Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 126, NWS Flagstaff, AZ

July 29, 2021Coconino County, Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 29, 2021, 3:41 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 29, 2021, 3:41 PM MST (22:41 UTC)
Expired: Jul 29, 2021, 6:45 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), 136 km from the middle of the area, began a volume at 22:43 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, 10.7 hours before the alert went out and 129 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.

415 
WGUS55 KFGZ 292241
FFWFGZ
AZC005-017-300145-
/O.NEW.KFGZ.FF.W.0126.210729T2241Z-210730T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
341 PM MST Thu Jul 29 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 645 PM MST.

* At 340 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over a large area from Hotevilla to Polacca to White 
  Cone to Seba Dalkai and Cedar Springs. 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...
  Seba Dalkai, Tees Toh, First Mesa, Cedar Springs, White Cone, 
  Navajo, Second Mesa, Polacca, Shongopovi, Kykotsmovi Village, Hopi 
  Reservation, Hotevilla and Navajo Reservation.

This includes the following highways...
	State Route 87 between mile markers 381 and 406.
	State Route 264 between mile markers 365 and 394.

This includes the following streams and drainages...
  Tees Toh Wash, Dinnebito Wash, Oraibi Wash, Bidahochi Wash, 
  Steamboat Wash, Polacca Wash, Wepo Wash, Coyote Wash, Bluebird 
  Canyon Wash, Jeddito Wash, Keams Canyon Wash, Ha-whi-yalin Wash 
  and Beshbito Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3558 11075 3573 11081 3587 11077 3596 11071
      3582 11026 3567 11001 3551 10997 3541 11015
      3543 11039 3547 11058

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

$$

Peterson

1 follow-up statement

214 
WGUS75 KFGZ 300050
FFSFGZ

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

AZC005-017-300145-
/O.CON.KFGZ.FF.W.0126.000000T0000Z-210730T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-Navajo AZ-
550 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MST THIS 
EVENING FOR COCONINO AND NAVAJO COUNTIES...

At 547 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1.5 and 2.5 inches of rain have 
fallen. Flash flooding is ongoing or expected to begin shortly. 
Light rain is currently falling over the warned area at a rate of 
around 0.25" per hour or less.

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...
  Seba Dalkai, Tees Toh, First Mesa, Cedar Springs, White Cone, 
  Navajo, Second Mesa, Polacca, Shongopovi, Kykotsmovi Village, Hopi 
  Reservation, Hotevilla and Navajo Reservation.

This includes the following highways...
	State Route 87 between mile markers 381 and 406.
	State Route 264 between mile markers 365 and 394.

This includes the following streams and drainages...
  Tees Toh Wash, Dinnebito Wash, Oraibi Wash, Bidahochi Wash, 
  Steamboat Wash, Polacca Wash, Wepo Wash, Coyote Wash, Bluebird 
  Canyon Wash, Jeddito Wash, Keams Canyon Wash, Ha-whi-yalin Wash 
  and Beshbito Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3558 11075 3573 11081 3587 11077 3596 11071
      3582 11026 3567 11001 3551 10997 3541 11015
      3543 11039 3547 11058

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

$$

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, 4:03 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	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.