Alert archive / Arizona / Flash Flood Warnings in 2001

Flash Flood Warning 12, NWS Flagstaff, AZ

August 20, 2001Apache County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 20, 2001, 5:12 PM MST for Apache County, Arizona. It was in force for . No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued: Aug 20, 2001, 5:12 PM MST (00:12 UTC)
Expired: Aug 20, 2001, 5:00 PM MST
In force
Issued by: NWS Flagstaff, AZ
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Apache County, AZ

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 00:00Z, 0.2 hours before the alert went out and 248 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: 734 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 1653 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 47 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

000 
WGUS55 KFGZ 210014
FFWFLG
AZC001-210100-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
512 PM MST MON AUG 20 2001

THE NATIONAL WEATHER SERVICE HAS EXTENDED THE 

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN APACHE COUNTY IN ARIZONA
 
* UNTIL 600 PM MST

* AT 510 PM MST...WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF  
  THUNDERSTORMS PRODUCING HEAVY RAIN WILL PASS OVER AREAS            
  SOUTHEAST OF LYMAN LAKE STATE PARK. 

* FLASH FLOODING WILL AFFECT LOWER COYOTE CREEK FROM OLD HIGHWAY 60  
  TO LYMAN LAKE...AND THE SMALLER CREEKS THAT RUN FROM LOCKHART ROAD 
  WESTWARD INTO LYMAN LAKE. DOPPLER RADAR ESTIMATES STORM TOTAL      
  RAINFALL OVER THIS AREA FROM THUNDERSTORMS EARLIER THIS AFTERNOON  
  IS BETWEEN 4 AND 6 INCHES. AN ADDITIONAL ONE TO TWO INCHES OF RAIN  
  IS LIKELY FROM THE NEXT LINE OF THUNDERSTORMS. 

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...NORMALLY DRY WASHES AND
ARROYOS...AS WELL AS FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.  
DO NOT ATTEMPT TO CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN 
DEPTH BY FOOT OR BY AUTOMOBILE. 

TO REPORT FLASH FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY 
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

LAT...LON 3437 10942 3424 10927 3438 10910 3447 10925

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Flagstaff, AZ wrote its last area forecast discussion before this flash flood warning went out at Aug 20, 3:45 PM MST, 1 hour 27 minutes earlier.

Area forecast discussion, Aug 20, 3:45 PM MST, 1 hour 27 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
345 PM MST MON AUG 20 2001

.SYNOPSIS...AN AREA OF HIGH PRESSURE OVER THE SOUTHWEST WILL
CONTINUE TO MOVE EASTWARD TODAY. AS A RESULT...SOUTHERLY FLOW ALOFT
WILL DEVELOP AND BRING AN INCREASE IN MONSOONAL MOISTURE TO MUCH OF
THE STATE. A SERIES OF UPPER LEVEL DISTURBANCES EMBEDDED IN THE FLOW
WILL KEEP THE ATMOSPHERE UNSTABLE. LOOK FOR THUNDERSTORMS TO DEVELOP
ONCE AGAIN TODAY AND TO CONTINUE INTO TONIGHT. BY WEDNESDAY...A
WESTERLY FLOW ALOFT WILL BRING DRIER AND WARMER WEATHER TO THE STATE
AND WILL CONTINUE INTO THE WEEKEND.

.DISCUSSION...HIGH PRESSURE CONTINUES TO MOVE TO THE EAST THIS
MORNING ALLOWING A DEEP SOUTHERLY FLOW TO DEVELOP OVER MUCH OF
ARIZONA. A S/W TROUGH IS EXITING THE STATE INTO UTAH THIS MORNING
AND CONVECTION CONTINUES WITH THIS FEATURE. ANOTHER S/W TROUGH
REMAINS TO THE SOUTHWEST OF ARIZONA THIS MORNING. MODELS SHOW
DIFFERENT DETAILS BUT ARE IN AGREEMENT THAT THIS FEATURE WILL MOVE
ACROSS THE STATE TODAY. WITH DEEP MOISTURE IN PLACE AND MODERATE
DYNAMICS WITH THIS S/W TROUGH...EXPECT ANOTHER ROUND OF CONVECTION
TO DEVELOP DURING THE DAY TODAY AND CONTINUE INTO THE NIGHT. HAVE
CHOSEN TO MAINTAIN HIGHER POPS INTO THE NIGHT SINCE IT APPEARS THAT
THE CONVECTION WILL CONTINUE WELL AFTER SUNSET.

ON TUESDAY...A STRONG S/W TROUGH APPROACHES THE AREA FROM THE WEST.
DIVQ FIELDS FROM BOTH AVN AND ETA INDICATE THAT THERE IS A STRONG
FORCING COUPLET ASSOCIATED WITH THIS WAVE. ZERO LINE OF THE COUPLET
MOVES ACROSS ARIZONA LATE IN THE AFTERNOON AND INTO THE EVENING
HOURS. MODELS ATTEMPT TO DRY OUT THE ATMOSPHERE IN ADVANCE OF THIS
SYSTEM BUT BELIEVE THIS IS OVERDONE AND ADEQUATE MOISTURE WILL BE IN
PLACE WHEN THE DYNAMICS ARRIVE. SHEAR PROFILES SHOULD INCREASE
SUBSTANTIALLY WITH THE APPROACH OF THE WAVE AND WILL NEED TO MONITOR
THE SITUATION FOR THE POSSIBILITY OF STRONG TO SEVERE THUNDERSTORMS
DEVELOPING ACROSS THE CWFA.

.EXTENDED...STRONG MID-LATITUDE TROUGH WILL MOVE ACROSS THE REGION
ON WEDNESDAY BRINGING MUCH DRIER CONDITIONS. EXPECT MOSTLY SUNNY
DAYS AND CLEAR NIGHTS THROUGH THE EXTENDED. THE ONLY EXCEPTION WILL
BE THE FAR EASTERN ZONES WHERE PARTLY CLOUDY SKIES AND A CHANCE OF
SHOWERS LINGER THROUGH WEDNESDAY BEFORE CLEARING.  DB

.FGZ...NONE.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 5:31 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	29 min
Aug 20, 6:08 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	37 min
Aug 20, 8:27 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	33 min
Aug 20, 8:27 PM MST	Severe Thunderstorm Warning	FGZ	Apache	33 min
Aug 21, 12:13 PM MST	Severe Thunderstorm Warning	FGZ	Navajo	32 min
Aug 21, 1:30 PM MST	Severe Thunderstorm Warning	FGZ	Apache	30 min

Nearby

Flash Flood Warnings in Arizona, 2001 Every flash flood warning in 2001

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.