Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 127, NWS Flagstaff, AZ

July 29, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 29, 2021, 4:03 PM MST for Coconino 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 29, 2021, 4:03 PM MST (23:03 UTC)
Expired: Jul 29, 2021, 7:00 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Coconino County, AZ

The radar

The Cedar City radar (KICX), 155 km from the middle of the area, began a volume at 23:02 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, 11.1 hours before the alert went out and 184 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: 156 J/kg
Mixed-layer CIN: -113 J/kg
Mixed-layer LCL: 1821 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

373 
WGUS55 KFGZ 292303
FFWFGZ
AZC005-300000-
/O.NEW.KFGZ.FF.W.0127.210729T2303Z-210730T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
403 PM MST Thu Jul 29 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  The Antelope Creek basin in...
  Coconino County in north central Arizona...

* Until 500 PM MST.

* At 400 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain south of Le Chee, over the central portions of the 
  Antelope Creek basin. Flash flooding is ongoing or expected to 
  begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Antelope
           Creek basin.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Antelope Creek basin.

* Some locations that will experience flash flooding include...
  Antelope Creek Basin, Antelope Canyon Near Sr 98.

This includes the following slot canyons...
	Upper Antelope Canyon, Lower Antelope Canyon.

This includes the following streams and drainages...
  Antelope Creek, Kaibito Creek and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get out of Antelope Canyon and other area slot canyons immediately! 
Deadly flash flooding is imminent or occurring!

&&

LAT...LON 3694 11143 3690 11138 3669 11123 3667 11133
      3689 11143 3694 11144

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

$$

Peterson

3 follow-up statements

640 
WGUS55 KFGZ 292306
FFWFGZ
AZC005-300200-
/O.EXT.KFGZ.FF.W.0127.000000T0000Z-210730T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
406 PM MST Thu Jul 29 2021

The National Weather Service in Flagstaff has extended the

* Flash Flood Warning for...
  The Antelope Creek basin in...
  Coconino County in north central Arizona...

* Until 700 PM MST.

* At 400 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain south of Le Chee, over the central portions of the 
  Antelope Creek basin. Flash flooding is ongoing or expected to 
  begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Antelope
           Creek basin.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Antelope Creek basin.

* Some locations that will experience flash flooding include...
  Antelope Creek Basin, Antelope Canyon Near Sr 98.

This includes the following slot canyons...
	Upper Antelope Canyon, Lower Antelope Canyon.

This includes the following streams and drainages...
  Antelope Creek, Kaibito Creek and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get out of Antelope Canyon and other area slot canyons immediately! 
Deadly flash flooding is imminent or occurring!

&&

LAT...LON 3694 11143 3690 11138 3669 11123 3667 11133
      3689 11143 3694 11144

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

$$

Peterson

702 
WGUS75 KFGZ 300103
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
603 PM MST Thu Jul 29 2021

AZC005-300200-
/O.CON.KFGZ.FF.W.0127.000000T0000Z-210730T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
603 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN REMAINS IN 
EFFECT UNTIL 7 PM MST THIS EVENING FOR COCONINO COUNTY...

At 601 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain over the Antelope Creek basin. Between 0.75 and 1.5 inches of 
rain have fallen. Only light rain at a rate of around 0.1 inches per 
hour is falling over and near the warned area at the present time. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding in and around the Antelope Creek basin.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Antelope Creek basin.

Some locations that will experience flash flooding include...
  Page, Antelope Creek Basin, Antelope Canyon Near Sr 98, Glen 
  Canyon National Recreation Area, Lake Powell and Navajo 
  Reservation.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac 
Canyon, Owl Canyon, Rattlesnake Canyon, Ramshead Canyon and Wind 
Pebble Canyon.

This includes the following streams and drainages...
  Antelope Creek, Kaibito Creek and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get out of Antelope Canyon and other area slot canyons immediately! 
Deadly flash flooding is imminent or occurring!

&&

LAT...LON 3694 11143 3690 11138 3669 11123 3667 11133
      3689 11143 3694 11144

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

$$

AT

559 
WGUS75 KFGZ 300158
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
658 PM MST Thu Jul 29 2021

AZC005-300208-
/O.EXP.KFGZ.FF.W.0127.000000T0000Z-210730T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
658 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN WILL EXPIRE AT 7 
PM MST THIS EVENING FOR COCONINO COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat.

LAT...LON 3694 11143 3690 11138 3669 11123 3667 11133
      3689 11143 3694 11144

$$

AT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 6:47 PM MST	Special Weather Statement	FGZ		28 min
Jul 28, 7:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 28, 7:18 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 29, 11:48 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Jul 29, 11:57 AM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	33 min
Jul 29, 12:21 PM MST	Severe Thunderstorm Warning	FGZ	Apache	24 min
Jul 29, 12:36 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	24 min
Jul 29, 12:44 PM MST	Severe Thunderstorm Warning	FGZ	Apache	31 min
Jul 29, 12:53 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Jul 29, 12:57 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Jul 29, 1:07 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	38 min
Jul 29, 1:10 PM MST	Severe Thunderstorm Warning	FGZ	Apache	50 min
Jul 29, 1:13 PM MST	Severe Thunderstorm Warning	FGZ	Apache	32 min
Jul 29, 1:23 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	37 min
Jul 29, 2:05 PM MST	Flash Flood Watch	FGZ	Apache, Coconino, Navajo, Yavapai	31 hr
Jul 29, 2:09 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 29, 2:16 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Jul 29, 2:41 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Jul 29, 3:03 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	27 min
Jul 29, 3:41 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Navajo	3 hr

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.