Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 156, NWS Tucson, AZ

August 28, 2021Pima County, Pinal County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 28, 2021, 5:03 PM MST for Pima County, Pinal County, Arizona. It was in force for 117 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 28, 2021, 5:03 PM MST (00:03 UTC)
Expired: Aug 28, 2021, 7:00 PM MST
In force: 117 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Pima County, AZ, Pinal County, AZ

The radar

The Tucson radar (KEMX), 73 km from the middle of the area, began a volume at 00:04 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, 0.1 hours before the alert went out and 36 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: 68 J/kg
Mixed-layer CIN: -165 J/kg
Mixed-layer LCL: 2343 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 113 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

248 
WGUS55 KTWC 290003
FFWTWC
AZC019-021-290200-
/O.NEW.KTWC.FF.W.0156.210829T0003Z-210829T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
503 PM MST Sat Aug 28 2021

The National Weather Service in Tucson has issued a

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

* Until 700 PM MST.

* At 503 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, Catalina, Oro Valley, Marana, Oracle, Casas Adobes, 
  Saddlebrooke, Tortolita, Catalina State Park, Catalina Foothills, 
  Oracle Junction, Biosphere 2 and Dove Mountain.

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 3258 11102 3260 11079 3251 11079 3235 11079
      3234 11112 3246 11109

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

$$

GZ

1 follow-up statement

718 
WGUS75 KTWC 290129
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
629 PM MST Sat Aug 28 2021

AZC019-021-290200-
/O.CON.KTWC.FF.W.0156.000000T0000Z-210829T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-Pinal AZ-
629 PM MST Sat Aug 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MST THIS EVENING 
FOR NORTHEASTERN PIMA AND SOUTHEASTERN PINAL COUNTIES...

At 629 PM MST, Doppler radar and automated rain gauges indicated 
thunderstorms over the past few hours have produced between 1 and 2 
inches of heavy rain in the Canada del Oro and Sutherland Wash 
basins on the western portions of the Catalina Mountains. An 
automated rain gage at Samaniego Peak recorded 1.42 inches of rain 
with 5 other gages along the CDO receiving at or around an inch of 
rain. This will result in flash flooding of several washes that 
drain into these main washes through 7 PM MST. Very high flows in 
the CDO Wash will persist through midnight.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Tucson, Catalina, Oro Valley, Marana, Oracle, Casas Adobes, 
  Saddlebrooke, Tortolita, Catalina State Park, Catalina Foothills, 
  Oracle Junction, Biosphere 2 and Dove Mountain.

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 3258 11102 3260 11079 3251 11079 3235 11079
      3234 11112 3246 11109

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

$$

CWR

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 28, 5:12 PM MST	Special Weather Statement	TWC	Pinal	48 min
Aug 28, 5:20 PM MST	Severe Thunderstorm Warning	TWC	Pinal	40 min
Aug 28, 6:31 PM MST	Severe Thunderstorm Warning	TWC	Pima	44 min
Aug 28, 6:47 PM MST	Special Weather Statement	TWC	Pinal	43 min
Aug 28, 7:01 PM MST	Areal Flood Warning	TWC	Pima, Pinal	3 hr
Aug 28, 7:14 PM MST	Severe Thunderstorm Warning	TWC	Pima	61 min
Aug 28, 7:41 PM MST	Flash Flood Warning	TWC	Pima	109 min
Aug 28, 8:03 PM MST	Severe Thunderstorm Warning	TWC	Pima	57 min
Aug 28, 8:25 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	2 hr
Aug 29, 2:32 PM MST	Special Weather Statement	TWC	Cochise	43 min
Aug 29, 3:53 PM MST	Special Weather Statement	TWC	Pima	37 min
Aug 29, 4:23 PM MST	Areal Flood Advisory	TWC	Pima	112 min
Aug 29, 4:46 PM MST	Special Weather Statement	TWC	Pinal	59 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.