Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 340 AM EDT Tue Sep 28 2021 Valid 12Z Tue Sep 28 2021 - 12Z Thu Sep 30 2021 ...Severe thunderstorms possible across portions of the Mid-Atlantic today... ...Increasing chances for thunderstorms and heavy rain found throughout the central and southern Plains through midweek... ...Record breaking warmth and critical fire weather forecast across the Northern Plains... The weather pattern across much of the Lower 48 is set become slightly more active to end the month of September. In the East, a cold front dropping south across the Northeast and Mid-Atlantic today will usher in cooler and more fall-like temperatures. However, a few strong to locally severe thunderstorms may develop along this frontal boundary this afternoon. Isolated thunderstorms will have the potential to produce damaging wind gusts and large hail. The Storm Prediction Center has issued a Slight Risk (level 2/5) of severe weather between northern Virginia and southern New Jersey. Farther west, a cold front currently pushing across the Northern Rockies and Intermountain West is expected to continue marching eastward until reaching the Northern Plains and Central Rockies by Wednesday, followed by the Southern Plains on Thursday. Scattered showers and much cooler temperatures are forecast behind the cold front, with a few snowflakes mixing into the highest elevations of the Rockies as well. Once the frontal boundary reaches the Great Plains on Wednesday, it will clash with a warm tropical airmass funneling out of the western Gulf of Mexico and spark numerous clusters of the showers and thunderstorms. The main concern with these storms across the Central Plains will be associated with heavy rain and the potential for isolated instances of flash flooding. By Thursday, the heavy rain threat will shift southward and into the Southern Plains. Meanwhile, the aforementioned tropical airmass will also help aid thunderstorm development across Texas and Lower Mississippi Valley over the next few days ahead of the approaching weather system. Slow-moving thunderstorms along with intense rainfall rates could produce isolated flash flooding. A few severe thunderstorms are also not out of the question across central Texas and southwestern Oklahoma along a dryline this afternoon. One more day of record-breaking warmth is forecast throughout the Northern Plains today as highs soar 20 to 30 degrees above average. High temperatures are forecast to soar into the upper 80s and 90s throughout much of the Great Plains and parts of the Midwest. A dozen daily high temperature records could fall across Nebraska and the Dakotas. By Wednesday, this wave of unseasonably warm temperatures will shift out of the Northern Plains into the Upper Midwest. In conjunction with the late-September heat, gusty winds and low relative humidity will make for dangerous fire weather conditions across the Northern Plains today. Red Flag Warnings have been issued throughout southeast Montana, northern Wyoming and the western Dakota in order to highlight the potential for new wildfires to spread uncontrollably. Snell Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php