Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 200 AM EST Tue Feb 06 2018 Valid 12Z Tue Feb 06 2018 - 12Z Thu Feb 08 2018 ...Heavy rain and a threat of flash flooding will set up for parts of the lower Mississippi Valley and Tennessee Valley later this evening and overnight... ...More snow and some ice will be developing across the Ohio Valley and the Northeast as a new storm system impacts the Eastern U.S by Wednesday... ...Very mild temperatures will continue over most of the Western U.S. through the middle to latter part of the week with some record warmth possible locally... The weather from the Pacific Northwest and the central to northern Rockies will tend to be relatively tranquil today with generally less rain and mountain snow, however, the pattern is expected to revert back to being unsettled toward the middle and latter part of the week as a new storm system drops southeast and approaches the region from British Columbia. This will allow a new surge of moisture to arrive which will bring rain to coastal areas of Washington, and locally very heavy snow across the northern Rockies. A particular emphasis will be on the Bitterroots where new snowfall totals of 2 to 3 feet can be expected by the end of the week. Some heavy snow will also be expected a little farther east out across the northern High Plains and especially central and western Montana to the east of the Continental Divide as Pacific moisture overruns an arctic frontal zone banked up against the eastern slopes of the northern Rockies. Snow totals here in excess of 6 inches will be expected at least locally. The remainder of the Western U.S. though will be quite the opposite as high pressure persisting over the Great Basin will keep very mild temperatures and dry weather intact across the region through the balance of the week. High temperatures will be a solid 10 to 20 degrees above normal draped across the region. Some record warmth will be possible and especially on Thursday as warmer air pools over the Great Basin ahead of the next storm system approaching the Pacific Northwest. Cold and dry air meanwhile has settled over the Ohio Valley, Mid-Atlantic and Northeast and there will be another cold front crossing this region today which will help to reinforce the cold air through the middle of the week. This will also be important in setting the stage for the next winter storm to impact this region as a storm system develops over the lower Mississippi Valley by later today and then lifts northeast up across the Tennessee Valley, central Mid-Atlantic and southern New England through Wednesday. Heavy snowfall can be expected north and west of the low track and areas of the northern Mid-Atlantic region and interior Northeast will see the heaviest snowfall with some areas seeing as much as 6 to 12 inches. Just south of this axis of heavy snow will be a stripe of freezing rain which will extend from the Ohio Valley northeast up across southern New England. Some locally significant icing is expected. Farther south across the Gulf Coast states and into the Southeast, the concern will be heavy rain and thunderstorms in association with the same storm system driving the winter weather hazards farther to the north. In fact, some very heavy rainfall totals will be possible this evening and overnight across parts of the lower Mississippi Valley and Tennessee Valley as a strong surge of moisture lifts north from the Gulf of Mexico and helps to focus an axis of training showers and thunderstorms. Runoff problems and some flash flooding will be possible as a result. Gradually this heavy rain will move off to the east and impacts the remainder of the Gulf Coast region and the Southeast through late Wednesday. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php