Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
337 PM EDT Fri Oct 23 2026
Day 2
Valid 12Z Sat Oct 24 2026 - 12Z Sun Oct 25 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF NEW
MEXICO AND COLORADO...

...2030Z Update...

No major changes were needed for this afternoon's update. The area
under a higher-end Slight was shrunk to the northeast corner of New
Mexico into southeast Colorado. This area remains as having the
best chance of seeing repeating thunderstorms capable of heavy
rainfall and resultant widely scattered instances of flash
flooding. A SSE'ly LLJ will pump Gulf moisture northward into west
Texas. Fortunately, compared to prior days, there will be only a
small amount of overlap in the heavy rainfall footprint by
Saturday. Elsewhere, the Slight is mostly unchanged. The El Paso
metro was removed from the Slight, due in part to less rain
expected in Day 1/today.

The Marginal risk area covering much of the I-95 corridor in
Florida is mostly unchanged, though some of the Miami and Ft.
Lauderdale metros were removed as the forecast for heaviest
rainfall has shifted northward a bit.

Wegman

...Previous Discussion...

...West Texas through southern Colorado and far western Kansas...

An upper level low will become cut off from the main upper trough
over the southwestern U.S., which will result in another day of
downstream convection from West Texas/New Mexico into the southern
and central High Plains. Widespread convection will develop across
this broad region on Saturday and will likely be enhanced in
coverage and intensity by an upper level shortwave ejecting into
the Plains ahead of the low. A strengthening mid/upper-level jet
ahead of the system will increase moisture transport into the
region and maintain anomalously high PWATs and instability. These
ingredients will support heavy rainfall, and deep unidirectional
southerly flow will support training/back-building storms from
eastern New Mexico into southeastern Colorado and far western
Kansas.

Global models show a broad area of 1-3 inch precipitation
totals across this region, and locally higher amounts are expected
with any training/repeat convection. Hi-res guidance suggests
rainfall rates may reach 1-2 inches per hour, which would rival
flash flood guidance. A Slight Risk of excessive rainfall covers
these area from West Texas through eastern New Mexico and into
southeastern Colorado and far western Kansas where heavy rainfall
may lead to scattered instances of flash flooding. A Marginal Risk
area surrounds the Slight and extends a bit further into the
central Plains where convection could produce locally heavy
rainfall but will be more progressive, resulting in a lower flash
flood threat.

...Four Corners region...

A Marginal Risk of excessive rainfall extends back into the Four
Corners region to include portions of Utah and northern Arizona
where convection in the vicinity of the upper low may result in
isolated instances of flash flooding. Though snow levels will be
dropping, they should remain high enough to allow for heavy
rainfall with slow moving storms. Models show some instability
developing across Utah and Arizona during the afternoon hours, and
there should be enough moisture to support widely scattered
convection with localized heavy rainfall. Given the preceding days
of heavy rainfall leading up to Saturday, the region may be more
sensitive to additional heavy rainfall.

...East Coast of Florida...

A mid-level low is expected to develop along a weak boundary east
of Florida on Saturday, which will enhance onshore northeasterly
flow along the East Coast and direct a plume of enhanced moisture
(PWATs ~1.5 inches) towards the Florida peninsula. Meanwhile, an
upper level shortwave is expected to drop south into the region,
which will provide upper level support and enhance precipitation
coverage and intensity. Coastal convergence will focus enhanced
precipitation totals right along the East Coast of Florida, which
could cause isolated flash flooding in urban, low-lying, and poor
drainage areas. A Marginal Risk of excessive rainfall encompasses
the Florida East Coast roughly from Jacksonville to Miami, with the
highest threat focusing along the Central Florida East Coast. The
Slight Risk over Southeast Florida was removed in this forecast
cycle due to slower timing of this event. The focus for
precipitation will gradually slide down the Florida East Coast, but
the enhanced threat for Southeast Florida looks to hold off until
Sunday.

Dolan


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