Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Oct 25 2021 Valid 12Z Mon Oct 25 2021 - 12Z Wed Oct 27 2021 ...There is a Slight Risk of excessive rainfall over the Sierra Nevada Mountains and coastal New England... ...Heavy snow for the Sierra Nevada Mountains... ...There is an Enhanced Risk of severe thunderstorms over parts of the Central/Southern Plains on Tuesday; there's a Slight Risk of severe thunderstorms for much of the Mid-Atlantic today... Heavy rain and snow is forecast to continue impacting the West coast as a powerful low pressure system churns its way through the West over the next day or so. Heavy rain is still likely across lowland parts of the Sierra Mountains and Pacific Northwest, as this atmospheric river event begins to wind down. Between 1-3 inches of rainfall is possible over the central California portion of the Sierra, with isolated higher amounts possible. A Slight Risk of Flash Flooding is in effect due to the terrain involvement as well as already saturated soils from the recent precipitation. Heavy snow is also expected over the higher elevations of the central California Sierra, where between 1-2 feet with isolated higher amounts, are possible today. Many of the highest Rocky Mountain peaks will pick up several inches of snow today as the cold front moves through the region. A cool Pacific air mass will settle over the West over the next couple of days as high pressure builds across the region. Meanwhile, rain and scattered thunderstorms are forecast to spread into the Mid-Atlantic and Northeast out ahead of a low pressure system currently gliding across the Midwest. A Slight Risk of severe thunderstorms was issued by the Storm Prediction Center over much of the Mid-Atlantic and parts of the Ohio Valley for today due to increased instability across the region. Damaging wind gusts appear to be the main concern associated with this severe weather threat, but a brief tornado or two are also possible in eastern Ohio/western West Virginia. Rainfall will focus the most over southern/coastal New England over the next two days leading to a Slight Risk for Excessive Rainfall leading to Flash Flooding for this area, particularly on Tuesday when this rain event will have entered its second day. Rainfall totals are forecast to be between 1-3 inches, with higher amounts possible along coastal Massachusetts. Temperatures will rise into the 70s and 80s across much of the East Coast before dropping behind the cold frontal passage on Tuesday. Temperatures are expected to climb to above average highs today along the foothills of the Rockies today as the deep upper trough associated with the potent Pacific system pulls warm southern air as far north as Montana. As the Pacific system emerges from the Rockies on Tuesday, it will bring with it an influx of moisture and instability to the Southern/Central Plains. This will lead to scattered thunderstorms and the threat of severe weather. An Enhanced Risk of Severe Thunderstorms is in effect for a swath stretching from northern Texas to southern Kansas where a dry line may setup. An MCS may develop toward Tuesday evening in this area while this environment may also be conducive to supercells and large hail greater than 2 inches possible. Kebede Graphics are available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php