FOUS30 KWBC 132035 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 335 PM EST Fri Nov 13 2026 Day 1 Valid 16Z Fri Nov 13 2026 - 12Z Sat Nov 14 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF NORTHERN/CENTRAL CALIFORNIA... A progressive cold front moving through northern and central California this morning/afternoon will likely generate scattered to organized thunderstorms. Heavy rainfall leading to isolated instances of flash flooding is possible, especially for urban areas like San Francisco and Sacramento. Precipitable water values around 1" and most unstable cape values peaking around 500J/Kg by late this afternoon/early evening may produce 0.25-0.5" rain rates. Hires guidance have anywhere between 1-3" of 24 hour QPF ending at 12z on Saturday morning. The marginal risk area (at least 5% chance) is consistent with Colorado State University's Machine Learning Product first guess field, which highlights much of northern/central California with 5-15% probabilities of excessive rainfall ending at 12z tomorrow morning. Kebede Day 2 Valid 12Z Sat Nov 14 2026 - 12Z Sun Nov 15 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS NORTHWEST WASHINGTON STATE IN THE AREA OF THE OLYMPIC PENINSULA AS WELL AS NORTH-CENTRAL TEXAS... ...2030z update... North-Central Texas Global and CAM models have begun to resolve upper-level trough phasing spread and converge on a location for heavy convective rainfall on Saturday. A mid-level trough responsible for the day 1 marginal will cut across the Rockies while phasing with a southern stream disturbance tonight. Surface cyclogenesis is likely to occur tomorrow night followed by convective initiation. Storms will propagate from eastern portions of the Texas panhandle through northern-central parts of the state Saturday night. Instability of about 100-400 J/Kg MU/ML CAPE paired with 1-1.25" precipitable water values through central Texas could yield efficient rain rates. Relative soil moisture is fairly dry so some of this rain may be more beneficial. RRFS 40km neighborhood probability of 24 hr QPF exceeding 1-3" is over 5%, which is consistent with WPC's marginal risk (at least 5% chance) area. Kebede ...Previous Discussion... 00Z guidance continues to show the arrival of another round of moderate to heavy rainfall across portions of northwest Washington and the Olympic peninsula on Saturday. The two-day rainfall total may be enough to result in isolated flash- and areal-flooding. Rainfall forecasts of an additional 1 inch to 3 inches, with locally higher amounts, are expected through Saturday night or early Sunday morning. Much of the rainfall is expected to occur in a 12-hr window before the passage of a cold front late in the forecast period. This could send some of the river banks overflowing and cause some local flood concerns, some of which could be flashy. Still felt there was no fundamental changes needed with the latest forecast. Bann Day 3 Valid 12Z Sun Nov 15 2026 - 12Z Mon Nov 16 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF COASTAL TEXAS/LOUISIANA SUNDAY... Storms from Saturday are expected to continue their southeastward track through eastern/coastal Texas on Sunday. The inherited marginal risk (at least 5% chance) of excessive rainfall area pulled back closer to the Texas/Louisiana coast for Sunday based on the latest global guidance trends. The greatest exceedance probabilities continue to be along the coast with maximum QPF values staying just offshore. Kebede ...Previous Discussion... Only minor adjustments to the Marginal Risk over eastern Texas and western Louisiana were made this outlook cycle given continued model signals for potentially excessive rainfall near the Gulf coast. There was little resolution to the question whether the heaviest rainfall stays off-shore or if makes its way inland. Consensus of the preferred guidance still indicates the heaviest amounts are likely to center near the upper Texas/southwestern Louisiana coasts, Some models are showing amounts that would warrant an upgrade along the coast as northern stream energy overtakes a leading southern stream wave. That would provide providing the necessary lift to support scattered convection. However, with limited instability would likely temper rates to the north. However, due to uncertainty regarding whether the heaviest rainfall will develop offshore, held off from upgrading to a Slight Risk once again. Bann Day 4 and Day 5 Valid 12Z Mon Nov 16 2026 - 12Z Wed Nov 18 2026 The probability of rainfall exceeding flash flood guidance is less than 5 percent. An upper-trough and accompanying cold front will progress eastward from the West Coast into the Interior West Monday-Tuesday. Increasing moisture along and with the frontal passage will lead to scattered showers and thunderstorms across the Desert Southwest. However, limited instability and modest moisture should keep rates low and the progressive nature of the system passage should limit rain totals overall. Roth/Putnam Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt $$