Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 458 PM EDT Thu Jul 31 2014 Valid 00Z Fri Aug 01 2014 - 00Z Sun Aug 03 2014 ...Cool and dry conditions along the East Coast will give way to higher chance of rain and thunderstorms towards the weekend... ...Showers and thunderstorms linger along the Gulf Coast and into the southern Rockies... The board and deep upper-level trough that has provided unusually cool mid-summer weather for much of the eastern two-thirds of the country is expected to gradually weaken over the next couple of days. As the trough "lifts out" or retreats into eastern Canada, return flow from the western Atlantic is expected to bring increasing moisture into the Eastern Seaboard by the end of the week. Showers and thunderstorms, aided by an upslope flow ahead of a warm front, will first appear in the southern Appalachians on Friday. The precipitation should then head northward and overspread the coastal mid-Atlantic and into southern New England by Saturday morning. Farther west across much of the central and northern U.S. however, conditions will remain cool and mostly rain-free through the rest of the week. A chance of rain and thunderstorms can be expected in the Great Lakes due to close proximity to the retreating upper trough. Farther south, showers and thunderstorms will be the rule near and south of a stalled front from Florida westward along the Gulf Coast and into the southern Rockies. Out west, widely scattered showers and thunderstorms can be expected across the interior mountains. Summer heat will gradually lose it grip in the interior Pacific Northwest into the northern Rockies by the end of the week. Otherwise, dry condition will prevail along the West Coast and into the Desert Southwest. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php