BBS: TELESC.NET.BR Assunto: HVYRAIN: Excessive Rainfall Discussion De: COD Weather Processor Data: Sat, 2 May 2026 00:58:39 +0000 ----------------------------------------------------------- FOUS30 KWBC 020058 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 858 PM EDT Fri May 1 2026 Day 1 Valid 01Z Sat May 02 2026 - 12Z Sat May 02 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE=20 CENTRAL GULF COAST INTO THE SOUTHEASTERN U.S.... As drier and more stable conditions continue to spread from west- to-east across the previously highlighted areas, the Slight Risk and much of the Marginal Risk areas were removed. However, a=20 Marginal Risk area was maintained for a portion of the region --=20 extending from southeastern Louisiana to southwestern Georgia and=20 the Florida Panhandle. A series shortwaves will continue to move through the base of a broader-scale trough centered over the northern Gulf. As this energy moves east, modest surface wave development is expected along the slow-moving boundary positioned over the northern Gulf. This low is forecast to move east along the northern Gulf Coast, with the trailing portion of the front and the leading edge of drier air dropping southeast. As the evening progresses, rain will diminish from west-to-east from eastern Texas into the lower=20 Mississippi Valley. Latest mesoanalysis shows the greater=20 instability south of the surface front and mostly out over the=20 northern Gulf -- keeping rainfall rates over land in check.=20 However, some pockets of greater instability and heavier rainfall=20 rates are brushing southeastern Louisiana and the Florida=20 Panhandle. This is expected to remain the case through the evening, with the better instability and greater potential for intense=20 rainfall rates confined mostly to the immediate coast. However,=20 while instability further inland will be limited, model soundings=20 show the column becoming more saturated as southerly flow=20 intensifies ahead of the wave. This deep saturation has the=20 potential to support highly-efficient rains, with heavy amounts=20 possible. The updated Marginal Risk area reflects where recent runs of the HRRR and the 18Z HREF indicate the greatest threat for=20 localized amounts over 2 inches this evening into the overnight. Pereira Day 2 Valid 12Z Sat May 02 2026 - 12Z Sun May 03 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THE SOUTHEAST U.S.... 21Z update... The latest QPF trends supported a minor southward nudge of the Marginal across the northern peninsula. The QPF footprint will largely span from Apalachee Bay through north- central/northeast Florida and across southeast Georgia. Campbell A progressive upper trough is expected to help focus and sustain showers and thunderstorms across portions of the Southeast United States on Saturday into the early morning hours of Sunday. More importantly...the trough should result in any convection moving with minimal risk of back-building or training. The setup promotes a relatively favorable environment suitable for heavy rainfall with the stronger cell cores capable of producing rainfall rates between 1-2"/hr in a region where Flash Flood Guidance values remain high. There was enough of a signal for the possibility of some urban flooding to warrant keeping a previously-issued Marginal Risk in place with minimal amount of changes needed. Bann Day 3 Valid 12Z Sun May 03 2026 - 12Z Mon May 04 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF THEM SOUTHEAST FLORIDA PENINSULA ON SUNDAY... 21Z update... Latest guidance and WPC QPF focuses the highest rainfall over portions of Palm Beach, Broward and Hendry Counties, which supported the reshaping of the western boundary of the Marginal Risk. Campbell A cold front associated with an area of low moving northeastward off the eastern US seaboard will be draped across the central portion of the Florida peninsula on Sunday...with the front separating an airmass with precipitable water values at or somewhat less than 0.5 inches in the panhandle and adjacent portions of the peninsula to values in the 1.75 inch to 2.00 inch over the southern half of the peninsula for much of Sunday and Sunday evening. Mid- and upper-level shortwave energy embedded within fast flow aloft will help focus and sustain thunderstorms that could produce 1.5 to 2.5 inch per hour along and south of the boundary. There remained enough of a signal for the potential of some urban flooding across the larger urban areas so opted to keep with the Marginal Risk area due to the high flash flood guidance. Even if the QPF remains similar in future cycles...where/how much rain falls in Days 1 and 2 will affect the flash flood guidance as Day 3 makes its way towards becoming a Day 1 outlook. Regardless...downpours and localized multiple-inch rainfall amounts in the major cities is more likely to have flood- related problems in either scenario. Bann Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-VUmGgX-LQdy1iuOcvwaMtITdDQiEHM4zTakhPYfALzI= 0skO57UOvglbmgNvTfs6dYmVWPY54ipeeIYlzeEkY10SRcU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-VUmGgX-LQdy1iuOcvwaMtITdDQiEHM4zTakhPYfALzI= 0skO57UOvglbmgNvTfs6dYmVWPY54ipeeIYlzeEkvpB3_UY$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-VUmGgX-LQdy1iuOcvwaMtITdDQiEHM4zTakhPYfALzI= 0skO57UOvglbmgNvTfs6dYmVWPY54ipeeIYlzeEktOblLRA$=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]