Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 306 PM EST Wed Feb 10 2021 Valid 00Z Thu Feb 11 2021 - 00Z Sat Feb 13 2021 ...Significant ice storm will continue tonight and Thursday from the Mid-Mississippi Valley to the Ohio Valley... ...Heavy snow possible across the Pacific Northwest beginning 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, with a plethora of winter weather hazards. First, the combination of a stationary front stretching from the Southern Plains northeastward into the Tennessee Valley and a strong arctic high pressure system to the north will lead to a threat of significant freezing rain/icing in between. Across portions of Arkansas eastward into Tennessee and Kentucky, total ice accretion is likely to exceed a quarter inch, while amounts in excess of half an inch are possible in some locations. This amount of ice will likely lead to hazardous travel conditions, power outages, and scattered tree damage, and Ice Storm Warnings are in effect for these areas. Accumulating freezing rain is also possible across central Texas through early Thursday, and some ice amounts over a tenth of an inch are forecast. Northeast of the freezing rain axis, a couple of rounds of light snow are expected from portions of the Ohio Valley and Central Appalachians to the Mid-Atlantic through Friday, and generally 2 to 6 inches of snow is forecast across the northern portions of the Mid-Atlantic region. Additionally, freezing rain is possible Friday across parts of the Central Appalachians and into parts of Virginia and northern North Carolina. Meanwhile on the warm side of the system throughout the Southeast, showers and thunderstorms could lead to an inch or two of rain through Friday, with locally higher amounts around the central Gulf Coast region. 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. Freezing rain could be another threat in lower elevations of northwestern Oregon in particular. Winter Storm Watches have been posted across the area, with Winter Storm Warnings in the Cascades given greater certainty on precipitation type. Another round of wintry weather is again possible there by Friday and Saturday. Snow and mixed precipitation are expected to spread across much of the Great Basin and into the Rockies as well. Meanwhile, the arctic airmass located over the 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 from nearly the entire Great Plains to the Great Lakes again on Thursday. 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 low records could fall. Wind Chill Advisories and Wind Chill Warnings remain in effect and stretch from Montana to northern Wisconsin. 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. Tate/Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php