Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 45, NWS Flagstaff, AZ

July 18, 2021Gila County, Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 18, 2021, 2:53 PM MST for Gila County, Navajo County, Arizona. It was in force for 102 min. 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 18, 2021, 2:53 PM MST (21:53 UTC)
Expired: Jul 18, 2021, 4:35 PM MST
In force: 102 min
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Gila County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 69 km from the middle of the area, began a volume at 21:53 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

Phoenix, AZ (KPSR), launched 12:00Z, 9.9 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: 453 J/kg
Mixed-layer CIN: -202 J/kg
Mixed-layer LCL: 2153 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 7 m²/s²
0-3 km storm-relative helicity: 40 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

348 
WGUS55 KFGZ 182153
FFWFGZ
AZC007-017-190100-
/O.NEW.KFGZ.FF.W.0045.210718T2153Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
253 PM MST Sun Jul 18 2021

The National Weather Service in Flagstaff has issued a

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

* Until 600 PM MST.

* At 252 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3.5 inches of 
  rain have fallen. Additional rainfall amounts of 1 to 1.5 inches 
  are possible in the warned area. Flash flooding is already 
  occurring.

  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...
  Young and Fort Apache Reservation.

This includes the following highways...
	State Route 288 near mile marker 308.

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 3416 11072 3397 11065 3388 11090 3410 11096

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

$$

EL

2 follow-up statements

337 
WGUS75 KFGZ 182241
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
341 PM MST Sun Jul 18 2021

AZC007-017-190100-
/O.CON.KFGZ.FF.W.0045.000000T0000Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Navajo AZ-
341 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 6 PM MST THIS EVENING 
FOR GILA AND NAVAJO COUNTIES...

At 340 PM MST, the heavy rain has ended across the warned area, 
however flooding can still occur as water drains. Between 2 and 3.5 
inches of rain have fallen. Additional rainfall amounts of 0.5 to 
0.75 inches are possible in the warned area.

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...
  Young and Fort Apache Reservation.

This includes the following highways...
	State Route 288 between mile markers 307 and 308.

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 3416 11072 3397 11065 3388 11090 3410 11096

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

$$

EL

963 
WGUS75 KFGZ 182335
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
435 PM MST Sun Jul 18 2021

AZC007-017-182345-
/O.CAN.KFGZ.FF.W.0045.000000T0000Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Navajo AZ-
435 PM MST Sun Jul 18 2021

...FLASH FLOOD WARNING IS CANCELLED FOR GILA AND NAVAJO COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3416 11072 3397 11065 3388 11090 3410 11096

$$

EL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 10:58 AM MST	Severe Thunderstorm Warning	FGZ	Yavapai	32 min
Jul 18, 11:14 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 18, 12:16 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	29 min
Jul 18, 1:03 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 18, 1:08 PM MST	Special Weather Statement	FGZ		37 min
Jul 18, 1:34 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 18, 2:12 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Navajo	33 min
Jul 18, 2:18 PM MST	Severe Thunderstorm Warning	FGZ	Gila	42 min
Jul 18, 2:31 PM MST	Areal Flood Advisory	FGZ	Coconino	100 min
Jul 18, 2:33 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	42 min
Jul 18, 3:02 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	108 min
Jul 18, 3:47 PM MST	Severe Thunderstorm Warning	FGZ	Gila	43 min
Jul 18, 3:54 PM MST	Special Weather Statement	FGZ		51 min
Jul 18, 4:10 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	51 min
Jul 18, 4:32 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	4 hr
Jul 18, 4:59 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	46 min

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.