Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 117, NWS Flagstaff, AZ

July 28, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 28, 2021, 4:35 PM MST for Yavapai County, Arizona. It was in force for 2 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 28, 2021, 4:35 PM MST (23:35 UTC)
Expired: Jul 28, 2021, 7:03 PM MST
In force: 2 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), 83 km from the middle of the area, began a volume at 23:40 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, 11.6 hours before the alert went out and 79 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: 395 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1065 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

576 
WGUS55 KFGZ 282335
FFWFGZ
AZC025-290245-
/O.NEW.KFGZ.FF.W.0117.210728T2335Z-210729T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
435 PM MST Wed Jul 28 2021

The National Weather Service in Flagstaff has issued a

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

* Until 745 PM MST.

* At 430 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain along SR169 between Dewey and I-17. 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...
  Cherry and Powell Springs Campground.

This includes the following streams and drainages...
  Osborne Spring Wash, Ash Creek, Cherry Creek, Hackberry Wash, 
  Racetrack Wash, Yarber Wash and Little Hackberry Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3466 11220 3467 11211 3465 11206 3459 11200
      3454 11201 3449 11205 3444 11207 3446 11209
      3449 11210 3454 11216 3460 11219

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

$$

Peterson

1 follow-up statement

081 
WGUS75 KFGZ 290203
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
703 PM MST Wed Jul 28 2021

AZC025-290213-
/O.CAN.KFGZ.FF.W.0117.000000T0000Z-210729T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
703 PM MST Wed Jul 28 2021

...FLASH FLOOD WARNING IS CANCELLED 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 3466 11220 3467 11211 3465 11206 3459 11200
      3454 11201 3449 11205 3444 11207 3446 11209
      3449 11210 3454 11216 3460 11219

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 7:28 PM MST	Special Weather Statement	FGZ		32 min
Jul 27, 8:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 28, 11:46 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 3:07 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 3:35 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 28, 4:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	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.