Alert archive / Arizona / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 77, NWS Tucson, AZ

August 27, 1999Pinal County, Arizona

NWS Tucson, AZ issued this severe thunderstorm warning at Aug 27, 1999, 3:50 PM MST for Pinal County, Arizona. It was in force for 45 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, 3:50 PM MST (22:50 UTC)
Expired: Aug 27, 1999, 4:35 PM MST
In force: 45 min
Issued by: NWS Tucson, AZ
Area: Whole counties

County Pinal County, AZ

The nearest sounding before it

Phoenix, AZ (KPSR), launched 12:00Z, 10.8 hours before the alert went out and 82 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: 746 J/kg
Mixed-layer CIN: -174 J/kg
Mixed-layer LCL: 2000 m above ground
0-6 km bulk shear: 3 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: -24 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 27, 2:15 PM MST, 1 hour 35 minutes earlier.

Area forecast discussion, Aug 27, 2:15 PM MST, 1 hour 35 minutes before

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In the hours before

Special weather statement, Aug 27, 12:45 PM MST, 3 hours 5 minutes before

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  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
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        Please try again in a few minutes.
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Special weather statement, Aug 27, 12:45 PM MST, 3 hours 5 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, 1:15 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

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.