Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 157, NWS Tucson, AZ

August 28, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 28, 2021, 7:41 PM MST for Pima County, Arizona. It was in force for 109 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, 7:41 PM MST (02:41 UTC)
Expired: Aug 28, 2021, 9:30 PM MST
In force: 109 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Phoenix radar (KIWA), 171 km from the middle of the area, began a volume at 02:44 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

Phoenix, AZ (KPSR), launched 00:00Z, 2.7 hours before the alert went out and 170 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: 645 J/kg
Mixed-layer CIN: -152 J/kg
Mixed-layer LCL: 3094 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: -11 m²/s²
0-3 km storm-relative helicity: 21 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

431 
WGUS55 KTWC 290241
FFWTWC
AZC019-290430-
/O.NEW.KTWC.FF.W.0157.210829T0241Z-210829T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  West Central Pima County in southeastern Arizona...

* Until 930 PM MST.

* At 741 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain along and east of Highway 85 near Organ Pipe National 
  Monument. Between 1 and 2 inches of rain have fallen. Flash 
  flooding is ongoing or expected to begin shortly, especially along 
  washes that drain into the Rio Sonoyta Wash, as well as San 
  Cristobol and Growler Washes.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Organ Pipe Cactus National Monument and Lukeville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3207 11262 3186 11274 3191 11290 3217 11281
      3217 11269

FLASH FLOOD...RADAR INDICATED

$$

CWR

1 follow-up statement

824 
WGUS75 KTWC 290425
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
925 PM MST Sat Aug 28 2021

AZC019-290435-
/O.EXP.KTWC.FF.W.0157.000000T0000Z-210829T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
925 PM MST Sat Aug 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MST THIS EVENING FOR 
WEST CENTRAL PIMA COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3207 11262 3186 11274 3191 11290 3217 11281
      3217 11269

$$

CWR

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 28, 5:03 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima, Pinal	117 min
Aug 28, 5:12 PM MST	Special Weather Statement	TWC	Pinal	48 min
Aug 28, 5:20 PM MST	Severe Thunderstorm Warning	TWC	Pinal	40 min
Aug 28, 6:31 PM MST	Severe Thunderstorm Warning	TWC	Pima	44 min
Aug 28, 6:47 PM MST	Special Weather Statement	TWC	Pinal	43 min
Aug 28, 7:01 PM MST	Areal Flood Warning	TWC	Pima, Pinal	3 hr
Aug 28, 7:14 PM MST	Severe Thunderstorm Warning	TWC	Pima	61 min
Aug 28, 8:03 PM MST	Severe Thunderstorm Warning	TWC	Pima	57 min
Aug 28, 8:25 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	2 hr
Aug 29, 2:32 PM MST	Special Weather Statement	TWC	Cochise	43 min
Aug 29, 3:53 PM MST	Special Weather Statement	TWC	Pima	37 min
Aug 29, 4:23 PM MST	Areal Flood Advisory	TWC	Pima	112 min
Aug 29, 4:46 PM MST	Special Weather Statement	TWC	Pinal	59 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.