Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 159, NWS Flagstaff, AZ

August 10, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 10, 2021, 12:46 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: Aug 10, 2021, 12:46 PM MST (19:46 UTC)
Expired: Aug 10, 2021, 3:45 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), 100 km from the middle of the area, began a volume at 19:48 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, 7.8 hours before the alert went out and 13 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: 609 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 962 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 118 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

236 
WGUS55 KFGZ 101946
FFWFGZ
AZC005-102245-
/O.NEW.KFGZ.FF.W.0159.210810T1946Z-210810T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1246 PM MST Tue Aug 10 2021

The National Weather Service in Flagstaff has issued a

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

* Until 345 PM MST.

* At 1245 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 1.5 inches of rain have fallen. Additional rainfall 
  amounts of 1 to 2 inches 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 and automated gauges.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Parks, Bellemont and Dogtown Lake Campground.

This includes the following highways...
	Highway 180 between mile markers 225 and 233.
	Interstate 40 between mile markers 169 and 186.

This includes the following streams and drainages...
  Sycamore Creek, Dogtown Wash, Red Lake Wash and Volunteer Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3516 11205 3521 11213 3529 11208 3539 11179
      3532 11173 3526 11175 3517 11188 3516 11199

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

$$

Humphreys

2 follow-up statements

993 
WGUS75 KFGZ 102059
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
159 PM MST Tue Aug 10 2021

AZC005-102245-
/O.CON.KFGZ.FF.W.0159.000000T0000Z-210810T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
159 PM MST Tue Aug 10 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 PM MST THIS 
AFTERNOON FOR COCONINO COUNTY...

At 158 PM MST, Heavy rainfall has ended over the warned area. Flash 
flooding will still remain a threat while flood waters recede.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Parks, Bellemont and Dogtown Lake Campground.

This includes the following highways...
	Highway 180 between mile markers 225 and 233.
	Interstate 40 between mile markers 169 and 186.

This includes the following streams and drainages...
  Sycamore Creek, Dogtown Wash, Red Lake Wash and Volunteer Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3516 11205 3521 11213 3529 11208 3539 11179
      3532 11173 3526 11175 3517 11188 3516 11199

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

$$

Humphreys

321 
WGUS75 KFGZ 102236
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
336 PM MST Tue Aug 10 2021

AZC005-102246-
/O.EXP.KFGZ.FF.W.0159.000000T0000Z-210810T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
336 PM MST Tue Aug 10 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 345 PM MST THIS AFTERNOON FOR 
COCONINO COUNTY...

Flood waters have receded and the heavy rain has ended. Flooding is 
no longer expected to pose a threat. Please continue to heed 
remaining road closures.

LAT...LON 3516 11205 3521 11213 3529 11208 3539 11179
      3532 11173 3526 11175 3517 11188 3516 11199

$$

Humphreys

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 9, 5:19 PM MST	Special Weather Statement	FGZ		41 min
Aug 9, 6:17 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 9, 6:56 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Aug 9, 7:27 PM MST	Special Weather Statement	FGZ		33 min
Aug 9, 7:50 PM MST	Special Weather Statement	FGZ	Gila	25 min
Aug 9, 8:44 PM MST	Special Weather Statement	FGZ	Gila	46 min
Aug 9, 9:18 PM MST	Areal Flood Advisory	FGZ	Gila, Navajo	3 hr
Aug 9, 9:32 PM MST	Special Weather Statement	FGZ	Gila	43 min
Aug 10, 11:35 AM MST	Special Weather Statement	FGZ		25 min
Aug 10, 11:55 AM MST	Severe Thunderstorm Warning	FGZ	Coconino	15 min
Aug 10, 12:02 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 10, 12:14 PM MST	Special Weather Statement	FGZ		31 min
Aug 10, 12:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 1:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	53 min
Aug 10, 2:22 PM MST	Special Weather Statement	FGZ	Yavapai	23 min
Aug 10, 2:26 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Aug 10, 2:35 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	40 min
Aug 10, 2:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 2:52 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Yavapai	38 min
Aug 10, 3:11 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Aug 10, 3:46 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 10, 4:13 PM MST	Flash Flood Warning Considerable damage threat	FGZ	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.