Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 258 AM EST Wed Feb 10 2021 Valid 12Z Wed Feb 10 2021 - 12Z Fri Feb 12 2021 ...Significant ice storm likely today and Thursday from the Mid-Mississippi Valley to the Ohio Valley... ...Heavy snow possible across the Pacific Northwest on Thursday and may extend into the lowlands of Washington and Oregon... ...Bitter arctic air to remain entrenched across the central U.S. through the rest of this week while slowing expanding southward... A very cold and active weather pattern is set to continue across the country to end the first full week of February. Two storm systems swinging underneath a bitter arctic airmass will lead to a plethora of winter weather hazards. The first system worth mentioning is already producing freezing rain/drizzle across portions of the Mid-Mississippi Valley. A stationary front draped across the Tennessee Valley and Southern Plains, combined with a strong, cold high pressure system located to the north will allow for a significant widespread ice storm from northern Arkansas to Kentucky. Throughout the day today, precipitation is expected to expand in coverage and last through Thursday as waves of freezing rain move parallel to the stalled frontal boundary. Total ice accretion could exceed a quarter inch from the Ozarks to the I-64 corridor in eastern Kentucky. Ice accumulation exceeding a half inch is possible in some locations. This amount of ice will likely lead to hazardous travel conditions, power outages, and scattered tree damage. As arctic air rushes in behind the winter storm, residents in these areas will contend with bitterly cold temperatures and wind chills. Further northeast, multiple rounds of light snow will be found from the Ohio Valley and Central Appalachians to the Mid-Atlantic through Friday. The highest snowfall totals of around 6 to 12 inches will be found across the mountains of far western Maryland and West Virginia. Otherwise, a general 3 to 6 inches of snow is expected across portions of northern Virginia, much of Maryland, Washington D.C., and Delaware. On the warm side of the system throughout the Southeast, showers and thunderstorms could lead to an inch or two of rain through Friday. Isolated flooding will be a concern across the Southern Appalachians on Thursday and Friday. Impactful winter weather is also a possibility across the Pacific Northwest beginning on Thursday. A low pressure system is forecast to enter southern Oregon Thursday evening while simultaneously interacting with very cold air draining into the region. This combination may lead to not only heavy snow across the typical mountainous locations, but in the lowlands as well. Snowfall accumulation will be possible in both Portland and Seattle, but exact amounts are uncertain at this time. Winter Storm Watches have been posted across the area. Meanwhile, the arctic airmass located over the north-central U.S. is not leaving anytime soon and is actually forecast to slowly expand over the next few days. High temperatures 20 to 40 degrees below average will cover a widespread area today from nearly the entire Great Plains to the Great Lakes. By Friday these cold temperatures could ooze southward to the Gulf Coast and as far east as the Lower Mississippi Valley. Temperatures will also make a nosedive across the Northwest, where several daily records could fall. Wind Chill Advisories and Wind Chill Warnings remain in effect and stretch from Montana to the U.P. of Michigan. Light wind combined with subzero temperatures could make it feel as cold as -50 degrees in some spots. This bitter cold can be dangerous and lead to frostbite in less than 10 minutes. Be sure to plan ahead and dress appropriately if spending time outdoors Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php