Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 347 AM EDT Sun Sep 22 2019 Valid 12Z Sun Sep 22 2019 - 12Z Tue Sep 24 2019 ...A potent cold front will bring heavy rain from the Great Lakes to the Southern Plains today... ...Severe thunderstorms and flash flooding will be possible across central and southern Arizona on Monday... ...Temperatures will be 10 to 20 degrees above average over much of the eastern United States... A strong cold front currently extending from the Upper Great Lakes southwestward to the Central Plains and Southern High Plains will move eastward to the Northeast/Mid-Atlantic Coast by Tuesday. This boundary will produce numerous showers and thunderstorms in the Great Lakes and Central Plains/Midwest today. The biggest threat with these storms will be from flash flooding. Thus, a Slight Risk of excessive rainfall and Flash Flood Watches are in effect from Oklahoma to Michigan. Total rainfall amounts in these areas could add up to around 1 to 2 inches today, with locally higher amounts. By Monday, weaker and more scattered showers and thunderstorms will advance into the Northeast. The combination of an approaching cold front and moisture associated with Tropical Depression Lorena will lead to the possibility of severe storms and flash flooding across portions of Arizona on Monday. The Storm Prediction Center has issued a Slight Risk for severe thunderstorms, with strong winds and damaging hail being the main threat. A Slight Risk of excessive rainfall has also been issued over roughly the same area, where around an inch of rain could fall by Tuesday morning. Ahead of the cold front, temperatures will remain as much as 10 to 20 degrees above average across much of the eastern U.S. through Tuesday. High temperatures will peak in the 80s and low 90s, with overnight lows only dropping into the 60s. These low temperatures could break several daily high minimum temperature records across the Northeast. Meanwhile, slightly below average temperatures will be found in the west behind the cold front. A few scattered Freeze Warnings and Frost Advisories are in effect across the higher elevations of Wyoming and Colorado. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php