095 FXUS02 KWBC 131959 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Wed May 13 2026 Valid 12Z Sat May 16 2026 - 12Z Wed May 20 2026 ...Central U.S. Heavy Rainfall/Runoff and Severe Weather Threat... ...Guidance/Predictability Assessment... The latest guidance captures the evolution from a zonal flow pattern at the beginning of the period, this weekend, to a more amplified one next week. There's uncertainty as to the timing and amplitude of certain embedded shortwaves within the broader digging trough in the West next week. There's consensus on a broad diffluent pattern setting up over the Central U.S., which will support severe storms and heavy rain potential. There's also a strong signal for an strong upper ridge to set up over the East. A general model blend consisting of the available deterministic guidance was used on day 3, followed by some inclusion of an ensemble mean on day 4 due to some of that uncertainty out West. Means are gradually increased in the blend through the end of the period due to some notable differences in another potential split flow pattern illustrated by the deterministic models. ...Weather/Hazards Highlights... Energetic upper trough/deepened surface low ejection over south- central then eastern Canada will lay down a trailing front with from the north-central U.S to the Northeast. Impulses, right entrance region upper jet lift and moisture/instability focus into the Upper Midwest portion of this front may support emerging convective development and potential for local training has prompted the expansion of a WPC Excessive Rainfall Outlook Marginal Risk area valid for Day 5/Sunday. Farther upstream system energies subsequently work into the West and downstream up across the central U.S. with less certainty this weekend into next week in amplifying flow. Passage may yield enhanced weekend winds and wildfire threat potential across the southern Rockies/high plains. There is also then an increasing signal that Plains cyclogenesis/frontogenesis, upper jet support and growing lead Gulf return flow may further set the stage to fuel an expanding central U.S. convective rainfall/runoff and severe weather threat pattern to monitor as indicated by SPC. Meanwhile, an eastward spreading upper ridge will spread well above normal pre-frontal temperatures across the Central to Eastern U.S. downstream this period that may support some local high temperature values. To the south, low level onshore flow will bring shower into Florida in proximity to upper low development near/east of the Bahamas. Kebede/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 $$