Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 AM EDT Wed Sep 30 2020 Valid 12Z Wed Sep 30 2020 - 12Z Fri Oct 02 2020 ...Below average temperatures to engulf the eastern half of the Lower 48 the second half of the week... ...California heat wave looks to continue through the remainder of the week; Fire weather danger persists in California and northern Plains... ...Wet morning followed by a drier afternoon in the Northeast, heavy rain and thunderstorms in South Florida, Scattered showers across the Great Lakes... As the calendar gets ready to flip over to October, temperatures from the Plains to the East Coast will plunge to October-like levels as a pair of cold fronts usher in reinforcing shots of cool Canadian air. A strong cold front exiting off the East Coast this morning results in a seasonally cool Wednesday for much of the eastern third of the country with only New England managing above normal high temps today. Meanwhile in the Midwest, another cold front races south and east today through the Nation's Heartland. North of the front, temperatures will feel more like mid-October while the Southern Plains stay balmy for one more day as high temps make a run at 90 degrees in some spots. Eventually, the front will push across the South-Central U.S. by Thursday, causing temperatures to drop to below normal levels as far south as the Gulf Coast by Friday. This same front crosses the Appalachians on Thursday and another round of below normal temperatures arrives up and down the East Coast by Friday. In contrast, a strong upper-level high over the West Coast is allowing sizzling temperatures to take shape in California with much above normal temps extending as far north as the Pacific Northwest. Heat Advisories are in place from San Diego to Los Angeles today with high temperatures ranging between 90 and 100 degrees on average. By Thursday, the stifling heat reaches the Bay Area where Heat Advisories are also in effect. Additionally, an elevated risk for fire weather sticks around for one more day over parts of the northern High Plains and in Southern California through Thursday. Due to excessive smoke in parts of the West, Air Quality Alerts have been posted for portions of California and the central High Plains. Much of the CONUS can expect mostly dry conditions through Friday morning but a few regions should still want the umbrella handy. New England will still be dealing with an influx of moisture ahead of the cold front advancing moving off the East Coast this morning. Heavy showers should quickly race northeast and lead to a drying trend this afternoon. The same front is forecast to stall near South Florida the next couple of days, which combined with deep tropical moisture is forecast to trigger heavy showers and thunderstorms. Localized urban flooding and flash flooding is possible in parts of South Florida with a better chance for flooding on Friday where a Slight Risk for excessive rainfall is in place. Lastly, a frontal system tracking across the Great Lakes will be responsible for developing scattered showers on Thursday. Temperatures at low levels are cold enough to form even lake effect showers throughout the region for the remainder of the work-week. Mullinax Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php