Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 358 PM EDT Sun May 14 2017 Valid 00Z Mon May 15 2017 - 00Z Wed May 17 2017 ...Heavy precipitation possible over parts of the Cascades... ...Heavy rain possible over parts of the Upper Great Lakes... Deep upper-level trough over the West Coast will slowly move inland to the Northern Rockies southward to the Southwest by Tuesday. The system will produce rain and higher elevation snow over parts of the Pacific Northwest/Northern California into parts of the Northern Rockies that will temporarily end over most places by Monday morning. Weak onshore flow over parts of the Northwest will stop overnight Sunday. A new round of onshore flow will move into the Pacific Northwest by Monday evening continuing into Tuesday. The increase of moisture will aid in developing additional rain and higher elevation snow over parts of the Pacific Northwest and the Northern Rockies on Monday afternoon into evening. On Monday evening, rain will develop over parts of California and into the Great Basin. The rain will mainly stop over California and the Great Basin by Tuesday. The rain will increase in intensity over the Northwest overnight Monday into Tuesday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php