Alert archive / Arizona / Flash Flood Warnings in 2012

Flash Flood Warning 21, NWS Flagstaff, AZ

August 20, 2012Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 20, 2012, 9:06 PM MST for Coconino County, Arizona. It was in force for 9 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 20, 2012, 9:06 PM MST (04:06 UTC)
Expired: Aug 21, 2012, 6:00 AM MST
In force: 9 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Flood severity: None

County Coconino County, AZ

The radar

The Cedar City radar (KICX), 123 km from the middle of the area, began a volume at 04:06 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

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 4.1 hours before the alert went out and 190 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: 217 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 1521 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -9 m²/s²
0-3 km storm-relative helicity: 19 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.

089 
WGUS55 KFGZ 210406
FFWFGZ
AZC005-211300-
/O.NEW.KFGZ.FF.W.0021.120821T0406Z-120821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
906 PM MST MON AUG 20 2012

THE NATIONAL WEATHER SERVICE IN FLAGSTAFF HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL COCONINO COUNTY IN ARIZONA INCLUDING THE PARIA 
  RIVER AND LEES FERRY...

* UNTIL 600 AM MST TUESDAY

* AT 900 PM MST...AUTOMATED STREAM GAGES ON THE PARIA RIVER IN 
  SOUTHERN UTAH INDICATED A SIGNIFICANT FLASH FLOOD WAS MOVING 
  DOWNSTREAM INTO NORTHERN ARIZONA.

* THE CREST OF THIS FLOOD IS EXPECTED TO REACH LEES FERRY AND 
  THE CONFLUENCE WITH THE COLORADO RIVER DURING THE PRE-DAWN 
  HOURS TUESDAY MORNING.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3700 11191 3700 11174 3686 11156 3684 11160

$$

DB

2 follow-up statements

641 
WGUS75 KFGZ 210527
FFSFGZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1027 PM MST MON AUG 20 2012

AZC005-211300-
/O.CON.KFGZ.FF.W.0021.000000T0000Z-120821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
COCONINO AZ-
1027 PM MST MON AUG 20 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 600 AM MST TUESDAY
FOR NORTH CENTRAL COCONINO COUNTY...

AT 1000 PM MST...AUTOMATED STREAM GAGES ON THE PARIA RIVER IN 
SOUTHERN UTAH INDICATED THAT THE FLOOD CREST HAD PASSED THE GAGING 
STATION. THE PEAK FLOW WILL CONTINUE DOWNSTREAM OVERNIGHT AND IS 
EXPECTED TO REACH LEES FERRY AND THE CONFLUENCE OF THE COLORADO 
RIVER IN THE PRE-DAWN HOURS.

THE PEAK FLOW FROM THIS FLOOD IS LESS THAN THAT EXPERIENCED 
YESTERDAY. HOWEVER...STREAM FLOWS ON THE PARIA RIVER AT LEES FERRY 
REMAIN ELEVATED FROM THE PREVIOUS EVENT...THUS EVEN A SMALL RISE MAY 
RESULT IN SUBSTANTIAL FLOODING.

AT THIS TIME...IT IS EXPECTED THAT THE PEAK FLOW WILL ARRIVE AT LEES 
FERRY BETWEEN 200 AM AND 400 AM MST...AND THAT THE RIVER WILL RISE 
ONE TO TWO FEET ABOVE ITS CURRENT LEVEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3700 11191 3700 11174 3686 11156 3684 11160

$$

DB

450 
WGUS75 KFGZ 211259
FFSFGZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
559 AM MST TUE AUG 21 2012

AZC005-211301-
/O.EXP.KFGZ.FF.W.0021.000000T0000Z-120821T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
COCONINO AZ-
559 AM MST TUE AUG 21 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 600 AM MST FOR NORTH
CENTRAL COCONINO COUNTY...

SPECIFICALLY FOR THE FOLLOWING STREAMS AND DRAINAGES...PARIA RIVER 
AND THE CONFLUENCE WITH THE COLORADO RIVER.

AT 500 AM MST...THE FLOOD CREST OR RAPIDLY RISING WALL OF WATER 
PASSED THE AUTOMATED STREAM GAGE ON THE PARIA RIVER NEAR LEES 
FERRY. THE STREAM MAY RISE SEVERAL MORE INCHES AND CREST SOMEWHERE 
ABOVE 6 FEET AND THEN RECEDE THIS MORNING. 

THERE IS NO LONGER ADDITIONAL THREAT OF FLASH FLOODING OTHER THAN 
ELEVATED FLOW ON THE PARIA RIVER AT THE CONFLUENCE WITH THE COLORADO 
RIVER. 

STAY AWAY FROM RAPIDLY FLOWING WATER.

LAT...LON 3700 11191 3700 11174 3686 11156 3684 11160

$$
TC

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 5:45 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Aug 21, 1:07 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Aug 21, 1:16 PM MST	Flash Flood Warning	FGZ	Yavapai	119 min
Aug 21, 1:51 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	24 min
Aug 21, 2:19 PM MST	Special Weather Statement	FGZ		26 min
Aug 21, 2:45 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	30 min
Aug 21, 2:46 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Aug 21, 2:59 PM MST	Severe Thunderstorm Warning	FGZ	Coconino, Navajo	31 min
Aug 21, 3:27 PM MST	Severe Thunderstorm Warning	FGZ	Gila	33 min
Aug 21, 3:29 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Aug 21, 3:37 PM MST	Severe Thunderstorm Warning	FGZ	Gila	23 min
Aug 21, 3:47 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Aug 21, 3:53 PM MST	Flash Flood Warning	FGZ	Gila	4 hr
Aug 21, 4:05 PM MST	Flash Flood Warning	FGZ	Yavapai	3 hr
Aug 21, 4:08 PM MST	Areal Flood Advisory	FGZ	Navajo	3 hr
Aug 21, 4:09 PM MST	Severe Thunderstorm Warning	FGZ	Gila	36 min
Aug 21, 4:54 PM MST	Special Weather Statement	FGZ	Gila	66 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.