Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 429 PM EDT Thu Oct 24 2013 Valid 00Z Fri Oct 25 2013 - 00Z Sun Oct 27 2013 ...Very cool and tranquil autumn weather expected to prevail across the eastern half of the country before the arrival of cold rain in the upper Great Lakes by Saturday... ...Mostly fine weather for the West except some snow or rain showers in Colorado and New Mexico... As a high amplitude upper-level ridge forecast to remain anchored over western Canada for the next few days, a cool flow from Canada is expected to persist across the eastern half of the country for the next couple of days. A cool high pressure system will continue to bring below normal temperatures eastward into the East Coast followed by a reinforcing shot of cool air from Canada on Friday and into the weekend. A low pressure system in between these two highs will drop southeastward from central Canada and will reach the Great Lakes area by Saturday. The lake-effect rain showers should become more widely scattered later on Friday before the arrival of cold rain in the upper Great Lakes early on Saturday. Temperatures are expected to be 5 to 15 degrees below normal from the central Plains eastward. Much of the West will enjoy mild and pleasant autumn weather under the upper-level ridge. The exception will be from the Four-Corners eastward into Colorado and New Mexico where some snow or rain showers are expected as energy associated with an upper-level shortwave moves across. Temperatures are expected to be 5 to 10 degrees above normal. By early Saturday, return flow from the Gulf of Mexico could begin to trigger isolated to scattered thunderstorms in the southern Plains. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php