Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 79, NWS Flagstaff, AZ

July 21, 2021Gila County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 21, 2021, 6:38 PM MST for Gila 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 21, 2021, 6:38 PM MST (01:38 UTC)
Expired: Jul 21, 2021, 9:45 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Gila County, AZ

The radar

The Flagstaff radar (KFSX), 73 km from the middle of the area, began a volume at 01:38 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

Phoenix, AZ (KPSR), launched 00:00Z, 1.6 hours before the alert went out and 86 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 760 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 3156 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

014 
WGUS55 KFGZ 220138
FFWFGZ
AZC007-220445-
/O.NEW.KFGZ.FF.W.0079.210722T0138Z-210722T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
638 PM MST Wed Jul 21 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Gila County in east central Arizona...

* Until 945 PM MST.

* At 638 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 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...
  mainly rural areas of Gila County

This includes the following highways...
	State Route 188 between mile markers 267 and 268.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3398 11125 3391 11112 3383 11119 3389 11126
      3390 11126 3390 11127 3393 11133 3397 11130

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

$$

McCollum

1 follow-up statement

421 
WGUS75 KFGZ 220441
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
941 PM MST Wed Jul 21 2021

AZC007-220451-
/O.EXP.KFGZ.FF.W.0079.000000T0000Z-210722T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-
941 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 945 PM MST THIS EVENING FOR 
GILA COUNTY...

The heavy rain has ended along State Route 188 mile markers 267 and 
268 in rural Gila County. Please continue to heed remaining road 
closures and avoid any portion of the road that may still be covered 
in water.

LAT...LON 3398 11125 3391 11112 3383 11119 3389 11126
      3390 11126 3390 11127 3393 11133 3397 11130

$$

McCollum

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 6:53 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	112 min
Jul 22, 12:28 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Jul 22, 2:10 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 22, 3:01 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	44 min
Jul 22, 3:31 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	115 min
Jul 22, 3:58 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 22, 4:04 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	116 min

Nearby

Flash Flood Warnings in Arizona, 2021 Every 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.