Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 349 AM EDT Sun Mar 21 2021 Valid 12Z Sun Mar 21 2021 - 12Z Tue Mar 23 2021 ...A storm system will become better organized across the central U.S. bringing rain and snow... The majority of the Eastern U.S. will enjoy a dry and cool airmass through Sunday and into Monday as a large Canadian surface high builds in from New England. However, an upper level trough over the southeast U.S. will support a surface low east of Florida that will slowly lift towards the northeast, along with a stationary frontal boundary just off the southeast U.S. coast. The latest indications suggest the heaviest rainfall will remain over the offshore waters, but some showers can be expected from the Outer Banks of North Carolina to northern Florida, along with some gusty winds and elevated tide levels. Across the central U.S., a slow moving cold front exiting the Rockies will initially have a limited amount of moisture to work with on Sunday. An intensifying surface low along the boundary across western Texas Monday morning will increase moisture transport across the central and southern Plains, and lead to greater coverage of rain across much of Kansas and extending northward across eastern Nebraska and Iowa. Some strong thunderstorms may develop across the southern Plains on Monday in the warm sector of the developing storm system. Not much in the way of precipitation is currently expected across Arizona and New Mexico given a drier airmass here and less forcing, but additional snow is likely for much of Colorado with the greatest accumulations for the Front Range, potentially over eight inches for some areas. Moderate to heavy snow is also likely for portions of the Cascades in Washington and Oregon as a second storm system brings a cold front across this region by late Sunday. Cooler high temperatures are likely for the Central Rockies and Intermountain West on Sunday as the western cold front moves eastward, and seasonably mild temperatures are forecast for the Southwest and the Central and Southern Plains ahead of the front. With high pressure building in across the eastern third of the nation, mild temperatures are also forecast to spread across the Midwest and Northeast through Monday. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php