Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 311 PM EDT Thu Jun 17 2021 Valid 00Z Fri Jun 18 2021 - 00Z Sun Jun 20 2021 ...Dangerous and record-breaking heat will continue across a large portion of the western U.S. and the central Plains... ...Severe thunderstorms and heavy rainfall producing flash flooding are possible throughout the Midwest today and Ohio Valley on Friday... ...Tropical rains and an increasing threat for flash flooding are expected along the northern Gulf Coast beginning Friday... As a dangerous heatwave continues, Excessive Heat Warnings and Heat Advisories remain in effect across much of California, Nevada, Arizona, and Utah. Temperatures are expected to once again reach record-breaking highs across much of the region today, with several records likely to fall on Friday and Saturday as well. Heat Advisories are also in effect for portions of the central Plains today. Well-above normal temperatures are expected today across the region, with record-breaking highs expected from Colorado to Iowa and Missouri. While a front dropping into the region is expected to offer some relief, temperatures are forecast to remain well-above average on Friday and into the weekend. Farther to the north, severe thunderstorms are expected late this afternoon into tonight across portions of the upper Mississippi Valley. The Storm Prediction Center is indicating an Enhanced Risk for severe thunderstorms across southern portions of Minnesota and Wisconsin, and northern portions of Iowa and Illinois, where conditions are likely to become favorable for severe thunderstorms to develop. These storms will have the potential to produce damaging wind and large hail, as well as a few tornadoes. Heavy rainfall, resulting in localized flooding is also possible. Severe storms are likely to develop farther south and east on Friday. The Storm Prediction Center is indicating an Enhanced Risk for severe thunderstorms across portions of Illinois, Indiana, and Ohio. Conditions across the region will likely become favorable for severe thunderstorms to develop -- capable of producing damaging wind, large hail, a few tornadoes, and localized flooding. Heavy rainfall and windy conditions are expected to develop along the northern Gulf Coast on Friday before spreading north over the weekend. A broad area of low pressure over the southwestern Gulf of Mexico continues to become better organized. This system is expected to move generally to the north, and a tropical or subtropical depression is likely to form over the west-central Gulf of Mexico tonight or early Friday. The National Hurricane Center has indicated that a Tropical Storm Warning will likely be required for a portion of the northern Gulf Coast later today. Regardless of development, heavy rainfall will be likely with the potential for flooding increasing along the coast Friday and Saturday. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php