199 FXUS02 KWBC 150747 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 347 AM EDT Mon Jun 15 2026 Valid 12Z Thu Jun 18 2026 - 12Z Mon Jun 22 2026 ...Significant Excessive Rainfall/Flooding Threat for the Gulf Coast States along with Ohio Valley/Mid-South Heavy Rainfall... ...Pattern Overview and Guidance/Predictability Assessment... Guidance forecast clustering overall remains better than average, keeping confidence in the evolution of the larger scale upper pattern evolution featuring a hot West/Southwest to Southern U.S.tier ridge shift and periodic downstream energy reinforcement from Canada into a central to eastern U.S. mean trough favoring Midwest/Ohio Valley/Mid-South heavy rainfall. This amplified pattern should trend more zonal late period, but remain active. The interaction of tropical features/deep moisture slated to feed from Mexico to the Gulf and already wet Gulf Coast states portends high likelihood of a copious/impactful rainfall/runoff event. Details are uncertain given the varied handling/focus, but NHC shows a 30 percent probability of tropical development to monitor. Overall, a favored guidance blend with some focus shift from the models later this week more toward ensemble means/machine learning guidance by the weekend provides a solid forecast basis with smaller scale system variances mitigated consistent with individual predictability. This solution is overall in line with National Blend of Models trends and offers good WPC product continuity. ...Weather/Hazards Highlights... A wavy front lingering from the Southeast U.S. through the Gulf Coast states this week and deep tropical moisture influx/pooling will provide a focus for ample/repeat heavy rain and thunderstorms. Regardless of any sort of tropical development in the northwest Gulf, deep tropical moisture return and instability will interact with the generally west to east oriented front to fuel an excessive rainfall/flash flooding threat. The WPC Day 4/Thursday Excessive Rainfall Outlook (ERO) shows a Gulf Coast Slight Risk area along with the introduction of a collaborated Moderate Risk area for the central Gulf Coast/Lower Mississippi Valley. The Day 5/Friday ERO shows a Slight Risk area broadly across this rain soaked region. Farther north, a heavy rain and strong thunderstorm threat remains meanwhile slated mid-later week as a series of energetic and progressive northern stream shortwave and surface lows/fronts dig from the north-central U.S. through the Ohio Valley/Mid-South. WPC Day 4/Thursday Marginal and Slight Risk areas are depicted, linking with the more tropically fueled Gulf Coast threat later week. There is also a SPC severe weather threat area from the Ohio Valley to the Mid-Atlantic Thursday to monitor. Threat potential may persist later period as systems refire activity, but also expand focus to the Northeast and Southeast with frontal approach. Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$