Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 342 AM EDT Mon Mar 18 2024 Valid 12Z Mon Mar 18 2024 - 12Z Wed Mar 20 2024 ...A few rounds of lake effect snow forecast downwind of the Great Lakes over the next few days... ...Cold morning temperatures bring a frost/freeze risk to parts of the Mid-South and Southeast on Tuesday... ...Record breaking warmth continues across the Pacific Northwest and northern Great Basin... The new workweek will start off by featuring a weather pattern consisting of high pressure stretching southward from the northern Plains to the Gulf Coast. As a result, continuous cold northwest flow will create lake effect snow chances throughout the Great Lakes today before the next clipper system swings over the region and into northern New England by early Wednesday. Accumulating snow is expected across the typical snow-belts downwind of lakes Erie and Ontario, as well as into northern Michigan, where Winter Weather Advisories have been issued. Snow showers could expand into the Interior Northeast and northern New England on Wednesday as the aforementioned clipper system swings eastward, with the potential for accumulating snowfall particularly in the elevated terrain. This push of cold air underneath and just east of the high pressure settling over the Deep South on Tuesday will allow for subfreezing temperatures to extend as far south as the Lower Mississippi Valley and Southeast. Frost/freeze conditions could damage and/or kill any unprotected sensitive vegetation, prompting Freeze Watches and Warnings to extend from Arkansas to the Carolinas. This cold isn't anticipated to be long-lived as temperatures gradually warm by midweek. Conversely, well above average spring warmth is expected to continue throughout the Northwest through Tuesday with highs reaching into the 70s. These temperatures could threaten daily record highs today in Portland, OR and Spokane, WA. One final day of summer-like warmth is also expected in southern Florida today ahead of a cold front as highs approach 90 degrees. This front may spark thunderstorms that could contain isolated hail and damaging winds for parts of the Florida Peninsula. Lastly, light shower activity is forecast to continue across southern Texas, as well as scattered rain and mountain snow showers through the Southwest over the next few days as an upper level low meanders over the region. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php