Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 331 AM EDT Wed Jun 02 2021 Valid 12Z Wed Jun 02 2021 - 12Z Fri Jun 04 2021 ...Record-breaking heat found across the western United States to spread into the Northern Plains by Thursday... ...Scattered showers and thunderstorms forecast throughout the Southern Plains and eastern third of the country over the next couple of days; severe weather possible in the Mid-Atlantic on Thursday... Persistent upper-level ridging over the western U.S. will bring at least an additional two days of potentially record-breaking heat from the Southwest to the northern Great Basin. High temperatures are forecast to reach the upper-90s and triple digits across a wide spanning region from the Desert Southwest to the northern High Plains. The largest temperature anomalies compared to average will be situated over interior sections of Oregon and Washington, where high temperatures are forecast to soar to near 30 degrees above the normal high for this time of year. Excessive Heat Warnings and Heat Advisories stretch from southern California to northern Washington and Idaho. Extreme heat in these locations will significantly increase the potential for heat related illnesses. Additionally, much of the Southwest and West is experiencing severe to exceptional drought conditions, which will undoubtedly be exacerbated by the current heat wave. By Thursday evening a weak cold front is expected to reach the Pacific Northwest and offer some relief from the early-season heat, along with a few isolated showers and thunderstorms. As the aforementioned upper-level ridge slowly slides eastward, well above average temperatures will spread into the Northern Plains to end the workweek. For the Southern Plains and areas east of the Mississippi River, scattered showers and thunderstorms may interrupt outdoor activities both today and Thursday. A weak area of low pressure currently located over the Lower Mississippi Valley is forecast to swing northeast and into the Lower Great Lakes by Thursday. At the same time, an associated warm front to its east will lift northward and usher in a warm and humid airmass to nearly the entire East Coast. Thunderstorms will also form along a slow moving cold front trailing the system from the Ohio and Tennessee valleys to southern Texas. Much of the scattered showers and thunderstorms will result in a marginal flash flood and severe weather risk. The only exception will be found throughout the Mid-Atlantic on Thursday, where a few storms ahead of the previously mentioned cold front may produce damaging wind gusts and isolated tornadoes. SPC has highlighted a region between south-central Virginia and southeast Pennsylvania, including Washington D.C. and much of central/southern Maryland, as having the greatest risk of severe weather. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php