Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue Nov 22 2022 07:51:32 FOUS30 KWBC 220751 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 250 AM EST Tue Nov 22 2022 Day 1 Valid 12Z Tue Nov 22 2022 - 12Z Wed Nov 23 2022 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE EAST CENTRAL COAST OF FLORIDA... The axis of above average PW values..2+ standard deviations above the mean...will persist across central Florida day 1. Onshore easterly to east southeasterly low level flow expected to persist in this high PW...supporting an area of defined boundary layer convergence along the east central Florida coast day 1, with continued potential for showers and isolated heavy totals. The 0000 UTC hi res guidance has trended mostly offshore for day 1 with any heavy precip potential. However, several of the global models (GFS, EC, CMC) along with a few of the latest hrrr runs show continued potential for locally heavy rainfall amounts.=20 Confidence is not great with respect to where heaviest totals will occur, but there is potential for slow moving or nearly stationary cells along the east central coastal sections of Florida that may produce isolated runoff issues, especially over more urbanized regions. With respect to changes to the previous outlook for this period, the north side was trimmed south out of JAX WFO to the northern border of WFO MLB. The southern portion was extended slightly farther to the south to the southern border of WFO MLB. Oravec Day 2 Valid 12Z Wed Nov 23 2022 - 12Z Thu Nov 24 2022 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Oravec Day 3 Valid 12Z Thu Nov 24 2022 - 12Z Fri Nov 25 2022 ....THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM NORTHEAST TEXAS INTO THE LOWER MISSISSIPPI VALLEY... Model guidance has come into better agreement with the developing closed low over the Southern Plains Thursday into Friday. There continues to be some timing differences with the GFS and ECMWF slightly more progressive than the NAM, CMC and UKMET. Despite these timing differences, there is model consensus for an expanding area of heavy precipitation late day 2 continuing into day 3 from northeast Texas, eastward into the Lower Mississippi as strengthening southerly low level flow off the western Gulf late day 2 will raise PW values to 1.5-1.75"+ (2+ standard deviations above the mean) from eastern Texas, eastward into the Lower Mississippi Valley. Much of this region has had below average precip totals over the past several weeks, save for upper coastal TX into southwest coastal LA. This is resulting in stream flows below average across much of this region. For this reason, only a marginal risk area is denoted day 3. This may be upgraded to a slight risk in subsequent outlooks if model consensus for the heaviest axis remains consistent. There will be potential for training of cells in a general south southwest to north northeasterly direction across the marginal risk area, supporting potential for totals in the 3-5"+ range where training occurs. Oravec Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!8s21G7S2FswhufwVf0s-SYU0IXbgKBH8xP7gsWJgmelI= JtajIz6UKekg8fjYiue873IBIyqg0-a2ayjXEW8TFnsKKvE$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!8s21G7S2FswhufwVf0s-SYU0IXbgKBH8xP7gsWJgmelI= JtajIz6UKekg8fjYiue873IBIyqg0-a2ayjXEW8TPkzIOvI$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!8s21G7S2FswhufwVf0s-SYU0IXbgKBH8xP7gsWJgmelI= JtajIz6UKekg8fjYiue873IBIyqg0-a2ayjXEW8TejbULjI$=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) .