Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
344 PM EDT Tue Oct 27 2026
Day 3
Valid 12Z Thu Oct 29 2026 - 12Z Fri Oct 30 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
WEST AND CENTRAL TEXAS...

21Z Update..

An expansion to the Slight Risk area was made in this update, with
a continued consensus of a heavy QPF core over western Texas to
eastern New Mexico among the latest suite of guidance. Remnant
moisture from T.C. Vance will move northward into north-central
Mexico, before being picked up by a mid-level shortwave trough and
moving into Texas and New Mexico. AI/ML guidance (EC-AIFS & AIGFS)
has also remained fairly consistent in the placement of the QPF
core, but has trended down in terms of rainfall amounts over a 24hr
period. Additionally, AI models suggest an increased areal
footprint along with the minor downtrend, justifying the expansion
of the SLGT Risk area. As such, a higher-end Slight remains, but
a potential upgrade could be justified in the coming updates,
especially as CAMs guidance becomes available.

Blanco-Alcala

..Previous Discussion..

...Texas and New Mexico...

Conditions will be favorable for widespread convection across
portions of Texas and New Mexico on Thursday as mid-level energy
associated with the remnants of TC Vance move into the region. As
the wave approaches, southeasterly low-level flow will bring
anomalous Gulf moisture into the south-central U.S., increasing
PWATs across Texas to 1.5-2 inches, which is 3 standard deviations
above normal and well above the climatological 90th percentile. In
addition to mid-level destabilization from the wave, enhanced upper
level divergence in the right entrance region of a southern stream
jet will support a broad region of ascent across Texas. These
ingredients combined with at least modest CAPE (slightly limited
due to widespread cloud cover) are expected to support an organized
heavy rainfall event.

Model guidance has been trending north and west with the QPF
footprint of this event during the Day 3 time frame. This has
resulted in shifting the Slight Risk area to include more of West
and Central Texas. There is good agreement among the deterministic
(physical and AI) and ensemble guidance that the highest rainfall
amounts will focus between the Edwards Plateau/western Hill Country
and the Midland area, which is facing a high-end Slight Risk on
Thursday. There is still quite a bit of uncertainty in QPF to the
west and north of this region, with some models showing a faster
and further north spread with the heavier totals and some showing
elevated amounts in the terrain of West Texas. The rest of West
Texas and portions of west-Central Texas up to the Panhandle have
been included in a Marginal Risk to account for this QPF
uncertainty. An isolated flash flood/Marginal risk will likely
extend into southern New Mexico as well where locally heavy
rainfall over sensitive terrain and burn scars could cause flash
flooding, especially considering how saturated soils are after
recent heavy rains.

Dolan

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