Alert archive / Colorado / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 126, NWS Denver/Boulder, CO

August 29, 19994 counties in Colorado

NWS Denver/Boulder, CO issued this severe thunderstorm warning at Aug 29, 1999, 3:58 PM MDT for 4 counties in Colorado. It was in force for 30 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 29, 1999, 3:58 PM MDT (21:58 UTC)
Expired: Aug 29, 1999, 4:28 PM MDT
In force: 30 min
Issued by: NWS Denver/Boulder, CO
Area: Whole counties

Counties Adams County, CO, Arapahoe County, CO, Elbert County, CO, Lincoln County, CO

The radar

The Denver radar (KFTG), 55 km from the middle of the area, began a volume at 22:00 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

Denver, CO (KDNR), launched 12:00Z, 10.0 hours before the alert went out and 87 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: 2 J/kg
Mixed-layer CIN: -293 J/kg
Mixed-layer LCL: 1920 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 39 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

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 Denver/Boulder, CO wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 29, 3:11 PM MDT, 47 minutes earlier.

Area forecast discussion, Aug 29, 3:11 PM MDT, 47 minutes before

AREA FORECAST DISCUSSION FOR NORTHEAST AND NORTH CENTRAL COLORADO
NATIONAL WEATHER SERVICE DENVER COLORADO
311 PM MDT SUN AUG 29 1999

CURRENTLY...WATER VAPOR PICTURES SHOWING SOME PRETTY HEALTHY DRYING
HEADING THIS WAY IN THE MID/UPPER LEVELS...AND AN UPPER LEVEL
FEATURE PUSHING OVER THE AREA.  RADAR IS INDICATING SOME POTENTIALLY
SEVERE CONVECTION OVER ZONE 46...AND THEN SOME WIDELY SCATTERED
SHOWERS OVER ZONES 40/41.  WITH THE SYNOPTIC SCALE ENERGY MOVING
EAST FAIRLY QUICKLY AND NO MID/UPPER LEVEL CLOUDINESS
UPSTREAM...WILL GO CLEARS AFTER THIS EVENINGS FESTIVITIES CEASE.

UPPER RIDGE CENTER STAYS SOUTHEAST OF US THROUGH THE FIRST FOUR
PERIODS...WITH AN UPPER TROUGH PROGGED INTO THE GREAT BASIN BY THE
END OF THE LAST PERIOD.  SOUTHWESTERLY FLOW ALOFT WILL BE ON THE
INCREASE MONDAY EVENING INTO THE EXTENDED PERIOD.  THE MOISTURE AND
THE THETA-E GRIDS DO KEEP US FAIRLY WET THROUGH THE PERIOD...BUT NOT
SURE I BELIEVE IT WITH WHAT THE SATELLITE PICTURES ARE INDICATING.
THE GRIDS ALSO SHOW AMPLE POTENTIAL INSTABILITY AROUND...BUT SOME
MID LEVEL WARMING IS INDICATING.  THIS WILL NOT HELP THE CONVECTION
CHANCES HOWEVER THE LAPSE RATES ARE STILL NOT THAT BAD.  WILL KEEP
SOME POPS IN THE AFTERNOONS AND EVENINGS.  THE TEMPERATURE/THICKNESS
GRIDS SHOW A TAD WARMER ON MONDAY...THEN SAME FOR TUESDAY.

IN THE EXTENDED PERIOD...MRF SHOWING UPPER RIDGE GIVING WAY TO
PRETTY LARGE UPPER TROUGH/CLOSED LOW LATE THURSDAY AND FRIDAY.  THE
RUN TO RUN CONSISTENCY HAS BEEN VERY POOR.  ITS ALSO SHOWING THE
MOISTURE CONTINUING.  A LITTLE HARD TO BELIEVE CONSIDERING CURRENT
WATER VAPOR PICTURES...BUT WELL SEE.  WILL KEEP CHANCE GOING NONE
THE LESS.                    RJK

.DEN...NONE.

In the hours before

Special weather statement, Aug 29, 10:10 AM MDT, 5 hours 48 minutes before

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Special weather statement, Aug 29, 10:10 AM MDT, 5 hours 48 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <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.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 29, 2:55 PM MDT	Severe Thunderstorm Warning	BOU	Arapahoe, Elbert, Lincoln, Washington	35 min
Aug 29, 4:49 PM MDT	Tornado Warning	BOU	Washington	31 min
Aug 29, 5:20 PM MDT	Tornado Warning	BOU	Washington	30 min
Aug 29, 5:40 PM MDT	Severe Thunderstorm Warning	BOU	Logan	35 min

Nearby

Severe Thunderstorm Warnings in Colorado, 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.