Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 118, NWS Tucson, AZ

August 12, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 12, 2021, 12:06 AM MST for Pima County, Arizona. It was in force for 103 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
Aug 12, 2021, 12:06 AM MST (07:06 UTC)
Expired
Aug 12, 2021, 1:49 AM MST
In force
103 min
Issued by
NWS Tucson, AZ
Area
Storm-based polygon
Flood severity
None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 87 km from the middle of the area, began a volume at 07:09 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, 7.1 hours before the alert went out and 48 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 2021-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 885 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 2021-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
885 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
1645 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

627 
WGUS55 KTWC 120706
FFWTWC
AZC019-120900-
/O.NEW.KTWC.FF.W.0118.210812T0706Z-210812T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
1206 AM MST Thu Aug 12 2021

The National Weather Service in Tucson has issued a

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

* Until 200 AM MST.

* At 1206 AM MST, Doppler radar and automated rain gages indicated 
  thunderstorms producing between 1 and 2 inches of heavy rain. An 
  automated rain at Trico Road to the north of manville reported 
  1.97 inches of rain in the past hour. Flash flooding is ongoing or 
  expected to begin shortly, especially in those dry washes that 
  drain into Brawley Wash.

  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...
  Marana, Avra Valley, Saguaro National Park West and Picture Rocks.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3238 11144 3250 11148 3250 11124 3225 11112
      3226 11138

FLASH FLOOD...RADAR INDICATED

$$

CWR
1 follow-up statement
631 
WGUS75 KTWC 120849
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
149 AM MST Thu Aug 12 2021

AZC019-120859-
/O.CAN.KTWC.FF.W.0118.000000T0000Z-210812T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
149 AM MST Thu Aug 12 2021

...FLASH FLOOD WARNING FOR NORTH CENTRAL PIMA COUNTY HAS BEEN 
REPLACED WITH A FLOOD ADVISORY...

LAT...LON 3238 11144 3250 11148 3250 11124 3225 11112
      3226 11138

$$

CR

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 11:52 PM MSTSpecial Weather StatementTWC38 min
Aug 12, 12:37 AM MSTAreal Flood AdvisoryTWCPima113 min
Aug 12, 1:49 AM MSTAreal Flood AdvisoryTWCPima116 min
Aug 12, 11:48 AM MSTFlash Flood WatchTWCCochise, Graham, Greenlee, Pima, Pinal, Santa Cruz5 days

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.