Extended Forecast Discussion NWS Weather Prediction Center College Park MD 259 AM EDT Fri Jun 10 2022 Valid 12Z Mon Jun 13 2022 - 12Z Fri Jun 17 2022 ...Dangerous/Record Heat to shift from the Plains into the east-central and Southeast U.S. next week... ...Heavy rain/runoff threat over parts of the northern Rockies/Plains early next week... ...Overview and Guidance/Predictability Evaluation... The medium range period will likely feature a transition between amplified regimes. The first part of the week will see a rather amplified upper trough crossing the West and a strong ridge covering the Southeast/east-central U.S. while a trough crosses the Northeast and begins to amplify into the Atlantic. Continued progression of the ejecting western energy across the northern U.S./southern Canada and the approach of another amplified upper trough toward the West Coast should promote upper ridging over the Plains late in the week. This evolution should promote active weather over parts of the northern tier into the East, hot weather from the central/southern Plains into the east-central U.S./Southeast with the best potential for record highs during Monday-Wednesday, and pronounced temperature swings (chilly early and warm to hot late) over parts of the West/High Plains. Latest models and ensembles are fairly agreeable in their depiction of the large scale pattern evolution but differ with some embedded details. Toward midweek the UKMET has tended to be on the slow side with the upper low anchoring the western U.S./southern Canada system, but this looks less extreme in light of the new 00Z ECMWF trend. Even versus the new run, the 00Z ECMWF strayed to the slow side on day 7 Friday. Other guidance develops typical spread for the overall trough that reaches the Great Lakes and east-central Canada late next week. In general clustering for the trough nearing the West Coast after midweek has been better than average thus far. The new 00Z GFS becomes somewhat southwest of consensus for the embedded upper low though. Meanwhile the guidance develops some spread for exact details of flow aloft along and offshore the East Coast, ultimately affecting the position of a potential backdoor front over the Mid-Atlantic/Carolinas. An early-period blend among the 12Z/18Z operational models followed by partial incorporation of the 18Z GEFS/12Z ECMWF means reflected the desired consensus/intermediate solution for significant features and yielded reasonable continuity. ...Sensible Weather/Threat Highlights... A vigorous and wavy frontal system reaching the northern Plains early next week should provide a focus for locally heavy rainfall over some areas. Currently the best combination of instability and anomalously high moisture along with antecedent conditions support maintaining a Slight Risk area over parts of North Dakota in the Weather Prediction Center experimental day 4 (Monday-Monday night) excessive rainfall outlook. Additional areas of enhanced rainfall may be possible as the front moves from the Plains into the East but it will take additional time to refine the details. A leading front extending into the East and impulses riding around the upper ridge may also help to produce one or more convective systems tracking southeast from the Upper Midwest and vicinity. It will likely take will into the short range period to clarify that aspect of the forecast. Within the area of heat transitioning from the Plains into east-central U.S./Southeast early-mid week, expect highs up to 10-20F above normal with some central Plains locations possibly reaching plus 20-25F anomalies on Monday. Numerous daily records for highs/warm lows will be possible during Monday-Wednesday. Even with temperatures moderating from west to east, the southern tier will remain on the hot side with plus 5-10F anomalies persisting into Friday. The upper trough crossing the West early in the week will bring a brief period of highs 10-20F below normal across the northern half of the region. The upper ridge that builds in behind this system will bring a rapid warming trend from the Southwest/Great Basin into the northern-central Plains during the latter half of the week. The central/northern West Coast should see below normal highs by Friday with the upper trough nearing that region. The system emerging from the West into the Plains may produce areas of brisk to strong winds during the first part of the week, contributing to increasing wildfire risk over and west of the southern Rockies. Check the Storm Prediction Center Fire Weather Outlooks for the latest information. Rausch 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