Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 AM EDT Tue Mar 21 2017 Valid 12Z Tue Mar 21 2017 - 12Z Thu Mar 23 2017 ...Heavy snow possible over the Sierras and northern Cascades... ...Heavy rain over parts of Northern California... ...Snow over parts of the Northern/Central Plains... Widespread rain with mountain snow is forecast for a majority of the West over the few days as multiple disturbances move through the region. Portions of northern and central California may have periods of higher rainfall amounts/intensities that could lead to rapid runoff and/or flash flooding today and on Wednesday. The area of potential concern will shift southward to southern California Wednesday afternoon into Thursday as a cold front passes through California and into the southern Great Basin. Higher snowfall totals are expected for the Sierras and the northern Cascades in this active wet period. As the upper low tracks over the Great Basin/Desert Southwest a surface low will develop and form a surface front from northern Utah to Mexico-- which will generate snow across the Great Basin... Wasatchs and the Wind River range by midweek. Meanwhile... upper-level energy over the Northern Intermountain Region/Northern Rockies will move eastward and dissipate over the Ohio Valley during the evening hours tonight. Snow and rain will spread over parts of Northern Intermountain Region/Northern Rockies into parts of the Northern/Central High Plains is forecast to dissipate by this evening as well. A second area of upper-level energy will move out of the Northern Rockies into the Central Plains Tuesday into Wednesday morning. The energy will produce rain and some snow over parts of the Central Rockies/Central High Plains that will move into parts of the Central/Northern Plains by Wednesday. Low pressure over the Ohio Valley will move offshore today and the associated front will advance southward to the interior Gulf Coast States and eastward off the Southern Mid-Atlantic Coast by Wednesday morning. Showers and thunderstorms along the frontal boundary is expected to end over the Mid-Atlantic by Wednesday afternoon. Campbell/Ziegenfelder Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php