Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 146 PM EST Thu Jan 18 2018 Valid 00Z Fri Jan 19 2018 - 00Z Sun Jan 21 2018 ...Colder temperatures and unsettled weather returning to the West... ...Dry conditions and warmer temperatures extending from the Great Plains to the East... The latter half of the week is expected to mark the onset of a pattern change across the contiguous U.S. -- with unsettled weather and colder temperatures returning to the western U.S., while dry conditions and warmer temperatures spread from the central to the eastern U.S. In the West, a well-defined cold front extending from the northern Rockies back through northern California is forecast to push southeast during the period, reaching the central Rockies and southwestern U.S. by the early part of the weekend. In addition to colder temperatures, this front is expected to bring widespread precipitation, including mountain snows to the northern Rockies, northern Great Basin as well as northern California Thursday night into Friday. Late Friday into Saturday, precipitation is expected to shift further southeast into the Four Corners region, as well as the central and southern Rockies. Across the Northwest, an area of low pressure lingering north of Vancouver Island will continue to support unsettled weather across the the Pacific Northwest through Friday. This will be followed by another frontal system which will approach the coast, bringing additional wet weather to the region on Saturday. Further east, high pressure currently centered over the lower Mississippi valley is forecast to shift further east -- allowing warmer air to spread east from the Great Plains into the eastern U.S. By Saturday, seasonal to above average temperatures are expected to prevail across much of the eastern two-thirds of the contiguous U.S., marking a stark contrast to temperatures observed earlier in the week. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php