Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Sat Oct 26 2019 Valid 12Z Sat Oct 26 2019 - 12Z Mon Oct 28 2019 ...Heavy rain associated with a low pressure system is expected to spread rapidly northward from the central Gulf Coast toward the Great Lakes... ...A round of moderate to heavy snow is forecast for the northern and central Rockies as well as nearby High Plains... ...Severe thunderstorms possible today over the central Gulf Coast as post-tropical cyclone Olga makes landfall... Active weather is expected to spread rapidly northward from the Deep South into the Midwest today. This is the result of an energetic upper-level trough interacting with post-tropical cyclone Olga, which is ready to make landfall on the central Louisiana coast early this Saturday morning. A compact low pressure system is forecast to intensify as it moves rapidly up the Mississippi Valley today. Widespread rain is already impacting the Mississippi and Ohio Valleys well ahead of the storm center. As the center of Olga makes landfall across Louisiana early in the morning, a period of heavy rain together with increasing winds as well as the possibility of severe thunderstorms will spread across eastern Louisiana and into southern Mississippi. In addition, the heavy rainfall will increase the possibility of flash flooding in these areas. As the system intensifies and moves northward, heavy rain will become focused just to the west and northwest of the storm track, resulting in 2 to 3 inches of heavy rainfall today along the Mid-Mississippi Valley, followed by the Midwest this evening. By Sunday, the system is expected to weaken as it moves across the Great Lakes into southeastern Canada. However, widespread rain will move into much of the East Coast where an inch of rain can be expected from the Mid-Atlantic up into New England before the storm moves out to sea Sunday night. Meanwhile, a surge of cold air from western Canada will push southward through much of th western U.S. over the next few days. This will be accompanied by a round of moderate to heavy snow for the northern and central Rockies as well as the nearby High Plains. Up to a foot of snow is forecast, especially over the higher elevations. Cold high pressure will then move into the interior Northwest and down into the High Plains during the weekend. Meanwhile, an expansive high pressure system in the Western U.S. will continue to promote favorable conditions for the spreading of wildfires from Northern California into Southern California through Saturday. The greater threat today is expected to exist across the Transverse and Peninsular Ranges surrounding the Los Angeles and San Diego metropolitan regions with a combination of gusty winds and low relative humidities. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php