Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 52, NWS Flagstaff, AZ

July 19, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 19, 2021, 2:30 PM MST for Coconino 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 19, 2021, 2:30 PM MST (21:30 UTC)
Expired: Jul 19, 2021, 4:49 PM MST
In force: 2 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Coconino County, AZ

The radar

The Flagstaff radar (KFSX), 126 km from the middle of the area, began a volume at 21:29 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, 9.5 hours before the alert went out and 39 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: 96 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 1290 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

203 
WGUS55 KFGZ 192130
FFWFGZ
AZC005-200030-
/O.NEW.KFGZ.FF.W.0052.210719T2130Z-210720T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
230 PM MST Mon Jul 19 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 530 PM MST.

* At 227 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain from the east end of Williams northward along the 
  Highway 64 corridor. Between 1 and 2.25 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...
  East side of Williams and Kaibab Lake Campground.

This includes the following highways...
	Business Interstate 40 near mile marker 165.
	State Route 64 between mile markers 186 and 204.
	Interstate 40 between mile markers 164 and 167.

This includes the following streams and drainages...
  Red Lake Wash, West Cataract Creek, Dogtown Wash, Cataract Creek 
  and Spring Valley Wash.

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 3526 11218 3531 11228 3552 11232 3553 11210
      3524 11212

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

$$

JJ

1 follow-up statement

229 
WGUS75 KFGZ 192349
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
449 PM MST Mon Jul 19 2021

AZC005-192359-
/O.CAN.KFGZ.FF.W.0052.000000T0000Z-210720T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
449 PM MST Mon Jul 19 2021

...FLASH FLOOD WARNING IS CANCELLED FOR THE AREA NORTH OF WILLIAMS 
IN COCONINO COUNTY...

The heavy rain has ended over the Highway 64 corridor from 
Interstate 40 northward to near Valle. Significant flows are likely 
to persist into this evening in area washes, but flooding is no 
longer expected to pose a threat. Please continue to heed any 
remaining road closures.

LAT...LON 3526 11218 3531 11228 3552 11232 3553 11210
      3524 11212

$$

JJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 5:31 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	59 min
Jul 18, 5:43 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	24 min
Jul 18, 6:14 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 18, 6:21 PM MST	Special Weather Statement	FGZ		24 min
Jul 19, 1:48 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 19, 1:54 PM MST	Special Weather Statement	FGZ		51 min
Jul 19, 2:08 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	37 min
Jul 19, 3:07 PM MST	Special Weather Statement	FGZ		23 min
Jul 19, 3:28 PM MST	Special Weather Statement	FGZ		32 min
Jul 19, 3:37 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 19, 4:01 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 19, 4:27 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	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.