Extended Forecast Discussion NWS Weather Prediction Center College Park MD 257 AM EDT Sun Jul 14 2019 Valid 12Z Wed Jul 17 2019 - 12Z Sun Jul 21 2019 ...Tropical Storm Barry expected to weaken and dissipate prior to the extended period but will continue to produce areas of heavy rainfall... ...Overview and Guidance/Predictability Assessment... ...Weather Highlights/Threats... Tropical Storm Barry made landfall in Louisiana Saturday afternoon and is forecast to continue to weaken and dissipate by Monday evening over Missouri/Mid-Mississippi Valley, prior to the start of the extended forecast. The low will become devoid of tropical characteristics and will be absorbed in the westerly flow by late Thursday. Heavier rain associated with the remnants of Barry will spread from western Tennessee to Ohio and western Pennsylvania by Wednesday morning; and may very well enhance rainfall across the Northeast/northern Mid-Atlantic region as the front passes through Thursday through Friday. As ridging over southern and central portions of the U.S. remains in place a vast majority of the Southwest, Southern and Central Rockies, and the High Plains will remain warmer and drier through this coming week. Warmer than average temperatures are expected across these parts and a few locations will have above normal temperatures that may tie or set new daily high minimum records. Above normal temperatures with some pockets of plus 10F or greater anomalies will spread from the Northern Plains to the Northeast U.S. through Wednesday, with some warmth lingering over the Northeast into Friday. Portions of the Central Plains and Middle Mississippi Valley will reach 10 to 15F above average by the end of the forecast period. Heat indices will be around 105 to 115F, which will likely require the future issuance of heat advisories. The Pacific Northwest will trend cooler by Friday with highs 5 to 10F cooler than average. Across the northern states a quasi-zonal flow pattern will develop. A series of disturbances will pass through southern Canada and the northern tier states. Showers and thunderstorms capable of producing up to 2.25 inches will move through the Northern Plains, Upper Mississippi Valley and into the Upper Great Lakes region Wednesday and Thursday. Then, into the Lower Great Lakes and Northeast Thursday through Friday. There may be periods where the rainfall amounts, or rates, become excessive as the frontal boundary stalls over the region. The pattern across the West will transition as a low approaches the Pacific Northwest toward the end of the week. This would bring a period of steadier rainfall with additional terrain enhancement between the Pacific Northwest coast and the Cascades. The latest model guidance shows some spread on the strength, timing and placement of this feature. Again, the ECMWF appeared to have better support from the ensemble means, and thus was weighted more heavily in the medium range forecast and maintains previous WPC forecast continuity. Campbell 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