Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 304 PM EST Wed Feb 06 2019 Valid 00Z Thu Feb 07 2019 - 00Z Sat Feb 09 2019 ...An intensifying low pressure system expected to spread heavy snow and freezing rain across the central Plains into the Great Lakes.... ...Heavy to flooding rains possible from the Mid Mississippi Valley into the Ohio Valley along a nearly stationary frontal boundary... A low pressure system currently developing over the central Rockies will bring a wide variety of unsettled weather across the eastern two-thirds of the country during the next couple of days. First of all, an arctic air mass has been in place across the Northern Tier, where temperatures are more than 30 degrees below normal over the northern High Plains. This is in stark contrast with well above normal temperatures across the Deep South and into the Mid-Atlantic region. Meanwhile, moist air from the Gulf of Mexico has been flowing northward across the Deep South towards an arctic front across the central Plains. In additional, upper-level moisture from the subtropical eastern Pacific is moving across northern Mexico towards the central Plains under a subtropical jet stream. These ingredients will ensure the low pressure system over the central Rockies to intensify over the central Plains on Thursday, moving towards the Great Lakes Thursday night. Scattered areas of light snow across the northern and central Rockies into the northern Plains are expected to expand towards the northern Plains and into the upper Midwest tonight. The snow should continue to pick up in intensity over the upper Midwest through Thursday night along with increasingly strong and gusty winds from the north and northwest as the intensifying storm center moves towards the central Great Lakes. Closer to the storm track, freezing rain and sleet will be likely across parts the central Plains early on Thursday, spreading into the central Great Lakes by the afternoon. Meanwhile, some wintry precipitation is expected across upstate New York and New England tonight north of a wave of low pressure along the arctic front. Farther south, persistent deep layer southwesterly flow ahead of the arctic front will bring an increasing chance of rain across the mid-Mississippi and Ohio Valleys. In fact, the rain could be heavy enough to result in flash flooding across the region through Thursday before the front passes through Thursday night. The rain will continue to spread up the East Coast, even into much of New England by Friday morning under strong southerly winds. Arctic air will then surge into the eastern U.S. during the day on Friday in the wake of the storm. Much of the western U.S. will see more quiet weather as the storm departs into the Plains on Thursday. Temperatures will remain below normal through Friday. It appears that moisture from a weakening Pacific cyclone will reach coastal California later on Friday. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php