FOUS30 KWBC 031951 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 251 PM EST Tue Nov 3 2026 Day 1 Valid 01Z Tue Nov 03 2026 - 12Z Wed Nov 04 2026 ...THERE IS SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF THE LOWER MISSISSIPPI TO THE TENNESSEE VALLEYS AND OVER PARTS OF SOUTHEAST FLORIDA... ...16Z Update... Only a subtle expansion of the Slight Risk area was made over Arkansas as line of pre-frontal showers and thunderstorms approach from the west. Reference Mesoscale Precipitation Discussion 1552 covering the area. The rainfall rates are not overwhelming but the risk of flooding results from the risk of cell training and repeat convecton. No changes needed to the Slight risk area along the urban corridor of southeaast Florida. Bann Previous Excessive Rainfall Discussion... ...East Texas to the Mid Mississippi, Lower Ohio, and Tennessee Valleys... Convection that has developed along a well-defined cold front will remain ongoing, producing areas of moderate to heavy rain and possibly isolated runoff concerns early in the period from central Missouri back into east Texas. Rainfall rates are likely to wane through the late morning hours before storms re-intensify farther east from southeastern Missouri to Louisiana during the afternoon. Ample moisture (PWs 1.50-1.75+) focused along a 40-50+ kt low level jet interacting with strong upper jet forcing ahead of an amplified shortwave will contribute to organized storms capable of producing heavy rates. While the forward motion of these storms may limit the threat for widespread heavy amounts and flooding concerns, the intense rates produced by these storms are expected to raise the threat for at least isolated runoff concerns, especially in poor drainage and urbanized areas. As these storms continue east across the Mid South, several hi-res guidance members show them converging with less-organzied storms lifting out of the southeast along the western edge of a persistent ridge that extends across the Southeast. These converging storms are expected produce an axis of heavy amounts centered from northwestern Alabama through Middle Tennessee into Kentucky. A Slight Risk was maintained across portions of the lower Mississippi Valley and Mid South into the Tennessee Valley where the REFS and HREF indicate widespread amounts of 1-2 inches, with locally heavier amounts, are likely. ...Southeast Florida... While the mid-level shortwave that helped organize heavy amounts across central and southern portions of the state is expected to weaken and drift west farther into the Gulf, deeper moisture will linger across southern Florida. Persistent easterly flow will maintain PWs around 2 inches across portions of Southeast Florida, supporting storms capable of producing efficient, heavy downpours. While storms that develop are expected to be less organized and the footprint of heavy rains more confined than yesterday, there is the potential for additional localized heavy amounts that may exacerbate ongoing flooding. A small Slight Risk was introduced across Southeast Florida where the HREF and REFS indicate that localized additional amounts of 3+ inches are likely today. Pereira Day 2 Valid 12Z Wed Nov 04 2026 - 12Z Thu Nov 05 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF SOUTHEAST FLORIDA AND FROM THE TENNESSEE VALLEY INTO THE LOWER OHIO VALLEY AND SOUTHERN APPALACHIANS... ...Tennessee Valley to the Lower Ohio Valley and Southern Appalachians... On-going convection at the start of the period will continue to be capable of producing sufficient rainfall rates to produce isolated threat for runoff concerns into the early hours of the Day 2 period. Then by the afternoon, moist southerly flow into the southern Appalachians along with modest mid-to-upper level forcing will contribute to an increasing chance for locally heavy showers and storms. The general consensus of the 12Z guidance indicates that orographically focused amounts of 1-2 inches, with isolated heavier amounts, can be expected across portions of the Tennessee Valley as well as from northern Georgia into the southern Blue Ridge. ...Southeast Florida... The threat for heavy amounts and flooding concerns will continue to diminish during the period. However, isolated heavy amounts with flash flooding especially in the urbanized coastal areas can not be entirely ruled out given some overlap with areas soaked since Saturday. While drier air will continue to spread into the region, especially late in the period, PWs remaining near 2 inches could support some additional afternoon heavy downpours, resulting in additional isolated runoff concerns. Pereira/Bann Day 3 Valid 12Z Thu Nov 05 2026 - 12Z Fri Nov 06 2026 The probability of rainfall exceeding flash flood guidance is less than five percent. Bann Day 4 and Day 5 Valid 12Z Fri Nov 06 2026 - 12Z Sun Nov 08 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR SOUTHERN NEW ENGLAND ON FRIDAY... 20z Update: Marginal risk was maintained from NYC into southern New England. The model consensus supported a minor eastward shift to the western extent of the Marginal, but otherwise a swath of 2-5" still appears probable across the area. While the 12z models show above average agreement on this axis, we are still 4 days out, and thus additional fluctuations in the rainfall axis are likely. Still in the realm of possibilities it shifts east and is mainly offshore...but enough model support and run to run consistency to maintain the Marginal, with the best chances of localized flash flooding appearing to be from Long Island into eastern CT, RI and eastern MA. Chenard ...Previous Discussion... A Marginal risk area was added for southern New England, NYC and Long Island with this update. There remains considerable uncertainty how fast the front over the Northeast sweeps east, especially into the Mid-Atlantic. However, there is better certainty about a corridor of heavier rain getting hung up across southern New England on Friday. Soils all up and down the Eastern Seaboard, with the notable exception of Florida, remain very dry after over 2 weeks without a drop of rain. Thus nearly all of the expected rainfall will be beneficial. However, the plume of moisture with PWATs over 1.5 inches stalling over New England, potential for some limited instability to support some convective elements, upslope, and plentiful urban areas will all support the possible development an isolated instance of flash flooding or two. This will be where the heaviest rains are most persistent. Thus, this is a low-end Marginal as considerable uncertainty remains. On Saturday, lingering rain in eastern Maine, and a weak tropical disturbance approaching the lower Texas coast both have the potential to cause an isolated instance of flash flooding or two in those respective areas. In Maine several pieces of guidance move the heaviest rains east into New Brunswick and Nova Scotia faster. Meanwhile in Texas, a lot of the expected rain may stay offshore where there will be much more instability. These factors precluded a Marginal Risk issuance for now in both areas. Wegman 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 $$