Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 429 PM EDT Thu Sep 04 2025 Valid 00Z Fri Sep 05 2025 - 00Z Sun Sep 07 2025 ...A few strong to severe thunderstorms possible along a reinforcing cold front Friday and Saturday for the Ohio/Tennessee Valleys to New England ...Moisture from Lorena to enhance the Southwest Monsoon and continue the threat of flash flooding... ... A cold early September air mass may bring daily record cool afternoon maximum temperatures across the Midwest and Great Lakes... Another significant reinforcing cold front and strengthening low pressure system is sweeping through the northern Plains today. Winds may gust as high as 50 mph with this deepening area of low pressure along the strong cold front. The cold front will continue to march to the south and east, reaching the southern Plains, Tennessee/Ohio Valleys and the Northeast late Friday into Saturday. A strong area of high pressure building in behind the cold front will bring cool morning low and max temperatures. In the Southwest, the trough moving into the Plains will transport moisture from Lorena northeastward from Mexico towards Arizona, New Mexico, and Texas by late weekend. Oppressive heat across the Northwest will begin to lessen by Saturday as upper-level riPWATSdging begins to retreat. Florida will continue to see numerous showers and thunderstorms as a stationary boundary interacts with a tropical air mass. Addressing severe weather hazards, a potent cold front will bring the risk of severe weather for the Ohio and Tennessee Valleys, as well as the Appalachians for tomorrow. The Storm Prediction Center has issued a Slight Risk as shear and instability may enable organized lines of storms capable of damaging winds and perhaps some isolated large hail. The cold front will then progress eastward towards the East Coast on Saturday and may continue to bring the threat of damaging winds with storms that form along the boundary. West of the Rockies, monsoonal moisture combined with strong surface heating will lead to the daily threat of scattered to numerous showers and thunderstorms across parts of the Southwest and Four Corners region through the end of the week. Moisture will surge farther north Friday into Saturday, partially attributed to moisture streaming northwards from T.S. Lorena, and expand the risk of showers and storms into the Great Basin and interior portions of the Pacific Northwest. Showers and storms will contain bursts of heavy rain which could lead to isolated instances of flash flooding in more vulnerable places like slot canyons, arroyos, steep terrain, burn scars, etc. A more concentrated threat of scattered flash flooding is possible tomorrow across portions of southern Arizona and New Mexico as moisture associated with Lorena will push PWATS near the 90th percentile and cause rainfall over saturated soils with lower flash flood guidance. Therefore, WPC has issued a Slight Risk for Excessive Rainfall for Friday. Towards the end of the short range period on Sunday, there is more uncertainty on the potential enhanced rainfall threat across West Texas. Stay tuned to the forecast. Additional heavy rainfall may be found across upstate New England on Saturday with a line of thunderstorms along the cold front. The dry soils should mostly make this rain beneficial with only very isolated flash flooding possible in susceptible areas. Across Central and South Florida, a stalled frontal boundary will likely serve as an abundant source for enhanced showers and thunderstorms, but the flooding threat is overall very marginal. Ponding water appears the most likely extent of any flooding that does occur. Perhaps the most gripping story line is yet another cold blast across the Plains and Great Lakes. Numerous sites may break daily record low temperatures and afternoon temperatures. Much of the northern Plains to the Great Lakes will see high temperatures in the 50s and low 60s through Saturday. Low temperatures will range from the middle 30s across Minnesota and North Dakota to the upper 40s as far south as the Ohio Valley. Cooler temperatures will reach the Tennessee Valley and southern Plains by Sunday as the front passes. Cold temperatures may be harmful to vegetation and unprotected crops for those who see morning low temperatures drop into the 30s. This air mass is about 15-20 degrees cooler than average for this time of the year. Wilder/Miller Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php