Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 247 AM EDT Sat Oct 31 2020 Valid 12Z Sat Oct 31 2020 - 12Z Mon Nov 02 2020 ...Cold air will be the main theme across much of the Eastern half of the US this weekend, with generally very warm and dry weather across the West and Southwest... ...Light Rain changing to lake enhanced snow showers across the Great Lakes into Northeast Sunday into Monday... A dome of high pressure and associated push of seasonally cold air across the northern Appalachians into the East Coast today. Frost and Freeze watches and warnings are in effect across the Ohio and northern Tennessee Valley stretching over to the Mid-Atlantic for this morning. The cold air will remain in place with daytime highs 10 to 20 degrees below average Saturday. A strong Pacific low has moved into the southern Canadian Prairies. The strong pressure gradient is leading to strong winds across the High Plains and into the Dakotas today with wind advisories and a few high wind warnings in effect. This storm will continue to progress quickly north of the Great Lakes but will bring some increased chances of light showers late Saturday into Sunday, before a reinforcing cold Canadian airmass drives through dropping the temperatures below average again into Sunday/Monday. This cold air should help to turn some showers into snow but also help to activate Lake-Effect snow in the traditional belts downstream of the warmer lakes. This shot of cold air will lead to 15-20 degrees below average temps across the Midwest bleeding into the Southern Plains and Lower Mississippi valley behind the cold front, though should generally dry away from the Great Lakes and south of the Ohio River. By Monday, return moisture flow off the Atlantic ahead of the cold front should increase the chance for showers particularly closer to the coast and into New England. Further south, persistent onshore flow in the vicinity of a stationary front across South Florida will keep continued chance for heavy rainfall producing thunderstorms. They will be scattered in nature but may produce some isolated localized flooding concerns as the Weather Prediction Center continues to maintain a Marginal Risk of Excessive Rainfall for this area. Elsewhere, it is fairly status quo across the Western US. The moisture stream continues to be well north and so sunny skies and dry conditions will continue the drought. Temperatures should not be extreme, but 10 to 15 degrees above average. Gallina Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php