Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sun Nov 20 2022 19:22:01 FOUS30 KWBC 201921 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 220 PM EST Sun Nov 20 2022 Day 1 Valid 16Z Sun Nov 20 2022 - 12Z Mon Nov 21 2022 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG A PORTION OF THE URBAN CORRIDOR IN SOUTH FLORIDA... 16Z update... Scattered to widespread bands of showers have been persistent in crossing the peninsula this morning while thunderstorms have developed near the stalled front in the vicinity of South Florida. This is expected to continue through the day. The latest hi-res models are showing very isolated rainfall rates nearing 2.0-2.5 inches/hour from the Miami-Dade to Palm Beach stretch of the coast. The Marginal Risk area in place is covering this area so no changes were made. Campbell Radar imagery has been showing increasing coverage of convection off-shore of the southern Florida peninsula during the early morning hours. The last several runs of the HRRR have started to show a consistent signal for localized rainfall rates/accumulations that would be problematic...especially in an urban environment. The 20/00Z ECMWF also showed a bulls-eye farther north than the HRRR along or near the Atlantic coast.=20 Even though there are differences in details...it appears there has been enough of signal for flooding to warrant at least a Marginal Risk area for the southern Florida peninsula. Bann Day 2 Valid 12Z Mon Nov 21 2022 - 12Z Tue Nov 22 2022 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE CENTRAL FLORIDA ATLANTIC COAST... 21Z update... The latest guidance has continued with the northward shift up the eastern coastline of Florida although still favors the higher QPF to be in the vicinity of Melbourne with areal averages of 1 to 3 inches. The Marginal Risk was further trimmed from the south to reflect the latest WPC QPF and model trends. Campbell There has been a shift in the numerical guidance to focus the better QPF a bit northward of the previous runs. As a result, trimmed some of the southern-most extent of the on-going Marginal Risk area as yesterday's Day 3 ERO moves into today's Day 2 ERO.=20 The overall pattern still shows an area of precipitable water values approaching 2 inches making their way northward from the Florida Strait on Monday morning that progresses northward during the late morning and afternoon so convection capable of producing some localized downpours remains a possibility. The expectation is that convection that develops across the southern portion of the Marginal Risk area will be more driven by instability while the support of upper level jet will start to aid the deep layer lift farther north. Either way.....there could be sufficiently high rainfall rates to be problematic in the urban areas. Bann Day 3 The Day 3 outlook will be updated by 2030Z. Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!-QS3REY-Z5KR7iZe_o1IF9RB7w3JRO8geomeTWYe-GXv= a7lmuY-I_hoLJfzbDfWygbtjLNVxTmXp2tEnNcsGvySdttU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!-QS3REY-Z5KR7iZe_o1IF9RB7w3JRO8geomeTWYe-GXv= a7lmuY-I_hoLJfzbDfWygbtjLNVxTmXp2tEnNcsGZqAf5NA$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!-QS3REY-Z5KR7iZe_o1IF9RB7w3JRO8geomeTWYe-GXv= a7lmuY-I_hoLJfzbDfWygbtjLNVxTmXp2tEnNcsGJm557BI$=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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .