Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 144 AM EST Thu Dec 19 2024 Valid 12Z Thu Dec 19 2024 - 12Z Sat Dec 21 2024 ...Clipper system to bring periods of heavy snow to the Upper Midwest Thursday with some light to moderate accumulations for the Appalachians/Interior Northeast Friday... ...Well above average temperatures and mild conditions continue across the West... ...Frontal passages will bring colder temperatures to much of the eastern U.S. through the end of this week and into the weekend... A clipper system dropping east-southeasterly through the northern Plains and into the Upper Midwest/Great Lakes will bring periods of heavy snow along a path from central Minnesota through northern Wisconsin and into the UP/northern LP of Michigan today. Winter Storm Warnings are in effect for snow totals generally between 3-6", locally higher. Gusty winds may lead to periods of blowing snow and hazardous travel conditions. Although snow has come to an end to the west over the northern Plains, very gusty winds will continue through this afternoon. The clipper system will continue quickly southeastward across the Ohio Valley, Appalachians, Northeast, and off the East Coast Friday, bringing wintry precipitation to the interior and some rain showers to the coast. Some moderate snow accumulations will be possible across the central Appalachians and downwind of Lake Erie, with lighter amounts more broadly over the Interior Northeast. Elsewhere, a few lingering showers and storms may occur over South Florida Thursday, with conditions drying out into Friday. An upper-level shortwave dropping southeastward over the northern Plains may lead to some renewed light snow chances Friday. An active storm track over the Pacific will also bring some periods of lower elevation/coastal rain and perhaps some mountain snow to the Pacific Northwest/northern California the next couple of days, though totals should remain much lighter than earlier this week. Temperatures across the West will remain well above average by 10-20 degrees for most locations to end the week as upper-level ridging remains in place. Forecast highs generally range in the 40s and 50s across the Interior West, Pacific Northwest, and northern California with 60s to low 80s for southern California and the Desert Southwest. A cooling trend is expected for much of the eastern half of the country following a cold frontal passage off the East Coast this morning and an additional cold front dropping southward with the clipper system. Very cold temperatures in the teens are forecast for the northern Plains/Upper Midwest today. Highs will drop into the 20s and 30s in the Midwest, the 30s and 40s in the Mid-South and central Plains, and the 50s and 60s in Texas by Friday. Highs along the East Coast range from the 20s to 40s in New England, the 30s and 40s in the Mid-Atlantic, and the 50s and 60s in the Southeast. Much colder temperatures are expected along the East Coast by this weekend. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php