Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 429 AM EDT Thu Sep 12 2013 Valid 12Z Thu Sep 12 2013 - 12Z Sat Sep 14 2013 ...Ongoing significant rainfall event is expected to continue across the central-southern Rockies and High Plain - promoting additional concerns for excessive amounts... ...Mid summer-like heat and humidity coming to an end across the East... ...Strong to severe thunderstorms will be possible across portions of the Northeast... The ongoing heavy to excessive rains occurring over portions of the central-southern Rockies and the adjacent High Plains are expected to continue through today. The Days 1 & 2 WPC Excessive Rainfall Outlooks, indicate a slight risk for excessive amounts across portions of the region from Thu into Sat morning. A series of weak impulses lifting out ahead of an upper low centered over the southwestern U.S. is expected to support heavy rains across the southern Rockies as they interact with a deep moisture plume streaming across the region. A larger threat is expected further to the north across central High Plain and Rockies, where in addition to the aforementioned impulses, moisture converging along and behind a front dropping through the region is expected to interact with strong upper jet dynamics to produce heavy rains across the region. Above average temperatures and mid summer-like humidity are expected to persist for another day across much of the East before coming to an end as an amplifying upper level system sends a series of cold fronts through the East, ushering in more autumn-like temperatures from the Great Lakes to the Northeast and mid Atlantic states near the end of the weak. With the break in the heat and humidity will come the possibility of showers and thunderstorms. Some of these storms may be strong to severe, especially across portions of the Northeast where the Storm Prediction Center has indicated a slight risk for severe storms today. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php