Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 225, NWS Flagstaff, AZ

September 2, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Sep 2, 2021, 1:54 PM MST for Yavapai County, Arizona. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 2, 2021, 1:54 PM MST (20:54 UTC)
Expired: Sep 2, 2021, 2:45 PM MST
In force: 51 min
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), 102 km from the middle of the area, began a volume at 20:56 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, 8.9 hours before the alert went out and 102 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: 14 J/kg
Mixed-layer CIN: -65 J/kg
Mixed-layer LCL: 833 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 14 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

970 
WGUS55 KFGZ 022054
FFWFGZ
AZC025-022145-
/O.NEW.KFGZ.FF.W.0225.210902T2054Z-210902T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
154 PM MST Thu Sep 2 2021

The National Weather Service in Flagstaff has issued a

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

* Until 245 PM MST.

* At 148 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.75 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 0.75 to 1.5 
  inches 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...
  Mayer and Poland Junction.

This includes the following highways...
	State Route 69 between mile markers 269 and 277.

This includes the following creeks, washes and rivers...
  Agua Fria River, Cedar Creek, Hackberry Creek, Pine Creek, Milk 
  Creek, Bear Creek, Turkey Creek, Brushy Wash, Grapevine Creek, 
  Little Wolf Creek, Wolf Creek and Big Bug Creek.

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.

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.

Report any flooding to local law enforcement and the NWS Flagstaff 
when you can do so safely.

&&

LAT...LON 3445 11237 3446 11236 3450 11218 3445 11214
      3439 11220 3435 11226 3428 11222 3432 11237
      3441 11240

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

$$

DB

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 5:00 PM MST	Areal Flood Advisory	FGZ	Coconino	2 hr
Sep 1, 5:10 PM MST	Special Weather Statement	FGZ		50 min
Sep 1, 5:42 PM MST	Areal Flood Advisory	FGZ	Apache, Navajo	3 hr
Sep 1, 5:52 PM MST	Special Weather Statement	FGZ		38 min
Sep 1, 6:17 PM MST	Special Weather Statement	FGZ		43 min
Sep 1, 6:52 PM MST	Special Weather Statement	FGZ		38 min
Sep 2, 11:53 AM MST	Special Weather Statement	FGZ	Yavapai	22 min
Sep 2, 1:24 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Sep 2, 2:31 PM MST	Areal Flood Advisory	FGZ	Coconino, Gila, Navajo	3 hr
Sep 2, 2:48 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Sep 2, 3:39 PM MST	Areal Flood Advisory	FGZ	Coconino	111 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.