Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 251 PM EST Tue Dec 04 2018 Valid 00Z Wed Dec 05 2018 - 00Z Fri Dec 07 2018 ...Storm system to bring rain and mountain snow to California beginning tonight... ...Blast of cold air coming to Montana, Wyoming into the northern and central Plains... High pressure across much of the nation has allowed for a quiet start to the sensible weather impacts early this week. Changes are coming however, at least for California, as a slow moving upper level disturbance nears the West Coast tonight. While the track of the system will keep the heaviest rain/wind near the coast or offshore, wind gusts up to 50 mph will be possible for the southern Sierra Nevada Mountains into the Transverse Ranges of southern California through Wednesday morning as the associated frontal boundary nears the area. Rain and higher elevation snow will also begin to impact the Golden State by Wednesday morning with locally heavy rain possible for the Channel Islands into portions of the southern California coast through the day on Wednesday. There will be possible runoff concerns where heavy rain overlaps with sensitive burn scar locations. Higher elevation snow for the mountains of southern California and the Sierra Nevada range can also be expected, although accumulations should remain fairly light as a whole, as the slow moving storm system continues to impact southern portions of California through much of Thursday. Precipitation for the remainder of the U.S. will remain relatively light or non-existent through mid-day Thursday given any significant moisture is displaced well offshore into the western Atlantic or Gulf of Mexico. A reinforcing shot of colder air is forecast to enter the U.S. from Canada Wednesday into Thursday which will have the effect of bringing below average temperatures to a large portion of the central and northern High Plains to the Mississippi River. Thursday's high temperatures are forecast to range 10-20 degrees below average in the wake of a cold front stretching from the Great Lakes to the Texas Panhandle. Light snow (northern locations) and light rain (southern locations) will accompany the front as it works south and east but precipitation totals will stay very light through Thursday.. Otto Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php