Alert archive / Arizona / Flash Flood Warnings in 2011

Flash Flood Warning 17, NWS Tucson, AZ

July 20, 2011Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Jul 20, 2011, 7:43 PM MST for Pima County, Arizona. It was in force for 92 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, 2011, 7:43 PM MST (02:43 UTC)
Expired: Jul 20, 2011, 9:15 PM MST
In force: 92 min
Issued by: NWS Tucson, AZ
Area: Storm-based polygon
Flood severity: None

County Pima County, AZ

The radar

The Tucson radar (KEMX), 45 km from the middle of the area, began a volume at 02:42 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, 2.7 hours before the alert went out and 21 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: 10 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 3126 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -18 m²/s²
0-3 km storm-relative helicity: 27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

620 
WGUS55 KTWC 210243
FFWTWC
AZC019-210415-
/O.NEW.KTWC.FF.W.0017.110721T0243Z-110721T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
743 PM MST WED JUL 20 2011

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL PIMA COUNTY IN SOUTH CENTRAL ARIZONA...

* UNTIL 915 PM MST

* AT 738 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS EAST CENTRAL PIMA     
  COUNTY...MAINLY IN THE MOUNTAINS. SEVERAL AUTOMATED RAIN GAUGES HAVE 
  REPORTED RAINFALL RATES OF OVER 1 INCH IN LESS THAN 1 HOUR. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SEVEN      
  FALLS...SABINO CANYON...MONT LEMMON HIGHWAY...REDINGTON PASS...AND 
  MOLINO CANYON. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF WASHES
AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE BANKS OF
CREEKS AND STREAMS.

&&

LAT...LON 3240 11082 3240 11059 3216 11058 3216 11072
      3223 11081

$$

2 follow-up statements

915 
WGUS75 KTWC 210322
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
822 PM MST WED JUL 20 2011

AZC019-210415-
/O.CON.KTWC.FF.W.0017.000000T0000Z-110721T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PIMA AZ-
822 PM MST WED JUL 20 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM MST FOR EAST
CENTRAL PIMA COUNTY...

AT 810 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED 
SCATTERED THUNDERSTORMS CONTINUING ACROSS THE FAR NORTHEAST PORTION 
OF THE TUCSON METRO AREA. MOVEMENT OF THESE THUNDERSTORMS WAS TO THE 
SOUTH AT 5 MPH. LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED 
TO SEVEN FALLS...SABINO CANYON...THE MOUNT LEMMON HIGHWAY...
REDINGTON PASS...AND MOLINO CANYON. DOPPLER RADAR RAINFALL ESTIMATES 
OF UP TO 1.5 INCHES IN ISOLATED LOCATIONS SINCE 745 PM MST. THE 
HIGHER RAINFALL AMOUNTS WILL CAUSE FLOODING. FLOWS WILL OCCUR IN 
VARIOUS AREA WASHES. THE BULK OF THIS ACTIVITY IS EXPECTED TO 
DIMINISH BY 10 PM MST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL 
CREEKS...STREAMS AND COUNTRY ROADS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 3240 11082 3240 11059 3216 11058 3216 11072
      3223 11081

$$

BF

985 
WGUS75 KTWC 210430
FFSTWC

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
930 PM MST WED JUL 20 2011

AZC019-210434-
/O.EXP.KTWC.FF.W.0017.000000T0000Z-110721T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PIMA AZ-
930 PM MST WED JUL 20 2011

...THE FLASH FLOOD WARNING HAS EXPIRED FOR EAST CENTRAL PIMA
COUNTY...

AT 924 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT THUNDERSTORMS HAD WEAKENED ACROSS EAST CENTRAL PIMA COUNTY. 
THUS THE FLASH FLOOD WARNING HAS BEEN ALLOWED TO EXPIRE. HOWEVER...
RAINFALL THAT OCCURRED EARLIER THIS EVENING WILL LEAD TO FLOWS IN 
VARIOUS AREA WASHES DURING THE NEXT SEVERAL HOURS.

LAT...LON 3240 11082 3240 11059 3216 11058 3216 11072
      3223 11081

$$

BF

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 5:17 PM MST	Special Weather Statement	TWC	Pinal	58 min
Jul 20, 5:49 PM MST	Areal Flood Advisory	TWC	Cochise	3 hr
Jul 20, 6:35 PM MST	Severe Thunderstorm Warning	TWC	Pima	25 min
Jul 20, 7:35 PM MST	Areal Flood Advisory	TWC	Pima	115 min
Jul 21, 12:52 PM MST	Areal Flood Advisory	TWC	Cochise	113 min

Nearby

Flash Flood Warnings in Arizona, 2011 Every flash flood warning in 2011

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.