Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Sun Mar 26 2017 Valid 00Z Mon Mar 27 2017 - 00Z Wed Mar 29 2017 ...There is a slight risk of severe thunderstorms over portions of the Southern Plains... ...Heavy rain possible over parts of the Tennessee Valley... ...Rain/freezing rain possible over parts of the Upper Great Lakes and the Northeast... A complex system will impact much of the Central/Lower plains and eastern U.S. over the next couple of days. Two main low pressure systems will be in play: one which will weaken as it moves across the Upper Great Lakes tonight and into Southeast Canada Monday, and a second will continue to strengthen as it moves across the Southern Plains tonight, and into the Mid/Lower Mississippi Valley Monday. This second system will eventually traverse the Ohio Valley Monday night, before reaching the Atlantic Coast by Tuesday. A series of frontal boundaries will connect these two centers, and will be the epicenter for precipitation and convective activity. In the northeast U.S., precipitation will be in the cold sector, falling as a freezing rain over the next couple of days. Freezing Rain Advisories and Winter Weather Advisories are in effect from far eastern New York upwards through Maine. Elsewhere near the frontal boundaries and low pressure systems, rain showers and thunderstorms are expected. Widespread rain, heavy at times, will occur from the Mid Atlantic to the Upper Great Lakes in relation to the northern most low pressure system, especially along the frontal boundary regions. For the Southern Plains system, showers and thunderstorms are also expected generally just ahead of the associated cold front. However, given the strong nature of this system, and the strong pull of warm and unstable air flowing in off the Gulf of Mexico, combining with strong lift along the frontal boundary and low pressure system, ingredients are in place to produce strong to severe convection. The Storm Prediction Center has outlined a portion of south central Oklahoma and a small portion of northeast Texas as being in an enhanced risk for severe weather this evening and overnight, with an enhanced and slight risk expanding farther to encompass much of Oklahoma, portions of Northeast Texas, and far eastern Oklahoma. High winds, large hail, and tornadoes are all possible hazards as storms develop. Please refer to the Storm Prediction Center's web page for more information: www.cps.ncep.noaa.gov. Over the West Coast, a front will move onshore by Sunday evening continuing to move eastward to the Rockies by Monday evening. The storm will begin to produce rain and higher elevation snow over parts of the Pacific Northwest/Northern California that will expand inland to parts of the Northern Rockies by Sunday evening. The rain and higher elevation snow will move into parts of the Great Basin on Monday and into parts of the Central Rockies/Southwest on Monday afternoon into Monday evening. Behind the system, onshore flow will aid in producing coastal rain and higher elevation snow over parts of the Pacific Northwest/Northern California on Monday into Monday evening. Wix/Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php