BBS: TELESC.NET.BR Assunto: HVYRAIN: Excessive Rainfall Discussion De: COD Weather Processor Data: Sat, 28 Mar 2026 19:21:29 +0000 ----------------------------------------------------------- FOUS30 KWBC 281921 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 321 PM EDT Sat Mar 28 2026 Day 1 Valid 16Z Sat Mar 28 2026 - 12Z Sun Mar 29 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ...16Z Update... No changes were needed with the blank outlook for the rest of today and tonight. In coordination with MFL/Miami, FL forecast office, there was agreement that the flooding threat in south Florida remains sub-Marginal. The CAMs are in good agreement that any convection that forms today will develop west of the urban I-95 corridor, then track southwest across relatively rural areas around Lake Okeechobee and into the Everglades and the Naples/Marco Island area. This should preclude any flooding concerns, especially given the ongoing drought and below average soil moisture levels broadly across south Florida. Wegman ...Previous Discussion... We will keep an eye on south FL, where convection is likely this afternoon into tonight. However, at this time the flash flood risk looks low. Initial convective development along the east coast of FL should move off to the southwest, limiting rainfall rate duration. Additional development this evening into tonight near and post frontal passage should generally stay transient in nature, with a downward trend in CAPE also expected overnight. The 00z HREF and REFS neighborhood probabilities of exceeding 3" are over 50%, but generally focused over inland areas of south FL...and 5" exceedance probabilities from the HREF are zero. For a Marginal risk we would like to see the higher 3" probabilities focused across the coastal urban areas and/or significantly higher 5" probabilities. Thus will continue with no risk area. Chenard Day 2 Valid 12Z Sun Mar 29 2026 - 12Z Mon Mar 30 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ...2030Z Update... No changes were needed for this update. Convective showers will likely move west off the Gulf Stream into the Miami area through the day, but due to lack of instability and dry soils, are not=20 expected to cause flash flooding. Wegman ...Previous Discussion... Additional showers and thunderstorms are expected across southeast FL, with a stream of activity potentially focused near the urban corridor. However, most model instability forecasts are below 1000 j/kg, and thus currently not expecting rainfall rates to be high enough for flash flooding, but we will continue to monitor. Chenard Day 3 Valid 12Z Mon Mar 30 2026 - 12Z Tue Mar 31 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. ...2030Z Update... There has been little change in the overall precipitation forecast across the Great Lakes. As noted in the previous discussion below, instability will increase into the evening from the south and west (Illinois/Indiana). However, the highest instability (> 1,000 J/kg) MUCAPE is unlikely to overlap the heaviest rainfall expected over northern Michigan. That said, there are likely to be some=20 convective elements embedded within the broader rain shield. Snowmelt may also contribute to higher river levels, but since snow on the ground in much of the area still amounts to over a foot,=20 especially into the U.P., it's likely the overall light amounts of=20 rain should be absorbed into the snowpack. The area will continue to be monitored as more high-resolution guidance resolve the=20 rainfall event. Wegman ...Previous Discussion... There is a non-zero risk for minor urban and small stream flooding across portions of MI, northwest PA and western NY Monday into Monday night. There is a notable increase in instability, with values exceeding 1000 j/kg. This is anomalous for the time of year, especially over portions of MI where the ECMWF EFI for CAPE is over 0.9. Combine this CAPE with above average PWs and strong moisture transport and we would expect there to be a potential for heavy rainfall rates. At the moment, not really seeing enough of a consistent model QPF signal to justify introducing a risk area, but we will have to continue to monitor trends, especially as we move more into the high res model timeframe. Chenard Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!61AGXzxjZ8YYq_1T_gVu2u1DJBs1u-dDbUL3K0W2w7PM= pnM1dPpzTNBQF4QAakQq3RBX6aEJy4z4pLL7bOm0W8w1lEs$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!61AGXzxjZ8YYq_1T_gVu2u1DJBs1u-dDbUL3K0W2w7PM= pnM1dPpzTNBQF4QAakQq3RBX6aEJy4z4pLL7bOm0cN3W6ls$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!61AGXzxjZ8YYq_1T_gVu2u1DJBs1u-dDbUL3K0W2w7PM= pnM1dPpzTNBQF4QAakQq3RBX6aEJy4z4pLL7bOm0IZPQGXI$=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]