Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 110, NWS Flagstaff, AZ

July 26, 2021Apache County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 26, 2021, 4:29 PM MST for Apache County, Arizona. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 26, 2021, 4:29 PM MST (23:29 UTC)
Expired
Jul 26, 2021, 7:30 PM MST
In force
3 hr
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Apache County, AZ

The radar

The Flagstaff radar (KFSX), 237 km from the middle of the area, began a volume at 23:32 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 11.5 hours before the alert went out and 246 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 2021-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.1939Sfc1 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
20 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
954 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

574 
WGUS55 KFGZ 262329
FFWFGZ
AZC001-270230-
/O.NEW.KFGZ.FF.W.0110.210726T2329Z-210727T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
429 PM MST Mon Jul 26 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Apache County in northeastern Arizona...

* Until 730 PM MST.

* At 429 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1 inch are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Canyon De Chelly National Monument, Red Lake Chapter House, Del 
  Muerto, Upper Wheatfields, Wheatfields, Fort Defiance, Window 
  Rock, Sawmill, St. Michaels and Navajo Reservation.

This includes the following highways...
	State Route 264 between mile markers 474 and 475.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3564 10905 3576 10934 3595 10948 3616 10953
      3622 10937 3628 10905 3625 10905

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Humphreys
2 follow-up statements
639 
WGUS75 KFGZ 270128
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
628 PM MST Mon Jul 26 2021

AZC001-270230-
/O.CON.KFGZ.FF.W.0110.000000T0000Z-210727T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Apache AZ-
628 PM MST Mon Jul 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MST THIS 
EVENING FOR APACHE COUNTY...

At 625 PM MST, heavy rain had moved out of the the warned area, 
however flash flooding is expected to remain a threat while water 
recedes.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Canyon De Chelly National Monument, Red Lake Chapter House, Del 
  Muerto, Upper Wheatfields, Wheatfields, Fort Defiance, Window 
  Rock, Sawmill, St. Michaels and Navajo Reservation.

This includes the following highways...
	State Route 264 between mile markers 474 and 475.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3564 10905 3576 10934 3595 10948 3616 10953
      3622 10937 3628 10905 3625 10905

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Humphreys
048 
WGUS75 KFGZ 270227
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
727 PM MST Mon Jul 26 2021

AZC001-270237-
/O.EXP.KFGZ.FF.W.0110.000000T0000Z-210727T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Apache AZ-
727 PM MST Mon Jul 26 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 730 PM MST THIS EVENING FOR 
APACHE COUNTY...

Flood waters have receded and the heavy rain has ended. Flooding is 
no longer expected to pose a threat. Please continue to heed 
remaining road closures.

LAT...LON 3564 10905 3576 10934 3595 10948 3616 10953
      3622 10937 3628 10905 3625 10905

$$

Humphreys

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 7:05 PM MSTFlash Flood Warning Considerable damage threatFGZApache, Navajo3 hr
Jul 26, 12:38 PM MSTSpecial Weather StatementFGZ37 min
Jul 26, 3:21 PM MSTSpecial Weather StatementFGZ39 min

Nearby

Flash Flood Warnings in Arizona, 2021Every flash flood warning in 2021

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; radar from the NEXRAD Level II archive.