Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 349 PM EDT Mon Mar 09 2020 Valid 00Z Tue Mar 10 2020 - 00Z Thu Mar 12 2020 ...Next big storm system will affect the southwestern U.S. through midweek... A frontal boundary currently over the Plains and Great Lakes region will continue to advance southeastward and reach the East Coast by Tuesday night. This will serve as a focus for periods of light to moderate rain from the central Gulf Coast and central Plains, to the Great Lakes region. A few strong storms will be possible across portions of the Plains near a surface low on the front. Heavy snow will be likely for northern Maine, which will be north of the main frontal boundary, and rain elsewhere for most of the Northeast U.S. Temperatures will be above average ahead of the front with 60s and 70s for highs being widespread. Over California, an occluded surface low over the eastern Pacific will slowly track eastward through the middle of the week and approach southern California. Rain and high mountain snow will increase as the cold front approaches the coast, mainly for the southern half of the state. With areal rainfall amounts of one half to one inch in lower elevations, and one to three inches for favored mountain areas, some instances of flooding will be possible, and therefore WPC maintains a Slight Risk for Excessive Rainfall on Tuesday. This moisture then reach Arizona by Wednesday with rounds of moderate to locally heavy rain expected across central portions of the state. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php