Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 PM EST Sat Nov 11 2017 Valid 00Z Sun Nov 12 2017 - 00Z Tue Nov 14 2017 ...Heavy rain possible for parts of the Pacific Northwest... West to east upper-level flow with low amplitude to upper-level impulses is contributing to difficulty in maintaining coherent surface features. One upper-level feature over the Northern Plains will move eastward to the Mid-Atlantic/Central Appalachians by Monday. The system produces rain over parts of the Central Plains/Middle Mississippi Valley that will move eastward to the Mid-Atlantic/Lower Great Lakes/Central Appalachians by Monday, too. A second feature over the Upper Great Lakes will move eastward to Northern Maine by Sunday evening. The energy will produce light snow over parts of the Upper Great Lakes through to Sunday afternoon. Meanwhile, moisture from the Gulf of Mexico will flow northward over The coldest weather of the season is making its presence known across much of the eastern U.S. after the passage of an arctic front earlier on Friday. High temperatures 15 to 25 degrees below average by early November standards are making it feel more like January, and numerous freeze warnings are in effect from South Carolina to Long Island, New York, for overnight lows in the 20s to low 30s. Record lows will be possible across parts of the Ohio Valley, Great Lakes, northern Mid Atlantic, and Northeast including many of the major cities in the region on Saturday morning and again on Sunday morning across the Northeast. Across the West, a front approaching the region from the Pacific will bring a period of widespread rain to western Washington, Oregon, and also northern California, and snow for the highest elevations. The southwestern U.S. will be under the influence of a strong upper level ridge providing warm and dry weather through the weekend. Scattered showers are possible along the East Coast of Florida with moist easterly flow behind the cold front. Given the lack of instability and deep moisture, little in the way of thunderstorm activity is expected nationwide. Krekeler Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php