Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Feb 05 2019 Valid 00Z Wed Feb 06 2019 - 00Z Fri Feb 08 2019 ...A developing storm expected to spread significant snow and freezing rain across the upper Midwest into the Great Lakes by Thursday... ...Very mild air in the eastern U.S. will remain in stark contrast with arctic air over the northern U.S. for the next few days... ...The beginning of a heavy rain/flooding pattern is setting up across the mid-Mississippi and Ohio Valleys... Active weather will continue for large sections of the country over the next few days as an energetic upper-level trough moving across the western U.S. interacts with a sharp front across the mid-section of the country. This interaction will result in an active storm track from across the central Plains towards the Great Lakes for the middle to latter part of this week. The sharp front will separate very mild air across the Deep South and the Southeast from the frigid air which is forecast to remain over the Northern Tier. Meanwhile, an energetic upper-level trough currently moving across the western U.S. will begin to interact with the sharp front as it moves towards the central Rockies on Wednesday. This will lead to the formation of a low pressure system over the central Plains Wednesday night into early Thursday, moving into the Great Lakes by Thursday evening. It appears that significant snowfall is possible on Thursday from the upper Midwest to the upper Great Lakes, while freezing rain appears likely across the central Great Lakes. Strong and gusty winds will likely develop across these area on Thursday as the storm continues to strengthen. As the aforementioned upper trough moves through the West, snow levels will continue to fall for southern California for the rest today, followed by the Four Corners region for Wednesday. Heavy snow can still be expected for the Sierra Nevada into the higher elevations of southern California today, spreading eastward into the Wasatch and Colorado Rockies where over a foot of new snow is expected through Wednesday. However, precipitation intensity will begin to wane from west to east as the storm system departs into the Great Plains Wednesday night. To the north of a strong front across the central U.S., high temperatures from Montana into northern High Plains will remain 20 to 40 degrees below average over the next few days, with the colder air filtering south and east for Thursday. This will be in stark contrast with the very mild temperatures expected to continue from the mid-section of the country to the Mid-Atlantic states where temperatures are forecast to be more than 20 degrees above average. Slightly cooler air is expected to filter into the northern Mid-Atlantic tonight as a back-door cold front brings cooler air from New England. As the Pacific storm system mentioned above moves east Wednesday into Thursday, moisture from the Gulf of Mexico together with strong upper-level dynamics will begin to bring an increasing chance of rain for the mid-Mississippi and Ohio Valleys. Total rainfall through Thursday could range between 3 to 5 inches for portions of the Ohio Valley which may cause flooding concerns. Kong/Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php