Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 11, NWS Tucson, AZ

July 4, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 4, 2021, 6:39 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 4, 2021, 6:39 PM MST (01:39 UTC)
Expired: Jul 4, 2021, 9:45 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), 62 km from the middle of the area, began a volume at 01:40 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, 1.7 hours before the alert went out and 27 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 494 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 2027 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -52 m²/s²
0-3 km storm-relative helicity: 11 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

963 
WGUS55 KTWC 050139
FFWTWC
AZC019-050445-
/O.NEW.KTWC.FF.W.0011.210705T0139Z-210705T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
639 PM MST Sun Jul 4 2021

The National Weather Service in Tucson has issued a

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

* Until 945 PM MST.

* At 639 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

Excessive rainfall over the Bighorn burn scar will result in debris 
flow moving through the Pima Canyon and Finger Rock Watersheds, as 
well as the Sutherland Wash. The debris flow can consist of rock, 
mud, vegetation and other loose materials.

  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...
  Catalina, Oro Valley, Casas Adobes, Catalina State Park and 
  Catalina Foothills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3249 11088 3235 11097 3229 11088 3238 11084
      3247 11082

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

$$

RH

1 follow-up statement

255 
WGUS75 KTWC 050440
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
940 PM MST Sun Jul 4 2021

AZC019-050450-
/O.EXP.KTWC.FF.W.0011.000000T0000Z-210705T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
940 PM MST Sun Jul 4 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 945 PM MST THIS EVENING FOR 
NORTHEASTERN PIMA COUNTY...

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

LAT...LON 3249 11088 3235 11097 3229 11088 3238 11084
      3247 11082

$$

JG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 4, 6:33 PM MST	Special Weather Statement	TWC		27 min
Jul 5, 4:31 AM MST	Areal Flood Advisory	TWC	Santa Cruz	2 hr
Jul 5, 10:38 AM MST	Areal Flood Advisory	TWC	Cochise	112 min
Jul 5, 11:48 AM MST	Special Weather Statement	TWC	Cochise	42 min
Jul 5, 2:24 PM MST	Special Weather Statement	TWC	Cochise	51 min
Jul 5, 4:12 PM MST	Special Weather Statement	TWC	Cochise	33 min
Jul 5, 4:32 PM MST	Severe Thunderstorm Warning	TWC	Cochise	28 min

Nearby

Flash Flood Warnings in Arizona, 2021 Every 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.