Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 160, NWS Tucson, AZ

August 30, 2021Pima County, Pinal County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 30, 2021, 6:19 PM MST for Pima County, Pinal County, Arizona. It was in force for 3 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: Aug 30, 2021, 6:19 PM MST (01:19 UTC)
Expired: Aug 30, 2021, 9:30 PM MST
In force: 3 hr
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Pima County, AZ, Pinal County, AZ

The radar

The Tucson radar (KEMX), 80 km from the middle of the area, began a volume at 01:20 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, 1.3 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: 480 J/kg
Mixed-layer CIN: -101 J/kg
Mixed-layer LCL: 2322 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -55 m²/s²
0-3 km storm-relative helicity: -71 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

027 
WGUS55 KTWC 310119
FFWTWC
AZC019-021-310430-
/O.NEW.KTWC.FF.W.0160.210831T0119Z-210831T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
619 PM MST Mon Aug 30 2021

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  Northern Pima County in southeastern Arizona...
  South Central Pinal County in southeastern Arizona...

* Until 930 PM MST.

* At 619 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts up to 1 inch 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 creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Catalina, Oro Valley, Marana, Tortolita and Dove Mountain.

This includes the following streams and drainages...
  Big Wash, Indian Well Wash, Canada del Oro, Santa Cruz River, 
  Chalk Creek, Chirreon Wash and Guild Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3252 11120 3254 11114 3254 11108 3254 11103
      3255 11093 3246 11093 3244 11102 3245 11109
      3241 11115 3247 11123

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

$$

JRM

2 follow-up statements

910 
WGUS75 KTWC 310242
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
742 PM MST Mon Aug 30 2021

AZC019-021-310430-
/O.CON.KTWC.FF.W.0160.000000T0000Z-210831T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-Pinal AZ-
742 PM MST Mon Aug 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM MST THIS 
EVENING FOR NORTHERN PIMA AND SOUTH CENTRAL PINAL COUNTIES...

At 742 PM MST, Doppler radar continues to indicate showers and 
thunderstorms producing heavy rain across the warned area. Between 1 
and 2 inches of rain have fallen. Localized amounts up to 3 inches 
have fallen on the Tortolita Mountains. Additional rainfall amounts 
up to 0.3 inches are possible in the warned area. Flash flooding is 
ongoing or expected to begin shortly. Flash flooding of area washes 
well downstream is likely.

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...
  Catalina, Oro Valley, Marana, Tortolita and Dove Mountain.

This includes the following streams and drainages...
  Big Wash, Indian Well Wash, Canada del Oro, Santa Cruz River, 
  Chalk Creek, Chirreon Wash and Guild Wash.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3252 11120 3254 11114 3254 11108 3254 11103
      3255 11093 3246 11093 3244 11102 3245 11109
      3241 11115 3247 11123

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

$$

JRM

516 
WGUS75 KTWC 310427
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
927 PM MST Mon Aug 30 2021

AZC019-021-310437-
/O.EXP.KTWC.FF.W.0160.000000T0000Z-210831T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-Pinal AZ-
927 PM MST Mon Aug 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 930 PM MST THIS EVENING FOR 
NORTHERN PIMA AND SOUTH CENTRAL PINAL COUNTIES...

The heavy rain ended earlier in the evening and flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

LAT...LON 3252 11120 3254 11114 3254 11108 3254 11103
      3255 11093 3246 11093 3244 11102 3245 11109
      3241 11115 3247 11123

$$

CC

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 5:18 PM MST	Special Weather Statement	TWC		42 min
Aug 30, 5:46 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Aug 30, 5:59 PM MST	Special Weather Statement	TWC	Pinal	46 min
Aug 30, 6:10 PM MST	Special Weather Statement	TWC	Pima	35 min
Aug 31, 1:59 AM MST	Areal Flood Advisory	TWC	Pima	3 hr
Aug 31, 2:47 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	7 hr
Aug 31, 3:14 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	5 hr
Aug 31, 4:00 PM MST	Special Weather Statement	TWC	Greenlee	45 min
Aug 31, 4:23 PM MST	Areal Flood Advisory	TWC	Graham, Greenlee	3 hr
Aug 31, 4:36 PM MST	Flash Flood Warning Considerable damage threat	TWC	Cochise	3 hr
Aug 31, 4:41 PM MST	Areal Flood Advisory	TWC	Cochise	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.