Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 40, NWS Flagstaff, AZ

July 16, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 16, 2021, 7:24 PM MST for Yavapai 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 16, 2021, 7:24 PM MST (02:24 UTC)
Expired: Jul 16, 2021, 10:30 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 99 km from the middle of the area, began a volume at 02:23 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 00:00Z, 2.4 hours before the alert went out and 85 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: 1249 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 2188 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 147 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

107 
WGUS55 KFGZ 170224
FFWFGZ
AZC025-170530-
/O.NEW.KFGZ.FF.W.0040.210717T0224Z-210717T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
724 PM MST Fri Jul 16 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Yavapai County in west central Arizona...

* Until 1030 PM MST.

* At 723 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across 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...
  Bumble Bee.

This includes the following streams and drainages...
  Agua Fria River, Black Canyon Creek, Antelope Creek, Sycamore 
  Creek, Turkey Creek, Castle Creek, North Fork Rock Creek, Black 
  Canyon, Rock Creek and Government Spring Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3405 11216 3410 11217 3412 11219 3418 11218
      3420 11219 3423 11222 3425 11221 3427 11220
      3429 11216 3429 11214 3429 11213 3428 11212
      3422 11212 3420 11216 3418 11216 3416 11216
      3414 11217 3412 11216 3411 11215 3406 11215

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

$$

MAS

1 follow-up statement

803 
WGUS75 KFGZ 170531
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1031 PM MST Fri Jul 16 2021

AZC025-170541-
/O.EXP.KFGZ.FF.W.0040.000000T0000Z-210717T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
1031 PM MST Fri Jul 16 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR YAVAPAI COUNTY...

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

LAT...LON 3405 11216 3410 11217 3412 11219 3418 11218
      3420 11219 3423 11222 3425 11221 3427 11220
      3429 11216 3429 11214 3429 11213 3428 11212
      3422 11212 3420 11216 3418 11216 3416 11216
      3414 11217 3412 11216 3411 11215 3406 11215

$$

MAS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 5:19 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	26 min
Jul 16, 5:30 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	26 min
Jul 16, 5:55 PM MST	Areal Flood Advisory	FGZ	Coconino, Gila, Yavapai	3 hr
Jul 16, 6:38 PM MST	Special Weather Statement	FGZ	Yavapai	52 min
Jul 16, 10:22 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	6 hr
Jul 17, 1:47 PM MST	Special Weather Statement	FGZ		28 min
Jul 17, 2:24 PM MST	Special Weather Statement	FGZ		21 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.