Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 124, NWS Flagstaff, AZ

July 29, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 29, 2021, 2:09 PM MST for Yavapai County, Arizona. It was in force for 3 hr. 1 report 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 29, 2021, 2:09 PM MST (21:09 UTC)
Expired: Jul 29, 2021, 5:15 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), 100 km from the middle of the area, began a volume at 21:08 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 29, 5:15 PM MST	FLASH FLOOD	7 Ne Prescott Airport, AZ	FOUR FEET OF RUNNING WATER THROUGH POQUITO WASH. TRAINED SPOTTER REPORTED FLOODING IN NEARBY HOMES IN NORTH PRESCOTT VALLEY.

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 70 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: 156 J/kg
Mixed-layer CIN: -113 J/kg
Mixed-layer LCL: 1821 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 35 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

614 
WGUS55 KFGZ 292109
FFWFGZ
AZC025-300015-
/O.NEW.KFGZ.FF.W.0124.210729T2109Z-210730T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
209 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 515 PM MST.

* At 205 PM MST, Doppler radar indicated thunderstorms producing 
  very heavy rain along SR 89A, between Jerome and Prescott Valley. 
  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...
  Far northeastern Prescott Valley and Potato Patch Campground.

This includes the following highways...
	State Route 89A between mile markers 327 and 338.

This includes the following streams and drainages...
  Granite Creek, Winters Wash, Coyote Wash, Munds Draw and Coyote 
  Spring.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3475 11216 3469 11214 3465 11216 3464 11224
      3466 11232 3468 11237 3471 11240 3477 11240
      3482 11238 3485 11229 3485 11222

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

$$

Peterson

1 follow-up statement

948 
WGUS75 KFGZ 300014
FFSFGZ

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

AZC025-300024-
/O.EXP.KFGZ.FF.W.0124.000000T0000Z-210730T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
514 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 515 PM MST THIS AFTERNOON FOR 
YAVAPAI COUNTY...

At 510 PM MST, National Weather Service Flagstaff Doppler radar 
indicated that widespread, heavy rain was no longer falling between 
Prescott Valley and Jerome.

No reports of flooding have been received, however, area washes, 
creeks and streams are likley running high. Please continue to heed 
remaining road closures.

LAT...LON 3475 11216 3469 11214 3465 11216 3464 11224
      3466 11232 3468 11237 3471 11240 3477 11240
      3482 11238 3485 11229 3485 11222

$$

Peterson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 6:47 PM MST	Special Weather Statement	FGZ		28 min
Jul 28, 7:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 28, 7:18 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 29, 11:48 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Jul 29, 11:57 AM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	33 min
Jul 29, 12:21 PM MST	Severe Thunderstorm Warning	FGZ	Apache	24 min
Jul 29, 12:36 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	24 min
Jul 29, 12:44 PM MST	Severe Thunderstorm Warning	FGZ	Apache	31 min
Jul 29, 12:53 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Jul 29, 12:57 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Jul 29, 1:07 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	38 min
Jul 29, 1:10 PM MST	Severe Thunderstorm Warning	FGZ	Apache	50 min
Jul 29, 1:13 PM MST	Severe Thunderstorm Warning	FGZ	Apache	32 min
Jul 29, 1:23 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	37 min
Jul 29, 2:05 PM MST	Flash Flood Watch	FGZ	Apache, Coconino, Navajo, Yavapai	31 hr
Jul 29, 2:16 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Jul 29, 2:41 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	34 min
Jul 29, 3:03 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	27 min
Jul 29, 3:41 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino, Navajo	3 hr
Jul 29, 4:03 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	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.