Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1200 PM EDT Fri Sep 13 2019 Valid 12Z Mon Sep 16 2019 - 12Z Fri Sep 20 2019 ...Potential Tropical Cyclone NINE to exit away from the Southeast next week... ...Overview and Guidance Evaluation/Preferences... Troughing in the West and ridging in the Midwest/East will be favored next week per the latest ensemble guidance. There remains uncertainty in the track/evolution of Potential Tropical Cyclone NINE just off the Southeast coast, but the models favor a track offshore after Monday at this point (see the latest information from the National Hurricane Center). In the Pacific, a larger amount of uncertainty at longer wavelengths suggests an increased weight toward the ensemble means by later next week, given significant run-to-run differences in most deterministic runs. Though a consensus blend sufficed to start, the 00Z/06Z GFS and Canadian departed from the ensemble consensus around Wednesday while the 00Z ECMWF appeared too aggressive out of the Gulf of Alaska around Thursday. With the 00Z GEFS mean likely too deep with central Pacific troughing and downstream ridging in the Pac NW, opted to rely on an ensemble blend of the 06Z GEFS mean, 00Z NAEFS mean, and 00Z ECMWF ensemble mean by next Friday that favored some troughing in the interior West as ridging moves into the Northeast/Atlantic Canada. ...Weather Highlights/Threats... Per the latest NHC track, "NINE" is forecast to bring some rain/wind to coastal areas of FL/GA/SC/NC before it turns eastward out to sea. With strong ridging in the central states, well-above average temperatures are expected next week from the High Plains/Upper Midwest into the Great Lakes region. Daytime max temperatures well into the 80s will be about 10-15F above average and overnight lows in the 60s to near 70F will be about 15-20F above average. Some locations may set record highs and/or record high minimums for the day. A frontal boundary will bring in cooler weather (back to near seasonal levels) and some generally light/modest rain fall midweek to the area. In the Pacific Northwest, a surface front and subsequent upper trough will bring a widespread chance of rain (some very high elevation snow) to the region early in the week, spreading through the northern/central Rockies before exiting onto the Plains. This may help tap some subtropical moisture out of Mexico on southwest flow aloft across the Southwest/Four Corners states early in the week before rainfall chances decrease. In the western Gulf of Mexico, a trough/wave associated with an upper low favors a chance of rainfall, potentially locally heavy, over southeastern/coastal Texas next week. Weak steering aloft may allow this area of rain to persist through the medium range forecast as some models show several inches of rainfall over the 5-day period. Fracasso Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml