Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 88, NWS Tucson, AZ

August 5, 2021Santa Cruz County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 5, 2021, 3:47 PM MST for Santa Cruz 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
Aug 5, 2021, 3:47 PM MST (22:47 UTC)
Expired
Aug 5, 2021, 6:45 PM MST
In force
3 hr
Issued by
NWS Tucson, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Santa Cruz County, AZ

The radar

The Tucson radar (KEMX), 63 km from the middle of the area, began a volume at 22:48 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, 10.8 hours before the alert went out and 90 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 2021-08-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1468 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 2021-08-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 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
1468 J/kg
Mixed-layer CIN
-213 J/kg
Mixed-layer LCL
1735 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
130 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted.

699 
WGUS55 KTWC 052247
FFWTWC
AZC023-060145-
/O.NEW.KTWC.FF.W.0088.210805T2247Z-210806T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
347 PM MST Thu Aug 5 2021

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  Southern Santa Cruz County in southeastern Arizona...

* Until 645 PM MST.

* At 347 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 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...
  Nogales and Kino Springs.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3133 11093 3140 11090 3140 11087 3141 11076
      3133 11076 3133 11080 3133 11088

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

$$

GZ
2 follow-up statements
092 
WGUS75 KTWC 052308
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
408 PM MST Thu Aug 5 2021

AZC023-060145-
/O.CON.KTWC.FF.W.0088.000000T0000Z-210806T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz AZ-
408 PM MST Thu Aug 5 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MST THIS 
EVENING FOR SOUTHERN SANTA CRUZ COUNTY...

At 408 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 3 inches of rain have 
fallen east of State Highway 82 and south of Kino Springs Drive. 
Flash flooding is ongoing or expected to begin shortly.

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...
  Nogales and Kino Springs.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3133 11093 3140 11090 3140 11087 3141 11076
      3133 11076 3133 11080 3133 11088

FLASH FLOOD...RADAR INDICATED

$$

GZ
318 
WGUS75 KTWC 060145
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
645 PM MST Thu Aug 5 2021

AZC023-060155-
/O.EXP.KTWC.FF.W.0088.000000T0000Z-210806T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz AZ-
645 PM MST Thu Aug 5 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHERN SANTA CRUZ 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 3133 11093 3140 11090 3140 11087 3141 11076
      3133 11076 3133 11080 3133 11088

$$

GZ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 5, 3:05 PM MSTSpecial Weather StatementTWCSanta Cruz40 min
Aug 5, 3:26 PM MSTSevere Thunderstorm WarningTWCSanta Cruz34 min
Aug 5, 3:36 PM MSTAreal Flood AdvisoryTWCSanta Cruz114 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.