Alert archive / Arizona / Flash Flood Warnings in 1999

Flash Flood Warning 40, NWS Tucson, AZ

August 27, 1999Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 27, 1999, 1:15 PM MST for Pima County, Arizona. It was in force for 60 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 27, 1999, 1:15 PM MST (20:15 UTC)
Expired: Aug 27, 1999, 2:15 PM MST
In force: 60 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), 21 km from the middle of the area, began a volume at 20:16 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, 8.3 hours before the alert went out and 19 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: 672 J/kg
Mixed-layer CIN: -86 J/kg
Mixed-layer LCL: 1305 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 38 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.

000 
TTAA00 KTWC 272016
FFWTUS
AZC019-272115-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
115 PM MST FRI AUG 27 1999

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN PIMA COUNTY IN ARIZONA

* UNTIL 215 PM MST

* AT 107 PM MST...WEATHER SERVICE DOPPLER RADAR INDICATED VERY HEAVY
  RAIN OVER EAST CENTRAL PIMA COUNTY...OR ABOUT 11 MILES SOUTHEAST OF
  TUCSON.

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR BY
AUTOMOBILE. IF YOUR VEHICLE STALLS, ABANDON IT IMMEDIATELY AND SEEK
HIGHER GROUND.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEAhTHER SERVICE FORECAST OFFICE IN
TUCSON.

LAT...LON 3213 11096 3173 11089 3183 11051 3230 11064

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 27, 9:15 AM MST, 4 hours earlier.

Area forecast discussion, Aug 27, 9:15 AM MST, 4 hours before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
915 AM MST FRI AUG 27 1999

SYNOPSIS...EAST TO SOUTHEST WINDS ALOFT OVER SOUTHERN ARIZONA HAS
BROUGHT PLENTY OF MOISTURE TO FEED THUNDERSTORMS. EARLY MORNING
THUNDERSTORMS WEST OF TUCSON HAVE WEAKENED BY MID MORNING BUT WILL
LIKELY DEVELOP AGAIN DURING THE AFTERNOON HOURS. LOW LEVEL WINDS
WILL REMAIN LIGHT THROUGH THE WEEKEND FOR A CONTINUED THUNDERSTORM
THREAT EACH AFTERNOON AND EVENING.

DISCUSSION...COPIOUS MOISTURE IN SOUTHERN ARIZONA THIS MORNING. 1.8
INCH PRECIPITABLE WATER IN TUCSON WITH ABOUT THE SAME THROUGH THE
LOW DESERT TO THE WEST. SPECIAL 18Z TUCSON SOUNDING TODAY SHOULD
HELP TO SHOW HOW MUCH OF THIS MOISTURE REMAINS WITH THE MORNING
THUNDERSTORM COMPLEX NOW WEST OF TUCSON. ALSO...MODELS SHOW SOME
WARMING ALOFT ON OUR DOORSTEP TO OUR EAST. HOPEFULLY 18Z SOUNDING
WILL SHOW IF THE AIRMASS IS WARMING ALOFT. AND FINALLY...MID LEVEL
WINDS THIS MORNING WERE PUSHING THE STORMS WEST NORTHWEST AT A GOOD
CLIP. MODELS INDICAT WINDS WILL WEAKEN THUS SLOWING THE STORM MOTION
AND ALLOWING HEAVY RAIN FROM STORMS THAT DEVELOP. CLOUD COVER OVER
SOUTHERN ARIZONA SLOWING THE WARMING THIS MORNING.

REMAINS OF BRET EVIDENT IN THE COPIOUS MOISTURE AND ALSO IN THE
INVERTED TROF NOW OVER SOUTHEAST ARIZONA. ALL THIS SHOULD CONTINUE
ITS SLOW NORTHWEST MOVEMENT NEXT 24 HOURS. THINK BEST THREAT FOR
REALLY ACTIVE WEATHER TODAY IS WESTERN SECTIONS. OF COURSE THIS
THINKING MAY CHANGE WITH RECEIPT OF 18Z SOUNDING LATER THIS MORNING.

PRF

.TWC...NONE.

In the hours before

Special weather statement, Aug 27, 12:45 PM MST, 30 minutes before

AZZ019-029>035-280500-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1245 PM MST FRI AUG 27 1999...THIS PRODUCT IS NOT UPDATED

                          *CONDITIONAL*   *CONDITIONAL*
COUNTY            AREAL    PROBABILITY  RAIN GREATER THAN   STORM
                 COVERAGE   OF SEVERE     1.00      2.00    MOTION

COCHISE             55          10         65        30     W 10
GRAHAM              60          10         75        40     NW 10
GREENLEE            60          10         75        40     NW 10
TUCSON/ERN PIMA     60          20         80        40     W 10
TOHONO OODHAM      55          20         80        40     W 10
SOUTHEAST PINAL     55          20         80        40     W 10
WESTERN PIMA        40          20         80        40     W 10
SANTA CRUZ          60          20         80        40     W 10

SYNOPSIS...THE ATMOSPHERE IS EXTREMELY MOIST AND UNSTABLE THIS
AFTERNOON AND EVENING. HEAVY RAIN THE MAIN CONCERN WITH SEVERE
POSSIBLE. ACTIVITY WILL LINGER IN THE LOWER DESERTS WELL INTO
THE EVENING HOURS.
*****************************************************************
KEY...
AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
                 THUNDERSTORMS
PROB OF SEVERE - THE PROBABILITY THAT AN INDIVIDUAL STORM WILL
                 REACH SEVERE LEVELS (DAMAGING WIND AND/OR
                 LARGE HAIL)
RAIN GRTR THAN - THE PROBABILITY THAT AN INDIVIDUAL STORM WILL
                 PRODUCE RAIN EXCEEDING 1 INCH OR 2 INCHES IN
                 ANY LOCATION
STORM MOTION   - GENERAL DIRECTION TO WHICH THE STORMS WILL
                 LIKELY MOVE AND SPEED IN MPH

NOTE...
VALID TIME IS FROM 12:45 PM TO 12 MIDNIGHT OF THE DAY OF ISSUANCE.
THIS PRODUCT IS NOT TO BE USED IN PLACE OF SEVERE THUNDERSTORM OR
FLASH FLOOD WARNINGS OR WATCHES. THIS PRODUCT IS ONLY USED FOR
OUTLOOK PURPOSES. CORRESPONDING GRAPHICS MAY BE FOUND ON THE NWS
TUCSON INTERNET PAGE AT
HTTP://WWW.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML

END/

Special weather statement, Aug 27, 12:45 PM MST, 30 minutes before

AZZ019-029>035-280500-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1245 PM MST FRI AUG 27 1999...THIS PRODUCT IS NOT UPDATED

                          *CONDITIONAL*   *CONDITIONAL*
COUNTY            AREAL    PROBABILITY  RAIN GREATER THAN   STORM
                 COVERAGE   OF SEVERE     1.00      2.00    MOTION

COCHISE             55          10         65        30     W 10
GRAHAM              60          10         75        40     NW 10
GREENLEE            60          10         75        40     NW 10
TUCSON/ERN PIMA     60          20         80        40     W 10
TOHONO OODHAM      55          20         80        40     W 10
SOUTHEAST PINAL     55          20         80        40     W 10
WESTERN PIMA        40          20         80        40     W 10
SANTA CRUZ          60          20         80        40     W 10

SYNOPSIS...THE ATMOSPHERE IS EXTREMELY MOIST AND UNSTABLE THIS
AFTERNOON AND EVENING. HEAVY RAIN THE MAIN CONCERN WITH SEVERE
POSSIBLE. ACTIVITY WILL LINGER IN THE LOWER DESERTS WELL INTO
THE EVENING HOURS.
*****************************************************************
KEY...
AREAL COVERAGE - PERCENT OF COUNTY OR AREA THAT WILL EXPERIENCE
                 THUNDERSTORMS
PROB OF SEVERE - THE PROBABILITY THAT AN INDIVIDUAL STORM WILL
                 REACH SEVERE LEVELS (DAMAGING WIND AND/OR
                 LARGE HAIL)
RAIN GRTR THAN - THE PROBABILITY THAT AN INDIVIDUAL STORM WILL
                 PRODUCE RAIN EXCEEDING 1 INCH OR 2 INCHES IN
                 ANY LOCATION
STORM MOTION   - GENERAL DIRECTION TO WHICH THE STORMS WILL
                 LIKELY MOVE AND SPEED IN MPH

NOTE...
VALID TIME IS FROM 12:45 PM TO 12 MIDNIGHT OF THE DAY OF ISSUANCE.
THIS PRODUCT IS NOT TO BE USED IN PLACE OF SEVERE THUNDERSTORM OR
FLASH FLOOD WARNINGS OR WATCHES. THIS PRODUCT IS ONLY USED FOR
OUTLOOK PURPOSES. CORRESPONDING GRAPHICS MAY BE FOUND ON THE NWS
TUCSON INTERNET PAGE AT
HTTP://WWW.WRH.NOAA.GOV/TUCSON/SWO/SWO.SHTML

END/

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 26, 5:14 PM MST	Severe Thunderstorm Warning	TWC	Pima	31 min
Aug 26, 7:21 PM MST	Severe Thunderstorm Warning	TWC	Pima, Santa Cruz	49 min
Aug 26, 8:08 PM MST	Severe Thunderstorm Warning	TWC	Santa Cruz	32 min
Aug 26, 8:49 PM MST	Flash Flood Warning	TWC	Pima	101 min
Aug 27, 12:40 PM MST	Flash Flood Warning	TWC	Pima	100 min
Aug 27, 1:11 PM MST	Severe Thunderstorm Warning	TWC	Pima	44 min
Aug 27, 1:55 PM MST	Severe Thunderstorm Warning	TWC	Pima	65 min
Aug 27, 3:00 PM MST	Severe Thunderstorm Warning	TWC	Pima, Pinal	45 min
Aug 27, 3:50 PM MST	Severe Thunderstorm Warning	TWC	Pinal	45 min

Nearby

Flash Flood Warnings in Arizona, 1999 Every flash flood warning in 1999

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.