Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
906 PM EDT Sun Jul 12 2026
Day 1
Valid 01Z Mon Jul 13 2026 - 12Z Mon Jul 13 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE SOUTHEAST AND SOUTHERN APPALACHIANS...
0100Z Update: Trimmed away the northern extent of the previous
outlook in the East as drier and more stable air should continue
to diminish the threat for additional heavy rainfall from north to
south, especially over the Ohio Valley and the Mid-Atlantic region.
Maintained a the Slight Risk from portions of the southern
Appalachians eastward into the southern Virginia Piedmont and the
Carolinas. Moisture pooling ahead of a low dropping south through
the Tennessee Valley and along a downstream front will continue to
fuel storms into the overnight. Some modest upslope flow, both
southerly winds ahead of the low into the Cumberland Plateau and
easterly flow into the southern Blue Ridge, may help to focus some
heavier totals in those areas. Both the HREF and REFS show high
probabilities for additional accumulations over 2 inches overnight
within parts the Slight Risk area, with the highest probabilities
centered along the North Carolina Coast and along and east of the
southern Appalachians.
Farther west, made smaller adjustments back across the southern
Plains and Southwest based on the observation trends and recent
hi-res guidance.
Pereira
1600Z Update: Relatively minor adjustments were made to the Day 1
ERO, most notably to extend the northern extent of the Slight Risk
area farther north into WV-VA, based on the current observational/
mesoanalysis trends and the latest (12Z) CAM guidance. While now
north of the quasi-stationary surface front, areas in VA-WV where
the Slight Risk is now included continues to be modestly unstable
(surface-based CAPEs 1500-2000 J/Kg) while PWs remain between
1.8-2.1 inches. While the bulk of the activity should remain
farther south given the more impressive thermodynamic profiles will
be (deep-layer instability), continued forcing (DPVA) ahead of the
postively-tilted, quasi west-east upper trough trough should
support some additional organized convective clusters farther north
into northeast KY-southern WV and central VA. Both the 12Z HREF and
REFS ensembles both show 1-3 hourly QPF exceedance probabilities
that would support the Slight Risk, especially over KY-WV given the
higher soil moisture and thus lower FFG.
Hurley
Previous discussion below..
...Southeast Quarter of the Country...
The Slight risk remains in place from portions of KY/TN into
southern VA and the Carolinas. The mid level shortwave feature has
evolved into a deeper closed low, with slow moving convection
expected in the vicinity of that low across portions of KY and TN.
While widespread convective organization is not expected, the slow
storm motions combined with PW values between 1.75" and 2" will
support locally heavy rainfall rates. FFG is lowered across this
region due to antecedent rainfall, making isolated to scattered
exceedance likely today.
Further east from VA into the Carolinas, there is greater
uncertainty regarding convective evolution within a messy mesoscale
environment. Large scale forcing ahead of the mid level trough will
interact with a slow moving backdoor front to trigger scattered
convection. Stable air is filtering into southwest VA and central
NC, while easterly flow off the Atlantic is pulling more
instability into eastern VA/NC. Stronger instability exists over
SC south of the front. So overall a messy setup and tough to pin
down where stronger convection may focus long enough for flash
flooding.
The primary convective focus will probably be from far southern NC
into SC where the instability is maximized near and south of the
front. A secondary local max could materialize from portions of
eastern/southeast VA into eastern NC where easterly flow enhances
convergence. While instability should largely wane tonight
persistent easterly upslope flow into the central and southern
Appalachians overlapping with at least some weak instability could
spark low topped convective development overnight somewhere across
southwest VA or central/western NC.
Overall the broad environmental setup within the Slight risk
remains conducive to heavy rainfall given PWs over 2" and multiple
low level convergence axes. While exact mesoscale boundaries
remain to be pinned down, isolated flash flooding is likely, and a
corridor or two of more concentrate impacts could emerge.
Surrounding the Slight risk, a broad Marginal encompasses eastern
NM, TX and much of the Southeast. A southward advancing cold front,
the aforementioned mid level shortwave/low, and upper jet support
will provide the necessary synoptic forcing for scattered
convection. PWs over 2" and CAPE of 2000-3000 J/kg where daytime
heating is maximized, will support heavy rainfall rates. While
conditions are close to Slight risk thresholds across this
corridor, regional FFG values are higher, and the latest HREF/REFS
EAS probabilities do not highlight a well defined axis of higher
convective concentration. Pockets of over 3" of rain are likely
within this Marginal risk area, but overall coverage is expected
to stay just below Slight risk thresholds.
Consideration was given to a Slight risk upgrade for portions of
north TX today, where a shortwave dropping south into the region
should help focus convection. Localized flash flooding is likely
here, particularly as an urban threat. However due to generally
high FFG and spatial discrepancies with the current model
guidance, we will hold at Marginal.
...Southwest...
Monsoonal moisture and instability will expand northwestward on
Sunday, necessitating a broader Marginal risk across AZ. While an
embedded Slight risk may eventually be needed, lingering questions
regarding storm coverage and organization keep the risk at
Marginal for now. Current indications suggest that while robust
convection will initiate over the terrain, it will propagate
westward quickly, potentially limiting the threat to isolate
instances of flash flooding.
Chenard
Day 1 threat area:
www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
906 PM EDT Sun Jul 12 2026
Day 2
Valid 12Z Mon Jul 13 2026 - 12Z Tue Jul 14 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
TEXAS INTO THE CENTRAL GULF COAST...
1930Z Update: Minimal changes were made to the Day 2 ERO. We did
expand the Slight Risk area a little farther south over South TX on
along the border with Mexico -- partly owing to the higher soil
moisture content/lower FFGs in that region, but also due to the
growing guidance consensus (esp with the CAMs) of heavier
rainfall (higher HREF/REFS QPF exceedance probabilities) dropping
farther south of DLF/Laughlin AFB.
Hurley
Previous discussion below...
...Texas and Central Gulf Coast...
The Slight risk has been expanded deeper into TX with this update.
Embedded shortwave energy is forecast to migrate westward
underneath a sprawling upper level ridge centered over the Northern
Plains. In the low levels we will see increasing southerly flow
and moisture transport. However, with northerly flow prevailing
aloft, cloud layer mean winds will become weak. Corfidi vectors
will also be oriented north to south, opposite the lower cloud
layer flow...which supports some backbuilding and training threat.
PW values are forecast to exceed 2" over much of central and
eastern TX, with values potentially topping 2.25" over east TX.
Some instances of flash flooding appear likely in this setup.
A favorable synoptic and mesoscale setup for training and
backbuilding is forecast to align along the central Gulf Coast.
Enhanced west to northwesterly low level flow south of the
persistent shortwave/low over the TN/GA vicinity will converge with
west-southwesterly inflow off the Gulf. This configuration is
conducive for upwind propagation and some training convection.
Based on latest model guidance, this threat may remain confined
pretty close to the coast. A very moist airmass with PWs around
2.25" will support heavy rainfall rates.
...Southeast and Southern Mid-Atlantic...
A broad Marginal risk remains from TN into the Southeast and
southern Mid-Atlantic. Similar to day 1, a lingering shortwave and
closed low will continue to interact with a a backdoor front. Model
guidance show some spread regarding the exact positioning of these
features and where the primary axis of instability will reside. An
embedded Slight risk upgrade may eventually be needed as these
mesoscale details clarify. At a minimum, localized flash flooding
will occur, but the potential exists for a more concentrated flash
flood threat to materialize. North GA into SC currently appear most
at risk, but will see how todays convection evolves and what the
new high res model show.
...Southwest...
A Marginal risk is maintained from southern NM into AZ, southeast
CA and southern NV. Deep monsoonal moisture will continue to push
northwestward with isolated to scattered convection expected to
result in at least a localized flash food threat.
Chenard
Day 2 threat area:
www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
906 PM EDT Sun Jul 12 2026
Day 3
Valid 12Z Tue Jul 14 2026 - 12Z Wed Jul 15 2026
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
TEXAS...
1930Z Update: The notable adjustment to the Day 3 ERO was to
expand the Slight Risk farther east to much of the
Houston/Galveston Metro and southern portions of the Piney Woods.
This as mesoscale-enhanced perturbations/vort lobes underneath the
closed mid-level ridge meander slowly westward. One MCV in
particular that continues to bear watching is the one expected to
flare along and near the TX Big Bend and bordering northeast
Mexico. With the 12Z run, the EC-AIFS once again continues to show
a multi-day heavy-rainfall signal across this area, with a
centroid of 2-2.5" mean QPF during day 3, and another larger area
of 2.5-3.0" during day 4. ECMWF EFI using the 00Z run remains over
0.9 during Day 3 (and 4), with Shift-Of-Tails of 2+ for both days.
Strengthening and persistent SE low-level flow will lead to a surge
in low-level moisture flux/transport and positive TPW advection
and forced upslope flow into the Edwards Plateau.
Still enough spatial spread in the guidance to preclude an upgrade
to a Moderate Risk in the current Day 3 ERO, but suspect if the
guidance trends continue and the risk area becomes honed in a bit
more, there will be an upgrade over the next forecast cycle or 2.
Hurley
Previous discussion..
...Central TX...
A Slight risk continues over much of central TX, with a setup
similar to day 2. Model guidance forecasts strengthening 850mb
southerly moisture transport interacting with a weak mean flow
regime, keeping the threat of backbuilding and training convective
clusters. There is the potential for at least locally significant
flash flooding from the Edwards Plateau into portions of the TX
Hill country. Higher end Slight risk probabilities are warranted
for this corridor, and future upgrades to a MDT risk are possible.
Notably, the AIFS has been highly persistent over multiple cycles
in indicating a possible higher end event...and the AIFS has a good
track record highlighting organized heavy rainfall events. This
will be multi day threat over this region, and so hydrologic
sensitivity should eventually elevate, increasing the risk for
locally higher end impacts.
...Southeast...
A Marginal risk is maintained across the Southeast as the same
low/shortwave migrates slowly southwestward. Deep moisture will
remain plentiful with PW value over 2". However, uncertainty
exists regarding the position of the instability axis and overall
convective organization, and model QPF signals are a bit more
muted than on days 1 and 2. Nonetheless, because multiple days of
rainfall may start to saturate soils and lower FFG thresholds, an
embedded Slight risk area remains a possibility in future updates.
...Southwest into Northern Rockies...
A Marginal risk stretches from AZ into MT. An expansive plume of
deep moisture, featuring PW values near mid-July climatology
maximums will extend across this corridor. The strongest
instability will be focused at the ends of this axis, across AZ and
MT, with weaker CAPE profiles in between. Cape should still be
sufficient for isolate stronger cells and a localized flash flood
threat.
Central and eastern MT will need to be closely monitored for a
potential Slight risk upgrade. An axis of strong instability is
projected across the state, overlapping with increasing easterly
low level moisture transport. While the mean flow is weak at 10-15
kts, cells could potentially grow upscale and forward propagate in
this environment. Given the high rainfall rate potential,
convective trends will be closely monitored.
Chenard
Day 3 threat area:
www.wpc.ncep.noaa.gov/qpf/99epoints.txt
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
906 PM EDT Sun Jul 12 2026
Day 4 and Day 5
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
WEST TEXAS ON DAY 4 AND DAY 5...
2030 Update...
Overall, the 12Z guidance did not present much reason to make
significant changes to the previous outlook, therefore the update
reflects mostly minor adjustments. There remains a notable signal for
a potentially higher-end event beginning earlier in the week and
continuing into the Day 4/5 period over portions of West Texas. NBM
probabilities for amounts over 2 inches continue to increase for
each day. As noted in the overnight discussion, portions of the
region are being considered a higher-end Slight on Day 4. This
area will continue to be closely monitored and an upgrade to a
Moderate may be forthcoming, especially if the signal for
successive days of heavy rainfall holds across the region.
Pereira
Previous Discussion...
...Texas...
An increasing threat for excessive rainfall is becoming more and
more pronounced as we move forward in time as consensus grows on a
prolonged heavy rain setup across portions of west TX with emphasis
on the Edwards Plateau, Big Bend, and parts of Hill Country. Dominant
ridging over the top into the northern tier of the CONUS will give
way to a broad upper trough migrating westward into the Southern
Plains along the southern flank of the ridge as we move into the
middle of the week. The introduction of troughing overhead will
lead to weakening flow aloft and a myriad of smaller mid-level
perturbations rotating under the dominant cyclonic flow. Lowering
heights and regional forcing align to foster a more suitable
convective environment across the western half of TX with an
emphasis currently on west and southwest TX as noted via the multi-
model consensus in both the deterministic and ensemble outputs. ML
guidance has also been suggestive of the same threat with the last
series of runs from both the AIGEFS and EC-AIFS ensemble coming in
very aggressive with their interpretations in current D3-5 QPF
output. This has also led to some correlation of elevated
probabilities within the ensembles, both ML and standard NWP for
24-hr totals each period >2".
01z NBM probabilities for >2" have risen to between 30-50% for the
D4 time frame with coverage extending from the Big Bend down into
Maverick County, a span that includes some major population centers
like Del Rio and Eagle Pass, TX. The 30-40% probs expand eastward
into the neighboring Hill Country as well, an area of interest the
prior D3 period, so there's a greater threat for overlap in this
current pattern. When you begin factoring the cumulative threat of
heavy rainfall, guidance has surely risen the bar in terms of the
potential with incredibly aggressive presentations allotting
several inches of rain for the D3-5 time frames. General maxima
continues to be focused over the Lower Trans Pecos over into the
neighboring Edwards Plateau and down through the central RGV where
the pattern would allow for greater low- level convergence and
prospects for organized convective clusters to sneak out of Mexico
(Mexican State of Coahuila). Considering a solid agreement within
the model suite this evening, felt confident enough to maintain a
SLGT risk on D4 with a high-end SLGT prospect now being factored
into the forecast as we move forward in time. Have also introduced
a SLGT risk across west TX over into the Edwards Plateau and
portions of the central RGV for D5 as the threat lingers into
Thursday before finally beginning to disperse by Friday, beyond the
D5 period. This is certainly an setup to monitor closely as
significant rainfall potential is plausible in the current synoptic
evolution being depicted, and further upgrades are not out of the
question as we move closer to the window of impact.
...Western U.S...
Very little change in the previous forecast with the pattern
repeating on the new D5 leading to general continuity in both the
D4 and D5 convective threat and risk areas. The Western U.S. will
lie within the western flank of the broad ridge pattern over the
Central and Eastern U.S which will provide a dominant southerly
flow over the region allowing for continued moisture advection and
enhanced surface troughing over AZ up through the Great Basin. This
pattern is a continuation of the Monsoonal presence out west with
a potential for increasing flash flood prospects as multi-day
impacts could spur targeted opportunities for repetition of areas
getting hit by convection in consecutive periods. This setup
remains very stable in terms of the broad synoptic pattern in place
over the western CONUS, however we will see a persistent moisture
plume advect more formidable deep layer moisture poleward as we
move into early-mid next week leading to PWAT anomalies pushing the
90-99th percentile according to the NAEFS and 00z ECENS outputs.
The strongest anomalies will lie within the Great Basin up into the
Northern Rockies on D4 with some modification by D5, but still
very much entrenched within the upper bounds of the anomalies,
especially over the Northern Rockies and Interior Northwest.
Increased upper troughing migrating from the west will slide under
the ridge across the Northern CONUS leading to an enhancement for
convective potential over a broader scope by D4, carrying into D5
with widespread thunderstorm prospects aligned from the Canadian
border in MT down through the Inter-Mountain West into the
Southwestern deserts. This setup can lead to sneaky significant
rainfall prospects for those in the interior with a more typical
Monsoonal presentation in the convective coverage.
With a very stable height field being depicted mid to late week,
the threat for widespread convective activity over a large portion
of the Western CONUS remains favored for a broad MRGL risk at the
current lead. The threat will likely induce some upgrade potential
on a day-to-day basis as we step forward in time and we get a
glimpse at previous period impacts and any overlap in where
activity could occur once again for areas hit previously. This is a
relatively solid signal at range, so the risk was deemed
reasonable as a MRGL with upgrades noteworthy once we get a better
focus on potential inside 72 hrs. D4 and D5 maintained a MRGL risk
in very similar areas with only minor deviations in the orientation
of the risk from D4 to D5.
Kleebauer
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
906 PM EDT Sun Jul 12 2026
Day 4 and Day 5
...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
WEST TEXAS ON DAY 4 AND DAY 5...
2030 Update...
Overall, the 12Z guidance did not present much reason to make
significant changes to the previous outlook, therefore the update
reflects mostly minor adjustments. There remains a notable signal for
a potentially higher-end event beginning earlier in the week and
continuing into the Day 4/5 period over portions of West Texas. NBM
probabilities for amounts over 2 inches continue to increase for
each day. As noted in the overnight discussion, portions of the
region are being considered a higher-end Slight on Day 4. This
area will continue to be closely monitored and an upgrade to a
Moderate may be forthcoming, especially if the signal for
successive days of heavy rainfall holds across the region.
Pereira
Previous Discussion...
...Texas...
An increasing threat for excessive rainfall is becoming more and
more pronounced as we move forward in time as consensus grows on a
prolonged heavy rain setup across portions of west TX with emphasis
on the Edwards Plateau, Big Bend, and parts of Hill Country. Dominant
ridging over the top into the northern tier of the CONUS will give
way to a broad upper trough migrating westward into the Southern
Plains along the southern flank of the ridge as we move into the
middle of the week. The introduction of troughing overhead will
lead to weakening flow aloft and a myriad of smaller mid-level
perturbations rotating under the dominant cyclonic flow. Lowering
heights and regional forcing align to foster a more suitable
convective environment across the western half of TX with an
emphasis currently on west and southwest TX as noted via the multi-
model consensus in both the deterministic and ensemble outputs. ML
guidance has also been suggestive of the same threat with the last
series of runs from both the AIGEFS and EC-AIFS ensemble coming in
very aggressive with their interpretations in current D3-5 QPF
output. This has also led to some correlation of elevated
probabilities within the ensembles, both ML and standard NWP for
24-hr totals each period >2".
01z NBM probabilities for >2" have risen to between 30-50% for the
D4 time frame with coverage extending from the Big Bend down into
Maverick County, a span that includes some major population centers
like Del Rio and Eagle Pass, TX. The 30-40% probs expand eastward
into the neighboring Hill Country as well, an area of interest the
prior D3 period, so there's a greater threat for overlap in this
current pattern. When you begin factoring the cumulative threat of
heavy rainfall, guidance has surely risen the bar in terms of the
potential with incredibly aggressive presentations allotting
several inches of rain for the D3-5 time frames. General maxima
continues to be focused over the Lower Trans Pecos over into the
neighboring Edwards Plateau and down through the central RGV where
the pattern would allow for greater low- level convergence and
prospects for organized convective clusters to sneak out of Mexico
(Mexican State of Coahuila). Considering a solid agreement within
the model suite this evening, felt confident enough to maintain a
SLGT risk on D4 with a high-end SLGT prospect now being factored
into the forecast as we move forward in time. Have also introduced
a SLGT risk across west TX over into the Edwards Plateau and
portions of the central RGV for D5 as the threat lingers into
Thursday before finally beginning to disperse by Friday, beyond the
D5 period. This is certainly an setup to monitor closely as
significant rainfall potential is plausible in the current synoptic
evolution being depicted, and further upgrades are not out of the
question as we move closer to the window of impact.
...Western U.S...
Very little change in the previous forecast with the pattern
repeating on the new D5 leading to general continuity in both the
D4 and D5 convective threat and risk areas. The Western U.S. will
lie within the western flank of the broad ridge pattern over the
Central and Eastern U.S which will provide a dominant southerly
flow over the region allowing for continued moisture advection and
enhanced surface troughing over AZ up through the Great Basin. This
pattern is a continuation of the Monsoonal presence out west with
a potential for increasing flash flood prospects as multi-day
impacts could spur targeted opportunities for repetition of areas
getting hit by convection in consecutive periods. This setup
remains very stable in terms of the broad synoptic pattern in place
over the western CONUS, however we will see a persistent moisture
plume advect more formidable deep layer moisture poleward as we
move into early-mid next week leading to PWAT anomalies pushing the
90-99th percentile according to the NAEFS and 00z ECENS outputs.
The strongest anomalies will lie within the Great Basin up into the
Northern Rockies on D4 with some modification by D5, but still
very much entrenched within the upper bounds of the anomalies,
especially over the Northern Rockies and Interior Northwest.
Increased upper troughing migrating from the west will slide under
the ridge across the Northern CONUS leading to an enhancement for
convective potential over a broader scope by D4, carrying into D5
with widespread thunderstorm prospects aligned from the Canadian
border in MT down through the Inter-Mountain West into the
Southwestern deserts. This setup can lead to sneaky significant
rainfall prospects for those in the interior with a more typical
Monsoonal presentation in the convective coverage.
With a very stable height field being depicted mid to late week,
the threat for widespread convective activity over a large portion
of the Western CONUS remains favored for a broad MRGL risk at the
current lead. The threat will likely induce some upgrade potential
on a day-to-day basis as we step forward in time and we get a
glimpse at previous period impacts and any overlap in where
activity could occur once again for areas hit previously. This is a
relatively solid signal at range, so the risk was deemed
reasonable as a MRGL with upgrades noteworthy once we get a better
focus on potential inside 72 hrs. D4 and D5 maintained a MRGL risk
in very similar areas with only minor deviations in the orientation
of the risk from D4 to D5.
Kleebauer
