Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 247 PM EST Wed Dec 18 2019 Valid 00Z Thu Dec 19 2019 - 00Z Sat Dec 21 2019 ...Long duration precipitation event to impact the Pacific Northwest as rainfall spreads across the Gulf Coast... ...Arctic air spills into New England while another round of mild temperatures begin to spread over the Great Plains... Multiple rounds of low pressure systems will cause a sustained period of continuous rainfall, and snowfall at higher elevations, over the Pacific Northwest through Saturday. Rainfall amounts between 3-6 inches are possible with some isolated areas ultimately receiving up to 10 inches. Thus, a slight risk of excessive rainfall has been issued for the northern and central coast of Oregon. Higher elevations could accumulate between 1-3 feet with locally higher amounts by Sunday morning. A closed upper level low will descend into Texas by Friday spawning a surface low pressure system and associated rainfall event for the Gulf coast this weekend. Meanwhile an upper level low currently over Ontario will produce lake effect snow for the Lower Great Lakes and New England areas tonight. Arctic air currently over the Northern Plains and Upper Midwest will spread into the Northeast behind the current system, and drop temperatures to around 15-20 degrees below normal. As the Northeast cools, the Great Plains and Lakes will warm as upper level ridging returns to the central U.S. this weekend. Kebede Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php