Subj : HVYRAIN: Excessive Rainfall Discussion To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Dec 14 2024 08:29:44 FOUS30 KWBC 140829 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 329 AM EST Sat Dec 14 2024 Day 1 Valid 12Z Sat Dec 14 2024 - 12Z Sun Dec 15 2024 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF=20 COASTAL CALIFORNIA FROM SANTA ROSA INTO SAN Francisco AND SAN=20 JOSE|... Even though a much of the areal coverage of moderate to locally heavy rainfall associated with an atmospheric river has already moved on shore...maintained the Slight risk area mainly along the coast from Santa Rosa southward into San Francisco and San Jose given an expected up-tick in rainfall rates as a compact shortwave trough approaches from the west. Short term guidance from the convective allowing mesoscale guidance shows several hundred Joules per kilogram of CAPE moving into that portion of California immediately ahead of the shortwave impulse. The 14/00Z HREF maintained a nearly 100 pct chance of half-inch per hour rainfall rates and nearly 40 percent chance of 1 inch per hour rates over and near the San Francisco Bay area during the early- to mid- morning hours. The combination of the rainfall rates and the urbanization of the area still points to an elevated risk of flood impacts. The overall impacts should be limited by the fairly short duration of heaviest rainfall...which looks to taper off quickly in the 15Z to 18Z period. Bann Day 2 Valid 12Z Sun Dec 15 2024 - 12Z Mon Dec 16 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Bann Day 3 Valid 12Z Mon Dec 16 2024 - 12Z Tue Dec 17 2024 The probability of rainfall exceeding flash flood guidance is less than 5 percent Bann Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/94epoints.txt__;!!DZ3fjg!5Hiz-WqlN8YexFVeOw6WTLG50WLjXhtJJw027PqUsADk= G3yfpaqYkFC8GumjUlhMnmVzRhiaERHJzjFRRq5pT9hFGoU$=20 Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/98epoints.txt__;!!DZ3fjg!5Hiz-WqlN8YexFVeOw6WTLG50WLjXhtJJw027PqUsADk= G3yfpaqYkFC8GumjUlhMnmVzRhiaERHJzjFRRq5p9fX8hSI$=20 Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go= v/qpf/99epoints.txt__;!!DZ3fjg!5Hiz-WqlN8YexFVeOw6WTLG50WLjXhtJJw027PqUsADk= G3yfpaqYkFC8GumjUlhMnmVzRhiaERHJzjFRRq5p7PKikMQ$=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 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .