FOUS30 KWBC 100828
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
328 AM EST Tue Nov 10 2026

Day 1
Valid 12Z Tue Nov 10 2026 - 12Z Wed Nov 11 2026

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

Kleebauer


Day 2
Valid 12Z Wed Nov 11 2026 - 12Z Thu Nov 12 2026

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

Kleebauer


Day 3
Valid 12Z Thu Nov 12 2026 - 12Z Fri Nov 13 2026

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

Kleebauer


Day 4 and Day 5

Valid 12Z Fri Nov 13 2026 - 12Z Sun Nov 15 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF CENTRAL AND SOUTH TEXAS SATURDAY-SATURDAY NIGHT...

The probability of rainfall exceeding flash flood guidance is less
than 5 percent on Day 4 (12Z Fri-12Z Sat).

On Day 5 (12Z Sat-12Z Sun), added a Marginal Risk area across the
Texas Coast into the Hill Country. The subtropical jet remains
active, and during this period the next southern stream upper jet
streak and attendant mid-upper shortwave traverses the outlook
area. The guidance is split on the heavy rainfall risk, with the
GFS and ECMWF QPF (both operational and ensemble means) coming in
heavier than their AI runs, while also heaver than the CMC and
UKMet. Given the transient nature of the deep layer forcing and
favorable thermodynamic profile (uptick in S-SE low-level flow off
the western Gulf and thus increasing theta-e/TPW/IVT advection),
the ERO risk at this point is considered a 'low-end' Marginal (i.e.
closer to a 5-10% neighborhood probability). However, the setup
would favor heavy rainfall, especially if the shortwave amplifies a
bit more which would slow the W-E progression somewhat. Moreover,
both the operational GFS and ECMWF show areas of 3-6" of rain on
Day 5, with these global (non CAM) high-end amounts indicative of
the heavy rainfall potential if the favorable ingredients can
persist over a sufficient period of time.

Hurley


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

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