Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Tue Sep 30 2025 Valid 12Z Tue Sep 30 2025 - 12Z Thu Oct 02 2025 ...Moisture associated with Imelda will continue to support showers and thunderstorms along the Southeast U.S. coastline today into tonight... ...A series of Pacific fronts will bring periodic waves of showers and thunderstorms to parts of the Great Basin and Pacific Northwest the next few days... ...Unseasonably hot temperatures continue for much of the Plains and Midwest through the remainder of the week... As Imelda begins its sharp turn to the northeast today, moisture associated with the tropical system will continue to pool along a stationary boundary draped along the Southeast U.S. coastline. The interaction between the front and Imelda's tropical moisture will result in additional showers and thunderstorms today into tonight, especially for coastal locations of the Carolinas. Some showers and storms will likely contain periods of heavier rainfall which could lead to localized ponding on roadways and in the most vulnerable low-lying and poor drainage areas. Imelda will quickly accelerate farther out to sea tonight into Wednesday, taking most shower and storm chances with it. However, strong high pressure is forecast to build southward from Canada before settling over the Northeast and Mid-Atlantic mid to late week. In addition to bringing a much more fall-like air mass to the East Coast, strong easterly winds on the southern periphery of this dome of high pressure will set up an extended period of onshore flow across much of the Southeast U.S. coast. The moist onshore flow will lead to numerous rounds of showers and thunderstorms, particularly along the east coast of the Florida beginning Wednesday into Thursday and likely lasting through at least the weekend. The repeating nature of this activity could lead to isolated flash flooding concerns heading into the latter part of the week. The prolonged onshore flow coupled with the increased wave action generated by both Imelda and Humberto will also lead to swells, high surf, and dangerous rip currents along much of the East Coast the next several days. Out west, a stretch of unsettled and unseasonably cool weather is in store for parts of the Pacific Northwest, Great Basin, and Intermountain West the next few days as a series of Pacific fronts push inland. These moisture-laden fronts will bring periodic waves of showers and thunderstorms, some of which could contain bursts of heavy rainfall. While the overall threat is low, localized flash flooding concerns can't be ruled out across parts of the Great Basin, northern Rockies, and the Olympic Peninsula. The increased presence of clouds and precipitation associated with the passing fronts and persistent upper-level troughing will result in high temperatures roughly 5 to 15 degrees below seasonal averages across much of the western U.S. through mid to late week. Downstream of the deep upper-level troughing along the west coasts of the U.S. and Canada is a highly amplified upper-level ridge located over the heart of North America. This ridge of high pressure has been responsible for the unseasonably hot weather across a large portion of the country east of the Rockies the last few days. With the ridge forecast to go nowhere anytime soon, this summer-like heat will continue through at least the end of the week. This will especially be the case from the northern/central Plains to the Upper Midwest, where high temperatures will soar well into the mid/upper 80s and low 90s. These temperatures are roughly 15 and 25 degrees above normal, making for a toasty end of September and start to October. Miller Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php