Subj : Flooding Likely CA To : All From : Mike Powell Date : Thu Nov 13 2025 08:22:04 AWUS01 KWNH 130959 FFGMPD CAZ000-ORZ000-132158- Mesoscale Precipitation Discussion 1221 NWS Weather Prediction Center College Park MD 458 AM EST Thu Nov 13 2025 Areas affected...much of central and northern California Concerning...Heavy rainfall...Flash flooding likely Valid 130958Z - 132158Z Summary...Heavier downpours should result in instances of urban flooding around San Francisco and vicinity during and after morning commute. Heavier rainfall will also spread into more of northern and central California from 13Z/6a PT through the evening. Flash flooding is expected especially near burn scars, urban areas, and other terrain-favored spots. Discussion...As of 0955Z, a band of convection was beginning to organize along a front extending from near 80 miles southwest of Eureka to 180 miles southwest of Monterrey. Individual convection along this band was streaming northward at a decent clip. However, the band was only moving slowly eastward and already favoring areas of repeating over open waters. 500 J/kg MUCAPE and areas of 1.3+ PW values were supporting the convective band, and MRMS data was already estimating 0.5-0.7 inch hourly rain rates over land just southwest of Eureka. The convective band and associated mid-level system are expected to make only slow eastward progress toward more land areas of California today. As the systems approach, low-level wind fields will strengthen, colliding with terrain and locally enhancing rain rates in many areas. Rates could reach 1 inch/hr on a localized basis. These rates will overspread portions of the San Francisco Metro beginning in the 12Z/5a PT hour and persist through the afternoon, impacting morning rush with wet roads and areas of excessive runoff. Portions of north-central through east-central California will also experience terrain-enhanced heavy rainfall, with some of the heavier rates (exceeding 0.75 inch/hr) falling on sensitive ground conditions and burn scars. Flash flooding is expected on at least an isolated basis. These areas could include terrain near/north of Redding (beginning around 13Z/6a PT) and upslope areas of the Sierra (near/east of Chico) beginning around 14Z/7a PT. Heavy rainfall could last for 8-12 hours in many of the aforementioned areas, with totals of 3-5 inches likely through 00Z Fri Nov 14. Again, at least a few instances of flash flooding are expected given the scenario. Cook ATTN...WFO...EKA...HNX...LOX...MFR...MTR...REV...STO... ATTN...RFC...PTR...RSA...NWC... LAT...LON 42252315 42102191 41712116 41262098 40792092 40142070 38461980 37801954 36581993 35282051 35472124 37712319 40152469 41802483 42162420 $$ --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1) .