Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 129, NWS Flagstaff, AZ

July 29, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 29, 2021, 6:45 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 29, 2021, 6:45 PM MST (01:45 UTC)
Expired: Jul 29, 2021, 9:45 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 Phoenix radar (KIWA), 111 km from the middle of the area, began a volume at 01:49 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, 1.8 hours before the alert went out and 82 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: 237 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 3197 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: 2 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

085 
WGUS55 KFGZ 300145
FFWFGZ
AZC025-300445-
/O.NEW.KFGZ.FF.W.0129.210730T0145Z-210730T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
645 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 945 PM MST.

* At 644 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Rainfall rates of 1.25 to 1.75 inches in 1 hour 
  were observed around 620 pm. 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...
  Castle Hot Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3412 11255 3413 11255 3413 11252 3412 11248
      3410 11246 3408 11243 3399 11232 3397 11231
      3394 11230 3392 11233 3395 11237 3397 11240
      3398 11250 3399 11252 3406 11257 3411 11257
      3412 11256

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1.25-1.75 INCHES IN 1 HOUR

$$

AT

3 follow-up statements

081 
WGUS75 KFGZ 300236
FFSFGZ

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

AZC025-300445-
/O.CON.KFGZ.FF.W.0129.000000T0000Z-210730T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
736 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM MST THIS 
EVENING FOR YAVAPAI COUNTY...

At 733 PM MST, Aside from some light to moderate rain over northern 
portions of the warned area, rain has ended for most of the warned 
area. Between 1.5 and 2.5 inches of rain fell between 530 and 630 
pm. 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...
  Castle Hot Springs.

This includes the following streams and drainages...
  Ash Creek, Buzzard Roost Creek, East Fork Castle Creek, Slim Jim 
  Creek, Tussock Spring Creek, Oak Creek, Black Butte Wash, Castle 
  Creek, Humbug Creek, French Creek, Amazon Gulch, Whipsaw Creek, 
  Buckhorn Creek, Banty Creek, Bitter Creek, Hamlin Wash, Hassayampa 
  River and Little Buckhorn Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3412 11255 3413 11255 3413 11252 3412 11248
      3410 11246 3408 11243 3399 11232 3397 11231
      3394 11230 3392 11233 3395 11237 3397 11240
      3398 11250 3399 11252 3406 11257 3411 11257
      3412 11256

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

$$

AT

050 
WGUS75 KFGZ 300336
FFSFGZ

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

AZC025-300445-
/O.CON.KFGZ.FF.W.0129.000000T0000Z-210730T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
836 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM MST THIS 
EVENING FOR YAVAPAI COUNTY...

At 834 PM MST, Doppler radar indicated rain has largely ended over 
the warned area. Between 1.5 and 2.5 inches of rain fell from 545 to 
645 pm. 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...
  Castle Hot Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3412 11255 3413 11255 3413 11252 3412 11248
      3410 11246 3408 11243 3399 11232 3397 11231
      3394 11230 3392 11233 3395 11237 3397 11240
      3398 11250 3399 11252 3406 11257 3411 11257
      3412 11256

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

$$

AT

093 
WGUS75 KFGZ 300447
FFSFGZ

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

AZC025-300457-
/O.EXP.KFGZ.FF.W.0129.000000T0000Z-210730T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
947 PM MST Thu Jul 29 2021

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

Flood waters have receded. Flooding is no longer expected to pose a 
threat this evening. Please continue to heed remaining road closures.

LAT...LON 3412 11255 3413 11255 3413 11252 3412 11248
      3410 11246 3408 11243 3399 11232 3397 11231
      3394 11230 3392 11233 3395 11237 3397 11240
      3398 11250 3399 11252 3406 11257 3411 11257
      3412 11256

$$

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, 5:38 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	112 min
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.