Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 59, NWS Flagstaff, AZ

July 20, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 20, 2021, 1:39 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 20, 2021, 1:39 PM MST (20:39 UTC)
Expired: Jul 20, 2021, 4:45 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 Flagstaff radar (KFSX), 119 km from the middle of the area, began a volume at 20:43 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 12:00Z, 8.7 hours before the alert went out and 99 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: 1057 J/kg
Mixed-layer CIN: -177 J/kg
Mixed-layer LCL: 1907 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

365 
WGUS55 KFGZ 202039
FFWFGZ
AZC025-202345-
/O.NEW.KFGZ.FF.W.0059.210720T2039Z-210720T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
139 PM MST Tue Jul 20 2021

The National Weather Service in Flagstaff has issued a

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

* Until 445 PM MST.

* At 136 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain in From just north of Crown King to Wagoner and south 
  along the Hassayampa River basin. Between 1 and 2.5 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
  Wagoner and Crown King.

This includes the following streams and drainages...
  Poland Creek, Spring Creek, Tiger Creek, Slim Jim Creek, Ash 
  Creek, Blind Indian Creek, Tuscumbia Creek, East Fork Castle 
  Creek, Bear Creek, Turkey Creek, North Fork Cellar Springs Creek, 
  Arrastre Creek, Hassayampa River, Arrastra Creek, Crazy Basin 
  Creek, Pine Creek, Cherry Creek, Amazon Gulch, Towers Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3421 11231 3419 11242 3406 11256 3414 11264
      3423 11256 3431 11250 3435 11237 3434 11235
      3432 11230

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

$$

JJ

2 follow-up statements

852 
WGUS75 KFGZ 202227
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
327 PM MST Tue Jul 20 2021

AZC025-202345-
/O.CON.KFGZ.FF.W.0059.000000T0000Z-210720T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
327 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS 
AFTERNOON FOR YAVAPAI COUNTY...

At 326 PM MST, Heavy rain has shifted out of the warning area, from 
just north of Crown King to Wagoner and south along the Hassayampa 
River basin. Between 1 and 2.5 inches of rain fell earlier this 
afternoon. 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...
  Wagoner.

This includes the following streams and drainages...
  Poland Creek, Spring Creek, Tiger Creek, Slim Jim Creek, Ash 
  Creek, Blind Indian Creek, Tuscumbia Creek, East Fork Castle 
  Creek, Bear Creek, Turkey Creek, North Fork Cellar Springs Creek, 
  Arrastre Creek, Hassayampa River, Arrastra Creek, Minnehaha Creek, 
  Amazon Gulch, Towers Creek, Cottonwood Creek and Cellar Springs 
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3421 11231 3419 11242 3406 11256 3414 11264
      3423 11256 3431 11250 3435 11237 3434 11235
      3432 11230

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

$$

JJ

369 
WGUS75 KFGZ 202338
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
438 PM MST Tue Jul 20 2021

AZC025-202348-
/O.EXP.KFGZ.FF.W.0059.000000T0000Z-210720T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
438 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 445 PM MST THIS AFTERNOON FOR 
YAVAPAI COUNTY...

The heavy rain has ended over the warning area from just north of 
Crown King to southwest of Wagoner. High flows could continue into 
this evening in some of the area washes and creeks. Please continue 
to heed remaining road closures and turn around if water is 
encountered over a road.

LAT...LON 3421 11231 3419 11242 3406 11256 3414 11264
      3423 11256 3431 11250 3435 11237 3434 11235
      3432 11230

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 6:31 PM MST	Severe Thunderstorm Warning	FGZ	Gila	29 min
Jul 20, 11:44 AM MST	Severe Thunderstorm Warning	FGZ	Yavapai	35 min
Jul 20, 11:53 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 20, 1:14 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 20, 1:23 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 20, 3:45 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 20, 4:57 PM MST	Special Weather Statement	FGZ		48 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.