Alert archive / Arizona / Flash Flood Warnings in 2012

Flash Flood Warning 39, NWS Phoenix, AZ

August 18, 2012Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 18, 2012, 5:09 PM MST for Maricopa County, Arizona. It was in force for 81 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: Aug 18, 2012, 5:09 PM MST (00:09 UTC)
Expired: Aug 18, 2012, 6:30 PM MST
In force: 81 min
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Flood severity: None

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 88 km from the middle of the area, began a volume at 00:10 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, 0.2 hours before the alert went out and 59 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: 944 J/kg
Mixed-layer CIN: -83 J/kg
Mixed-layer LCL: 1674 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 57 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.

298 
WGUS55 KPSR 190009
FFWPSR
AZC013-190130-
/O.NEW.KPSR.FF.W.0039.120819T0009Z-120819T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PHOENIX AZ
509 PM MST SAT AUG 18 2012

THE NATIONAL WEATHER SERVICE IN PHOENIX HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL MARICOPA COUNTY IN SOUTH CENTRAL ARIZONA...
  FOR THE WESTERN SHORES OF LAKE PLEASANT...AND THE DIRT ROAD 
  TOWARD CASTLE HOT SPRINGS.

* UNTIL 630 PM MST

* AT 456 PM MST...THUNDERSTORMS WITH HEAVY RAIN DEVELOPED OVER AND 
NEAR THE WESTERN SHORES OF LAKE PLEASANT...MOVING SLOWLY SOUTH AT 5 
MPH.  THE AIRMASS IS EXTREMELY HUMID...ANY RAINFALL FROM 
THUNDERSTORM RAINS WILL LIKELY CAUSE FLOODING OF NORMALLY DRY WASHES 
AND ROADWAYS. THE ROAD TO CASTLE HOT SPRINGS IS ESPECIALLY 
VULNERABLE TO FLOODING. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LAKE
  PLEASANT

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT PEOPLE ALONG THE BANKS OF WASHES AND
CREEKS SHOULD MOVE TO HIGHER GROUND IMMEDIATELY. NORMALLY DRY WASHES
AND STREAMS WILL SUDDENLY HAVE RUNNING WATER AND MAKE UNBRIDGED
CROSSINGS IMPASSABLE. STREETS...UNDERPASSES...AND LOW SPOTS WILL
BECOME INUNDATED MAKING DRIVING HAZARDOUS IN THE WARNED AREA.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF NORMALLY
DRY WASHES AND CREEKS...ROADS...AND LOW LYING SPOTS. UNBRIDGED
CROSSINGS WILL BE ESPECIALLY DANGEROUS.

&&

LAT...LON 3380 11223 3379 11242 3392 11241 3391 11235
      3390 11228 3392 11224 3396 11224 3397 11223

$$

HV

1 follow-up statement

607 
WGUS75 KPSR 190112
FFSPSR

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PHOENIX AZ
612 PM MST SAT AUG 18 2012

AZC013-190130-
/O.CON.KPSR.FF.W.0039.000000T0000Z-120819T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MARICOPA AZ-
612 PM MST SAT AUG 18 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM MST FOR NORTH
CENTRAL MARICOPA COUNTY...

THE FLASH FLOOD WARNING ISSUED EARLIER FOR THE WESTERN SHORES OF 
LAKE PLEASANT AND SURROUNDING AREAS CONTINUES UNTIL 630 PM.  RADAR 
DETECTED VERY HEAVY RAIN IN THE AREA BETWEEN 5 PM AND 545 PM. 

ALTHOUGH THUNDERSTORM RAINS HAVE ENDED...RUNOFF AND FLOODING OF 
NORMALLY DRY WASHES WILL TAKE A WHILE TO WORK THEIR WAY 
DOWNSTREAM...AND COULD STILL IMPACT MOTORISTS.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT PEOPLE ALONG THE BANKS OF WASHES AND
CREEKS SHOULD MOVE TO HIGHER GROUND IMMEDIATELY. NORMALLY DRY WASHES
AND STREAMS WILL SUDDENLY HAVE RUNNING WATER AND MAKE UNBRIDGED
CROSSINGS IMPASSABLE. STREETS...UNDERPASSES...AND LOW SPOTS WILL
BECOME INUNDATED MAKING DRIVING HAZARDOUS IN THE WARNED AREA.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF NORMALLY
DRY WASHES AND CREEKS...ROADS...AND LOW LYING SPOTS. UNBRIDGED
CROSSINGS WILL BE ESPECIALLY DANGEROUS.

&&

LAT...LON 3380 11223 3379 11242 3392 11241 3391 11235
      3390 11228 3392 11224 3396 11224 3397 11223

$$

HV

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 6:42 PM MST	Areal Flood Advisory	PSR	Maricopa	68 min
Aug 18, 6:49 PM MST	Flash Flood Warning	PSR	Maricopa	56 min
Aug 18, 7:14 PM MST	Special Weather Statement	PSR		76 min
Aug 19, 1:41 PM MST	Areal Flood Advisory	PSR	Gila, Maricopa, Pinal	2 hr
Aug 19, 4:38 PM MST	Areal Flood Advisory	PSR	Gila	112 min
Aug 19, 4:50 PM MST	Special Weather Statement	PSR	Gila	70 min
Aug 19, 4:52 PM MST	Flash Flood Warning	PSR	Gila	83 min

Nearby

Flash Flood Warnings in Arizona, 2012 Every flash flood warning in 2012

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.