Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 450 PM EDT Sun Sep 20 2015 Valid 00Z Mon Sep 21 2015 - 00Z Wed Sep 23 2015 ...Showers expected to continue for portions of the Pacific Northwest... ...Showers and thunderstorms will increase in coverage across the southwestern U.S. on Monday... A strong, Canadian cold front continues to move south toward the Pacific Northwest today. As the cold front approaches the region from the northwest, strong onshore flow is allowing showers to move across the coastal portions of Washington state and the Cascades. This will continue through Sunday evening and into the early hours of the morning. By Monday morning, the cold front advances eastward toward the northern Rockies; consequently, precipitation will taper off with the exception of a few lingering showers in the higher elevations. Unfortunately, conditions will stay dry along the front as it moves across the Intermountain West. Behind the front, low dew points and strong winds are expected which could further aggravate fire weather conditions. An area of low pressure will drift northward along Baja California Sunday and into Monday. This low will bring a plume of tropical moisture which will spill across the Southwest by Monday afternoon as the low approaches southern Arizona. Southern California, Arizona and New Mexico can expect showers and thunderstorms to increase in coverage on Monday and will persist into Tuesday. Flash flooding will be a concern for these regions on both Monday and Tuesday. Please see WPC's excessive rainfall product for more information. The cold front that pushed off the East Coast this morning is bringing pleasant, fall-like conditions across the Upper Midwest to the Mid-Atlantic. Farther south, the front has stalled across the southern Plains and Southeast. This is generating showers and thunderstorms across north Texas and Oklahoma this afternoon. This area of convection will slide southeast across east Texas during early Monday morning and will move eastward across portions of the Southeast along the stationary front. Fanning Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php