Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 227 PM EST Tue Jan 30 2024 Valid 00Z Wed Jan 31 2024 - 00Z Fri Feb 02 2024 ...Heavy to Excessive Rainfall impact the West Coast this week, while Heavy snow to blankets the Sierra Nevada, Intermountain West and Rockies... ...Above average warm air expands from Great Plains into Mississippi Valley... Tonight, a low pressure system moving across the Ohio Valley will spread some light rain showers over the region through portions of the Mid-Atlantic. Snow showers and a wintry mix are possible over the Central Appalachians of western Virginia, eastern West Virginia and western North Carolina. Some light snow may also work its way into eastern Pennsylvania, northern New Jersey, southern Upstate New York and New York City through early tomorrow morning. Little to no accumulations/impacts are expected from this winter weather. Meanwhile, tonight, a strong surface low pressures system, supported by a deep upper-level low will arrive over the West Coast. This system will transport deep moisture into the West over the course of the next few days. Heavy rainfall and scattered thunderstorms are possible from the southern coast of Oregon down into Los Angeles County. A Slight Risk of Excessive Rainfall leading to Flash Flooding is in effect for portions of the southern Oregon coast down through central California on Wednesday due, in part, to the potential presence of instability generating higher rainfall rates over vulnerable surfaces. Heavy mountain snow (6000-7000') kicks off over the Shasta Siskiyous and Sierra on Wednesday afternoon. Once the upper trough moves ashore and the surface cold front moves into the Great Basin on Thursday, snow levels will drop to about 4000-5000' leading to lower elevation heavy snowfall potential in the Sierra. Total snowfall accumulations will range between 1-3 feet by Friday, when conditions are expected to improve. The focus for heavy rainfall will shift into southern California on Thursday, enhanced by a digging trough aloft, an embedded surface wave and attendant cold front at the surface. Rain and snow showers spread into the Great Basin, Intermountain West, and Rockies on Thursday. Meanwhile, a low pressure system moving across Ontario and Quebec will produce light snowfall over portions of northern Upstate New York/New Hampshire, Vermont and Maine beginning Thursday morning. An omega block high with embedded shortwave energy will continue to support increased heights over the Central U.S.. Warm temperature anomalies ranging between 20-40 degrees above average will expand across the Great Plains and Mississippi Valley through the end of the week as a result. The potential for widespread record low temperatures will pick up later in the week over the Northern/Central Plains and Upper/Middle Mississippi Valley. Lower heights in the West will generate cooler temperatures around 10-20 degrees below average later this week and into the weekend. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php