Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Fri Apr 20 2018 Valid 00Z Sat Apr 21 2018 - 00Z Mon Apr 23 2018 ...Heavy rainfall to set up over the Arklatex into the Lower Mississippi Valley and mid-South region... ...Continued dry, windy conditions will support a threat for dangerous wildfire development over southern New Mexico into far west Texas... An expansive upper low spinning over the Four Corners region will continue migration eastward during the next couple of days. As the system treks toward the southern/central High Plains, a marked uptick in Gulf moisture transport will lend itself to an organized heavy rainfall threat from the Arklatex eastward. Before this occurs, some of the initial convection invigorating along the New Mexico/Texas border may take on severe characteristics with large hail and damaging winds the most likely hazards. As the convective activity begins to consolidate, the system should shift toward being heavy rainfall producer. This will particularly be the case from the Red River eastward through the Lower Mississippi Valley and into sections of Mississippi and Alabama. As such, pockets of flash flooding are expected over the Arklatex region toward the southern U.S. While widespread rainfall amounts will reside in the 1 to 2 inch range, spots of locally heavier amounts are likely where training and repeat convection occurs. While severe weather and flash flooding are possibilities with this mentioned system, it will also produce higher elevation snows across the Colorado Rockies while also continuing the threat for wildfire production over southern New Mexico into west Texas. Dry, windy conditions on top of already dry soils across the region will continue to foster the development of additional fire-related issues. By early in the weekend, the threat area should only cover far west Texas into the Big Bend region as the system translates eastward. A system accelerating through the Pacific Northwest will spread modest precipitation amounts over the Olympics and Washington Cascades. Given appreciable cold air aloft accompanying this trough, some snowfall accumulations are possible across the higher elevations of the mentioned terrain. Regarding temperatures, most locations from the southern/central Rockies eastward can expect below average readings given extensive cloud cover and widespread precipitation. Departures from climatology may reach the 10 to 15 degree range underneath the upper low itself which covers much of Kansas and Oklahoma. Otherwise, expect slightly above average readings over the western states, particularly over the central Great Basin. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php