Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 217, NWS Flagstaff, AZ

August 28, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 28, 2021, 6:39 PM MST for Yavapai County, Arizona. It was in force for 111 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
Aug 28, 2021, 6:39 PM MST (01:39 UTC)
Expired
Aug 28, 2021, 8:30 PM MST
In force
111 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), 174 km from the middle of the area, began a volume at 01:42 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 00:00Z, 1.7 hours before the alert went out and 143 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-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 00:00Z on 2021-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 215 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 00:00Z on 2021-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
215 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
2514 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
-5 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

617 
WGUS55 KFGZ 290139
FFWFGZ
AZC025-290330-
/O.NEW.KFGZ.FF.W.0217.210829T0139Z-210829T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
639 PM MST Sat Aug 28 2021

The National Weather Service in Flagstaff has issued a

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

* Until 830 PM MST.

* At 635 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain southeast of Bagdad. 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...
  Portions of SR96 and SR97 south and southeast of Bagdad.

This includes the following highways...
	State Route 97 between mile markers 164 and 166.
	State Route 96 between mile markers 2 and 12.

This includes the following streams and drainages...
  Santa Maria River, Big Shipp Wash, Bridle Creek, Iron Spring Wash, 
  Little Sycamore Wash, Cottonwood Creek, Quail Spring Wash and 
  Little Shipp Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3459 11312 3462 11304 3459 11302 3455 11302
      3451 11303 3447 11304 3444 11306 3442 11310
      3443 11315 3445 11317 3448 11317 3452 11317
      3456 11315

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

$$

Peterson
1 follow-up statement
810 
WGUS75 KFGZ 290327
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
827 PM MST Sat Aug 28 2021

AZC025-290337-
/O.EXP.KFGZ.FF.W.0217.000000T0000Z-210829T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
827 PM MST Sat Aug 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 830 PM MST THIS EVENING FOR 
YAVAPAI COUNTY...

At 825 PM MST, National Weather Service Flagstaff Doppler radar 
indicated that rainfall had ended southeast of Bagdad. No reports of 
Flash Flooding have been received and the Flash Flood Warning will 
be allowed to expire. A 16 inch rise was recorded on Little Sycamore 
Wash, so area creeks and streams may still have higher than normal 
flow.

Please continue to heed remaining road closures.

LAT...LON 3459 11312 3462 11304 3459 11302 3455 11302
      3451 11303 3447 11304 3444 11306 3442 11310
      3443 11315 3445 11317 3448 11317 3452 11317
      3456 11315

$$

Peterson

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 28, 6:15 PM MSTSevere Thunderstorm WarningFGZYavapai45 min
Aug 29, 2:25 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai2 hr

Nearby

Flash Flood Warnings in Arizona, 2021Every 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.