478 FXUS02 KWBC 161848 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 248 PM EDT Tue Jun 16 2026 Valid 12Z Fri Jun 19 2026 - 12Z Tue Jun 23 2026 ...Significant Excessive Rainfall/Flooding Threat to persist for the Gulf Coast States and Southeast into Friday/Saturday... ...Weekend to early next week heavy rains emerge from the Central Plains/Midwest/Ohio Valley to the Northeast/Mid-Atlantic... ...Pattern Overview and Guidance/Predictability Assessment... The leftover moisture associated with current Potential Tropical Cyclone One will still be entangled with a frontal boundary over the Southeast at the start of the period, continuing a heavy/excessive rainfall and flash flooding threat at the end of the week. Elsewhere, hot West/Southwest upper ridging will tend to flatten and become east-west oriented over the southern tier this period as an east Pacific upper trough progresses over the northern two- thirds of the CONUS. Upper ridging may start to increase over Texas by next Tuesday and beyond. Otherwise, quasi-zonal flow will dominate which leads to decreased confidence in system timing. Guidance forecast spread remains generally better than average for the Fri-Sun period then increases next week with flow transition. Accordingly, mostly favor a compatible multi-model and ensemble mean and machine learning guidance blend for the period which does not favor any specific deterministic solution. This also acts to maintain best WPC product continuity. ...Weather/Hazards Highlights... Potential Tropical Cyclone One will likely be absorbed into a front over the Southeast by the start of this period, but the infusion of deep tropical moisture and instability will maintain the excessive rainfall/flash flooding threat. Please also see the WPC Excessive Rainfall Discussion (ERD) and Hazards Outlook Chart (linked below) for additional risk details. This weekend, a Colorado low looks to form and track over the Central Plains to the Great Lakes then the Northeast. Deepening moisture lifting into this system and associated frontal system genesis should lead to sizable areas of heavy convective rain with weekend focus across the Central Plains/Midwest/Ohio Valley states expanding to the Northeast/Mid-Atlantic early next week. West Coast upper ridging keeps temperatures 10-20 degrees above normal over the Northwest/northern Intermountain West on Friday with a northern stream low over BC breaking down the ridge into the weekend, knocking down temperatures back toward normal. Some ridging looks to return to the West Coast early next week with warmer temperatures again for the Pac NW and northern Great Basin. Otherwise, closer to normal summer temperatures are expected across the Lower 48, though the tropical moisture along the Gulf Coast will maintain high nighttime temperatures that, along with southern tier upper ridging, may support hazardous heat and high humidity levels over portions of the Florida Peninsula and the Gulf Coast. HeatRisk levels may exceed Moderate to Major levels from parts of Texas eastward to the Southeast/Florida next week. Fracasso/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 $$