Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 161, NWS Tucson, AZ

August 31, 2021Cochise County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 31, 2021, 4:36 PM MST for Cochise 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 31, 2021, 4:36 PM MST (23:36 UTC)
Expired: Aug 31, 2021, 7:45 PM MST
In force: 3 hr
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Cochise County, AZ

The radar

The Tucson radar (KEMX), 76 km from the middle of the area, began a volume at 23:36 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, 11.6 hours before the alert went out and 115 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: 305 J/kg
Mixed-layer CIN: -163 J/kg
Mixed-layer LCL: 1600 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: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

986 
WGUS55 KTWC 312336
FFWTWC
AZC003-010245-
/O.NEW.KTWC.FF.W.0161.210831T2336Z-210901T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
436 PM MST Tue Aug 31 2021

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  Southwestern Cochise County in southeastern Arizona...

* Until 745 PM MST.

* At 436 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Additional rainfall amounts up to 0.3 inches are 
  possible in the warned area. 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...
  Sierra Vista, Bisbee, Hereford, Naco and Palominas.

This includes the following Flash Flood Prone Locations...
	Moson Rd from SR 90 and Hereford Rd.

This includes the following streams and drainages...
  San Pedro River and Spring Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 11011 3147 11023 3156 11023 3156 11009
      3145 11001 3133 10990 3133 10993 3133 11000

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

$$

JRM

2 follow-up statements

145 
WGUS75 KTWC 010032
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
532 PM MST Tue Aug 31 2021

AZC003-010245-
/O.CON.KTWC.FF.W.0161.000000T0000Z-210901T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cochise AZ-
532 PM MST Tue Aug 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM MST THIS 
EVENING FOR SOUTH CENTRAL COCHISE COUNTY...

At 532 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain ended across the warned area. Between 1 and 3 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...
  Sierra Vista, Hereford, Naco and Palominas.

This includes the following streams and drainages...
  San Pedro River and Spring Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 11011 3150 11018 3152 11016 3153 11011
      3141 11003 3133 10991 3133 10993 3133 11000

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

$$

JRM

774 
WGUS75 KTWC 010240
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
740 PM MST Tue Aug 31 2021

AZC003-010250-
/O.EXP.KTWC.FF.W.0161.000000T0000Z-210901T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cochise AZ-
740 PM MST Tue Aug 31 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 745 PM MST THIS EVENING FOR 
SOUTH CENTRAL COCHISE COUNTY...

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

A Flash Flood Watch remains in effect until 500 AM MST Thursday for 
a portion of Southeast Arizona.

LAT...LON 3133 11011 3150 11018 3152 11016 3153 11011
      3141 11003 3133 10991 3133 10993 3133 11000

$$

JRM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 5:18 PM MST	Special Weather Statement	TWC		42 min
Aug 30, 5:46 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima	3 hr
Aug 30, 5:59 PM MST	Special Weather Statement	TWC	Pinal	46 min
Aug 30, 6:10 PM MST	Special Weather Statement	TWC	Pima	35 min
Aug 30, 6:19 PM MST	Flash Flood Warning Considerable damage threat	TWC	Pima, Pinal	3 hr
Aug 31, 1:59 AM MST	Areal Flood Advisory	TWC	Pima	3 hr
Aug 31, 2:47 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	7 hr
Aug 31, 3:14 PM MST	Areal Flood Advisory	TWC	Pima, Pinal	5 hr
Aug 31, 4:00 PM MST	Special Weather Statement	TWC	Greenlee	45 min
Aug 31, 4:23 PM MST	Areal Flood Advisory	TWC	Graham, Greenlee	3 hr
Aug 31, 4:41 PM MST	Areal Flood Advisory	TWC	Cochise	2 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.