Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 70, NWS Tucson, AZ

July 27, 2021Santa Cruz County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 27, 2021, 1:52 PM MST for Santa Cruz County, Arizona. It was in force for 2 hr. 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 27, 2021, 1:52 PM MST (20:52 UTC)
Expired: Jul 27, 2021, 4:15 PM MST
In force: 2 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), 67 km from the middle of the area, began a volume at 20:54 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 27, 2:30 PM MST	FLASH FLOOD	1 Ssw Nogales, AZ	MINOR FLOODING TO SEVERAL HOMES IN THE VICINITY OF WESTERN AVE.

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 12:00Z, 8.9 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-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: 487 J/kg
Mixed-layer CIN: -150 J/kg
Mixed-layer LCL: 1850 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -20 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.

486 
WGUS55 KTWC 272052
FFWTWC
AZC023-272315-
/O.NEW.KTWC.FF.W.0070.210727T2052Z-210727T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
152 PM MST Tue Jul 27 2021

The National Weather Service in Tucson has issued a

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

* Until 415 PM MST.

* At 152 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Up to 
  1.5 inches of rain have fallen with two automated gauges recording 
  1.25 inches in 30 minutes. Flash flooding is ongoing or expected 
  to begin shortly.

  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...
  Nogales.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3133 11103 3141 11103 3141 11088 3133 11086

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

$$

AH

2 follow-up statements

766 
WGUS75 KTWC 272147
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
247 PM MST Tue Jul 27 2021

AZC023-272315-
/O.CON.KTWC.FF.W.0070.000000T0000Z-210727T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz AZ-
247 PM MST Tue Jul 27 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM MST THIS 
AFTERNOON FOR SOUTH CENTRAL SANTA CRUZ COUNTY...

At 247 PM MST, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Up to 2 
inches of rain have fallen. The Ephriam Wash Gauge recorded 1.73 
inches in one hour. Flash flooding is ongoing or expected to begin 
shortly.

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...
  Nogales.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3133 11103 3141 11103 3141 11088 3133 11086

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

$$

AH

477 
WGUS75 KTWC 272308
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
408 PM MST Tue Jul 27 2021

AZC023-272318-
/O.EXP.KTWC.FF.W.0070.000000T0000Z-210727T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Santa Cruz AZ-
408 PM MST Tue Jul 27 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 415 PM MST THIS AFTERNOON FOR 
SOUTH CENTRAL SANTA CRUZ COUNTY...

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

LAT...LON 3133 11103 3141 11103 3141 11088 3133 11086

$$

JD

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 27, 1:56 PM MST	Special Weather Statement	TWC	Santa Cruz	49 min
Jul 27, 2:15 PM MST	Special Weather Statement	TWC	Santa Cruz	45 min
Jul 27, 2:33 PM MST	Areal Flood Advisory	TWC	Cochise, Pima, Santa Cruz	3 hr
Jul 27, 3:29 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Jul 27, 3:35 PM MST	Special Weather Statement	TWC	Santa Cruz	40 min
Jul 27, 3:49 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Jul 27, 4:00 PM MST	Special Weather Statement	TWC		45 min
Jul 27, 4:05 PM MST	Areal Flood Advisory	TWC	Pima	115 min
Jul 27, 4:25 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Jul 27, 4:34 PM MST	Blowing Dust Advisory	TWC	Pima, Pinal	87 min
Jul 27, 4:42 PM MST	Flash Flood Warning	TWC	Pima	3 hr
Jul 27, 4:56 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr

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.