Extended Forecast Discussion NWS Weather Prediction Center College Park MD 216 PM EDT Sun Jun 05 2022 Valid 12Z Wed Jun 08 2022 - 12Z Sun Jun 12 2022 ...Overview and Sensible Weather/Threat Highlights... A series of shortwaves within near zonal flow will act to locally enhance a broadly active convective weather pattern from the Rockies/Plains to the East this week as heavy rainfall and strong thunderstorms are fueled by moisture and instability pooling near a wavy frontal boundary. Exact locations of the heaviest rain will remain extremely difficult to pinpoint given the convective nature of this activity, though local flooding concerns may be possible within convective clusters and where cells repeat/train. The best signal at this point for this would be across the Tennessee Valley on Wednesday, and from the central Plains to Mid-Mississippi Valley on Thursday (where SPC highlights a chance for severe weather as well). The pattern looks to amplify by the latter half of the period, bringing a cold front and possibly more widespread rains to parts of the East next weekend. Meanwhile, much of the West should stay dry until late week into next weekend when a Pacific system approaching the coast brings a period of enhanced moisture and rainfall mainly to the Pacific Northwest. An upper ridge centered over the south will continue near record daytime temperatures more than 10 degrees above normal across Texas through most of the period. And lead upper ridge amplification ahead of the system into the West also favors building excessive heat across the interior valleys of California and the Desert Southwest late week into next weekend to include some local record values. ...Model Guidance Evaluation/Preferences... Guidance continues to show above average agreement and predictability with the mid-larger scale flow evolution through mid-late week in a pattern with relatively zonal flow, at least to start. There remain some questions in the smaller scale details which likely will take until the short range to resolve but a general model blend of the GFS/ECMWF/UKMET/Canadian seems to provide a good starting point Wednesday into Friday. Models and ensembles continue to increasingly show a signal for a more amplified flow pattern by next weekend, though with increasing forecast spread. The 00z CMC was stronger/more amplified with the troughing into the East next weekend, while the GFS and ECMWF offered something a little weaker and faster. The ensemble means were also weaker, as expected, but a little slower than the GFS and ECMWF with the trough axis. Timing issues out west between the GFS/ECMWF and the CMC also increased late period uncertainty. WPC products into days 6-7 (next weekend) increasingly weighed towards the GEFS/ECMWF ensemble means, with lesser input from the best matched GFS/ECMWF for better system definition. This also helped to maintain good WPC product continuity. Santorelli/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, experimental excessive rainfall outlook, 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/#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