Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 52, NWS Tucson, AZ

July 21, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 21, 2021, 1:38 PM MST for Pima 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: Jul 21, 2021, 1:38 PM MST (20:38 UTC)
Expired: Jul 21, 2021, 4:45 PM MST
In force: 3 hr
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Pima County, AZ

The radar

The Phoenix radar (KIWA), 110 km from the middle of the area, began a volume at 20:40 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 12:00Z, 8.6 hours before the alert went out and 76 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: 1436 J/kg
Mixed-layer CIN: -133 J/kg
Mixed-layer LCL: 1758 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 17 m²/s²
0-3 km storm-relative helicity: 22 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

318 
WGUS55 KTWC 212038
FFWTWC
AZC019-212345-
/O.NEW.KTWC.FF.W.0052.210721T2038Z-210721T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
138 PM MST Wed Jul 21 2021

The National Weather Service in Tucson has issued a

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

* Until 445 PM MST.

* At 138 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 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...
  Queens Well and Sil Nakya.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3244 11176 3243 11153 3225 11155 3222 11164
      3215 11179 3218 11185

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

$$

AH

2 follow-up statements

804 
WGUS75 KTWC 212206
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
306 PM MST Wed Jul 21 2021

AZC019-212345-
/O.CON.KTWC.FF.W.0052.000000T0000Z-210721T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
306 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS 
AFTERNOON FOR NORTH CENTRAL PIMA COUNTY...

At 306 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 3 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...
  Queens Well and Sil Nakya.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3244 11176 3243 11153 3225 11155 3222 11164
      3215 11179 3218 11185

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

$$

AH

501 
WGUS75 KTWC 212347
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
447 PM MST Wed Jul 21 2021

AZC019-212357-
/O.EXP.KTWC.FF.W.0052.000000T0000Z-210721T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
447 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR NORTH 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 3244 11176 3243 11153 3225 11155 3222 11164
      3215 11179 3218 11185

$$

AH

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 6:00 PM MST	Areal Flood Advisory	TWC	Pima	3 hr
Jul 20, 6:44 PM MST	Special Weather Statement	TWC		46 min
Jul 20, 7:17 PM MST	Special Weather Statement	TWC	Santa Cruz	43 min
Jul 20, 8:02 PM MST	Severe Thunderstorm Warning	TWC	Pinal	58 min
Jul 20, 8:14 PM MST	Special Weather Statement	TWC		61 min
Jul 20, 8:17 PM MST	Severe Thunderstorm Warning	TWC	Pima	58 min
Jul 20, 8:40 PM MST	Areal Flood Advisory	TWC	Pima	2 hr
Jul 20, 8:46 PM MST	Severe Thunderstorm Warning	TWC	Pima	30 min
Jul 20, 9:13 PM MST	Special Weather Statement	TWC		62 min
Jul 20, 9:24 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	51 min
Jul 20, 9:42 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	2 hr
Jul 20, 9:53 PM MST	Severe Thunderstorm Warning	TWC	Pinal	52 min
Jul 21, 1:50 AM MST	Flash Flood Watch	TWC	Cochise, Graham, Greenlee, Pima, Pinal, Santa Cruz	5 days
Jul 21, 8:18 AM MST	Blowing Dust Advisory	TWC	Pima, Pinal	8 hr
Jul 21, 1:00 PM MST	Special Weather Statement	TWC	Pima	45 min
Jul 21, 1:12 PM MST	Severe Thunderstorm Warning	TWC	Pima	48 min
Jul 21, 1:57 PM MST	Special Weather Statement	TWC	Pima	48 min
Jul 21, 2:09 PM MST	Special Weather Statement	TWC	Pima	51 min
Jul 21, 2:16 PM MST	Severe Thunderstorm Warning	TWC	Pima	44 min
Jul 21, 2:21 PM MST	Dust Storm Advisory	TWC	Pima, Pinal	84 min
Jul 21, 2:51 PM MST	Areal Flood Advisory	TWC	Pima	3 hr
Jul 21, 3:01 PM MST	Dust Storm Warning	TWC	Pinal	32 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.