Alert archive / Arizona / Flash Flood Warnings in 1999

Flash Flood Warning 39, NWS Tucson, AZ

August 27, 1999Pima County, Arizona

NWS Tucson, AZ issued this flash flood warning at Aug 27, 1999, 12:40 PM MST for Pima County, Arizona. It was in force for 100 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 27, 1999, 12:40 PM MST (19:40 UTC)
Expired
Aug 27, 1999, 2:20 PM MST
In force
100 min
Issued by
NWS Tucson, AZ
Area
Whole counties

County Pima County, AZ

The radar

The Tucson radar (KEMX), 112 km from the middle of the area, began a volume at 19:42 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, 7.7 hours before the alert went out and 84 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-pSkew-T log-p diagram, Tuscon, AZ at 12:00Z on 1999-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 672 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tuscon, AZ at 12:00Z on 1999-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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 KTUS 271941
FFWTUS
AZC019-272120-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
1240 PM MST FRI AUG 27 1999

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN PIMA COUNTY IN SOUTHERN ARIZONA
  INCLUDING ORO VALLEY AND CATALINA STATE PARK

* UNTIL 220 PM MST

* AT 1240 PM... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  THUNDERSTORM WITH VERY HEAVY RAIN 2 MILES EAST OF ORO VALLEY...
  NEARLY STATIONARY.

* EXPECT RAINFALL AMOUNTS IN EXCESS OF 2 INCHES WITH THIS STORM.
  REDEVELOPMENT IS POSSIBLE IN THIS AREA INTO THE EARLY AFTERNOON.
  A FLASH FLOOD WARNING MEANS FLOODING IS IMMINENT.

WJM

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, 3 hours 25 minutes earlier.

Area forecast discussion, Aug 27, 9:15 AM MST, 3 hours 25 minutes 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.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 26, 5:14 PM MSTSevere Thunderstorm WarningTWCPima31 min
Aug 26, 7:21 PM MSTSevere Thunderstorm WarningTWCPima, Santa Cruz49 min
Aug 26, 8:08 PM MSTSevere Thunderstorm WarningTWCSanta Cruz32 min
Aug 26, 8:49 PM MSTFlash Flood WarningTWCPima101 min
Aug 27, 1:11 PM MSTSevere Thunderstorm WarningTWCPima44 min
Aug 27, 1:15 PM MSTFlash Flood WarningTWCPima60 min
Aug 27, 1:55 PM MSTSevere Thunderstorm WarningTWCPima65 min
Aug 27, 3:00 PM MSTSevere Thunderstorm WarningTWCPima, Pinal45 min
Aug 27, 3:50 PM MSTSevere Thunderstorm WarningTWCPinal45 min

Nearby

Flash Flood Warnings in Arizona, 1999Every 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.