Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 335 AM EDT Sun Sep 13 2015 Valid 12Z Sun Sep 13 2015 - 12Z Tue Sep 15 2015 ...Temperatures will be 15 to 20 degrees above average over parts of the Northern Plains into the Central High Plains... Low pressure over the Northeast will slowly move northward into Southeastern Canada by Monday evening. The system will produce showers and thunderstorms over parts of the Northeast/Lower Great Lakes into the Central Appalachians and Coastal Mid-Atlantic that will likewise lift sluggishly into Southeastern Canada. By Monday evening only light rain will linger over parts of Northern Maine. In addition, the associated front will linger over the southern portion of Florida aiding in the development of showers and thunderstorms over the region through Monday. A second front will move slowly out of Southwestern Canada into the Northern Tier States coming to rest over parts of the Upper Mississippi Valley westward to the Northern Plains and over parts of the Pacific Northwest/Northern California by Monday evening. Upper-level energy will move inland over parts of the Pacific Northwest on Monday. The energy will trigger showers and thunderstorms over parts of the interior Pacific Northwest and Northern California eastward to the Northern Rockies by Monday evening. Additionally, weak onshore flow over parts of the Northwest Coast will trigger light rain along some of the coastal regions of the Northwest on Monday evening. Meanwhile, upper-level energy over California will move northeastward to the Central Rockies by Monday. A plume of moisture off the Gulf of California will interact with the energy to produce showers and thunderstorms over parts of the Southwest Sunday afternoon into evening that will expand into parts of the Great Basin and parts of the Southern/Central Rockies on Monday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php