Flash Flood Warning 129, NWS Tucson, AZ

991 
WGUS75 KTWC 120513
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1013 PM MST Tue Aug 11 2026

AZC003-023-120645-
/O.CON.KTWC.FF.W.0129.000000T0000Z-260812T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cochise AZ-Santa Cruz AZ-
1013 PM MST Tue Aug 11 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM MST THIS
EVENING FOR SOUTHWESTERN COCHISE AND SOUTHEASTERN SANTA CRUZ
COUNTIES...

At 1013 PM MST, trained weather spotters reported thunderstorms
producing heavy rain across the warned area. Between 1 and 2 inches
of rain have fallen. Additional rainfall amounts up to 1 inch are
possible in the warned area. Flash flooding is ongoing or expected to
begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters reported.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Sierra Vista, Hereford, Fort Huachuca, Parker Canyon Lake,
  Palominas, Ramsey Canyon Preserve, Coronado National Memorial and
  Canelo.

This includes the following highways...
Route 90 between mile markers 315 and 333. Route 80 between mile
markers 323 and 327. Route 92 between mile markers 322 and 342. Route
83 between mile markers 3 and 16.

This includes the following Flash Flood Prone Locations...
Moson Rd from HWY 90 and Hereford Rd.

This includes the following streams and drainages...
  Spring Creek, Santa Cruz River, Turkey Creek, San Pedro River,
  Slaughter House Wash and Babocomari River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3167 10997 3156 11005 3144 11007 3133 11008
      3133 11055 3147 11059 3160 11051 3161 11025

FLASH FLOOD...OBSERVED

$$

AWH

277 
WGUS75 KTWC 120639
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1139 PM MST Tue Aug 11 2026

AZC003-023-120649-
/O.EXP.KTWC.FF.W.0129.000000T0000Z-260812T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cochise AZ-Santa Cruz AZ-
1139 PM MST Tue Aug 11 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 1145 PM MST THIS EVENING FOR
SOUTHWESTERN COCHISE AND SOUTHEASTERN SANTA CRUZ COUNTIES...

Flood waters are starting to recede as the heavy rain has ended.
However scattered light to moderate showers will continue through 1
am Wednesday. Flash flooding is no longer expected to pose a threat.
Please continue to heed remaining road closures.

&&

LAT...LON 3167 10997 3156 11005 3144 11007 3133 11008
      3133 11055 3147 11059 3160 11051 3161 11025

$$

Area Forecast Discussion
National Weather Service Tucson AZ
1211 PM MST Tue Aug 11 2026

.SYNOPSIS...The combination of a shifting weather pattern aloft
and deep moisture residing across the region will result in
scattered to numerous showers and thunderstorms across Southeast
Arizona with the potential for heavy rain the next few days.
Although most of the storms will produce between a half and one
inch of rain, the stronger storms are capable of producing
locally heavier amounts between 1-3 inches. Otherwise, a drier
southwest flow aloft will bring a downturn in daily storm
activity Friday into the weekend. High temperatures will be near
normal today, then 3 to 6 degrees below normal tomorrow and
Thursday before temperatures warm again into the weekend.

&&

.DISCUSSION...The upper pattern late this morning is defined by
an upper-level ridge of high pressure centered just east of the
Four Corners and an inverted trough oriented SW-NE across Chihuahua
Mexico. The moisture profile is defined by the GOES precipitable
water imagery, indicating some drier air hanging out along the
AZ/NM border (PWATs 1.00-1.10 inches), with deeper moisture
moving east into Tucson (PWATs 1.25 inches) and very deep
moisture PWATs between 1.50-2.00 inches across the western
deserts.

I have been around here long enough to know that the bigger and
more active thunderstorm days for Southeast Arizona usually
align with big movements of the upper high. Today is no different.
The upper-high center near the Four Corners will move east over
the next 24 to 36 hours, eventually making its way to central
Oklahoma by 13/00Z Wednesday afternoon. As this happens, not
only will we experience general deformation aloft assisting
lift across the region, but that inverted trough in Chihuahua
Mexico will rotate up into the far SE corner of AZ by this
afternoon providing a better lifting mechanism. The best lift
today will initially occur across SRN Cochise early this
afternoon, then expand toward the NW into north-central Pima and
SE Pinal counties by 12/06Z this evening.

The drier airmass residing along the AZ/NM border today will
increase the potential for strong organized thunderstorm outflows
with the initial development. This is supported by the 11/12Z
HREF which suggests a 10 percent probability for wind gusts 50+
kts in SE Cochise county this afternoon. As the storms progress
to the northwest, they move into that deeper moist airmass which
shifts the potential from wind to heavy rain. The 11/12Z HREF
3-hr probability-matched mean QPF indicates a 10 percent
probability for rainfall in excess of 3 inches across southern
Cochise and Santa Cruz counties between 2-5 pm MST, expanding
across the eastern half of Pima county and SE Pinal counties
between 5-8 pm MST. Given this, and the deep moisture to the
west that would feed into the storms in the low-to-mid levels,
we decided to expand the coverage of the Flash Flood Watch to
include central Pima county (including the Tohono O'odham
Nation) as well as SE Pinal county. My concern is that as the
upper-high center moves east, the NW progress of the convection
will stall out across the central portions of the CWA late this
evening and stick around through the night. Granted, the
convective complex will continue to weaken, but even moderate
rainfall over the same spot will keep the concern for flash
flooding into the early morning hours.

Otherwise, Wednesday and Thursday still look quite wet as the
flow becomes southerly and any wiggle/disturbance in the flow
will easily result in convection across our neck of the woods.
Re-iterating the previous forecast discussion...expect a downturn
in daily thunderstorm activity Friday into the weekend as drier
air pushes across the area under southwest flow aloft. Isolated
thunderstorms at best, and mostly east of Tucson. Temperatures
will be near normal today, then be about 3 to 6 degrees below
normal Wednesday and Thursday, with warming thereafter to above
normal values for this weekend.

&&

.AVIATION... Valid thru 13/00Z. SCT-BKN 8-12k ft AGL with
widely scattered -SHRA/-TSRA thru 11/22z then scattered to
numerous -SHRA/TS contg thru end of valid pd. Isold vsbys 1SM
+TSRA. Gusty erratic winds of 35-50 kts possible with any
thunderstorm, especially near KDUG this afternoon. Outside of
storms SFC winds WLY/NWLY at 8-12 kts with ocnl gusts to 20 kts
this aftn and evening. SFC winds light and terrain driven after
12/06Z. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...The combination of a shifting weather pattern aloft
and deep moisture residing across the region will result in
scattered to numerous showers and thunderstorms across Southeast
Arizona with the potential for heavy rain the next few days.
Although most of the storms will produce between a half and one
inch of rain, the stronger storms are capable of producing
locally heavier amounts between 1-3 inches. Otherwise, a drier
southwest flow aloft will bring a downturn in daily storm
activity Friday into the weekend. Minimum relative humidity
will be 20-40 percent through Thursday lowering to around 15-30
percent thereafter. Temperatures will be near normal through
Tuesday, dropping to below normal Wednesday and Thursday, then
warming again next weekend. Outside of thunderstorms, winds
terrain driven to around 10 mph with occasional afternoon gusts
to 20 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 2 PM MST this afternoon through this evening
for AZZ502>509-511>515.

&&

Visit us on Facebook, X, YouTube, and at weather.gov/Tucson