Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Flagstaff, AZ

July 13, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 13, 2021, 1:29 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 13, 2021, 1:29 PM MST (20:29 UTC)
Expired: Jul 13, 2021, 4:30 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 Flagstaff radar (KFSX), 23 km from the middle of the area, began a volume at 20:33 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, 8.5 hours before the alert went out and 83 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: 854 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1003 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -72 m²/s²
0-3 km storm-relative helicity: 195 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

633 
WGUS55 KFGZ 132029
FFWFGZ
AZC005-132330-
/O.NEW.KFGZ.FF.W.0018.210713T2029Z-210713T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
129 PM MST Tue Jul 13 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 430 PM MST.

* At 127 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain from the Clear Creek drainage across Highway 87 
  northward to the Jack Canyon and Canyon Diablo drainages. 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...
  Tremaine Lake, Starlight Pines, Chavez Mountain and Long Lake.

This includes the following highways...
	State Route 87 between mile markers 304 and 321.

This includes the following streams and drainages...
  Clear Creek, Diablo, Canyon, Sawmill Wash, Anderson Canyon, 
  Wallace Canyon, Yaeger Canyon, Grapevine Canyon, Willow Creek and 
  Jacks Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3458 11109 3475 11122 3496 11135 3501 11105
      3477 11094 3468 11090

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

$$

JJ

1 follow-up statement

237 
WGUS75 KFGZ 132334
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
434 PM MST Tue Jul 13 2021

AZC005-132344-
/O.EXP.KFGZ.FF.W.0018.000000T0000Z-210713T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
434 PM MST Tue Jul 13 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR COCONINO COUNTY...

The heavy rain has ended in southeast Coconino County in the Jacks 
Canyon and Canyon Diablo drainages. Heavy storm runoff will continue 
this evening in this area. Please continue to heed remaining road 
closures.

LAT...LON 3458 11109 3475 11122 3496 11135 3501 11105
      3477 11094 3468 11090

$$

JJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 5:40 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Yavapai	35 min
Jul 12, 5:56 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	34 min
Jul 12, 7:10 PM MST	Areal Flood Advisory	FGZ	Coconino, Yavapai	3 hr
Jul 13, 12:41 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Navajo	3 hr
Jul 13, 1:57 PM MST	Special Weather Statement	FGZ		33 min
Jul 13, 2:25 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	2 hr
Jul 13, 2:38 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	112 min
Jul 13, 2:54 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	29 min
Jul 13, 3:06 PM MST	Special Weather Statement	FGZ	Yavapai	39 min
Jul 13, 3:27 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	33 min
Jul 13, 4:14 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 13, 4:25 PM MST	Areal Flood Advisory	FGZ	Coconino, Yavapai	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.