Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 159, NWS Tucson, AZ

August 30, 2021Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 30, 2021, 5:46 PM MST for Pima 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 30, 2021, 5:46 PM MST (00:46 UTC)
Expired
Aug 30, 2021, 8:45 PM MST
In force
3 hr
Issued by
NWS Tucson, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 75 km from the middle of the area, began a volume at 00:46 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, 0.8 hours before the alert went out and 42 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 00:00Z on 2021-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 480 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 00:00Z on 2021-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -55 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
480 J/kg
Mixed-layer CIN
-101 J/kg
Mixed-layer LCL
2322 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-55 m²/s²
0-3 km storm-relative helicity
-71 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

714 
WGUS55 KTWC 310046
FFWTWC
AZC019-310345-
/O.NEW.KTWC.FF.W.0159.210831T0046Z-210831T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
546 PM MST Mon Aug 30 2021

The National Weather Service in Tucson has issued a

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

* Until 845 PM MST.

* At 546 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts up to 1 inch 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...
  Three Points, Saguaro National Park West and Picture Rocks.

This includes the following Flash Flood Prone Locations...
	Manville Rd at Brawley Wash.

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 3209 11131 3207 11132 3205 11142 3214 11145
      3227 11149 3229 11145 3229 11140 3230 11134
      3230 11121 3226 11121 3223 11126 3215 11128

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

$$

JRM
1 follow-up statement
636 
WGUS75 KTWC 310133
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
633 PM MST Mon Aug 30 2021

AZC019-310345-
/O.CON.KTWC.FF.W.0159.000000T0000Z-210831T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima AZ-
633 PM MST Mon Aug 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM MST THIS 
EVENING FOR NORTH CENTRAL PIMA COUNTY...

At 633 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain has ended across the warned area. Between 1 and 2.5 inches of 
rain have fallen. Flash flooding is likely ongoing.

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...
  Three Points, Saguaro National Park West and Picture Rocks.

This includes the following Flash Flood Prone Locations...
	Manville Rd at Brawley Wash.

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 3209 11131 3207 11132 3205 11142 3214 11145
      3227 11149 3229 11145 3229 11140 3230 11134
      3230 11121 3226 11121 3223 11126 3215 11128

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

$$

JRM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 30, 5:18 PM MSTSpecial Weather StatementTWC42 min
Aug 30, 5:59 PM MSTSpecial Weather StatementTWCPinal46 min
Aug 30, 6:10 PM MSTSpecial Weather StatementTWCPima35 min
Aug 30, 6:19 PM MSTFlash Flood Warning Considerable damage threatTWCPima, Pinal3 hr
Aug 31, 1:59 AM MSTAreal Flood AdvisoryTWCPima3 hr
Aug 31, 2:47 PM MSTAreal Flood AdvisoryTWCPima, Pinal7 hr
Aug 31, 3:14 PM MSTAreal Flood AdvisoryTWCPima, Pinal5 hr
Aug 31, 4:00 PM MSTSpecial Weather StatementTWCGreenlee45 min
Aug 31, 4:23 PM MSTAreal Flood AdvisoryTWCGraham, Greenlee3 hr
Aug 31, 4:36 PM MSTFlash Flood Warning Considerable damage threatTWCCochise3 hr
Aug 31, 4:41 PM MSTAreal Flood AdvisoryTWCCochise2 hr

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.