565 FOUS30 KWBC 111914 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 314 PM EDT Mon May 11 2026 Day 1 Valid 16Z Mon May 11 2026 - 12Z Tue May 12 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR ALONG THE I-10 CORRIDOR IN LOUISIANA... ...16Z Update... An MCS currently just off the coast of Louisiana is expected to continue drifting along and just off the coast through the day. Its existence shows there is ample moisture and instability in place along the Gulf Coast. Guidance suggests that the associated cold pool will move north and collide with an incoming cold front approaching from the north and west. This additional lift with ample Gulf moisture will spawn a new round of convection towards peak heating this afternoon. The storms associated with the front/cold pool collision will be the ones that are of greatest concern for potential flash flooding...as the guidance suggests these storms could be along I-10/I-12 near Baton Rouge. Towards New Orleans things are a bit more uncertain as interactions between the MCS to the southeast and the storms along the front to the north and west could make for a "dry slot" of sorts in between, or the cold pools of the two areas of storms could interact and allow for additional convection to blossom in between in and around the New Orleans metro. Regardless, the frontal storms to the northwest will propagate east into the early evening, which should bring some amount of heavy-rain-producing storms over the New Orleans metro. In coordination with LIX/Slidell, LA and LCH/Lake Charles, LA forecast offices, a Slight Risk upgrade was introduced with this update to account for the combination of nearly saturated soils from heavy rains in this area from 2 days ago and the expectation of slow-moving storms producing heavy rain again this afternoon and evening. The more urban I-10/I-12 corridors were highlighted. The surrounding Marginal was left largely unchanged. There are more uncertainties as to how far west down I-10 towards Houston the convection fires up later today, and towards the east, soils are much more receptive to additional rainfall such that the flooding risk across the Florida Panhandle and south Georgia remains low, despite the potential for a more long-duration moderate rainfall event going well into tonight. Wegman Day 2 Valid 12Z Tue May 12 2026 - 12Z Wed May 13 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR ALONG THE I-95 CORRIDOR IN FLORIDA... A Marginal Risk of excessive rainfall was introduced on the east coast of Florida, encompassing the I-95 corridor. A cold front will continue pushing south through FL, and with sufficient PWATs (over 1.75in.), and low-level onshore flow, should support heavy rainfall early on. Diurnal seabreeze effects will interact further with the cold front, with a convergence axis expected along the east coast of FL. HREF neighborhood probabilities suggest a high likelihood (over 90%) of QPF exceeding 3 inches, and a moderate chance (around 60-80%) over the urban center of Jacksonville. As a result, isolated flash flooding will be possible, particularly in the urban centers of Jacksonville and Miami. Due to ongoing drought conditions, most of the rainfall will be beneficial which will result in a low-end marginal threat. Blanco-Alcala Day 3 Valid 12Z Wed May 13 2026 - 12Z Thu May 14 2026 The probability of rainfall exceeding flash flood guidance is less than five percent. Blanco-Alcala Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt