Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
749 PM EST Thu Dec 4 2025
Day 3
Valid 12Z Sat Dec 06 2025 - 12Z Sun Dec 07 2025
The probability of rainfall exceeding flash flood guidance is less
than 5 percent.
The low-end Marginal Risk that was in effect across parts of the
Southeast (North FL and Panhandle, southern AL-GA, southern SC) has
been removed. Model QPFs from the 12Z have trended lower, while
also still showing latitudinal spread with the axis of max totals.
All of the rainfall is post-frontal, so any available instability
would be elevated, and even then there's not much per the guidance
(<500 J/Kg). Probability Match Mean (PMM) of 12Z global guidance is
generally 0.75-1.00" in 24hrs, which is actually lower than the 17Z
NBM.
Given the latest areal-average deterministic QPF (again ~0.75-1.00
in the 24hr period from 12Z Sat to 12Z sun 4hrs), along with the
fact that much of the Southeast is between a D2-D4 drought with 3
hourly FFGs between 2.5-3", probabilities of even getting close to
those values are quite low -- certainly sufficiently low to remove
the Marginal.
Hurley
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt
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