Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
621 PM EST Sat Nov 22 2025

Day 1
Valid 01Z Sun Nov 23 2025 - 12Z Sun Nov 23 2025

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF SOUTHEAST ARIZONA INTO CENTRAL ARIZONA...

Infrared satellite imagery shows cooling cloud tops in association
with showers and thunderstorms across central and southeast AZ 
within a region of 700 hPa confluence ahead of a progressive deep 
layer low, with some recent uptick in coverage.  Pockets of 500+ 
J/kg of MU CAPE exist across west- central and southeast AZ per SPC
mesoanalyses, with instability increasing due to cooling aloft and
some degree of daytime heating/sunshine, particularly across 
southeast AZ. Effective bulk shear of 30-50 kts exists here, which 
is leading to an environment with both organized and ordinary 
convective cells, with the organized activity edging east of due 
north while the less organized storms move just west of due north. 
Precipitable water values of 0.5-1" lie here. The atmosphere is 
cool, with 1000-500 hPa thickness values of 5550-5600 meters. When 
combined with the available moisture, the column is approaching 
saturation.

The mesoscale guidance implies increasing convective coverage and
an increasing incidence of 0.5"+ an hour amounts over the next
several hours, with the 12z REFS and 18z HREF guidance suggesting
the heaviest rainfall in the 01-05z time frame before fading
thereafter. This could be due to cell training, occasional 
mesocyclone formation, or cell mergers between more and less 
organized convective activity. As the upper level system continues 
marching northeast, winds should veer somewhat which should allow 
convection to shift somewhat to the east with time, with activity 
shifting increasingly into mountainous areas. With hourly amounts 
to 1" and local totals to 2" possible, the incidence of impactful 
heavy rain is expected to be isolated to widely scattered, mainly 
within arroyos/dry washes, box canyons, and any area burn scars.

Roth


Day 2
Valid 12Z Sun Nov 23 2025 - 12Z Mon Nov 24 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF CENTRAL
AND NORTHERN TEXAS INTO PORTIONS OF SOUTHERN OKLAHOMA...

...20z Update...

Consensus QPF guidance has continued to focus on the western side
of the inherited Slight Risk, making the primary adjustment with
this update to shift both the MRGL and SLGT areas a bit west. The
upper-level system driving the expected rainfall (which is expected
mostly after 00z on Mon) continues to look less amplified and cut-
off, placing the area of concern closer to the base of the trough
and tilted the QPF axis a bit more west-to-east than previously.
While this may increase the risk locally for training convection,
the main axis is also now more solidly north of the bulk of the
Hill Country (particularly where heavy rainfall occurred earlier
this week) into much of the Big Country/Northwest TX. While the
rainfall axis still impinges on western portions of the Dallas-
Fort Worth metro, the best probabilities for 3" exceedance are
concentrated to the west of the populous areas (as well as north
of San Angelo proper). While this less populated region of Central/
Northwest TX within the south-central portion of the updated SLGT
risk has indications of 5"+ potential (per 40-km HREF 5" exceedance
probs of ~15%), this signal is being driven seemingly entirely by
one member (the FV3, which is generally one of the less reliable
members) with the bulk of the CAM guidance in good agreement
indicating 2-4" totals. Given that much of this QPF is also
expected in the last 6 hour period of the forecast, there is still
plenty of time to see if this FV3 run is an outlier or if more CAM
guidance comes into alignment with this heavier solution. This may
necessitate a future targeted upgrade to Moderate Risk (which is
also possible for San Angelo and/or the DFW metro areas, should the
QPF axis shift a bit south and/or east).

Churchill


...Previous Discussion...

The latest guidance continues to depict a southwest-northeast
orientated axis of heavy rain panning from the northern part of the
Hill Country to northeast Texas. General consensus suggests 1 to 3
inches however, the ECMWF is persistent on the higher end with
amounts 3 to 5+ inches and placed further south/southwest than
other solutions. This is somewhat concerning, as this brings the
forecast axis of QPF even more into alignment with areas that
realized heavy rainfall in prior days.

A Slight Risk remains in effect and seems appropriate given at
least three days of recovery from the previous heavy rainfall
event and uncertainty with regard to the amount of training and
resultant QPF.

Campbell/Churchill


Day 3
Valid 12Z Mon Nov 24 2025 - 12Z Tue Nov 25 2025

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR MUCH OF
ARKANSAS AND NORTH TEXAS INTO ADJACENT PORTIONS OF SOUTHEASTERN
OKLAHOMA, NORTHERN LOUISIANA, AND NORTHWEST MISSISSIPPI...

...20z Update...

Organized convection is expected to be ongoing Monday morning
across a good portion of North TX and into southeastern OK and the
Ark-La-Tex, moving east across Arkansas and into the Mid-South
during the day. Confidence is highest in robust convection in the
vicinity of North TX early in the period, whereas solutions diverge
somewhat later in the day...with one camp of guidance suggesting
training convection and localized totals as high as 3-5" from a
relatively hydrologically sensitive region from southwest OK into
northwest/north-central AR (mainly driven by the GFS/GEFS) and the
other camp indicating higher odds for 3" exceedance farther south
into the Ark-La-Tex and southern AR (led by the ECMWF/ECENS, but
also having greater support from the CMC suite and UKMET as well).
Overall this led relatively to little change to the inherited SLGT
risk, mainly shifting the area a bit west and flattening it out to
account for the (aforementioned) less amplified upper-level trough.
There may need to be considerations for a future targeted Moderate
risk upgrade, though for this to occur more guidance would most
likely need to shift towards the northern solution (or consolidate
towards the southern solution while also getting wetter, as FFGs
indicate much less sensitive soils that would require a broader
area of 3"+ before meeting Moderate coverage criteria).

Churchill


...Previous Discussion...

The broad area of showers and thunderstorms are expected to shift
to the eastern portion of the Southern Plains and the Lower
Mississippi Valley. The highest amounts are expected to focus over
the AK-LA-TX region. While areal averages of 1 to 3 inches are
forecast, isolated maximums of 4+ inches will be possible. There
will be some overlap of heavy rainfall from the previous day which
will lower local FFGs. Training and back building of storms may be
possible, particularly for norther Texas and Arkansas. A Slight
Risk is in effect from northeast Texas/northern Louisiana to
western Tennessee/northwest Mississippi.

Campbell


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