Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Tue Jun 04 2024 Valid 00Z Wed Jun 05 2024 - 00Z Fri Jun 07 2024 ...A Moderate Risk of Excessive Rainfall leading to Flash Flooding over parts of southeastern Oklahoma and the ArkLaTex through tonight... ...Severe thunderstorms and heavy rain possible from the lower Mississippi Valley across the south-central Plains and through the upper Midwest through tonight... ...Growing Excessive Heat concerns over portions of California's central valley region as well as the Desert Southwest with Heat Risk persisting over southern Texas... Over the next couple of days, a shift in the weather pattern will gradually push the active weather that has been persisting over the mid-section of the country toward the eastern U.S. This shift in the weather pattern will also bring a heatwave into the western U.S. A low pressure system currently advancing across the northern Plains has prompted High Wind Warnings and Wind Advisories from the northern Rockies into the northern Plains. This system will act as a catalyst for the weather pattern change as the trailing front marches across the country through the next couple of days. Showers and thunderstorms are expected to be most active ahead of the cold front across the Midwest and farther south where it meets a low pressure wave over Oklahoma, where the chance of severe thunderstorms and flash flooding will be the highest through tonight. By Wednesday, the system will push steadily eastward, ending much of the active weather over the mid-section of the country while bringing widespread showers and embedded thunderstorms across the Great Lakes, Ohio and Tennessee Valleys, and down toward the lower Mississippi Valley. The inclement weather will reach into much of the East Coast on Thursday as a cold front continues its eastward progress. There appears to be a greater chance for New England to see stronger thunderstorms later on Thursday as a warm front lifting northward meets the eastward-advancing cold front. Much cooler, damp, and windy conditions will gradually spread from the northern Plains eastward into the upper Midwest and the Great Lakes through the next couple of days behind the cold front and a deep low pressure system over southern Canada. On the opposite side of the country, a heatwave is in store for the southwestern portion of the country as a strong ridge of high pressure intensifies and takes control. Areas of particular concern for the heat include the low elevation regions of California's central valley, where high temperatures will likely climb well up into the 100s at the hottest location while 110s will be common over the interior desert region including Las Vegas, NV especially by Thursday afternoon. There is a good chance for the temperature to top 112 degrees in Las Vegas on Thursday, which would become the city's earliest observed 112 degrees on record. Widespread temperature records are also expected to be tied or broken elsewhere across much of the aforementioned areas. Excessive Heat Warnings and Watches extend from the central valley down through southern California's deserts, southern Nevada and southern/western Arizona. Heat Risk will peak over California's central valley on Wednesday before expanding into the Desert Southwest later this week. Little overnight relief will make for dangerous conditions for those without effective cooling and/or adequate hydration. Meanwhile, Heat Risk over southern Texas peaks today but is expected to persist for the next few days. Kong/Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php