Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 257 AM EST Sun Mar 05 2017 Valid 12Z Sun Mar 05 2017 - 12Z Tue Mar 07 2017 ...Heavy snow possible over the Cascades, Sierras, and the Intermountain West... ...Well above normal temperatures for the Central and Northern Plains... ...Heavy rains expected to wane across Southeastern Texas today... A cold front that moved across the Pacific Northwest and portions of the Intermountain West yesterday will progress southeast across southern California and toward the Rockies today. Continued onshore flow behind the front will lead to a prolonged period of moderate to heavy snow, especially in the higher elevations. Rain and thunderstorms can also be expected along much of the Pacific Coast, aided by yet another area of low pressure grazing the Pacific Northwest throughout the day. Winter Storm Warnings are currently in effect for much of northern California and the Sierra Nevada Mountain range through Monday, where accumulations of 3 to 4 feet are possible above 5,000 feet. Winter Weather Advisories are also in effect for portions of the Intermountain West and Pacific Northwest for continued heavy snow today. While the cold front is pushing across the Intermountain West, west to southwesterly flow sweeping off the Continental Divide will lead to a continued 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 once more today, continuing the springlike thermal seesaw. Meanwhile, strong high pressure will protect the eastern U.S. in the form of a cold air wedge east of the Appalachians. This will lead to below normal temperatures into Monday for this area, before warmer air slowly erodes the wedge. On the southwestern edge of this high pressure, strong return flow is present, resulting in a deep layer of warm and moist air across southern Texas and the Lower Mississippi Valley. A disturbance aloft is interacting with this moist and unstable airmass, sparking showers and thunderstorms across southern and eastern Texas. These will spread eastward into the Lower Mississippi Valley today, and then northward up the Mississippi Valley and into the Upper Great Lakes during the day Monday. Heavy rain will continue to be a concern along the Gulf Of Mexico in Texas through this morning, waning by the afternoon. Looking ahead to Monday and Tuesday...a merger of two low pressure systems will take place across the Northern Plains on Monday. The new system will gain strength quickly as it pushes across the Upper Mississippi Valley and into Canada Monday night into Tuesday. From this system will extend a strong cold front, expected to sweep across the Mississippi River Valley and Southern Plains Tuesday. A deep pull of Gulf moisture will take place ahead of this system (an extension of the warm surge already taking place across Texas and the Lower Mississippi Valley today), leading to widespread showers and thunderstorms across much of the Eastern U.S. Monday night through Tuesday. Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php