Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 128, NWS Flagstaff, AZ

July 29, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 29, 2021, 5:38 PM MST for Yavapai County, Arizona. It was in force for 112 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 29, 2021, 5:38 PM MST (00:38 UTC)
Expired: Jul 29, 2021, 7:30 PM MST
In force: 112 min
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), 106 km from the middle of the area, began a volume at 00:42 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 00:00Z, 0.6 hours before the alert went out and 72 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: 222 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 1896 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 104 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

987 
WGUS55 KFGZ 300038
FFWFGZ
AZC025-300230-
/O.NEW.KFGZ.FF.W.0128.210730T0038Z-210730T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
538 PM MST Thu Jul 29 2021

The National Weather Service in Flagstaff has issued a

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

* Until 730 PM MST.

* At 530 PM MST, Trained weather spotters reported flooding in the 
  northern sections of Prescott Valley, including Poquito Valley 
  Road and Coyote Springs Road. Up to 4 feet of water has been 
  reported flowing across property in the area. This water should 
  eventually drain into Granite Creek and then the Verde River, with 
  diminishing crests. Flash flooding is ongoing.

  HAZARD...Life-threatening flash flooding.

  SOURCE...Trained spotters reported.

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

* Some locations that will experience flash flooding include...
  North Prescott Valley.

This includes the following streams and drainages...
  Poquito Wash, Coyote Springs, Verde River, Little Chino Valley and 
  Granite Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3469 11225 3467 11231 3466 11234 3467 11239
      3473 11240 3480 11241 3486 11244 3488 11242
      3488 11236 3485 11231 3480 11228 3474 11226

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Peterson

2 follow-up statements

996 
WGUS75 KFGZ 300203
FFSFGZ

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

AZC025-300230-
/O.CON.KFGZ.FF.W.0128.000000T0000Z-210730T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
703 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MST THIS 
EVENING FOR YAVAPAI COUNTY...

At 700 PM MST, Earlier this evening, trained weather spotters 
reported flooding in the northern sections of Prescott Valley, 
including Poquito Valley Road and Coyote Springs Road. Up to 4 feet 
of water was reported flowing across property in the area. This 
water should eventually drain into Granite Creek and then the Verde 
River, with diminishing crests. Flooding is expected to continue 
decreasing this evening.

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

SOURCE...Trained spotters reported.

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

Some locations that will experience flash flooding include...
  Prescott Valley.

This includes the following streams and drainages...
  Verde River, Little Chino Valley and Granite Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3469 11225 3467 11231 3466 11234 3467 11239
      3473 11240 3480 11241 3486 11244 3488 11242
      3488 11236 3485 11231 3480 11228 3474 11226

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

AT

575 
WGUS75 KFGZ 300232
FFSFGZ

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

AZC025-300242-
/O.EXP.KFGZ.FF.W.0128.000000T0000Z-210730T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
732 PM MST Thu Jul 29 2021

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

Flood waters will continue to recede overnight. The threat from 
flooding will keep decreasing over the next few hours. Please 
continue to heed remaining road closures.

LAT...LON 3469 11225 3467 11231 3466 11234 3467 11239
      3473 11240 3480 11241 3486 11244 3488 11242
      3488 11236 3485 11231 3480 11228 3474 11226

$$

AT

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 5:05 PM MST	Special Weather Statement	FGZ	Coconino	40 min
Jul 29, 5:35 PM MST	Special Weather Statement	FGZ		25 min
Jul 29, 6:45 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 29, 6:56 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 29, 8:12 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	5 hr
Jul 30, 5:58 AM MST	Areal Flood Warning	FGZ	Coconino	5 hr
Jul 30, 11:34 AM MST	Areal Flood Advisory	FGZ	Navajo	2 hr
Jul 30, 12:44 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	2 hr
Jul 30, 1:15 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Jul 30, 1:47 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 30, 2:01 PM MST	Special Weather Statement	FGZ		29 min
Jul 30, 2:18 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	27 min
Jul 30, 4:09 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Gila	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.