Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Sun Sep 13 2015 Valid 00Z Mon Sep 14 2015 - 00Z Wed Sep 16 2015 ...Showers and a few thunderstorms expected for the Northeast tonight... ...Well above-average temperatures will expand from the central and northern plains to the Upper Midwest on Monday... An occluded low-pressure system will move across New England tonight, bringing showers and a few thunderstorms to much of the Northeast. Showers will persist into Monday morning, but should begin to taper off Monday afternoon as the surface low lifts northward into Quebec. A large area of high pressure behind the frontal system is bringing below average temperatures to most of the eastern U.S. today, and this will continue into Monday. Afternoon high temperatures on Monday will be 5 to 10 degrees below average across much of the eastern U.S. A cold front moving across the northern Intermountain West tonight will initially be mostly dry. This will begin to change on Monday as a vigorous upper-level disturbance from the Pacific Ocean begins to move into the West. Moisture will increase across the West and scattered showers and thunderstorms will become more common across the West Monday afternoon as well as Tuesday. Another Pacific low pressure system will approach the Northwest coastline late Tuesday, returning showers to the coastal Pacific Northwest. Also on Tuesday, a deepening surface low will move from the Intermountain West into the northern plains. Deep moisture will be rather slow to increase across the plains ahead of this system. Nonetheless, scattered thunderstorms are possible Tuesday afternoon from portions of the central plains into the Upper Midwest. Warm advection and rising heights ahead of this system will result in well above average temperatures across the central and northern plains on Monday, with afternoon high temperatures 10 to 20 degrees above average. These warm temperatures will expand eastward into parts of the Midwest on Tuesday. Ryan Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php