Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 79, NWS Tucson, AZ

July 30, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 30, 2021, 7:59 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 30, 2021, 7:59 PM MST (02:59 UTC)
Expired
Jul 30, 2021, 11:00 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 Tucson radar (KEMX), 19 km from the middle of the area, began a volume at 03:00 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, 3.0 hours before the alert went out and 23 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, Tuscon, AZ at 00:00Z on 2021-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 211 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 00:00Z on 2021-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 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
211 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
2641 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

917 
WGUS55 KTWC 310259
FFWTWC
AZC019-310500-
/O.NEW.KTWC.FF.W.0079.210731T0259Z-210731T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
759 PM MST Fri Jul 30 2021

The National Weather Service in Tucson has issued a

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

* Until 1000 PM MST.

* At 759 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 1.5 inches of rain have fallen. The automated rain gauge at 
  Corona de Tucson has reported 1.02 inches of rainfall in 15 
  minutes. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar and automated gauges.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Corona De Tucson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3203 11087 3202 11079 3199 11073 3190 11075
      3191 11084

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

$$

GZ
3 follow-up statements
080 
WGUS75 KTWC 310409
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
909 PM MST Fri Jul 30 2021

AZC019-310500-
/O.CON.KTWC.FF.W.0079.000000T0000Z-210731T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
909 PM MST Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM MST THIS 
EVENING FOR EAST CENTRAL PIMA COUNTY...

At 909 PM MST, Doppler radar and automated rain gauges indicated 
that thunderstorms had produced between 1 and 1.5 inches across the 
warned area.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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...
  Corona De Tucson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3203 11087 3202 11079 3199 11073 3190 11075
      3191 11084

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

GZ
852 
WGUS55 KTWC 310452
FFWTWC
AZC019-310600-
/O.EXT.KTWC.FF.W.0079.000000T0000Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
952 PM MST Fri Jul 30 2021

The National Weather Service in Tucson has extended the

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

* Until 1100 PM MST.

* At 952 PM MST, Doppler radar and automated rain gauges indicated 
  that thunderstorms had produced between 1 and 1.5 inches of 
  rainfall in the warned area. Light to moderate rainfall continues 
  to fall within the warning area.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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...
  Corona De Tucson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3203 11087 3202 11079 3199 11073 3190 11075
      3191 11084

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

GZ
052 
WGUS75 KTWC 310556
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1056 PM MST Fri Jul 30 2021

AZC019-310606-
/O.EXP.KTWC.FF.W.0079.000000T0000Z-210731T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
1056 PM MST Fri Jul 30 2021

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

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

LAT...LON 3203 11087 3202 11079 3199 11073 3190 11075
      3191 11084

$$

GZ

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 30, 5:20 PM MSTSevere Thunderstorm WarningTWCPima55 min
Jul 30, 5:22 PM MSTSevere Thunderstorm WarningTWCPima29 min
Jul 30, 6:11 PM MSTAreal Flood AdvisoryTWCPima2 hr
Jul 30, 6:33 PM MSTSpecial Weather StatementTWC42 min
Jul 30, 6:52 PM MSTSpecial Weather StatementTWC38 min
Jul 30, 7:10 PM MSTAreal Flood AdvisoryTWCPima2 hr
Jul 30, 7:20 PM MSTAreal Flood AdvisoryTWCPima4 hr
Jul 30, 7:40 PM MSTSpecial Weather StatementTWC65 min
Jul 30, 7:49 PM MSTSevere Thunderstorm WarningTWCPima41 min
Jul 30, 7:51 PM MSTAreal Flood AdvisoryTWCPima114 min
Jul 30, 7:57 PM MSTSevere Thunderstorm WarningTWCPima48 min
Jul 30, 8:20 PM MSTSevere Thunderstorm WarningTWCPima40 min
Jul 30, 8:29 PM MSTFlash Flood Warning Considerable damage threatTWCPima3 hr
Jul 30, 8:35 PM MSTAreal Flood AdvisoryTWCPima115 min
Jul 30, 8:47 PM MSTFlash Flood WarningTWCPima118 min
Jul 30, 9:55 PM MSTSpecial Weather StatementTWCPinal65 min
Jul 30, 10:11 PM MSTFlash Flood WarningTWCPima4 hr
Jul 30, 11:37 PM MSTFlash Flood WarningTWCPima2 hr
Jul 31, 2:06 AM MSTAreal Flood AdvisoryTWCPima3 hr
Jul 31, 3:51 PM MSTAreal Flood AdvisoryTWCPinal114 min
Jul 31, 4:13 PM MSTSpecial Weather StatementTWC47 min

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.