Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 417 PM EDT Sun Mar 31 2024 Valid 00Z Mon Apr 01 2024 - 00Z Wed Apr 03 2024 ...Widespread showers and storms will bring the threat of severe weather and flash flooding from the Southern Plains eastward through the Middle Mississippi/Ohio Valleys Monday... ...Another Critical Risk of Fire Weather for the Southern High Plains Monday... ...Advancing storm system will bring increasing showers and storm chances to much of the eastern U.S. Tuesday, with another risk of severe weather in the Ohio/Tennessee Valleys and Mid-Atlantic... ...Unsettled weather in the West, with lower elevation rain and higher elevation snow, continues Sunday night but will taper off through the day Monday... A storm system passing through the central and eastern U.S. will bring the threat of severe weather and flash flooding as well a risk of fire weather over the next couple of days. A deep, energetic upper-level trough over the West will begin to shift eastward over the Plains Sunday night into Monday. Increased height falls will help to deepen/organize an area of low pressure in the lee of the Rockies over the Central Plains, with increased flow helping to reinforce a quasi-stationary frontal boundary extending eastward through the Middle Mississippi/Ohio Valleys and a dryline extending southward through the Southern Plains, with a cold front approaching from the west through the Southern Rockies/High Plains. Showers and storms will first expand in coverage Sunday night along the quasi-stationary boundary through the Middle Mississippi Valley eastward into the Ohio Valley and Mid-Atlantic as moisture advecting northward from the gulf continues to pool along the boundary. Enough shear will be present that a few storms may produce some large hail from northern Missouri eastward through central Illinois/Indiana through Sunday evening, with a Slight Risk of Severe Weather (level 2/5) in place from the Storm Prediction Center. An isolated threat for flash flooding will exist here as well, extending eastward into the Upper Ohio Valley, as heavy rain may have the tendency to repeat over areas as storms run parallel to the boundary. Another day of return flow from the Gulf as well as the arrival of the upper-level trough from the west on Monday will bring a much broader area of showers and thunderstorms along the east-west boundary as well as southward along the dryline through the Central/Southern Plains. Some supercells are expected to develop along the boundary from southern Missouri west through southeastern Kansas and southward along the dryline into central Oklahoma by late afternoon/early evening in the presence of increasing buoyancy and upper-level shear. The Storm Prediction Center has issued an Enhanced Risk (level 3/5) of severe weather for the chance of very large hail as well as damaging winds and a few tornadoes. Some more isolated storms will be possible further south into northern Texas, with a Slight Risk in place. A Slight Risk also extends eastward through the Ohio Valley where some isolated daytime storms and the arrival of storms growing upscale upstream over the Middle Mississippi Valley/Plains will bring the threat of damaging winds, as well as large hail and a few tornadoes. By evening, increasing storm coverage and the potential for upscale growth into an organized complex of storms, as well as the tendency for storms to move parallel to the frontal boundary, will lead to a higher chance of locally heavy rainfall totals and some scattered flash flooding, with a Slight Risk of Excessive Rainfall (level 2/4) in place. In addition to the threat of severe weather and flash flooding, very strong winds upwards of 40 to 50 mph, with gusts as high as 75 mph, combined with very dry conditions behind the dryline over portions of the Southern High Plains have prompted another Critical Risk of Fire Weather (level 2/3) from the Storm Prediction Center Monday. The system will continue eastward Tuesday, with widespread showers and thunderstorms expected to redevelop along the quasi-stationary boundary and ahead of the eastward moving cold front over the Upper Ohio Valley. The Storm Prediction Center has included another Enhanced Risk of Severe Weather for the potential of some large hail, damaging winds, and tornadoes. A more isolated threat extends southwestward ahead of the cold front into the Tennessee Valley, as well as eastward along the boundary into the Mid-Atlantic, with Slight Risks in place. An isolated threat for some flash flooding will exist Tuesday afternoon and evening from the Ohio/Tennessee Valleys eastward into the Appalachians and Mid-Atlantic, though the increasing storm speed as the cold front sweeps eastward should keep rainfall totals lower than on Monday. Light to moderate showers will expand further northward into the Great Lakes and Interior Northeast throughout the day Tuesday as well. Elsewhere, a wintry mix will continue with precipitation over the colder air north of the boundary into the Northern Plains Sunday night through Monday morning, with some light additional accumulations possible over portions of northern Nebraska and southern South Dakota. Widespread lower elevation coastal/valley rain showers and thunderstorms as well as higher elevation mountain snow will also continue through Sunday night from Southern California eastward into the Desert Southwest/Four Corners region and central/southern Rockies as the deep upper-level trough remains overhead. Some moderate to locally heavy rainfall totals will be possible for southern Arizona, and some additional moderate to locally heavy snowfall accumulations are forecast over the ranges of the central Rockies into early Monday. Precipitation chances will taper off from west to east through the day Monday as the trough moves eastward over the Plains. Temperature-wise, warm, much above average temperatures are most likely for eastern/southern portions of the country ahead of the approaching storm system. The cold front will usher in much cooler, below average temperatures to the Middle Mississippi Valley and Central/Southern Plains Tuesday. Conditions will initially remain much below average Monday over portions of the Northern Plains into the West under the upper-level trough. However, as the trough departs to the east, much warmer temperatures will begin to expand from the West Coast eastward into portions the Interior West and the Northern Plains by Tuesday. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php