Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Jan 17 2023 Valid 00Z Wed Jan 18 2023 - 00Z Fri Jan 20 2023 ...Potential for severe thunderstorms and flash flooding from the Lower Mississippi Valley into the Ohio Valley on Wednesday... ...Winter storm to impact the Central High Plains into the Upper Midwest through Thursday morning... ...Light to moderate rain/snow to affect the Pacific Northwest into northern California Wednesday/Thursday... A storm system over the Four Corners region this afternoon will move into the Great Plains tonight, spreading snow into the Central High Plains. Snow will develop over northeastern Colorado late this evening to the north of a developing surface low, forecast to move east-northeastward over the next 12-36 hours. Areas of heavy snow with snowfall rates of 1 to 2 inches per hour will be possible within the heaviest snow bands from northeastern Colorado into Nebraska and northwestern Iowa along with storm totals over 10 inches from northeastern Colorado to the Missouri Valley. Areas of freezing rain are expected south of the heaviest snow from southeastern Nebraska into central/southern Iowa. Needless to say, travel will be difficult across portions of the Plains/Midwest with this storm system. Ahead of the storm system's cold front, showers and thunderstorms will develop from portions of eastern Texas into the Lower Mississippi Valley Wednesday morning, expanding north and east during the day. High temperatures ahead of the cold front and south of the warm front will be 10 to 20 degrees above average which will help support the potential for severe thunderstorms and flash flooding. The greatest threat for flash flooding and severe thunderstorms will be from eastern Texas/Louisiana into the Lower Mississippi Valley Wednesday and Wednesday night. Behind the cold front, a combination of gusty winds and low relative humidity will pose a Critical Fire Weather area (per SPC) across central to western Texas on Wednesday. Above average warmth will spread into the Midwest and Mid-Atlantic on Thursday along with areas of rain. A wintry mix of snow, sleet and freezing rain is expected to spread into interior portions of the Northeast Thursday afternoon, but the threat for severe storms and flash flooding will be diminished compared to Wednesday's threats. Across the West, an upper level disturbance will send a Pacific cold front into the Northwest on Wednesday. Coastal rain and mountain snow can be expected to push south and east Wednesday night and Thursday with locally moderate snowfall accumulations for the higher elevations. The heaviest rain of 1 to 2 inches locally is expected from the coasts of Washington, Oregon and northern California with lighter rainfall totals anticipated farther south down the West Coast as the upper level storm system moves into the Great Basin. Otto Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php