Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 431 AM EDT Fri Sep 08 2017 Valid 12Z Fri Sep 08 2017 - 12Z Sun Sep 10 2017 ...Hurricane Irma will begin impacting Florida this weekend... ...Very heavy rain possible for the southern tip of Florida... ...Heavy rain possible over the Northeast Coast of Florida... An old front draped over Southern Florida will slowly move northward to the northern parts of the Florida peninsula by Saturday evening. Tropical moisture will interact with the boundary to produce showers and thunderstorms over parts of the Florida peninsula through Saturday evening. Showers and thunderstorms associated with Hurricane Irma will begin to impact Southern Florida overnight Friday and continue Saturday night into Sunday. For the latest information on Irma, please refer to the National Hurricane Center latest advisory for information on storm track, intensity, and storm total precipitation(www.nhc.noaa.gov). Meanwhile, a deep upper-level trough over the Northeast/Great Lakes will aid in producing rain with embedded thunderstorms over parts of the Great Lakes into the Northeast on Friday. As the trough moves eastward, rain with embedded thunderstorms will be over parts of the Northeast on Saturday. In addition, circulation around and upper-level low along the Central Californian Coast will direct moisture from the Gulf of California and the Pacific into the Southwest/Southeastern California through Saturday evening. Diurnal heating will aid in producing showers and thunderstorms over parts of the Great Basin/Southwest/Southeastern California into parts of the Central/Southern Rockies through Saturday night. The areal coverage will be the greatest during the late afternoon into late evening on Friday and Saturday. Additionally, upper-level energy moving over the Northwest followed by a front moving onshore on Saturday will aid in producing rain over parts of the Pacific Northwest through Saturday night. Farther inland, upper-level impulses will aid in producing showers and thunderstorms over parts of the Northern Intermountain Region/Northern Rockies through Saturday. Another region of upper-level energy over the Northern High Plains will move into the Northern Plains overnight Friday into Saturday. The energy will aid in producing showers and thunderstorms over parts of the Northern Plains/Central High Plains overnight Friday moving into parts of the Northern/Central Plains on Saturday. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php