Alert archive / Arizona / Flash Flood Warnings in 2011

Flash Flood Warning 3, NWS Phoenix, AZ

August 27, 2011Maricopa County, Yuma County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 27, 2011, 9:38 PM MST for Maricopa County, Yuma 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 27, 2011, 9:38 PM MST (04:38 UTC)
Expired
Aug 28, 2011, 12:30 AM MST
In force
3 hr
Issued by
NWS Phoenix, AZ
Area
Storm-based polygon
Flood severity
None

Counties Maricopa County, AZ, Yuma County, AZ

The radar

The Yuma radar (KYUX), 104 km from the middle of the area, began a volume at 04:37 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

Phoenix, AZ (KPSR), launched 00:00Z, 4.6 hours before the alert went out and 167 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, Phoenix, AZ at 00:00Z on 2011-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 527 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 00:00Z on 2011-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 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
527 J/kg
Mixed-layer CIN
-108 J/kg
Mixed-layer LCL
3311 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
-11 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, in the capitals the NWS used until 2016.

378 
WGUS55 KPSR 280438
FFWPSR
AZC013-027-280730-
/O.NEW.KPSR.FF.W.0003.110828T0438Z-110828T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
938 PM MST SAT AUG 27 2011

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EXTREME SOUTHWESTERN MARICOPA COUNTY IN SOUTH CENTRAL ARIZONA...
  EAST CENTRAL YUMA COUNTY IN SOUTHWEST ARIZONA...

* UNTIL 1230 AM MST

* AT 929 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED 
THUNDERSTORMS PRODUCING HEAVY RAINFALL ACROSS PORTIONS OF SOUTHWEST 
MARICOPA AND EASTERN YUMA COUNTIES...MAINLY BETWEEN THE COMMUNITIES 
OF HYDER...SENTINEL...DATELAND...ROLL AND TACNA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO TYSON...  
PALOMA...AND ALONG POTIONS OF INTERSTATE 8 IN THE AREA.

THE COMPLEX OF THUNDERSTORMS PRODUCING HEAVY RAIN IS SLOWLY MOVING 
WEST...AND RAINFALL RATES OF UP TO 3 INCHES PER HOUR ARE OCCURRING 
OVER THIS AREA.

MANY DRY WASHES WILL BEGIN TO SEE A FLOW OF WATER...AND RUN OFF MAY 
SUDDENLY COVER LOW WATER CROSSING AND BEGIN TO POOL IN LOW LYING 
AREAS. SOME OF THE WASHING THAT MAY BE IMPACTED INCLUDE THE TEN MILE 
WASH...THE COPPER WASH AND THE COLUMBUS WASH...AND MANY OTHER 
SMALLER DRAINAGES THAT FEED INTO THE GILA RIVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

RUNOFF FROM HEAVY RAINFALL WILL CAUSE NORMALLY DRY WASHES TO RUN AND 
CAUSE CONSIDERABLE PONDING OF WATER ON ROADS AND LOW LYING SPOTS. 
UNBRIDGED CROSSINGS MAY BECOME TOO DANGEROUS FOR DRIVING.

NEVER DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. WHEN ENCOUNTERING FLOODED ROADS MAKE THE SMART 
CHOICE...TURN AROUND...DONT DROWN.

&&

LAT...LON 3281 11399 3291 11370 3300 11351 3308 11312
      3276 11311 3263 11397

$$

MEYERS
1 follow-up statement
964 
WGUS75 KPSR 280646
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
1146 PM MST SAT AUG 27 2011

AZC013-027-280730-
/O.CON.KPSR.FF.W.0003.000000T0000Z-110828T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
YUMA AZ-MARICOPA AZ-
1146 PM MST SAT AUG 27 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 AM MST FOR
EXTREME SOUTHWESTERN MARICOPA AND CENTRAL YUMA COUNTIES...

AT 1129 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR DETECTED 
ONLY LIGHT RAIN SHOWERS OVER THE WARNED AREA. THE THREAT FOR 
ADDITIONAL HEAVY RAIN HAS ENDED IN THE WARNED AREA. 

BETWEEN 8 PM AND 1030 PM...NATIONAL WEATHER SERVICE RADAR INDICATED 
THAT BETWEEN 1.5 AND 3 INCHES OF RAIN FELL ALONG AND NEAR INTERSTATE 
8 IN A 15 MILE WIDE ZONE EXTENDING FROM 10 MILES WEST OF GILA BEND 
TO NEAR TACNA. HEAVIEST RAINFALL...POSSIBLY IN EXCESS OF 3 
INCHES...FELL ALONG A NARROW BAND EXTENDING FROM 5 MILES SOUTH OF 
SENTINEL TO 5 MILES SOUTHEAST OF DATELAND. SOME OF THE AREA AFFECTED 
BY HEAVY RAINFALL PROBABLY RECEIVED MORE THAN HALF OF THEIR AVERAGE 
YEARLY RAINFALL WITH THIS STORM. WASHES OVER FAR SOUTHWEST 
MARICOPA COUNTY AND EAST-CENTRAL YUMA COUNTY ARE RUNNING...AND MANY 
LOW WATER CROSSINGS WILL BE FLOODED. MANY OF THE AFFECTED WASHES 
DRAIN INTO THE GILA RIVER.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING. 
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATERS 
OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY AUTOMOBILE.

&&

LAT...LON 3281 11399 3291 11370 3300 11351 3308 11312
      3276 11311 3263 11397

$$

DG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 5:01 PM MSTSevere Thunderstorm WarningPSRGila, Maricopa, Pinal59 min
Aug 27, 5:36 PM MSTSpecial Weather StatementPSRLa Paz39 min
Aug 27, 6:11 PM MSTSpecial Weather StatementPSR79 min
Aug 27, 6:14 PM MSTSevere Thunderstorm WarningPSRPinal46 min
Aug 27, 6:23 PM MSTDust Storm WarningPSR97 min
Aug 27, 6:58 PM MSTSevere Thunderstorm WarningPSRMaricopa25 min
Aug 27, 7:59 PM MSTSpecial Weather StatementPSR76 min
Aug 27, 8:38 PM MSTSevere Thunderstorm WarningPSRMaricopa, Yuma52 min
Aug 27, 9:18 PM MSTAreal Flood AdvisoryPSRMaricopa, Yuma3 hr
Aug 27, 9:25 PM MSTSevere Thunderstorm WarningPSRYuma65 min
Aug 27, 9:46 PM MSTDust Storm WarningPSR2 hr
Aug 27, 10:02 PM MSTSevere Thunderstorm WarningPSRYuma58 min
Aug 28, 12:26 AM MSTSpecial Weather StatementPSRLa Paz79 min
Aug 28, 3:39 AM MSTExcessive Heat WarningPSR40 hr

Nearby

Flash Flood Warnings in Arizona, 2011Every 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.