Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 132, NWS Flagstaff, AZ

July 30, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 30, 2021, 12:44 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 30, 2021, 12:44 PM MST (19:44 UTC)
Expired: Jul 30, 2021, 3:10 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), 77 km from the middle of the area, began a volume at 19:48 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, 7.7 hours before the alert went out and 18 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1217 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 21 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

020 
WGUS55 KFGZ 301944
FFWFGZ
AZC005-302245-
/O.NEW.KFGZ.FF.W.0132.210730T1944Z-210730T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1244 PM MST Fri Jul 30 2021

The National Weather Service in Flagstaff has issued a

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

* Until 345 PM MST.

* At 1243 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.75 and 1.25 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly. This warning does not concern run off from the Museum 
  Scar.

  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...
  Flagstaff.

This includes the following highways...
	Route 66 between mile markers 197 and 198.
	Interstate 40 between mile markers 196 and 199.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3521 11161 3520 11158 3518 11156 3516 11156
      3514 11160 3516 11163 3517 11167 3520 11165

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

$$

ET

2 follow-up statements

323 
WGUS75 KFGZ 302037
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
137 PM MST Fri Jul 30 2021

AZC005-302245-
/O.CON.KFGZ.FF.W.0132.000000T0000Z-210730T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
137 PM MST Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 PM MST THIS 
AFTERNOON FOR COCONINO COUNTY...

At 136 PM MST, light rain continues across the warned area. Between 
1.00 and 2.40 inches of rain have fallen. Flash flooding is likely 
ongoing.

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...
  Flagstaff.

This includes the following highways...
	Route 66 between mile markers 197 and 199.
	Interstate 40 between mile markers 196 and 199.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

&&

LAT...LON 3521 11161 3520 11158 3518 11156 3516 11156
      3514 11160 3516 11163 3517 11167 3520 11165

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

$$

ET

316 
WGUS75 KFGZ 302210
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
310 PM MST Fri Jul 30 2021

AZC005-302220-
/O.CAN.KFGZ.FF.W.0132.000000T0000Z-210730T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
310 PM MST Fri Jul 30 2021

...FLASH FLOOD WARNING IS CANCELLED FOR COCONINO COUNTY...

Heavy rainfall has ended in the Flagstaff area and no reports of 
flooding have been received.

A Flash Flood Watch remains in effect until 1100 PM MST Friday for 
portions of north central Arizona and west central Arizona.

LAT...LON 3521 11161 3520 11158 3518 11156 3516 11156
      3514 11160 3516 11163 3517 11167 3520 11165

$$

Peterson

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, 6:45 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
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, 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.