Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Tue Jan 01 2019 Valid 00Z Wed Jan 02 2019 - 00Z Fri Jan 04 2019 ...New winter storm to develop over the Southwest and eject east across the Southern Plains... ...Heavy rain and the potential for flash flooding will exist across eastern Texas, the Lower Mississippi Valley and Mid-South... A new storm system will gradually be developing over the Southwest by Wednesday and will then eject off to the east and impact a large area of the southern Plains and the lower Mississippi Valley going through Thursday. Multiple hazards are expected with this system which will initially include heavy snow over areas of eastern Arizona and southwest New Mexico going through Wednesday evening where locally as much as 6 inches of snowfall is expected. Downstream across areas of central and northern Texas, and also southern Oklahoma, there will be a shallow layer of subfreezing temperatures that will be conducive for some freezing rain as moisture and energy begins to arrive from the southern High Plains. By Wednesday night and Thursday, a more substantial axis of snow and also freezing rain will tend to focus out across areas of northern and western Texas and also much of central and southwest Oklahoma with several inches of accumulating snow and concerns of a coating of ice. Travel conditions are likely to become hazardous as a result. The cold air that will facilitate the winter weather concerns will be driven by high pressure initially out over the central Plains, and will result in high temperatures that will be as much as 10 to 20 degrees below normal from the Southwest east out across the southern Plains for the next couple of days. Meanwhile, as concerns for snow and ice evolve out across the Southwest and southern Plains region, there will be an increasingly strong transport of moisture to the north out of the western Gulf of Mexico as a wave of low pressure develops along a frontal zone offshore the Texas coastline. This will result in a widespread area of rain with perhaps some embedded thunderstorms impacting initially eastern Texas by Wednesday afternoon and evening, but then advancing east across the lower Mississippi Valley Wednesday night and across portions of the Mid-South through Thursday. Some of the rain is expected to be heavy with storm totals of as much as 2 to 4 inches expected and localized amounts possibly exceeding 5 inches where heavy rainfall and thunderstorms train over the same area. Given the wet antecedent conditions already from recent heavy rainfall, there will be an elevated concern for flash flooding and runoff problems. The Weather Prediction Center as a result has highlighted a Slight Risk of excessive rainfall across this region. Elsewhere, a system over the Pacific Ocean will approach the Pacific Northwest by Thursday and allow a cold front to cross the coastal ranges and move inland. Heavy rain with an emphasis on western Washington can be expected, and some areas of the Olympic Peninsula will see as much as 3 to 5 inches of rain by Thursday evening. This surge of Pacific moisture will also allow heavy precipitation to reach into the northern Washington Cascades where it will be cold enough for heavy accumulating snowfall for the highest peaks. In fact, locally as much as 1 to 2 feet of new snow will be possible for this area. In terms of temperatures, the Pacific Northwest will be near to slightly above normal, but expect areas downstream across the northern Plains by Thursday to see plenty of warm, downsloping winds that will promote high temperatures of as much as 15 to 25 degrees above normal. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php