Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 90, NWS Tucson, AZ

August 6, 2021Pima County, Santa Cruz County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 6, 2021, 3:57 PM MST for Pima County, Santa Cruz County, Arizona. It was in force for 4 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 6, 2021, 3:57 PM MST (22:57 UTC)
Expired
Aug 6, 2021, 8:00 PM MST
In force
4 hr
Issued by
NWS Tucson, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Pima County, AZ, Santa Cruz County, AZ

The radar

The Tucson radar (KEMX), 66 km from the middle of the area, began a volume at 23:00 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.

What was reported inside it

TimeReportWhereRemark
Aug 6, 5:49 PM MSTFLASH FLOOD22 Sw Green Valley, AZARIVACA RD CLOSED DUE TO FLOODING BY ARIZONA GAME AND FISH. WASHES ARE FLOWING APPROXIMATELY 3 FEET DEEP ACROSS THE ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Tuscon, AZ (KTUS), launched 12:00Z, 11.0 hours before the alert went out and 67 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 12:00Z on 2021-08-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1100 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 12:00Z on 2021-08-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 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
1100 J/kg
Mixed-layer CIN
-195 J/kg
Mixed-layer LCL
1879 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
-10 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

860 
WGUS55 KTWC 062257
FFWTWC
AZC019-023-070200-
/O.NEW.KTWC.FF.W.0090.210806T2257Z-210807T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
357 PM MST Fri Aug 6 2021

The National Weather Service in Tucson has issued a

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

* Until 700 PM MST.

* At 357 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.7 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...
  Arivaca, Arivaca Lake and Arivaca Road.

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 3152 11120 3152 11136 3163 11145 3174 11138
      3178 11129 3177 11112 3170 11110

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

$$

GZ
3 follow-up statements
496 
WGUS75 KTWC 070035
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
535 PM MST Fri Aug 6 2021

AZC019-023-070200-
/O.CON.KTWC.FF.W.0090.000000T0000Z-210807T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-Santa Cruz AZ-
535 PM MST Fri Aug 6 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MST THIS EVENING 
FOR SOUTH CENTRAL PIMA AND NORTH CENTRAL SANTA CRUZ COUNTIES...

At 535 PM MST, Doppler radar indicated that thunderstorms earlier 
had produced very heavy rainfall, with between 2 and 3 inches of 
rain occuring in the warning area. This heavy rainfall fell along 
Arivaca Road.

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...
  Arivaca and Arivaca Lake.

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 3152 11120 3152 11136 3163 11145 3174 11138
      3178 11129 3177 11112 3170 11110

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

$$

GZ
180 
WGUS55 KTWC 070137
FFWTWC
AZC019-023-070300-
/O.EXT.KTWC.FF.W.0090.000000T0000Z-210807T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
637 PM MST Fri Aug 6 2021

The National Weather Service in Tucson has extended the

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

* Until 800 PM MST.

* At 637 PM MST, Doppler radar indicated that thunderstorms earlier 
  had produced very heavy rainfall, with between 2 and 3 inches of 
  rain occurring in the warning area. This heavy rainfall fell along 
  Arivaca Road and there have been reports that portions of Arivaca 
  Road are closed due to flash flooding.

  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...
  Arivaca and Arivaca Lake.

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 3152 11120 3152 11136 3163 11145 3174 11138
      3178 11129 3177 11112 3170 11110

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

$$

GZ
227 
WGUS75 KTWC 070301
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
801 PM MST Fri Aug 6 2021

AZC019-023-070311-
/O.EXP.KTWC.FF.W.0090.000000T0000Z-210807T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-Santa Cruz AZ-
801 PM MST Fri Aug 6 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL PIMA AND NORTH 
CENTRAL SANTA CRUZ COUNTIES...

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

LAT...LON 3152 11120 3152 11136 3163 11145 3174 11138
      3178 11129 3177 11112 3170 11110

$$

GZ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 5:21 PM MSTSpecial Weather StatementTWCPima39 min
Aug 6, 12:52 PM MSTSpecial Weather StatementTWCSanta Cruz38 min
Aug 6, 1:16 PM MSTAreal Flood AdvisoryTWCCochise, Santa Cruz3 hr
Aug 6, 1:26 PM MSTSevere Thunderstorm WarningTWCSanta Cruz34 min
Aug 6, 1:58 PM MSTSevere Thunderstorm WarningTWCSanta Cruz47 min
Aug 6, 2:05 PM MSTAreal Flood AdvisoryTWCSanta Cruz115 min
Aug 6, 2:29 PM MSTSevere Thunderstorm WarningTWCCochise31 min
Aug 6, 2:36 PM MSTSpecial Weather StatementTWCPima24 min
Aug 6, 2:43 PM MSTAreal Flood AdvisoryTWCGraham2 hr
Aug 6, 2:46 PM MSTSevere Thunderstorm WarningTWCCochise, Graham44 min
Aug 6, 2:51 PM MSTSpecial Weather StatementTWCSanta Cruz24 min
Aug 6, 2:57 PM MSTSevere Thunderstorm WarningTWCSanta Cruz33 min
Aug 6, 3:00 PM MSTAreal Flood AdvisoryTWCSanta Cruz2 hr
Aug 6, 3:10 PM MSTFlash Flood Warning Considerable damage threatTWCSanta Cruz3 hr
Aug 6, 3:16 PM MSTAreal Flood AdvisoryTWCPima119 min
Aug 6, 3:26 PM MSTAreal Flood AdvisoryTWCPima2 hr
Aug 6, 3:31 PM MSTSevere Thunderstorm WarningTWCCochise29 min
Aug 6, 3:40 PM MSTAreal Flood AdvisoryTWCCochise3 hr
Aug 6, 3:46 PM MSTSevere Thunderstorm WarningTWCPima, Santa Cruz29 min
Aug 6, 3:59 PM MSTSevere Thunderstorm WarningTWCCochise46 min
Aug 6, 4:12 PM MSTAreal Flood AdvisoryTWCPima2 hr
Aug 6, 4:19 PM MSTAreal Flood AdvisoryTWCCochise116 min
Aug 6, 4:55 PM MSTAreal Flood AdvisoryTWCPima2 hr
Aug 6, 4:58 PM MSTSpecial Weather StatementTWCPima32 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.