Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
108 PM EST Tue Jan 20 2026

Day 1
Valid 16Z Tue Jan 20 2026 - 12Z Wed Jan 21 2026

Texas coast...
An area of moisture convergence/frontogenesis has been the focus
of showers trying to stream into the Middle TX Coast off the Gulf
of Mexico. The 0.5"+ an hour rain amounts have been focused off the
coast, along the lines of the output from the 12z HREF guidance.
With time, the RAP shows the flow veering in this area, showing
less of a surface focus for the convection with time. The 12z HREF
is focusing whatever heavy rain threat that exists just offshore of
Port O'Connor, mostly during the 16-20z time frame, before fading.
Local totals to 3" are expected just offshore. Even if this
activity were to unexpectedly drift ashore, the heavy rainfall risk
appears too isolated and too limited for a Marginal Risk area, so
left the graphic area-free.

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Roth


Day 2
Valid 12Z Wed Jan 21 2026 - 12Z Thu Jan 22 2026

South Florida...
The best signal for heavy rainfall this period focuses near an
inverted trough sharpening along the South Florida coast,
as precipitable water values rise to 1.5" and instability tries to
move ashore from the Gulf Stream. The 12z HREF/06z REFS advertise
0.5"+ an hour amounts right at the end of the period Thursday
morning, with a 40%+ chance of 2"+ somewhere between coastal
Broward and Martin Counties. At the moment, the threat of flash
flooding here appears too isolated and too marginal for a Marginal
Risk to be depicted.

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Roth


Day 3
Valid 12Z Thu Jan 22 2026 - 12Z Fri Jan 23 2026

South Florida...
The best signal remains near South Florida Thursday morning where
enough moisture and instability appear to exist for locally heavy
rain. The guidance appears to drift this activity northward as the
low- level flow veers; convection is not expected to sit in any
particular location for too long. At the moment, the threat of
flash flooding here appears too isolated/marginal for a Marginal
Risk to be depicted.

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Roth

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt