Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 301 AM EST Tue Nov 19 2024 Valid 12Z Tue Nov 19 2024 - 12Z Thu Nov 21 2024 ...Powerful Pacific low pressure system to produce significant high wind impacts and heavy mountain snow across the Northwest, while a strong atmospheric river takes aim at northern California by Wednesday... ...Potent storm system over the northern Plains to produce gusty winds and locally heavy snow throughout the region before a redeveloping area of low pressure brings unsettled weather to the Great Lakes, central Appalachians, and Northeast from midweek onward... ...Heavy rain and flash flooding potential continues throughout portions of the central and eastern Gulf Coast today... No shortage of active weather across the Nation this week as two separate strong low pressure systems produce hazardous conditions in the form of high winds, heavy rain, and snowfall. Starting with the Pacific Northwest, a rapidly strengthening and extremely powerful low pressure system forecast to pass roughly 300 miles west of the Olympic Peninsula tonight is anticipated to begin impacting the region today. Damaging winds with gusts up to 70 mph are possible across northern California, as well as parts of Oregon and Washington, with the highest winds expected along the coast and high terrain. These winds are likely to produce numerous power outages and tree damage in the most impacted regions. When combined with heavy snowfall at the higher elevations, blizzard conditions are in the forecast throughout the Washington Cascades. As an associated frontal boundary slides southeastward and stalls near northern California on Wednesday, a deep and continuous plume of anomalous atmospheric moisture content will flow into the Redwood Coast of California and northern mountain ranges of the Golden State. Heavy rain and rising snow levels will increase the threat of numerous floods and potential mudslides, exacerbated by the duration of heavy rainfall through the end of the week. In fact, WPC has issued a High Risk (level 4/4) of Excessive Rainfall across parts of northwest California on Thursday in order to further highlight this flooding threat. Residents and visitors throughout the Northwest are urged to have multiple ways to receive warnings, listen to advice from local officials, and avoid traveling through hazardous weather conditions if possible. In the north-central U.S. another potent low pressure system is lifting northward and producing unsettled weather of its own across the Upper Midwest and northern Plains today. A tight pressure gradient being produced by the storm is forecast to create strong winds across much of Nebraska, eastern Montana, and the Dakotas through Wednesday with maximum wind gusts up to 65 mph possible. Strong winds may also overlap with moderate to locally heavy snow throughout North Dakota and northwest Minnesota as the storm system stalls tonight over south-central Canada. Probabilities for at least 6 inches of total snowfall are high (>70%) across northern North Dakota. Meanwhile, scattered showers are forecast to spread eastward into the Midwest, Great Lakes, and eventually the Mid-Atlantic ahead of an advancing cold front today. By Wednesday night, a redeveloping low pressure system rapidly strengthening over the Great Lakes will help produce another round of precipitation over the Great Lakes, central Appalachians and Northeast through the end of the week. The greatest impacts from this precipitation is expected throughout the higher elevations of West Virginia and western Maryland, where up to a foot of snowfall is possible through Friday. Elsewhere, heavy rain and a risk for scattered flash floods remains a concern across the central and eastern Gulf Coast as a cold front, weak area of low pressure, and ample atmospheric moisture content spark numerous showers and thunderstorms capable of containing intense rainfall rates through tonight. The greatest risk for flash flooding specifically exists from far eastern Louisiana to the western Florida Panhandle, with urban and poor drainage regions most susceptible to rapid water rises. Temperatures will be on a roller coaster ride this week as well above average temperatures are found in the East before an advancing cold front knocks readings down below average by Thursday. Meanwhile, cooler temperatures over much of the West are forecast to return to near normal as upper ridging builds into place. Snell Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php