Alert archive / Arizona / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 71, NWS Tucson, AZ

August 26, 1999Pima County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 26, 1999, 5:14 PM MST for Pima County, Arizona. It was in force for 31 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 26, 1999, 5:14 PM MST (00:14 UTC)
Expired: Aug 26, 1999, 5:45 PM MST
In force: 31 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 00:14 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 00:00Z, 0.2 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-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: 398 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 2913 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 3 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 270019 RRA
SVRTUS
AZC019-270045-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE TUCSON AZ
514 PM MST THU AUG 26 1999

THE NATIONAL WEATHER SERVICE IN TUCSON HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN PIMA COUNTY IN SOUTHERN ARIZONA
  INCLUDING ORGAN PIPE NATIONAL MONUMENT

* UNTIL 545 PM MST

* AT 513 PM MST...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM 23
  MILES SOUTH OF AJO OR IN THE VICINITY OF ORGAN PIPE NATL MON...
  MOVING SOUTHWEST AT 5 MPH.

ZELL

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Aug 26, 2:30 PM MST, 2 hours 44 minutes earlier.

Area forecast discussion, Aug 26, 2:30 PM MST, 2 hours 44 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
230 PM MST THU AUG 26 1999

SYNOPSIS...HIGH PRESSURE CENTERED NEAR THE FOUR CORNERS REGION WILL
PROVIDE A STEADY STREAM OF MOISTURE INTO THE AREA OVER THE NEXT FEW
DAYS. THIS HIGH WILL STEER REMNANTS OF THE FORMER HURRICANE BRET
ACROSS THE AREA THROUGH THE WEEKEND LEADING TO AN INCREASE IN
THUNDERSTORM ACTIVITY.

DISCUSSION...MOST OF SOUTHEAST ARIZONA THIS AFTERNOON IS IN DOLDRUM
AREA. TO THE NORTH H5 TEMPS AND MOISTURE ARE COLD ENOUGH TO GENERATE
STRONG STORMS. TO THE SOUTH DEEPER MOISTURE FIELD ALLOWS STORMS TO
IGNORE WARM H5 TEMPS IN BRETS CIRCULATION. WE STILL GET SHOWERS AND
WEAK THUNDERSTORMS BUT NOTHING SEEMS TO ORGANIZED AT THIS TIME AND
FOR THE NEXT SEVERAL HOURS AM NOT EXPECTING ANYTHING SIGNIFICANT.
ITS POSSIBLE THAT STORMS DOWN IN MEXICO WILL PROPOGATE NORTHWEST
INTO SOUTHEAST ARIZONA TONIGHT BUT NOT COUNTING ON THAT. TOMORROW
SEEMS TO BE A BETTER DAY...LOW DESERTS STILL HAVE PLENTY OF MOISTURE
AND WE MAY GET A LOW LEVEL WIND FLOW FROM THAT DIRECTION ON
FRIDAY...OR AT LEAST FROM A MORE SOUTHERLY DIRECTION IN RESPONSE TO
THE TROF KICKING OUT TO THE NORTH. WHATEVER THE CASE MODEL POPS ARE
WAY HIGH AND DONT SEE ANY REASON TO IGNORE THIS GIVEN ALL THE
MOISTURE THAT IS AROUND.

.TWC...NONE.

In the hours before

Special weather statement, Aug 26, 1:38 PM MST, 3 hours 36 minutes before

AZZ019-029>035-270500-
SPECIAL WEATHER STATEMENT...SOUTHEAST ARIZONA CONVECTIVE OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1245 PM MST THU AUG 26 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         15         5    W 15
GRAHAM              55          10         15         5    W 15
GREENLEE            60           5         20        10    W 15
TUCSON/ERN PIMA     50          15          5         0   SW 10
TOHONO OODHAM      50          15          5         0   SW 10
SOUTHEAST PINAL     35          10          5         0    W 10
WESTERN PIMA        40          15          0         0   SW 10
SANTA CRUZ          55          15         15         5   SW 10

SYNOPSIS...REMNANTS OF BRET HAVE SPREAD MOISTURE INTO SOUTHEAST
ARIZONA BUT STORM MOTION IS EXPECTED TO BE FAST ENOUGH TO LIMIT
FLASH FLOODING THREAT.
*****************************************************************
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://NIMBO.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, 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, 1:15 PM MST	Flash Flood Warning	TWC	Pima	60 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

Severe Thunderstorm Warnings in Arizona, 1999 Every severe thunderstorm 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.