Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 259 AM EST Sat Mar 04 2017 Valid 12Z Sat Mar 04 2017 - 12Z Mon Mar 06 2017 ...Heavy snow possible over the Cascades, Sierras, Intermountain West... ...Well above normal temperatures for the Central and Northern Plains... ...Heavy rain and flash flooding possible across South Texas this weekend... A cold front that moved onshore across the Pacific Northwest yesterday will continue to move slowly inland today, pushing across northern California and the Intermountain West, and then into the Rockies by Sunday. Onshore flow behind the front will direct moisture into the Coastal range, Cascades, and northern and central Sierras today. The slow motion of the front will lead to a prolonged period of moderate to heavy snow in these areas, as well as inland across the intermountain west and into the Rockies by Sunday. The coastal regions from Oregon to California can expect rain and thunderstorms during this time. Winter Weather Advisories and Winter Storm Warnings are in effect for portions of the Intermountain West, Pacific Northwest, and California for heavy snow. While the cold front is pushing across the Pacific Northwest, west to southwesterly flow over the Continental Divide will lead to a warming and drying trend across much of the Central and Northern Plains. Temperatures will soar to as much as 20 to 30 degrees above normal, making it feel much more like spring. Strong high pressure will build over the eastern U.S., leading to below normal temperatures, however those will moderate toward the end of the period as the warmth pushes east. On the western edge of this high pressure, strong return flow will be present, with a deep layer of warm and moist air filtering into Texas from the Gulf of Mexico. A mid level shortwave will interact with this unstable and water loaded airmass, sparking showers and thunderstorms across southern and eastern Texas today. These will spread eastward into the Lower Mississippi Valley Sunday, and then northward up the Mississippi Valley and into the Upper Great Lakes during the day Monday. The Weather Prediction Center continues to carry a slight risk for excessive rainfall and flash flooding across southern Texas for today. Please refer to our website for more information concerning the heavy rain threat. The rainfall and cloud cover will also lead to below normal temperatures across Texas today as well. Krekeler/Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php