Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 429 PM EDT Mon May 08 2017 Valid 00Z Tue May 09 2017 - 00Z Thu May 11 2017 ...There is a slight risk for severe thunderstorms across portions of the Central/Southern High Plains... ...Heavy rain possible over parts of the Ohio Valley... ...Temperatures will be 10 to 20 degrees below average over the Southwest... A wave of low pressure over Northern Plains/Upper Mississippi Valley will move southeastward to the Ohio Valley by Wednesday morning. Showers and thunderstorms will develop along the associated boundary from parts of the Upper/Middle Mississippi Valley into the Ohio Valley that will extend from the Southern Mid-Atlantic to the Ohio Valley to the Central Plains by Wednesday. Meanwhile, a deep upper-level low over Northwestern Mexico/Southern California will slowly move northeastward to the Southwest/Southern Rockies by Wednesday. The storm will produce showers and thunderstorms over parts of Central/Southern California eastward to the Central/Southern High Plains that will move eastward into the Central/Southern Plains while ending over the western portion of the Great Basin/Central California by Wednesday. The showers and thunderstorms will continue over the other portions of the region. Elsewhere, another deep upper-level low over the Northeast will slowly weaken while a portion of the low will move eastward off New England Coast by Wednesday. The northwestern portion of the upper-level low will move northwestward into South-Central Canada by Wednesday, too. The system will produce rain and snow showers over parts of the Lower Great Lakes/Northern Appalachians through Tuesday afternoon. Rain showers will continue over parts of Northern New England through Wednesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php