Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 17, NWS Flagstaff, AZ

July 13, 2021Coconino County, Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 13, 2021, 12:41 PM MST for Coconino County, Navajo 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, 12:41 PM MST (19:41 UTC)
Expired: Jul 13, 2021, 3:45 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Coconino County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 52 km from the middle of the area, began a volume at 19:46 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, 7.7 hours before the alert went out and 110 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.

346 
WGUS55 KFGZ 131941
FFWFGZ
AZC005-017-132245-
/O.NEW.KFGZ.FF.W.0017.210713T1941Z-210713T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1241 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...
  Navajo County in north central Arizona...

* Until 345 PM MST.

* At 1239 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain in Clear Creek and Chevelon Canyon drainages including 
  along Highway 99 south of Winslow. 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...
  mainly rural areas of Coconino and Navajo Counties

This includes the following highways...
	State Route 99 between mile markers 23 and 37.

This includes the following streams and drainages...
  Potato Wash, Clear Creek, Chevelon Canyon, Jacks Canyon and Black 
  Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3477 11083 3490 11075 3497 11070 3492 11051
      3470 11065 3470 11066 3474 11075

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

$$

JJ

1 follow-up statement

384 
WGUS75 KFGZ 132241
FFSFGZ

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

AZC005-017-132251-
/O.EXP.KFGZ.FF.W.0017.000000T0000Z-210713T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-Navajo AZ-
341 PM MST Tue Jul 13 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 345 PM MST THIS AFTERNOON FOR 
COCONINO AND NAVAJO COUNTIES...

The heavy rain has ended over the warning area along the Clear Creek 
and Chevelon Canyon drainages south of Winslow. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3477 11083 3490 11075 3497 11070 3492 11051
      3470 11065 3470 11066 3474 11075

$$

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, 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, 2:25 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.