Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Thu Oct 18 2018 Valid 00Z Fri Oct 19 2018 - 00Z Sun Oct 21 2018 ...Heavy rainfall and localized flash flooding continuing into Friday across portions of central Texas... ...Scattered rain will accompany a cold front as it passes through the Ohio Valley and the Northeast... ...Chilly overnight temperatures on Thursday resulting in some frost advisories and freeze warnings for parts of the lower Ohio Valley and northern Mid-Atlantic... Moisture overriding a stationary front in the northern Gulf of Mexico will continue to produce showers and thunderstorms across Texas, with pockets of heavy rainfall possible. Excessive rainfall and flash flooding will be possible, especially in portions of the already very saturated Hill Country. Flash flood watches and warnings remain in effect through Friday morning. A secondary area of heavy rainfall is also expected along the southern and central Texas Gulf Coast, which is should persist through the rest of the week as the boundary in the Gulf of Mexico eventually shifts very slowly northward. Scattered showers and thunderstorms will also persist through the short range period across northern Florida near the eastern extent of this stationary front. A cold front dropping into the northern tier by Friday will allow for the development of scattered rain showers along the boundary as it shifts eastward through the Midwest on Friday, and into the Northeast and Mid-Atlantic by Saturday. Locally heavy rainfall is possible in spots, but this boundary should be fairly quick moving which would limit any threat for flash flooding. Expect showers to also extend southward into portions of the Mississippi Valley and Southern Plains as lingering Gulf of Mexico moisture gets pulled northward towards the front. Cold air filtering in behind the boundary may also allow for light snow showers across the Great Lakes and the Upper Midwest. Temperature wise, broad upper level troughing and surface high pressure will keep temperatures near or slightly below normal for this time of the year across the Eastern states. Numerous frost advisories and pockets of freeze warnings are in effect from the lower Ohio Valley to the northern Mid-Atlantic and parts of the Northeast due to near freezing overnight lows tonight. A cold front passing through the nations mid-section will also keep temperatures through the short range period chilly, with below normal temperature anomalies of 5 to 15 degrees possible, especially across portions of the Upper Great Lakes and the Southern Plains. Out west, upper level ridging should keep temperatures rather warm for this time of the year. Santorelli Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php