Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 354 PM EDT Sun Sep 06 2020 Valid 00Z Mon Sep 07 2020 - 00Z Wed Sep 09 2020 ...There is an Slight Risk of severe thunderstorms over parts of the Upper Great Lakes/Middle Mississippi Valley and Western Ohio Valley... ...There are winter weather advisory and winter storm watches along parts of the Northern/Central Rockies/High Plains... ...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... A strong front over the Upper Great Lakes will aid in producing showers and thunderstorms over the area will move eastward into the Ohio Valley on Monday. The SPC has issued a slight risk of severe thunderstorms over parts of the Upper Great Lakes/Middle Mississippi Valley and Western Ohio Valley through Monday morning. The main hazards associated with the severe thunderstorms are frequent lightning, large hail, severe thunderstorm wind gust, and a few tornadoes. Cold high pressure over Western Canada will sink southward to the Northern Rockies/Northern Plains by Tuesday evening. Upslope flow associated with the high will aid in producing rain over the Northern High Plains overnight Sunday that will slowly expand eastward into the Northern Plains by Monday and into the Upper Midwest on Monday evening into Tuesday. Cold air associated with the high pressure has prompted winter weather advisory and winter storm watches along parts of the Northern/Central Rockies/High Plains on Monday evening into Tuesday. Snow is forecast to develop over the higher elevations of the Northern/Central Rockies/High Plains. Meanwhile, 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. Furthermore, 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. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php