Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 252 AM EST Mon Nov 04 2019 Valid 12Z Mon Nov 04 2019 - 12Z Wed Nov 06 2019 ...Light scattered snow from parts of the Northern High Plains to parts of the Northeast... ...Air Stagnation Advisories are up for parts of the Pacific Northwest to the Northern Intermountain Region... A front extending from the Great Lakes to the Central Plains then banked up against the foot hills of the Rockies will move to the Eastern Seaboard by Tuesday evening. A secondary front associated with colder air will move out of Central Canada into the Upper Great Lakes by Monday evening and into the Lower Great Lakes by Tuesday evening before dissipating over the Northeast by Wednesday. A wave of low pressure will develop a long the western portion of the front over the Central Plains by Tuesday evening that will move into the Middle Mississippi Valley by Wednesday. The lead front will aid in producing mainly rain over parts of the Great Lakes that will move into parts of the Lower Great Lakes and the Ohio Valley to parts of the Lower Mississippi Valley overnight Monday. On the northwestern side of the system, light snow will develop over parts of the Upper Great Lakes and Upper Mississippi Valley that will move into parts of the Lower Peninsula of Michigan, likewise, overnight Monday. Light snow over parts of the Northern High Plains/Northern Plains will slowly come to an end by Monday evening. As high pressure over Northwestern Canada builds southeastward on Monday evening, upslope flow will aid in producing scattered snow showers over parts of the Northern High Plains that will slowly expand eastward to the Northern Plains and the Upper Mississippi Valley/Upper Great Lakes on Tuesday evening into Wednesday. Elsewhere, a lingering old front over Southern Florida will aid in producing scattered showers and thunderstorms over parts of Florida through Wednesday. Upper-level dynamics and return flow of moisture off the Gulf of Mexico and Atlantic that will aid in producing scattered showers over parts of the Southeast on Tuesday into Wednesday. In a similar fashion, upper-level dynamics and moisture coming off the Gulf of Mexico will aid in producing showers and thunderstorms over parts of the Southern Plains and Southern Rockies overnight Tuesday into Wednesday. Upper-level ridging and high pressure at the surface will aid in producing conditions that are favorable for Air stagnation to develop over parts of the Pacific Northwest into the Northern Intermountain Region through Tuesday morning. The stagnation will be an issue across portions of the Pacific Northwest, particularly in sheltered valley locations. This will lead to reduced air quality early in the week with no major weather systems expected. Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php