Subj : HVYRAIN: Excessive Rainfa To : All From : Mike Powell Date : Fri Nov 21 2025 09:38:12 FOUS30 KWBC 210824 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 324 AM EST Fri Nov 21 2025 Day 1 Valid 12Z Fri Nov 21 2025 - 12Z Sat Nov 22 2025 ....THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA... Showers and thunderstorms are expected across southern California, southern Nevada and southwest Arizona as lobes of vorticity rotate to the east of the low offshore. Instability appears to be on the weak side which will likely be a limiting factor, however some brief heavier rates are still possible from short training segments within the deep layer southerly flow. A Slight Risk for excessive rainfall remains in effect for southern California and southwest Arizona and a Marginal Risk spans from the California coast to south-central Arizona. For the Missouri/Ohio/Tennessee Valleys there will be an elevated threat for locally excessive rainfall. During this period a steady stream of above average moisture will be transported northward and encounter an east-west boundary. Isolated areas of moderate to heavy rainfall that leads to spotty problems from run-off can be expected. However...the flow aloft becomes increasingly flat and confluent during the day which will reduce the risk of any excessive rainfall. A Marginal Risk area was maintained from eastern Kansas to West Virginia/western Virginia/western North Carolina. Campbell Day 2 Valid 12Z Sat Nov 22 2025 - 12Z Sun Nov 23 2025 The probability of rainfall exceeding flash flood guidance is less than 5 percent. Campbell Day 3 Valid 12Z Sun Nov 23 2025 - 12Z Mon Nov 24 2025 ....There is a Slight Risk for excessive rainfall in the Southern Plains... The low pressure system that brought heavy rainfall for the West Coast during the Day 1 period will be exiting into the Southern Plains and the warm, moist air will support scattered to widespread heavy rainfall. There is an increasing signal that this setup could be a significant event, especially for north-central portions of Texas and into southern Oklahoma where a couple of solutions are suggesting a narrow swath of 4 to 6 inches possible. A Slight Risk for excessive rainfall is in effect for for much of north- central/northeast Texas and south/east Oklahoma. A broader Marginal Risk spans from the Big Bend vicinity to southwest Missouri and western Arkansas. This part of the country will continue to be monitored for a possible upgrade to a Moderate with future updates. Campbell $$ --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1) .