Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 333 AM EDT Sat May 01 2021 Valid 12Z Sat May 01 2021 - 12Z Mon May 03 2021 ...Heavy rain and flash flooding to continue across south-central and southeast Texas before shifting into the lower Mississippi Valley along with the threat of severe weather on Sunday... ...Summer-like heat across the northern/central Plains today will be followed by late-season wet snow over the northern Rockies late this weekend... Wet and stormy weather is set to continue across parts of southeast Texas for the first day of May. A slow moving closed upper-level low combined with a stalled frontal boundary will remain the focus for showers and thunderstorms today across the Lone Star State. As a warm front slowly begins to lift north this evening, heavy rain is expected to finally start shifting out of south-central/southeast Texas. Rain will then reach the lower Mississippi Valley by Sunday morning. Total additional rainfall amounts are expected to reach up to 4 inches along the middle/upper Texas Coast, as well as into portions of central Louisiana. Flash flooding will remain a concern over the next few days due to downpours occurring over areas that have already seen over 2 inches of rain over the last 24 hours. WPC has issued a Slight Risk of Excessive Rainfall for today across central and southeast Texas, as well as tomorrow for central Louisiana. Flash Flood Watches also remain in effect. A few thunderstorms may turn severe across the aforementioned regions today, with greater chances for severe thunderstorms across the lower Mississippi Valley on Sunday. The Storm Prediction Center has issued a Slight Risk of severe weather for Sunday that includes most of Mississippi, Louisiana, and far southeast Texas. Elsewhere in the U.S., an unseasonably cold airmass has settled in across the eastern third of the country behind a departing cold front. Frost Advisories and Freeze Warnings are in effect from eastern Kentucky to northwest Pennsylvania this morning. Temperatures will be quick to rebound to more typical May standards on Sunday. On the flip side, the northern and central Plains will experience summer-like heat today ahead of an approaching cold front. High temperatures are forecast to soar into the low 90s throughout much of Nebraska. A few new daily high temperature records could be set as a result. By Sunday, the approaching frontal boundary will cool things down and produce scattered showers and thunderstorms from the central High Plains to the Upper Great Lakes. Rain is likely to changeover to snow across the Central Rockies Sunday night, where accumulations are expected to add up to over 6 inches in the highest terrain. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php