Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 457 PM EDT Wed Aug 05 2015 Valid 00Z Thu Aug 06 2015 - 00Z Sat Aug 08 2015 ...Wet weather expected from the Ohio and Tennessee River Valleys into the Mid-Atlantic region through Friday morning... ...Triple digit temperatures for the southern Plains will continue and expand toward the east... Hot and humid conditions will persist across the southeastern quadrant of the country, south of a slow moving front which currently extends from the mid-Atlantic coast to the Kansas/Oklahoma border. Moisture near this frontal boundary will interact with an upper level disturbance currently located over Missouri, forecast to reach the central and southern Appalachians Thursday evening, helping to produce wet weather along and south of the Ohio River and east of the Mississippi through Thursday. Periods of heavy rain will likely be greatest near the front this evening and along the mid-Atlantic coast Thursday night into Friday as low pressure organizes near eastern North Carolina. Given wet antecedent conditions near the Ohio River Valley, the threat for flash flooding will be greatest from southeastern Missouri into Kentucky. Upper level ridging over Arizona and New Mexico will expand over the next couple of days while shifting east. The result will be at least a continuation of, and perhaps an increase in, the number of 100+ degree high temperatures, which will extend from eastern New Mexico to the lower Mississippi River Valley. Given high humidity, heat indices will be greatest, from 100 to 110 degrees, from Texas and Oklahoma to the lower Mississippi River Valley through the end of the week. Across the north-central U.S., a combination of two upper level disturbances and a complex frontal pattern will result in wet conditions throughout the northern Plains. Rainfall will not be constant, but periods of heavy rainfall will accompany showers and thunderstorms over the next 48 hours with one to two inches expected for several locations. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php