Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 116, NWS Flagstaff, AZ

July 28, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 28, 2021, 3:35 PM MST for Coconino 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 28, 2021, 3:35 PM MST (22:35 UTC)
Expired: Jul 28, 2021, 6:45 PM MST
In force: 3 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), 169 km from the middle of the area, began a volume at 22:36 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, 10.6 hours before the alert went out and 111 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: 395 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1065 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

074 
WGUS55 KFGZ 282235
FFWFGZ
AZC005-290145-
/O.NEW.KFGZ.FF.W.0116.210728T2235Z-210729T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
335 PM MST Wed Jul 28 2021

The National Weather Service in Flagstaff has issued a

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

* Until 645 PM MST.

* At 330 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over Moenkopi and Tuba City. 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...
  Tuba City, Moenkopi, Hopi and Navajo Reservation.

This includes the following highways...
	Highway 160 between mile markers 318 and 328.
	State Route 264 between mile markers 322 and 337.

This includes the following streams and drainages...
  Moenkopi Wash, Pasture Canyon and Fivemile Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3617 11129 3619 11118 3618 11114 3612 11106
      3604 11103 3596 11107 3598 11119 3604 11128
      3612 11131

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

$$

Peterson

1 follow-up statement

211 
WGUS75 KFGZ 290136
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
636 PM MST Wed Jul 28 2021

AZC005-290146-
/O.EXP.KFGZ.FF.W.0116.000000T0000Z-210729T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
636 PM MST Wed Jul 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 645 PM MST THIS EVENING FOR 
COCONINO COUNTY...

The heavy rain threat has ended in the Tuba City area. Flooding is 
no longer expected to pose a threat. Please continue to heed 
remaining road closures.

LAT...LON 3617 11129 3619 11118 3618 11114 3612 11106
      3604 11103 3596 11107 3598 11119 3604 11128
      3612 11131

$$

TPS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 7:28 PM MST	Special Weather Statement	FGZ		32 min
Jul 27, 8:06 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 28, 11:46 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 3:07 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 28, 4:35 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	2 hr
Jul 28, 4:43 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.