Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 225 PM EST Sat Nov 30 2024 Valid 00Z Sun Dec 01 2024 - 00Z Tue Dec 03 2024 ...Big temperature differences across the Lower 48 with above average temperatures from the West coast into the Rockies, while below average temperatures stretch from the Northern Plains to the East coast... ...Active Lake effect snows to continue downwind of the Great Lakes over the next few days... ...Poor air quality expected from the interior California Valley into the Pacific Northwest and Northern Great Basin... ...Much of the Lower 48 will be dry over the next few days, save for downwind of the Great Lakes and across far South Texas... The mid to upper level flow across North America is expected to remain amplified over the next few days, comprised of a mean trof from eastern Canada, south into the eastern U.S., while an amplified ridge stretches from western Canada into the Pacific Northwest and the Great Basin. This flow pattern will keep temperatures below average from the Northern Plains, southeast through the Mississippi Valley and across all of the east. High temperatures expected to be 10 to 20 degrees below average Sunday and Monday from the Northern Plains into the Ohio Valley, with the 10 to 20 degree below average temperatures spreading farther southeast along much of the east coast by Monday. In contrast, above average temperatures are on tap from the West coast into the Great Basin, Southwest, Rockies and the Central to Southern High Plains, with highs over the next two days 10 to 15 degrees above average. The cold air streaming across the relatively warm Great Lakes will keep lake effect snows very active over the next few days. The heaviest snow totals are expected downwind of lakes Erie and Ontario, affecting areas from northeast Ohio, far northwest Pennsylvania, western New York State and portions of northwest New York state. Cold air blowing along the long axes of lakes Erie and Ontario have produced intense single banded snow squalls that have already produced 1 to 1.5 feet of snow. This favorable low level flow off of Erie and Ontario will continue through Sunday, bringing the potential for additional snow totals of 1 to 3 feet across areas that have already seen very heavy totals. Lake effect snows will also be active downwind of Lake Superior and Michigan, with snow totals in excess of a foot possible across the Upper Peninsula of Michigan and the Lower Peninsula of Michigan along the Lake Michigan shoreline. While large sections of the West are expected to see above average temperatures over the next few days, some of the Valley locations from the interior or California into the Pacific Northwest and Northern Great Basin will see cooler temperature. These locations will be prone to stagnant air conditions, leading to areas of dense fog and poor air quality. Much of the Lower 48 will be dry over the next few days, with the exceptions being downwind of the Great Lakes into the upslope of the Central Appalachians and over far South Texas. This will bring no additional relief to the widespread drought conditions affecting large portions of the Lower 48. Oravec Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php