Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 309 AM EST Thu Feb 19 2015 Valid 12Z Thu Feb 19 2015 - 12Z Sat Feb 21 2015 ***Areas of snow from the Great Lakes to New England*** ***Historic cold for the eastern U.S. through Friday*** ***Developing storm system over the southern U.S.*** The overall weather pattern through the end of the week will continue to be featured with a pronounced and anomalous upper level trough over the eastern half of the country, and a big upper level ridge for the western states. This will keep most of the West Coast, the Great Basin, and the Desert Southwest warmer and drier than normal, and the central and eastern parts of the U.S. much colder than normal. Although the weather is pleasant out west, the drought continues for California and much of the Intermountain West, and no appreciable rain is in the forecast over the next couple of days. Over the eastern half of the nation, we all know that it has been quite cold over the past week. Get ready for an even more impressive surge of arctic air later this week as another cold front drops south from Canada. There are indications that this could be some of the coldest weather since the mid-1990s for some parts of the Southeast U.S., Mid-Atlantic, and central Appalachians. An eddy of the polar vortex will add to the potency of the surface cold front, thus creating a deep layer of bitterly cold air. Highs on Thursday and Friday will struggle to get out of the teens for many of these areas, and overnight lows could reach zero degrees or even lower in some places! Wind chill advisories and warnings are currently in effect. The overnight lows on Thursday night will be the coldest in those areas where the wind goes calm, allowing for additional radiational cooling. After Friday, temperatures are forecast to moderate and get closer to February averages. In the precipitation department, a developing surface low over the southern Plains will tap moisture from the Gulf of Mexico, and result in an expanding area of rain, wintry mix, and snow from the Deep south to the Ohio Valley by Friday night. Another sleet and freezing rain event is appearing increasingly likely from Missouri to northern Georgia, before a change-over to rain happens later on Saturday. Elsewhere, there will be periods of light snow and snow showers from the Great Lakes to the Mid-Atlantic and New England as shortwave energy with the arctic front moves across the region on Thursday. Upslope flow near the eastern side of the Rockies will likely lead to light snow for the region on Friday. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php