Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 97, NWS Tucson, AZ

August 8, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 8, 2021, 9:03 PM MST for Pima County, Arizona. It was in force for 117 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 8, 2021, 9:03 PM MST (04:03 UTC)
Expired: Aug 8, 2021, 11:00 PM MST
In force: 117 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 38 km from the middle of the area, began a volume at 04:04 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

Tuscon, AZ (KTUS), launched 00:00Z, 4.1 hours before the alert went out and 40 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: 742 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 2449 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: -60 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

805 
WGUS55 KTWC 090403
FFWTWC
AZC019-090600-
/O.NEW.KTWC.FF.W.0097.210809T0403Z-210809T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
903 PM MST Sun Aug 8 2021

The National Weather Service in Tucson has issued a

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

* Until 1100 PM MST.

* At 903 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. 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 creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Sahuarita, Green Valley and Arivaca Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Remain alert for flooding even in locations not receiving rain. 
Washes, streams, and rivers can become raging killer currents in a 
matter of minutes, even from distant rainfall.

&&

LAT...LON 3187 11111 3188 11094 3177 11089 3173 11107

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

$$

RH

1 follow-up statement

895 
WGUS75 KTWC 090553
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1053 PM MST Sun Aug 8 2021

AZC019-090603-
/O.EXP.KTWC.FF.W.0097.000000T0000Z-210809T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
1053 PM MST Sun Aug 8 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 11 PM MST THIS EVENING FOR 
EAST CENTRAL PIMA COUNTY...

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

LAT...LON 3187 11111 3188 11094 3177 11089 3173 11107

$$

RH

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 8, 5:03 PM MST	Special Weather Statement	TWC	Cochise	42 min
Aug 8, 5:18 PM MST	Special Weather Statement	TWC	Santa Cruz	27 min
Aug 8, 5:22 PM MST	Special Weather Statement	TWC	Pima	38 min
Aug 8, 5:22 PM MST	Severe Thunderstorm Warning	TWC	Cochise	38 min
Aug 8, 5:28 PM MST	Special Weather Statement	TWC	Cochise	47 min
Aug 8, 5:51 PM MST	Special Weather Statement	TWC	Pima	24 min
Aug 8, 6:09 PM MST	Severe Thunderstorm Warning	TWC	Cochise	66 min
Aug 8, 6:10 PM MST	Areal Flood Advisory	TWC	Pima	2 hr
Aug 8, 6:13 PM MST	Special Weather Statement	TWC	Pima	32 min
Aug 8, 6:14 PM MST	Severe Thunderstorm Warning	TWC	Cochise	20 min
Aug 8, 6:19 PM MST	Severe Thunderstorm Warning	TWC	Pima	41 min
Aug 8, 6:37 PM MST	Areal Flood Advisory	TWC	Cochise	5 hr
Aug 8, 6:46 PM MST	Flash Flood Warning Considerable damage threat	TWC	Cochise	5 hr
Aug 8, 6:56 PM MST	Dust Storm Advisory	TWC	Cochise, Pima, Pinal	70 min
Aug 8, 8:45 PM MST	Severe Thunderstorm Warning	TWC	Pima, Santa Cruz	45 min
Aug 8, 9:28 PM MST	Areal Flood Advisory	TWC	Cochise, Pima, Santa Cruz	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.