The first, which extends from the Great Lakes through the Great Plains and Intermountain West, will be responsible for the latest round of appreciable snowfall over the Central/Southern Rockies and Central Plains.
Enhanced moisture availability combined with instability along and behind the front has prompted snowfall accumulation forecasts of 4 to 8 inches for an area encompassing northeastern Colorado, locations adjacent to the Nebraska/Kansas border, and northwestern Missouri.
Winter Storm Warnings and Winter Weather Advisories are currently in effect for portions of the Central/Southern Rockies, Central Plains, and western Middle Mississippi Valley.
The southward progression of the frontal boundary over the next couple days will allow for surface high pressure to descend into and build over the Great Plains, carrying with it a frigid Arctic airmass that is forecast to drop daily high and low temperatures as much as 20 to 30 degrees below normal for much of the central US on Thursday and Friday.
For areas out of reach of the invading oppressive cold temperatures are forecast to remain at or near normal into the weekend.
The second of the two high-impact frontal boundaries can be found over the Southeast and is forecast to remain there into the weekend.
An abundance of available atmospheric moisture will allow for moderate to heavy rainfall to develop along the front with rain rates reaching 1 to 2 inches per hour in some areas.
These high rain rates combined with 24 hour rainfall totals of 1 to 2+ inches has prompted the issuance of a Marginal Risk of Excessive Rainfall by the Weather Prediction Center for portions of the Southeast that will be maintained into the weekend.
Thunderstorms are also expected to accompany the heavy rainfall, some of which may become severe due to the presence of sufficient instability over the region.
Given the potential for damaging wind gusts, isolated hail, and few tornadoes to develop within these thunderstorms, the Storm Prediction Center has issued a Slight Risk of Severe Thunderstorms from northenr Florida to eastern South Carolina through tomorrow morning.
The risk of severe weather is forecast to drop off on Friday as the environment becomes less favorable for the development of strong thunderstorms, though isolated instances of damaging winds gusts will be possible.
Elsewhere, high winds associated with a low pressure wave are expected to pass over moderately dry fuels in the Southern High Plains.
With ambient relative humidity values forecast to remain low throughout the day, the Storm Prediction Center has highlighted a Critical Fire Weather threat area from southern New Mexico through the Texas and Oklahoma Panhandles.
Red Flag Warnings are currently in effect for portions of the far northern and far western Texas and Oklahoma Panhandles, respectively.
These environmental conditions are expected to persist over southern New Mexico and western Texas tomorrow, prompting the maintenance of an Elevated Fire Weather threat area over these regions into Friday.
Meanwhile, light to moderate snowfall associated with a coastal low is forecast to taper off over the Central Appalachians and Northeast this evening.
Widespread additional accumulations of 1 to 4 inches are expected, with isolated higher totals of 6 to 8 inches likely at higher elevations.
A mix of Winter Storm Warnings and Winter Weather Advisories are in effect from central Pennsylvania through western New England, which are set to expire later this evening. ■