Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Mon Aug 13 2018 Valid 00Z Tue Aug 14 2018 - 00Z Thu Aug 16 2018 ...Heavy rain possible over parts of the Northern/Central Appalachians... ...Heavy rain possible over parts of the Central/Southern Plains and parts of the Middle/Lower Mississippi Valley... A quasi-stationary front extending along the coast of the New England, the Mid-Atlantic and Southeast will result in chances of showers and thunderstorms through the next couple days. A surface low pressure system embedded in this frontal system, combined with a strong upper level low, will allow for strong moisture advection into the northern Mid Atlantic and southern New England, where rain and thunderstorms will be likely today through Tuesday. The Weather Prediction Center has issued a slight risk of excessive rainfall and flash flooding in this region through tonight. Furthermore, eastern Pennsylvania, southern New York, and northwest New Jersey are outlined in a moderate risk through tonight, highlighting that rain and flash flood potential will be greatest in this area. Flash Flood Watches and warnings are also currently in effect this afternoon for this region. The threat for flash flooding will taper off through the day Tuesday as the upper level low driving this system shifts inland and loses strength, becoming an open wave. Meanwhile, the back side of the above mentioned frontal system will stretch back into the southern Plains. Here another strong upper level low pressure system will couple with a surface low pressure system, and allow for the strong advection of warm and moist air northward into the Plains from the Gulf of Mexico. This will also be an epicenter for scattered to numerous showers and thunderstorms through at least mid-week. The Weather Prediction Center has outlined a portion of the Central and Southern Plains as being in a slight risk for excessive rainfall and flash flooding through tonight. This area will transition slightly eastward and encompass a portion of the Middle Mississippi Valley for Tuesday and Tuesday night, and then continue into the Middle Mississippi and Ohio Valley for Wednesday and Wednesday night. Elsewhere, weak monsoonal moisture and daytime heating will aid in producing showers and thunderstorms over parts of the Southwest/Great Basin and the Southern/Central Rockies through this evening. Air Quality Alerts also remain in place across a large portion of Central California as well as much of inland Washington and northern Idaho as wildfires continue to infuse the air with copious amounts of smoke. Red Flag warnings and Fire Weather Watches are also in effect for much of Nevada, as well as portions of southern Wyoming. Wix Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php