Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 81, NWS Tucson, AZ

July 30, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 30, 2021, 8:47 PM MST for Pima County, Arizona. It was in force for 118 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 30, 2021, 8:47 PM MST (03:47 UTC)
Expired: Jul 30, 2021, 10:45 PM MST
In force: 118 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 52 km from the middle of the area, began a volume at 03:47 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.

What was reported inside it

Time	Report	Where	Remark
Jul 30, 8:58 PM MST	FLASH FLOOD	3 Wsw Tucson, AZ	FIRE DEPARTMENT RESCUED A VEHICLE IN THE WASH.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Tuscon, AZ (KTUS), launched 00:00Z, 3.8 hours before the alert went out and 13 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: 211 J/kg
Mixed-layer CIN: -25 J/kg
Mixed-layer LCL: 2641 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: 26 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

203 
WGUS55 KTWC 310347
FFWTWC
AZC019-310545-
/O.NEW.KTWC.FF.W.0081.210731T0347Z-210731T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
847 PM MST Fri Jul 30 2021

The National Weather Service in Tucson has issued a

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

* Until 1045 PM MST.

* At 847 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. 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...
  Tucson, Davis-Monthan Air Force Base, Drexel Heights, South 
  Tucson, Pascua Pueblo Yaqui Reservation, Valencia West, Tucson 
  Estates, Tucson International Airport, Saguaro National Park West, 
  Summit, San Xavier Mission and Ryan AirField.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 3225 11087 3209 11088 3213 11124 3225 11126
      3227 11110

FLASH FLOOD...RADAR INDICATED

$$

GZ

2 follow-up statements

910 
WGUS75 KTWC 310444
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
944 PM MST Fri Jul 30 2021

AZC019-310545-
/O.CON.KTWC.FF.W.0081.000000T0000Z-210731T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
944 PM MST Fri Jul 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1045 PM MST THIS 
EVENING FOR EAST CENTRAL PIMA COUNTY...

At 944 PM MST, Doppler radar and automated rain gauges indicated 
that thunderstorms had produced between 1 and 1.5 inches of rainfall 
across portions of the warning area. Light to moderate rainfall 
continues to fall within 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, Drexel Heights, South 
  Tucson, Pascua Pueblo Yaqui Reservation, Valencia West, Tucson 
  Estates, Tucson International Airport, Saguaro National Park West, 
  Summit, San Xavier Mission and Ryan AirField.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

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 3225 11087 3209 11088 3213 11124 3225 11126
      3227 11110

FLASH FLOOD...RADAR INDICATED

$$

GZ

021 
WGUS75 KTWC 310544
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
1044 PM MST Fri Jul 30 2021

AZC019-310554-
/O.EXP.KTWC.FF.W.0081.000000T0000Z-210731T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
1044 PM MST Fri Jul 30 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1045 PM MST THIS EVENING FOR 
EAST CENTRAL 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 3225 11087 3209 11088 3213 11124 3225 11126
      3227 11110

$$

GZ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 30, 5:20 PM MST	Severe Thunderstorm Warning	TWC	Pima	55 min
Jul 30, 5:22 PM MST	Severe Thunderstorm Warning	TWC	Pima	29 min
Jul 30, 6:11 PM MST	Areal Flood Advisory	TWC	Pima	2 hr
Jul 30, 6:33 PM MST	Special Weather Statement	TWC		42 min
Jul 30, 6:52 PM MST	Special Weather Statement	TWC		38 min
Jul 30, 7:10 PM MST	Areal Flood Advisory	TWC	Pima	2 hr
Jul 30, 7:20 PM MST	Areal Flood Advisory	TWC	Pima	4 hr
Jul 30, 7:40 PM MST	Special Weather Statement	TWC		65 min
Jul 30, 7:49 PM MST	Severe Thunderstorm Warning	TWC	Pima	41 min
Jul 30, 7:51 PM MST	Areal Flood Advisory	TWC	Pima	114 min
Jul 30, 7:57 PM MST	Severe Thunderstorm Warning	TWC	Pima	48 min
Jul 30, 7:59 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Jul 30, 8:20 PM MST	Severe Thunderstorm Warning	TWC	Pima	40 min
Jul 30, 8:29 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Jul 30, 8:35 PM MST	Areal Flood Advisory	TWC	Pima	115 min
Jul 30, 9:55 PM MST	Special Weather Statement	TWC	Pinal	65 min
Jul 30, 10:11 PM MST	Flash Flood Warning	TWC	Pima	4 hr
Jul 30, 11:37 PM MST	Flash Flood Warning	TWC	Pima	2 hr
Jul 31, 2:06 AM MST	Areal Flood Advisory	TWC	Pima	3 hr
Jul 31, 3:51 PM MST	Areal Flood Advisory	TWC	Pinal	114 min
Jul 31, 4:13 PM MST	Special Weather Statement	TWC		47 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.