Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 348 AM EDT Sun Mar 17 2024 Valid 12Z Sun Mar 17 2024 - 12Z Tue Mar 19 2024 ...Locally heavy snow continues across the Southern Rockies today, while lake effect snow impacts the Great Lakes region through early this week... ...Strong cold front ushers in frost/freeze potential throughout the Southeast by Tuesday... ...Scattered showers and thunderstorms forecast across the Gulf Coast States this St. Patrick's Day... Even as the Spring Equinox approaches this Tuesday, winter weather continues to impact parts of the Nation with localized heavy snow. The same closed upper low that has lingered over the Southwest over the last few days is expected to continue producing areas of heavy mountain snow throughout the Southern Rockies and Four Corners region today before the system weakens and precipitation becomes widely scattered. The heaviest remaining snow is expected over the mountainous terrain of New Mexico, which could lead to treacherous travel at times. Meanwhile, a potent low pressure system crossing from southern Ontario to southern Quebec, Canada today will aid in lake effect snow downwind of the Great Lakes through early this week. The cold airmass advecting from the northwest across the relatively warm lakes will allow for numerous snow showers and localized areas of moderate to heavy snow. Specifically, the U.P. of Michigan and Tug Hill Plateau of western New York could see several inches of accumulation snow. Snowfall chances also extend to upslope portions of the central Appalachians on Monday and Tuesday. As a cold front pushes south and clears the Southeast by Monday, much colder temperatures and high pressure will build in its wake. Low temperatures are forecast to dip into the 20s and 30s from the Midwest to the Tennessee Valley on Monday, prior to this cold sinking into the Mid-South and Southeast on Tuesday. Vegetation in these regions are susceptible to frost/freeze damage given the relatively mild late winter temperatures, thus any unprotected sensitive plants could be damaged or killed. Meanwhile, warm temperatures will remain locked in place over the Pacific Northwest, where highs into the low 70s are forecast and anticipated to spread into the northern High Plains by Monday. One more day of shower and thunderstorm activity is expected today along the Gulf Coast as a lingering frontal boundary focuses rainfall chances. Heavy rain could lead to flooding concerns from southeast Texas to southern Louisiana due to saturated soils from recent rainfall. A Slight Risk (level 2 of 4) of Excessive Rainfall is in effect. A few isolated severe thunderstorms could also impact the immediate Gulf Coast region as well this St. Patrick's Day. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php