Extended Forecast Discussion NWS Weather Prediction Center College Park MD 238 AM EDT Sun Jun 05 2022 Valid 12Z Wed Jun 08 2022 - 12Z Sun Jun 12 2022 ...Overview and Sensible Weather/Threat Highlights... 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 heaviest rain will remain extremely difficult to pinpoint given the convective nature of this activity. Convective clusters and repeat/training cells could produce early period local runoff issues with perhaps the strongest signal from the Central Plains to the Mid-South and again later week as upper trough amplification/diffluence may refocus and better organize convective rainfall potential in this susceptable area and vicinity. Activity will try to work into the summer warmth across a U.S southern tier under the inlfuence of an upper ridge. Near record daytime temperatures more than 10F above normal are possible in this airmass over parts of Texas. Meanwhile, much of the West should stay dry until late week into the next weekend when a Pacific system approaching the coast brings a period of enhanced moisture and rainfall mainly to the Pacific Northwest. Lead upper ridge amplification 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. There remain some questions in the smaller scale details which likely will take until the short range to resolve. A general model blend of the GFS/ECMWF/UKMET/Canadian and National Blend of Models seems to provide a good starting point Wednesday into Friday. Models and ensembles increasingly show a signal for a more amplified flow pattern by next weekend, though with increasing forecast spread. WPC products into days 6-7 (next weekend) increasingly weighed towards the decently clustered GEFS/ECMWF ensemble means, with lesser input from the best matched GFS/ECMWF for better system definition. WPC product continuity is well maintained. 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 overtop U.S. southern tier upper ridging Summer heat across the South may near record levels over parts of Texas.