, where the fuels (grasses) are even drier than they were before the major wildfire outbreak in late February that sparked the historic Smokehouse Creek Fire.

The extreme fire danger includes areas scorched by the Smokehouse Creek Fire. While that area has already been burned over, other areas including around the heavily populated cities of Amarillo and Lubbock were untouched by that series of wildfires, making those areas more vulnerable because there is ample dry fuel around to burn.

Amarillo, Lubbock and Roswell, New Mexico, are cities under red flag warnings Wednesday.

On Thursday, 23 million people from Texas to Indiana could see severe storms including cities such as Dallas, Memphis, Little Rock, St. Louis and Paducah. Large hail remains the primary threat.