815 FXUS02 KWBC 010642 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 242 AM EDT Sun Jun 1 2025 Valid 12Z Wed Jun 04 2025 - 12Z Sun Jun 08 2025 ...Overview... With ridging in place over the northeastern Pacific Ocean and building over the western Atlantic much of the CONUS will be under a broad trough. This pattern will be favorable for multiple progressive systems to pass through the flow and focusing the bulk of the precipitation across the Midwest and Plains. ...Guidance/Predictability Assessment... The most recent model runs are mostly agreeable with the overall pattern evolution through the extended period therefore the forecast was based off of a consensus approach. For fronts, pressures, to some degree QPF/PoPs, and winds, this forecast was based on a multi-model blend of the 12Z CMC/UKMET/ECMWF and 18/00Z GFS initially before adding the EC and GEFS ensemble means into the mix. Other fields were derived primarily from the 1Z NBM. ...Weather/Hazards Highlights... the central part of the country will be wet for the start of the extended period as a frontal system advances through the Northern and Central Plains toward the Mississippi Valley. Scattered to widespread convection is expected along and ahead of the front with some of the embedded storms potentially producing heavy rainfall. There is a growing signal for 3 to 7 inches to focus across Texas and Oklahoma and for 3 to 5 inches for Iowa, Illinois and Missouri WPC maintained the Slight Risk area for excessive rainfall/flash flooding across for day 4 and added Slight Risk for the new Day 5 period for much of the same area in addition to western Arkansas. Areas near the Iowa/Illinois border, the flash flood threat would be primarily in urban areas. The front and associated shield of precipitation is expected to track east/southward into the Southern Plains and Lower Mississippi Valley/Mid-South by the end of next week. For the West and East Coasts drier conditions are expected under the ridge. Florida which may see more appreciable rainfall over the southern portions in the vicinity of a dying oceanic boundary, where a Marginal Risk area for excessive rainfall/flash flooding was added for day 4/Tuesday. Some mountain areas of Wyoming may see a few inches of snow as colder air comes in behind the front. With time, temperatures will rise to near or above normal for the eastern half of the country which will elevate the Heat Risk threat level to Moderate. Daily maximums in the 80s/90s may increase heat stress for some regions-- take precautions in the heat such as increased water intake and more time in air conditioned areas to avoid heat exhaustion and heat stroke. Parts of South Texas will see more days of highs into the upper 90s and low 100s with low probabilities (20-40%) of reaching heat index values of at least 110F. Much cooler temperatures will follow behind the cold front, starting in the Rockies on Monday then into the Plains thereafter, but moderating with time. Much of the West will see near to slightly above normal temperatures, especially later in the week. Campbell/Roth 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 (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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 $$