Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 19, NWS Flagstaff, AZ

July 13, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 13, 2021, 2:25 PM MST for Coconino County, Arizona. It was in force for 2 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, 2:25 PM MST (21:25 UTC)
Expired: Jul 13, 2021, 4:30 PM MST
In force: 2 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), 68 km from the middle of the area, began a volume at 21:25 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, 9.4 hours before the alert went out and 32 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.

761 
WGUS55 KFGZ 132125
FFWFGZ
AZC005-132330-
/O.NEW.KFGZ.FF.W.0019.210713T2125Z-210713T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
225 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 223 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain along and south of Interstate 40 from the Walnut Canyon 
  area to Twin Arrows. 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...
  Winona, Cosnino, Walnut Canyon National Monument and Walnut Canyon 
  Visitors Center.

This includes the following highways...
	Route 66 near mile marker 204.
	Interstate 40 between mile markers 204 and 219.

This includes the following streams and drainages...
  Babbitt Wash, Yellow Jacket Canyon, Padre Canyon, San Francisco 
  Wash, Youngs Canyon and Walnut Creek.

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 3519 11156 3524 11150 3514 11123 3501 11133
      3513 11157

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

$$

JJ

1 follow-up statement

056 
WGUS75 KFGZ 132329
FFSFGZ

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

AZC005-132339-
/O.EXP.KFGZ.FF.W.0019.000000T0000Z-210713T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
429 PM MST Tue Jul 13 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 430 PM MST THIS AFTERNOON FOR 
COCONINO COUNTY...

The heavy rain has ended. Flooding is expected to diminish this 
evening as runoff continues. Please continue to heed remaining road 
closures.

LAT...LON 3519 11156 3524 11150 3514 11123 3501 11133
      3513 11157

$$

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, 1:29 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 13, 1:57 PM MST	Special Weather Statement	FGZ		33 min
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.