Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 93, NWS Flagstaff, AZ

July 23, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 23, 2021, 2:12 PM MST for Yavapai County, Arizona. It was in force for 2 hr. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 23, 2021, 2:12 PM MST (21:12 UTC)
Expired: Jul 23, 2021, 4:15 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), 103 km from the middle of the area, began a volume at 21:11 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.

What was reported inside it

Time	Report	Where	Remark
Jul 23, 3:00 PM MST	FLASH FLOOD	1 Ssw Prescott Valley, AZ	ROAD WASHED OUT DUE TO FLOODING.
Jul 23, 4:20 PM MST	FLASH FLOOD	1 S Prescott Valley, AZ	ROADWAY UNDERWATER DUE TO FLOODING.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 9.2 hours before the alert went out and 83 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: 503 J/kg
Mixed-layer CIN: -51 J/kg
Mixed-layer LCL: 915 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 45 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

535 
WGUS55 KFGZ 232112
FFWFGZ
AZC025-232315-
/O.NEW.KFGZ.FF.W.0093.210723T2112Z-210723T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
212 PM MST Fri Jul 23 2021

The National Weather Service in Flagstaff has issued a

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

* Until 415 PM MST.

* At 210 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the Prescott Valley region. Between 1 and 2 
  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...
  Prescott Valley, Agua Fria near Dewey-Humboldt, Yavapai County 
  Fairgrounds and Prescott Valley Event Center.

This includes the following highways...
	State Route 69 between mile markers 279 and 292.
	State Route 89A between mile markers 319 and 331.

This includes the following streams and drainages...
  Agua Fria River, Winters Wash, Granite Creek, Osborne Spring Wash, 
  Little Chino Valley, Bottleneck Wash, Coyote Wash, Chaparral 
  Gulch, Coyote Spring, Yarber Wash and Lynx Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3464 11242 3473 11243 3474 11223 3456 11215
      3449 11223 3453 11238

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

$$

JJ

2 follow-up statements

259 
WGUS75 KFGZ 232235
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
335 PM MST Fri Jul 23 2021

AZC025-232315-
/O.CON.KFGZ.FF.W.0093.000000T0000Z-210723T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
335 PM MST Fri Jul 23 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM MST THIS 
AFTERNOON FOR YAVAPAI COUNTY...

At 331 PM MST, Doppler radar indicated that moderate rainfall in 
moving back into Prescott Valley area where flooding has already 
been reported. Between 1 and 2.5 inches of rain have fallen. 
Additional rainfall amounts of 0.25 to 0.5 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...
  Prescott Valley, Dewey-humboldt, Yavapai County Fairgrounds and 
  Prescott Valley Event Center.

This includes the following highways...
	State Route 69 between mile markers 279 and 292.
	State Route 89A between mile markers 319 and 331.

This includes the following streams and drainages...
  Agua Fria River, Winters Wash, Granite Creek, Osborne Spring Wash, 
  Little Chino Valley, Bottleneck Wash, Coyote Wash, Chaparral 
  Gulch, Coyote Spring, Yarber Wash and Lynx Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3464 11242 3473 11243 3474 11223 3456 11215
      3449 11223 3453 11238

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

$$

JJ

011 
WGUS75 KFGZ 232310
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
410 PM MST Fri Jul 23 2021

AZC025-232320-
/O.EXP.KFGZ.FF.W.0093.000000T0000Z-210723T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
410 PM MST Fri Jul 23 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 415 PM MST THIS AFTERNOON FOR 
YAVAPAI COUNTY...

The heavy rain has ended across the area of the Prescott Valley. 
Lighter showers will continue through much of the afternoon. Ponding 
of water on roads and flowing water in low water crossings remains a 
threat.  Drive with caution and please heed any road closures.

A Flash Flood Watch remains in effect until 1200 AM MST Monday for 
portions of east central Arizona, north central Arizona, northeast 
Arizona and west central Arizona.

LAT...LON 3464 11242 3473 11243 3474 11223 3456 11215
      3449 11223 3453 11238

$$

McCollum

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 7:01 PM MST	Areal Flood Warning	FGZ	Navajo	5 min
Jul 22, 7:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 22, 8:08 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Jul 22, 10:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Gila, Navajo	4 hr
Jul 23, 12:57 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	4 hr
Jul 23, 1:50 AM MST	Areal Flood Advisory	FGZ	Coconino, Gila, Yavapai	3 hr
Jul 23, 4:07 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	4 hr
Jul 23, 11:21 AM MST	Areal Flood Warning	FGZ	Gila	6 hr
Jul 23, 11:38 AM MST	Special Weather Statement	FGZ	Coconino	37 min
Jul 23, 12:07 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	4 hr
Jul 23, 12:14 PM MST	Special Weather Statement	FGZ	Coconino	46 min
Jul 23, 12:19 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	2 hr
Jul 23, 12:51 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	114 min
Jul 23, 1:17 PM MST	Special Weather Statement	FGZ		43 min
Jul 23, 1:31 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Jul 23, 2:24 PM MST	Special Weather Statement	FGZ	Yavapai	36 min
Jul 23, 2:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	7 hr
Jul 23, 3:26 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Yavapai	3 hr
Jul 23, 3:43 PM MST	Special Weather Statement	FGZ	Navajo	47 min
Jul 23, 4:01 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Jul 23, 4:28 PM MST	Flash Flood Warning Considerable damage threat	FGZ	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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.