Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 337 AM EDT Wed Oct 23 2013 Valid 12Z Wed Oct 23 2013 - 12Z Fri Oct 25 2013 ***Unseasonably cool over the eastern half of the U.S.*** ***Lake-effect rain and snow showers near the Great Lakes*** ***Nice weather for the West Coast and Inter-Mountain West*** The main story making weather headlines through the end of the work week will be the much cooler temperatures east of the Mississippi River. A pronounced trough has developed over the Eastern U.S., and this will allow for a series of disturbances to move southeastward from the Upper Midwest and into the Southeast states. Each of these systems will help to reinforce the unseasonably cool weather that is expected to continue through Friday. Many locations in the Ohio Valley have frost and freeze advisories/warnings for expected overnight lows in the upper 20s to mid 30s, which is at least 10 degrees below normal. The trough pattern is creating enough wind flow over the Great Lakes to produce some of the first lake-effect precipitation of the season. Temperatures will be marginal concerning snowfall potential, and the chance of snow will be highest during the overnight hours and for any higher elevations in Michigan and Upstate New York. Elsewhere, cold showers can be expected from time to time. Some rainfall is also likely near the Mid-Atlantic coast as a surface low develops over the offshore waters of the western Atlantic Ocean. Scattered showers and storms are likely for South Florida as the cold front advances through the state. Over the Western U.S., very pleasant conditions can be expected through Friday as upper level ridging governs the weather pattern. Sunny to partly cloudy conditions along with seasonal to above average temperatures are expected. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php