Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 401 AM EDT Sun Sep 06 2020 Valid 12Z Sun Sep 06 2020 - 12Z Tue Sep 08 2020 ...There is an Slight Risk of severe thunderstorms and for excessive rainfall across the Upper Mississippi Valley/Upper Midwest fall over parts of the Upper/Middle Mississippi Valley... ...Excessive heat continues across the West, potentially setting new daily records... ...Critical conditions for wildfires persist across the West, Northern/Central Rockies and High Plains... Sweltering heat will persist with the ridge anchored in place over the West. With some locations climbing 20 to 30 degrees above average- daily highs in the upper 90s to triple digits, daily temperature records may be established. The hot temperatures and dry airmass will be problematic for a vast portion of the West Coast, Great Basin, Northern/Central Rockies and the adjacent High Plains. Overnight low temperatures will struggle to cool down, relative humidity/dewpoint values will likely not be able to recover. This means that the fuels (grass, trees, shrubs, dried leaves etc) will be extremely dry and the slightest of sparks could cause a wildfire that quickly spreads out of control. Critical Fire conditions span from the West/Pacific Northwest to the Plains, with numerous Red Flag Warnings in effect from coastal Washington/Oregon to Nebraska. Excessive Heat Warnings blanket the area from southwest Oregon to southern Arizona with a handful of Heat Advisories from northeast California to southern Nevada. Additionally, several of the ongoing large wildfires across the region are also causing areas to have hazy skies and reduced/poor air quality. Scattered showers and thunderstorms expected near a stalled frontal boundary for parts of the Gulf Coast and the Southeast over the next couple of days. A low pressure system and associated surface cold front will deepen as it tracks across the Plains toward the Upper Mississippi Valley/Great Lakes regions through early next week. Organized convection along and ahead of this approaching front will result in strong/severe thunderstorms to track across the Upper Mississippi Valley today and toward the Great Lakes area on Monday. The Storm Prediction Center has identified portions of this region as having a Slight Risk for severe storms. WPC also has a Slight Risk for excessive rainfall in effect for nearly the same area. The central low with this system will continue to deepen as it lifts northeast into Canada. Colder, Canadian air will surge south into the Rockies and Plains as surface high pressure slides south in the wake of the cold front. This will result in near or below normal temperatures, as well as, bringing snow to the highest terrain of the Northern and Central Rockies. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php