Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 405 PM EDT Sun Apr 23 2017 Valid 00Z Mon Apr 24 2017 - 00Z Wed Apr 26 2017 ...Heavy rain over the Southeast is expected to move up the East Coast Monday into Tuesday... ...Unsettled weather continues across much of the western U.S.... A trend towards a more amplified upper-level pattern is anticipated across the U.S., which will translate to more unsettled conditions during the next few days. A deepening low pressure system has been bringing widespread rain over the interior section of the Southeast along with some thunderstorms near the Gulf Coast. This low will begin to interact with a tropical low currently bringing heavy rain over southern Florida, and merge as they approach coastal Carolinas Monday evening. Abundant moisture will then spread northward up the mid-Atlantic coast on Monday and into New England on Tuesday. It appears that the low will be slow to move out as rain should continue to last into Tuesday evening across much of the mid-Atlantic and New England coasts. As tropical moisture is expected to be injected into the system, there is some potential for heavy rainfall along the East Coast during the next couple of days. Over the western U.S., persistent deep-layer onshore flow has been bringing unsettled weather and cool conditions into the region. This pattern is expected to continue for the next few days with periods of rain and high-elevation snow across a wide area from all of the Pacific Northwest down to the Sierra Nevada and eastward across the Intermountain and much of the northern and central Rockies. The upper-level energy will reach the Plains and interact with a cold front over the northern Plains on Monday. Temperatures will be cold enough to support wintry precipitation near the Canadian border on Monday with rain farther south and falling temperatures behind the cold front. As the cold front pushes southward, the chance of thunderstorms will increase across the central Plains Tuesday evening. Above normal temperatures will drastically drop well below normal across the Plains on Tuesday following the frontal passage. Kong Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php