Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Thu Jul 28 2016 Valid 00Z Fri Jul 29 2016 - 00Z Sun Jul 31 2016 ...Heavy rain possible from the lower Mississippi valley to the Mid-Atlantic through Saturday... ...Severe thunderstorms possible Thursday evening for portions of the plains and the Mid-Atlantic... ...Hot and mostly dry conditions will persist through Friday across the West... Friday and much of the weekend will be quite wet for the eastern half of the U.S. as waves of low pressure along a quasi-stationary boundary move eastward over the next few days. The first significant wave of low pressure will move across the Mid-Atlantic and Northeast regions during Thursday evening and into Thursday night. The bulk of precipitation will concentrate along the central Appalachians in the evening and move towards Delmarva by tonight. Flash flooding and severe weather are both potential threats with this activity. By Friday, most of the precipitation will move across coastal New England while the Mid-Atlantic dries out. By Saturday, another wave of low pressure approaches the Mid-Atlantic, and convection will spread across the Tennessee Valley, Mid-Atlantic, and Northeast. Flash flooding will once again be a concern along with a marginal risk for severe weather. For more information on severe weather over the next few days, see the products issued by the Storm Prediction Center. The quasi-stationary front impacting the eastern U.S. also extends across the central and southern Plains and will remain there through the short term period. An upper level disturbance will help fire off a cluster of thunderstorms will move south from the northern Plains on Thursday evening and will move southward toward the southern Plains by Friday morning. The upper level disturbance driving this will move eastward along the stationary boundary by Friday afternoon. Thus, convection will begin to expand across the lower Mississippi Valley throughout Friday. By Friday night and into Saturday, scattered showers and thunderstorms can be expected across the Mississippi Valley and portions of the central/southern Plains. Typical diurnally driven thunderstorms across the central and eastern Gulf coast states can be expected on both Friday and Saturday--with the height of activity occurring during the late afternoon/evening. Isolated thunderstorms can also be expected across the higher terrain in the Southwest with most of the activity also occuring during the late afternoon/evening hours. With the upper level ridge continuing to sit over the western U.S., expect temperatures 5 to 15 degrees above average on Friday. By Saturday, this ridge will weaken--and thus high temperatures especially across the Pacific Northwest will return back to normal. There is an elevated risk for wild fires over the next few days for the West due to higher than normal temperatures and dry conditions. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php