Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 319 AM EDT Sun Jul 13 2014 Valid 12Z Sun Jul 13 2014 - 12Z Tue Jul 15 2014 ...Heavy showers and thundershowers will affect a large area from Colorado Front Range eastward to the Ohio Valley and the Northeast... ...Heat to continue in the Pacific Northwest although some relief briefly possible in coastal locations... ...Midsummer cool snap still on store for North Central US into the Midwest during a period that is often the hottest time of the year... Lots of factors will be coming together over next several days for widespread showers and thunderstorms as an unusually active pattern will take hold over next several days. A series of initially weak weather disturbances will give way to a strong cold front that will push eastward in fits and starts. This cold front will drag very cool area across the northern heartland of the country will fire up numerous showers and thunderstorms from the Front Range of the Rocky Mountains across the Central Plains, the Mid Mississippi Valley, the Midwest, Ohio Valley and Northeast. On Sunday, Monday and Tuesday, the possibility of localized flash flooding and severe weather will track eastward with widespread thunderstorm activity especially in the late afternoon and evening. Hot weather with some scattered afternoon and evening scattered thundershowers will continue over the far West with 100 degree weather extending into the Pacific Northwest. An upper disturbance is expected to move onshore on Monday...bringing some temporary relief to the unusually hot temperatures along coastal Oregon and Washington. The leading edge of the expected July cool snap has already moved across North Dakota and northern Minnesota and will continue to move south and eastward over the next 3 days. As cooler air spreads across the Northern Plains, Upper Mississippi Valley and Midwest on Sunday, very cool air aloft will lead to instability showers across the Upper Midwest on late Sunday into Monday. Daytime temperatures on Monday may be in the 50s which is more typical for late September than what is typically the warmest time of the year. The cool air will continue to move eastward across the Ohio Valley into the Northeast on Tuesday, accompanied by widespread showers and thunderstorms followed by temperatures and humidity that will be atypically low for mid July. Kocin Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php