Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 168, NWS Tucson, AZ

September 5, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Sep 5, 2021, 5:09 PM MST for Pima County, Arizona. It was in force for 111 min. 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, 5:09 PM MST (00:09 UTC)
Expired
Sep 5, 2021, 7:00 PM MST
In force
111 min
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), 46 km from the middle of the area, began a volume at 00:11 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

Phoenix, AZ (KPSR), launched 00:00Z, 0.2 hours before the alert went out and 166 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, Phoenix, AZ at 00:00Z on 2021-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 48 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, Phoenix, AZ at 00:00Z on 2021-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.193958Sfc1 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
48 J/kg
Mixed-layer CIN
-147 J/kg
Mixed-layer LCL
3562 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

397 
WGUS55 KTWC 060009
FFWTWC
AZC019-060200-
/O.NEW.KTWC.FF.W.0168.210906T0009Z-210906T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  Eastern Pima County in southeastern Arizona...

* Until 700 PM MST.

* At 509 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.3 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...
  Tucson, Davis-Monthan Air Force Base, Casas Adobes, Drexel 
  Heights, Flowing Wells, South Tucson 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 3216 11076 3215 11104 3231 11104 3231 11093
      3230 11093 3225 11092 3225 11082

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

$$

GZ
2 follow-up statements
408 
WGUS75 KTWC 060103
FFSTWC

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

AZC019-060200-
/O.CON.KTWC.FF.W.0168.000000T0000Z-210906T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
603 PM MST Sun Sep 5 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MST THIS EVENING 
FOR EASTERN PIMA COUNTY...

At 603 PM MST, Doppler radar indicated that thunderstorms earlier 
had produced very heavy rainfall, with between 0.5 and 1.5 inches of 
rainfall occurring in the warning area.

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, Davis-Monthan Air Force Base, Casas Adobes, Drexel 
  Heights, Flowing Wells, South Tucson 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 3216 11076 3215 11104 3231 11104 3231 11093
      3230 11093 3225 11092 3225 11082

FLASH FLOOD...RADAR INDICATED

$$

GZ
858 
WGUS75 KTWC 060200
FFSTWC

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

AZC019-060210-
/O.EXP.KTWC.FF.W.0168.000000T0000Z-210906T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
700 PM MST Sun Sep 5 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR EASTERN 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 3216 11076 3215 11104 3231 11104 3231 11093
      3230 11093 3225 11092 3225 11082

$$

GZ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 5, 5:01 PM MSTSevere Thunderstorm WarningTWCGraham, Pinal59 min
Sep 5, 5:18 PM MSTSevere Thunderstorm WarningTWCCochise, Graham, Pima42 min
Sep 5, 5:37 PM MSTDust Storm AdvisoryTWCPima, Pinal95 min
Sep 5, 5:41 PM MSTFlash Flood WarningTWCPinal2 hr
Sep 5, 5:58 PM MSTSevere Thunderstorm WarningTWCPima, Pinal47 min
Sep 5, 6:02 PM MSTSpecial Weather StatementTWC43 min
Sep 5, 6:39 PM MSTAreal Flood AdvisoryTWCPima, Pinal2 hr
Sep 5, 7:05 PM MSTSpecial Weather StatementTWCPima40 min
Sep 5, 10:09 PM MSTAreal Flood AdvisoryTWCPima3 hr

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.