Alert archive / Arizona / Flash Flood Warnings in 2025

Flash Flood Warning 35, NWS Flagstaff, AZ

August 26, 2025Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 26, 2025, 2:44 PM MST for Coconino County, Arizona. It was in force for 9 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 26, 2025, 2:44 PM MST (21:44 UTC)
Expired
Aug 27, 2025, 12:00 AM MST
In force
9 hr
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Coconino County, AZ

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.7 hours before the alert went out and 68 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 2025-08-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2025-08-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
1305 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Flagstaff, AZ wrote its last area forecast discussion before this flash flood warning went out at Aug 26, 2:16 PM MST, 28 minutes earlier.

Area forecast discussion, Aug 26, 2:16 PM MST, 28 minutes before
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In the hours before

Local storm report, Aug 26, 9:49 AM MST, 4 hours 55 minutes before
Preliminary Local Storm Report
National Weather Service Flagstaff AZ
949 AM MST Tue Aug 26 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0815 PM     Flash Flood      1 NNE Prescott Courthou 34.55N 112.46W
08/25/2025                   Yavapai            AZ   Cocorahs

            Post-event report from Monday night (8/25).
            A USGS stream gage on Granite Creek (GCRA3)
            measured a 4.6 foot rise in 30 minutes. A
            CoCoRaHS observer upstream of the gage
            confirmed water nearing a business parking
            lot in downtown Prescott. The observer
            measured 2.05 inches of rain.

&&

MCT
Special weather statement, Aug 26, 11:23 AM MST, 3 hours 21 minutes before
Special Weather Statement
National Weather Service Flagstaff AZ
1123 AM MST Tue Aug 26 2025

AZZ010-011-261900-
Chinle Valley AZ-Chuska Mountains and Defiance Plateau AZ-
1123 AM MST Tue Aug 26 2025 /1223 PM MDT Tue Aug 26 2025/

...A STRONG THUNDERSTORM WILL IMPACT AREAS TSAILE IN APACHE COUNTY
UNTIL NOON MST /1 PM MDT/...

At 1123 AM MST /1223 PM MDT/, Doppler radar was tracking a strong
thunderstorm 6 miles southwest of Wheatfields Lake, or 21 miles east
of Chinle, moving northeast at 15 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is possible.

Locations impacted include...
  Sehili, Wheatfields Lake, Sonsela Buttes, Canyon De Chelly
  National Monument, Lower Wheatfields, Wheatfields, Upper
  Wheatfields and Tsaile.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

Torrential rainfall is also occurring with this storm and may lead
to flash flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3617 10932 3636 10922 3629 10905 3617 10905
      3608 10912
TIME...MOT...LOC 1823Z 208DEG 14KT 3616 10920

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Humphreys

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 25, 5:38 PM MSTSevere Thunderstorm WarningFGZGila37 min
Aug 25, 6:36 PM MSTSpecial Weather StatementFGZYavapai24 min
Aug 25, 6:51 PM MSTDust Storm WarningFGZYavapai24 min
Aug 25, 7:53 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr
Aug 26, 11:23 AM MSTSpecial Weather StatementFGZ37 min
Aug 26, 11:46 AM MSTSevere Thunderstorm WarningFGZApache29 min
Aug 26, 12:29 PM MSTSevere Thunderstorm WarningFGZApache, Navajo46 min
Aug 26, 1:43 PM MSTSevere Thunderstorm WarningFGZApache, Navajo32 min
Aug 26, 2:01 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino4 hr
Aug 26, 2:12 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai4 hr
Aug 26, 2:24 PM MSTFlash Flood Warning Considerable damage threatFGZGila, Yavapai4 hr

Nearby

Flash Flood Warnings in Arizona, 2025Every flash flood warning in 2025

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.