Alert archive / Arizona / Flash Flood Warnings in 2001

Flash Flood Warning 44, NWS Tucson, AZ

August 30, 2001Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 30, 2001, 4:45 PM MST for Pima County, Arizona. It was in force for 75 min. 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 30, 2001, 4:45 PM MST (23:45 UTC)
Expired: Aug 30, 2001, 6:00 PM MST
In force: 75 min
Issued by: NWS Tucson, AZ
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Pima County, AZ

The radar

The Tucson radar (KEMX), 89 km from the middle of the area, began a volume at 23:46 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 12:00Z, 11.8 hours before the alert went out and 54 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: 815 J/kg
Mixed-layer CIN: -112 J/kg
Mixed-layer LCL: 1380 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

000 
WGUS55 KTWC 302345
FFWTUS
FFWTUS
AZC019-310200-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
445 PM MST THU AUG 30 2001

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL PIMA COUNTY IN ARIZONA

* UNTIL 700 PM MST

* AT 431 PM MST...AMATEUR WEATHER SPOTTERS REPORTED A FLASH FLOOD    
  OVER THE FAR WEST SIDE OF MARANA. 

THIS IS A PARTICULARLY DANGEROUS FLASH FLOOD SITUATION A SPOTTER ON 
THE FAR WEST SIDE OF MARANA REPORTED OVER 4 INCHES OF RAIN IN ABOUT 
AN HOUR. RADAR ALSO INDICATES THAT OVER 4 INCHES OF RAIN HAS FALLEN 
ON THE MOUNTAINS SOUTH OF SILVERBELL. 

ALTHOUGH THE HEAVY RAIN HAS ENDED...MAJOR FLASH FLOODING IS LIKELY 
OVER NORTHERN SECTIONS OF THE AVRA VALLEY AS THIS WATER RUNS OFF 
INTO TRIBUTARIES OF THE BLANCO AND LOS ROBLES WASHES. MANY ROADS IN 
THIS AREA ARE LIKELY TO FLOOD. 

THIS WARNING EXTENDS THE PREVIOUS FLASH FLOOD WARNING FOR NORTH 
CENTRAL PIMA COUNTY.

LAT...LON 3214 11158 3213 11128 3251 11127 3251 11157

PYTLAK

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 Tucson, AZ wrote its last area forecast discussion before this flash flood warning went out at Aug 30, 2:30 PM MST, 2 hours 15 minutes earlier.

Area forecast discussion, Aug 30, 2:30 PM MST, 2 hours 15 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST THU AUG 30 2001

.SYNOPSIS...MONSOON MOISTURE WILL GENERATE AFTERNOON AND EVENING
THUNDERSTORMS...WITH SOME HEAVY RAIN POSSIBLE TONIGHT. THEN THE RAIN
CHANCES WILL BE FROM TUCSON AND EAST FRIDAY AND SATURDAY.

.DISCUSSION...ANOTHER STRONG SURGE OF MOISTURE THIS MORNING WITH
PRECIPITABLE WATER VALUES WELL OVER AN INCH. STORMS NOW DEVELOPING
OVER MOUNTAINS EXPECTED TO DEVELOP IN VALLEYS IN AFTERNOON
HOURS...WITH HEAVY RAIN AND GUSTY WINDS POSSIBLE. SOME AREAS WILL
GET MORE THAN 15 DROPS OF RAIN.

MODELS STILL INSISTING ON DRYING...WILL TAKE US TO LOW PACKAGE FOR
TOMORROW...NOT THAT I BELIEVE THE DRYING BUT GOING MORE WITH UP/DOWN
DAY SCENARIO. WILL KEEP IT DOWN AGAIN SATURDAY AFTERNOON BUT SHOULD
SEE SOME INCREASE SATURDAY EVENING.

REMNANTS OF FLOSSIE MAY SPRUCE THINGS UP SUNDAY...DIFFICULT TO TELL
WHAT EXACT IMPACT WILL BE BUT HAVE PUT ALL OF THE AREA IN CHANCE
WORDING. OTHERWISE THE EXTENDED IS STANDARD MONSOON PACKAGE.

.TWC...NONE.

In the hours before

Special weather statement, Aug 30, 11:55 AM MST, 4 hours 50 minutes before

AZZ019-029>035-310700-

SOUTHEAST ARIZONA HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1155 AM MST THU AUG 30 2001

.SYNOPSIS...THE COMBINATION OF A MOIST ATMOSPHERE...DAYTIME HEATING
AND SOME WEAK VERTICAL MOTION OVER THE AREA...WILL LEAD TO
THUNDERSTORM ACTIVITY LATER THIS AFTERNOON AND EVENING...ESPECIALLY
FROM TUCSON EAST.

.DISCUSSION...LOW LEVEL MOISTURE CONTINUES TO STREAM NORTHWARD OFF
THE GULF OF CALIFORNIA AND FROM NORTHERN MEXICO. DEWPOINTS HAVE
RISEN INTO THE LOWER 60S...WITH PRECIPITABLE WATERS OF 1 TO 1.4
INCHES ACROSS ALL OF SOUTHERN ARIZONA. A JET STREAK ALSO EXTENDS
FROM SOUTHERN CALIFORNIA...ACROSS SOUTHERN ARIZONA AND INTO WEST
TEXAS. THIS WILL PROVIDE SOME UPPER LEVEL DYNAMIC SUPPORT FOR STORM
DEVELOPMENT. MODERATE TO TOWERING CUMULUS CLOUDS ARE ALREADY FORMING
AND UNLIKE YESTERDAY ARE NOT CONFINED TO JUST THE HIGHER TERRAIN.
TEMPERATURES IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE REMAIN
COOL...WITH LITTLE IF ANY CAPPING INVERSION. STORMS THAT DEVELOP
LATER THIS AFTERNOON AND EVENING WILL HAVE THE POTENTIAL FOR STRONG
WINDS AND FLASH FLOODING. THE RISK OF SEVERE THUNDERSTORMS AND FLASH
FLOODING INCREASES TO THE SOUTH AND EAST OF TUCSON METRO AREA. WILL
GO NEAR CLIMATOLOGY FOR THE RISK OF SEVERE STORMS AND FLASH FLOODING
WEST OF TUCSON AND ABOVE CLIMATOLOGY FROM TUCSON EAST.

STORM MOTION WILL BE SOUTHEAST AT 10 TO 15 MPH.

ZELL

Local storm report, Aug 30, 4:28 PM MST, 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON ARIZONA
0428 PM MST THU AUG 30 2001

TIME (MST) .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0420 PM    5W MARANA                 AZ   FLASH FLOOD
08/30/01   PIMA                           2.25 INCHES OF RAIN IN ONE HOUR.
                                          TRIBUTARY OF BLANCO WASH FLOODING
                                          AND RISING RAPIDLY

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 3:26 PM MST	Flash Flood Warning	TWC	Pima	34 min
Aug 30, 4:34 PM MST	Flash Flood Warning	TWC	Santa Cruz	26 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; radar from the NEXRAD Level II archive.