Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 240 AM EST Mon Nov 18 2024 Valid 12Z Mon Nov 18 2024 - 12Z Wed Nov 20 2024 ...A potent storm system over the central U.S. today will create chances for heavy rainfall, severe thunderstorms, and gusty winds, while moderate snowfall is possible across the northern Plains by Tuesday... ...Heavy rain and flash flooding potential exists throughout the central and eastern Gulf Coast over the next few days... ...Powerful Pacific low pressure system to impact the Northwest with high winds and heavy mountain snow, while an atmospheric river takes aim at northern California by Wednesday... An amplified weather pattern and two separate strong storm systems are set to impact the Nation during the first half of this week. First, a deep low pressure system ejecting out of West Texas early this morning is anticipated to further organize over the central U.S. today and produce areas of heavy rain, severe weather, and gusty winds to the southern/central Plains. Thunderstorms forming along an attached cold front may contain damaging winds and perhaps a few tornadoes between central Oklahoma and North Texas today. This region is where the Storm Prediction Center has hoisted a Slight Risk (level 2/5) of severe thunderstorms. As the system progresses northward into the Upper Midwest on Tuesday, showers are also forecast to spread north throughout parts of the Midwest and Great Lakes. Meanwhile, cold air working into the western side of the storm will likely allow for precipitation to fall as snow across parts of North Dakota and northern Minnesota into Wednesday. Snowfall may also be accompanied by gusty winds, leading to lower visibility on roadways. Current snowfall probabilities for at least 4 inches of snow are greatest (70-90%) across north-central North Dakota. As the associated cold front pushes eastward through Tuesday, numerous showers and thunderstorms interacting with a surge of moisture being lifted northward from the Gulf of Mexico could contain intense rainfall rates capable of producing flash flooding. Heavy rainfall is most likely tonight across eastern Louisiana and southern Mississippi, with the threat expanding east to the Florida Panhandle on Tuesday. Scattered flash floods are most likely throughout low-lying and urban regions. Residents and visitors are reminded to have multiple ways to receive warnings and never drive across flooded roadways. For much of the Northwest, northern Great Basin, and northern Rockies, a cold front pushing across the region today and enhanced onshore flow will allow for unsettled weather to continue ahead of a powerful storm system forecast to develop off the coast of the Northwest on Tuesday. This appetizer of precipitation to start the workweek will mainly include the potential for moderate to heavy snowfall across the Cascades and northern Rockies. However, by Tuesday night the rapidly strengthening Pacific low pressure system will aid in producing high winds across the Pacific Northwest and increasing precipitation intensity. Wind gusts up to 70 mph are possible across parts of northern California and Oregon, with strong winds also expected over parts of western Washington. These winds will have the potential to knock down trees and produce power outages. Heavy snowfall with amounts potentially exceeding two feet are possible over the northern California ranges and Cascades. By Wednesday, an associated atmospheric rive event is expected to take shape and direct continuous Pacific moisture towards northern California and southwest Oregon. Widespread rainfall amounts of 4 to 7 inches are expected through Wednesday across this region, which could produce areas of river flooding and increase the risk of mudslides. Heavy rain and the associated weather hazards from this atmospheric river event are also expected to continue beyond midweek. Below average temperatures are forecast to remain over much of the western U.S. over the next few days while gradually spreading eastward into the Great Plains. Meanwhile, high pressure over the East will continue to create mild and dry conditions through Tuesday as rainfall chances enter the Mid-Atlantic and Northeast on Wednesday. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php