Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EST Tue Jan 09 2018 Valid 12Z Tue Jan 09 2018 - 12Z Thu Jan 11 2018 ...High risk of flash flooding over portions of California in areas of burn scars... ...Milder conditions expected over most of the U.S... As a Pacific frontal system moves into southern California, heavy rainfall will continue spreading across the region. Terrain will also aid in increasing rainfall rates. Burn scars from the active fire weather season will make conditions favorable for flash flooding--in addition to mudslides, debris flow, and other hydrologic issues. Because of the heavy rainfall and other conditions in place, a high risk of flash flooding is possible through Tuesday night. By Wednesday, the front will move east toward the southern Plains--diminishing the rainfall over southern California. In addition to the heavy rainfall across the area, snow across the Sierra Nevada will also occur during this event. A separate frontal system will also approach the Pacific Northwest this morning and move inland during the day. Onshore flow will promote an increase in rainfall across the area throughout the day in addition to higher elevation snow--which will begin to taper off by Wednesday morning. The front will continue pushing eastward across the Intermountain West on Tuesday evening and into Wednesday morning. Precipitation, including higher elevation snow, will spread across the entire Intermountain West on Wednesday. By Thursday, most of this activity will have shifted east of the Rockies. There will be no rest for the weary, however, as another system approaches the Pacific Northwest on Thursday morning--giving way to more precipitation across that area. Temperatures across the central and eastern U.S. will be well above normal through Thursday. However, another Arctic airmass begins to dive across the northern Plains by Thursday--bringing very cold temperatures to the U.S. once again. These temperatures are expected to spread eastward beyond the short term period. Reinhart Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php