Alert archive / Arizona / Flash Flood Warnings in 2017

Flash Flood Warning 21, NWS Tucson, AZ

July 20, 2017Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 20, 2017, 5:54 PM MST for Pima County, Arizona. It was in force for 96 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: Jul 20, 2017, 5:54 PM MST (00:54 UTC)
Expired: Jul 20, 2017, 7:30 PM MST
In force: 96 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 49 km from the middle of the area, began a volume at 00:55 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 (KDMA), launched 00:00Z, 0.9 hours before the alert went out and 12 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: 526 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 2141 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

136 
WGUS55 KTWC 210054
FFWTWC
AZC019-210230-
/O.NEW.KTWC.FF.W.0021.170721T0054Z-170721T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Tucson AZ
554 PM MST THU JUL 20 2017

The National Weather Service in Tucson has issued a

* Flash Flood Warning for...
  Eastern Pima County in southeastern Arizona...

* Until 730 PM MST

* At 553 PM MST, Doppler radar and automated rain gauges indicated 
  heavy rain from strong thunderstorms in the Catalina Foothills 
  moving south into the city. Up to one inch of rain has already 
  fallen. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Tucson, Casas Adobes, Tanque Verde, Catalina Foothills and Seven
  Falls.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3234 11099 3233 11077 3219 11077 3219 11094

$$

2 follow-up statements

901 
WGUS75 KTWC 210148
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
648 PM MST THU JUL 20 2017

AZC019-210230-
/O.CON.KTWC.FF.W.0021.000000T0000Z-170721T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
648 PM MST THU JUL 20 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM MST FOR
EASTERN PIMA COUNTY...

At 645 PM MST, Doppler radar indicated that the area of heavy rain 
that extended from the Catalina Foothills south across central 
Tucson has diminished in intensity. Automated gauges have recorded 
between one and two inches with this event which may lead to flash 
flooding. 

Normally dry washes and low water crossings may be inundated in the 
following locations... Tucson, Catalina Foothills and Seven Falls.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3234 11099 3233 11077 3219 11077 3219 11094

$$

356 
WGUS75 KTWC 210222
FFSTWC

Flash Flood Statement
National Weather Service Tucson AZ
722 PM MST THU JUL 20 2017

AZC019-210231-
/O.EXP.KTWC.FF.W.0021.000000T0000Z-170721T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Pima-
722 PM MST THU JUL 20 2017

...THE FLASH FLOOD WARNING FOR EASTERN PIMA COUNTY WILL EXPIRE AT 730
PM MST...

Flooding is no longer expected to pose a threat. However light to 
locally moderate rain will continue across eastern Pima county 
through 9 pm. Please continue to heed any remaining road closures. 

LAT...LON 3234 11099 3233 11077 3219 11077 3219 11094

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 5:08 PM MST	Special Weather Statement	TWC		37 min
Jul 20, 5:20 PM MST	Special Weather Statement	TWC		40 min
Jul 20, 6:05 PM MST	Special Weather Statement	TWC	Pinal	25 min
Jul 20, 6:10 PM MST	Areal Flood Advisory	TWC	Cochise	2 hr
Jul 20, 6:11 PM MST	Special Weather Statement	TWC		34 min
Jul 21, 1:18 PM MST	Special Weather Statement	TWC	Cochise	42 min
Jul 21, 1:22 PM MST	Severe Thunderstorm Warning	TWC	Cochise	38 min
Jul 21, 3:05 PM MST	Special Weather Statement	TWC	Graham	40 min
Jul 21, 3:55 PM MST	Special Weather Statement	TWC	Santa Cruz	35 min
Jul 21, 4:15 PM MST	Special Weather Statement	TWC	Santa Cruz	30 min

Nearby

Flash Flood Warnings in Arizona, 2017 Every flash flood warning in 2017

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.