Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 257 AM EST Thu Feb 14 2019 Valid 12Z Thu Feb 14 2019 - 12Z Sat Feb 16 2019 ...Heavy rain and snow for the western U.S. and turning colder across the Plains through the end of the week... The big thing that will make weather headlines through the end of the week will be the ongoing atmospheric river event affecting California. A strong storm system approaching the coast will have an anomalous surge of tropical moisture surging inland ahead of the cold front. Several inches of rainfall is expected across much of southern California, with the highest totals for the coastal mountain ranges. There is a high risk of excessive rainfall on Thursday for the southern California mountains, capable of causing flash flooding and mudslides. Farther to the north, the Siskiyou Mountains and Sierra Nevada will get hammered with very heavy snow and blizzard conditions, with snowfall totals in excess of 3 feet for the higher mountains. Heavy snow is also in the forecast across the central and northern Rockies. A strong cold front surging southward across the Plains will usher in a much colder airmass from the Dakotas to Oklahoma, with temperatures on the order of 10 to 20 degrees below normal by Friday for many areas. A wave of low pressure developing on the frontal boundary should produce enough ascent and moisture for a band of light snow from the central plains to Kentucky through Friday night. Ahead of the front, mild conditions are expected across the Gulf Coast region and eastern U.S. to close out the week before colder weather arrives in time for the weekend. Snow is also expected across the northern Great Lakes and northern New England as the surface low lifts northward over Ontario and Quebec by Thursday night. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php