Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 245 AM EST Mon Feb 05 2018 Valid 12Z Mon Feb 05 2018 - 12Z Wed Feb 07 2018 ...A new threat of heavy rain will be developing for the lower Mississippi and Tennessee Valleys toward the middle of the week... ...More snow and some ice will be setting up across the Ohio Valley and the Northeast as a new storm impacts the Eastern U.S in the coming days... ...Mild temperatures continue over most of the Western U.S. while frigid weather remains east of the Rockies... More tranquil weather is expected across the Southern and Eastern U.S. today as we start off the new week. Drier and notably colder conditions will be noted across these areas as high pressure over the Ohio Valley shifts quickly toward the Mid-Atlantic region by tonight. However, the dry weather will be short-lived as energy advancing southeast from the Northwest U.S. and out across the Plains begins to organize an area of low pressure across the lower Mississippi Valley region by late Tuesday. This developing wave of low pressure will tap plenty of moisture from the Gulf of Mexico and the result will be the development of widespread heavy rain and some thunderstorm activity across parts of the lower Mississippi and Tennessee Valleys late Tuesday through early Wednesday. Locally as much as a few inches of rain will be possible across these locations and as a result there may be some runoff concerns and possible flooding. This storm system will be lifting northeast across the Tennessee Valley and Mid-Atlantic region through Wednesday, and ultimately this will bring widespread precipitation to areas of the Ohio Valley, Mid-Atlantic and Northeast through late Wednesday. Heavy snowfall along with a narrow stripe of ice 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. Farther south, there will be plenty of shower and some thunderstorm activity for the Southeast and spread out across the Gulf Coast states. Areas of the Pacific Northwest, and the northern and central Rockies will continue to see some additional unsettled weather at least into early Tuesday, but the deeper fetch of Pacific moisture that has been impacting this region over the last several days should begin to thin out which will end the threat of heavy rain and snow. Regardless, there will still be as much as an additional foot of snow across parts of the Washington Cascades, and the interior ranges of the northern Rockies including the Bitterroots. Some heavy snow will also be possible at least for today across the western and northern Colorado high country. The remainder of the Western U.S. will otherwise start off the week very mild and dry with temperatures especially over the Great Basin again as much as 10 to 20 degrees above normal. Meanwhile, the area east of the spine of the central and northern Rockies and especially across the northern Plains and upper Midwest will be seeing temperatures that are much colder as this part of the country will continue to see intrusions of arctic air dropping south from Canada. This will foster temperatures locally as much as 10 to 20 degrees below normal with actual daytime readings in some cases struggling to get out of the single digits. Overnight lows will be as much as 20 degrees below zero. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php