Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 166, NWS Tucson, AZ

September 5, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Sep 5, 2021, 4:12 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
Sep 5, 2021, 4:12 PM MST (23:12 UTC)
Expired
Sep 5, 2021, 7:15 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), 35 km from the middle of the area, began a volume at 23:11 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, 11.2 hours before the alert went out and 21 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 2021-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1016 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 2021-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 53 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
1016 J/kg
Mixed-layer CIN
-184 J/kg
Mixed-layer LCL
1856 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
53 m²/s²
0-3 km storm-relative helicity
20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

766 
WGUS55 KTWC 052312
FFWTWC
AZC019-060115-
/O.NEW.KTWC.FF.W.0166.210905T2312Z-210906T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
412 PM MST Sun Sep 5 2021

The National Weather Service in Tucson has issued a

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

* Until 615 PM MST.

* At 412 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...
  Tucson, Tanque Verde, Saguaro National Park East and Catalina 
  Foothills.

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 3212 11059 3210 11073 3227 11083 3232 11077
      3229 11059

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

$$

GZ
2 follow-up statements
787 
WGUS55 KTWC 060059
FFWTWC
AZC019-060215-
/O.EXT.KTWC.FF.W.0166.000000T0000Z-210906T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
559 PM MST Sun Sep 5 2021

The National Weather Service in Tucson has extended the

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

* Until 715 PM MST.

* At 559 PM MST, Doppler radar indicated that thunderstorms earlier 
  had produced very heavy rainfall, with between 1 and 2.5 inches of 
  rain occurring in the warning area. Therefore, the Flash Flood 
  Warning has been extended another hour.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  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...
  Tucson, Tanque Verde, Saguaro National Park East and Catalina 
  Foothills.

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 3212 11059 3210 11073 3227 11083 3232 11077
      3229 11059

FLASH FLOOD...RADAR INDICATED

$$

GZ
634 
WGUS75 KTWC 060215
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
715 PM MST Sun Sep 5 2021

AZC019-060225-
/O.EXP.KTWC.FF.W.0166.000000T0000Z-210906T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
715 PM MST Sun Sep 5 2021

...FLASH FLOOD WARNING HAS EXPIRED 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 3212 11059 3210 11073 3227 11083 3232 11077
      3229 11059

$$

GZ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 5, 11:52 AM MSTSpecial Weather StatementTWCSanta Cruz23 min
Sep 5, 12:12 PM MSTSpecial Weather StatementTWCCochise33 min
Sep 5, 12:24 PM MSTSevere Thunderstorm WarningTWCCochise51 min
Sep 5, 12:37 PM MSTAreal Flood AdvisoryTWCCochise7 min
Sep 5, 12:44 PM MSTFlash Flood Warning Considerable damage threatTWCCochise106 min
Sep 5, 12:58 PM MSTSevere Thunderstorm WarningTWCCochise19 min
Sep 5, 1:02 PM MSTSevere Thunderstorm WarningTWCPima, Santa Cruz43 min
Sep 5, 1:26 PM MSTAreal Flood AdvisoryTWCSanta Cruz2 hr
Sep 5, 2:10 PM MSTSpecial Weather StatementTWCSanta Cruz50 min
Sep 5, 2:15 PM MSTSpecial Weather StatementTWCGraham45 min
Sep 5, 2:25 PM MSTSpecial Weather StatementTWCSanta Cruz50 min
Sep 5, 2:29 PM MSTSevere Thunderstorm WarningTWCGraham, Greenlee61 min
Sep 5, 2:31 PM MSTSevere Thunderstorm WarningTWCCochise, Pima44 min
Sep 5, 2:34 PM MSTSpecial Weather StatementTWCGraham41 min
Sep 5, 2:54 PM MSTAreal Flood AdvisoryTWCPima111 min
Sep 5, 3:08 PM MSTSevere Thunderstorm Warning Considerable damage threatTWCPima, Santa Cruz37 min
Sep 5, 3:13 PM MSTFlash Flood Warning Considerable damage threatTWCPima2 hr
Sep 5, 3:15 PM MSTTornado WarningTWCPima15 min
Sep 5, 3:22 PM MSTDust Storm WarningTWCPima113 min
Sep 5, 3:24 PM MSTSevere Thunderstorm WarningTWCGraham, Greenlee66 min
Sep 5, 3:37 PM MSTSevere Thunderstorm WarningTWCPima, Santa Cruz53 min
Sep 5, 3:40 PM MSTSevere Thunderstorm Warning Considerable damage threatTWCPima50 min
Sep 5, 3:41 PM MSTFlash Flood Warning Considerable damage threatTWCGraham2 hr
Sep 5, 3:52 PM MSTSevere Thunderstorm WarningTWCPima38 min
Sep 5, 3:55 PM MSTAreal Flood AdvisoryTWCPima2 hr
Sep 5, 4:00 PM MSTSevere Thunderstorm Warning Considerable damage threatTWCGraham45 min
Sep 5, 4:06 PM MSTAreal Flood AdvisoryTWCPima114 min
Sep 5, 4:16 PM MSTSevere Thunderstorm Warning Considerable damage threatTWCPima59 min
Sep 5, 4:30 PM MSTSevere Thunderstorm WarningTWCPima45 min
Sep 5, 4:42 PM MSTDust Storm WarningTWCPima, Pinal93 min
Sep 5, 4:42 PM MSTSevere Thunderstorm WarningTWCCochise, Graham63 min
Sep 5, 4:47 PM MSTSevere Thunderstorm WarningTWCPima, Pinal43 min
Sep 5, 4:48 PM MSTFlash Flood WarningTWCPima117 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.