Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 54, NWS Flagstaff, AZ

July 19, 2021Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 19, 2021, 5:01 PM MDT for 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 19, 2021, 5:01 PM MDT (23:01 UTC)
Expired: Jul 19, 2021, 8:00 PM MDT
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 213 km from the middle of the area, began a volume at 23:00 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, 11.0 hours before the alert went out and 177 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: 96 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1290 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

341 
WGUS55 KFGZ 192301
FFWFGZ
AZC017-200200-
/O.NEW.KFGZ.FF.W.0054.210719T2301Z-210720T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
401 PM MST Mon Jul 19 2021

The National Weather Service in Flagstaff has issued a

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

* Until 700 PM MST.

* At 359 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain along and south of Highway 160, south of Tsegi and east 
  of Shonto. This includes the Moenkopi, Dinnebito, and Oraibi 
  washes. Between 1 and 2.25 inches of rain have fallen. Additional 
  rainfall amounts of 0.25 to 0.75 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.

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

* Some locations that will experience flash flooding include...
  Portions of the Navajo Reservation and Hopi Reservation.

This includes the following highways...
	Highway 160 between mile markers 366 and 377.
	State Route 564 between mile markers 375 and 377.

This includes the following streams and drainages...
  Dinnebito Wash, Moenkopi Wash, Shonto Wash, Oraibi Wash and Tyende 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3662 11059 3650 11004 3622 11017 3615 11043
      3621 11070 3640 11065 3649 11063

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

$$

JJ

2 follow-up statements

790 
WGUS75 KFGZ 200012
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
512 PM MST Mon Jul 19 2021

AZC017-200200-
/O.CON.KFGZ.FF.W.0054.000000T0000Z-210720T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
512 PM MST Mon Jul 19 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MST THIS EVENING 
FOR NAVAJO COUNTY...

At 509 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain have ended along and south of Highway 160 south of Tsegi and 
east of Shonto. This includes the Moenkopi, Dinnebito, and Oraibi 
washes. Between 1 and 2.25 inches of rain have fallen. Light 
additional rainfall amounts up to 0.25 inches are possible in the 
warned area. Flash flooding is ongoing.

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...
  Portions of the Navajo Reservation and Hopi Reservation.

This includes the following highways...
	Highway 160 between mile markers 366 and 377.
	State Route 564 between mile markers 375 and 377.

This includes the following streams and drainages...
  Dinnebito Wash, Moenkopi Wash, Shonto Wash, Oraibi Wash and Tyende 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3662 11059 3650 11004 3622 11017 3615 11043
      3621 11070 3640 11065 3649 11063

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

$$

TPS

806 
WGUS75 KFGZ 200156
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
656 PM MST Mon Jul 19 2021

AZC017-200206-
/O.EXP.KFGZ.FF.W.0054.000000T0000Z-210720T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Navajo AZ-
656 PM MST Mon Jul 19 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 7 PM MST THIS EVENING FOR 
NAVAJO COUNTY...

The heavy rain threat has ended, but remain cautious of water 
flowing through creeks and washes. Flooding is no longer expected to 
pose a threat. Please continue to heed remaining road closures.

LAT...LON 3662 11059 3650 11004 3622 11017 3615 11043
      3621 11070 3640 11065 3649 11063

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 6:31 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Gila	59 min
Jul 18, 6:43 PM MDT	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	24 min
Jul 18, 7:14 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 18, 7:21 PM MDT	Special Weather Statement	FGZ		24 min
Jul 19, 2:48 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 19, 2:54 PM MDT	Special Weather Statement	FGZ		51 min
Jul 19, 3:08 PM MDT	Severe Thunderstorm Warning	FGZ	Coconino	37 min
Jul 19, 3:30 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	2 hr
Jul 19, 4:07 PM MDT	Special Weather Statement	FGZ		23 min
Jul 19, 4:28 PM MDT	Special Weather Statement	FGZ		32 min
Jul 19, 4:37 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 19, 5:27 PM MDT	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	2 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.