Alert archive / Nebraska / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 417, NWS Omaha, NE

September 7, 2001Johnson County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Sep 7, 2001, 11:13 AM CDT for Johnson County, Nebraska. It was in force for 32 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: Sep 7, 2001, 11:13 AM CDT (16:13 UTC)
Expired: Sep 7, 2001, 11:45 AM CDT
In force: 32 min
Issued by: NWS Omaha, NE
Area: Whole counties; the outline is the Mesonet’s reconstruction

County Johnson County, NE

The radar

The Omaha radar (KOAX), 103 km from the middle of the area, began a volume at 16:13 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

Topeka, KS (KTOP), launched 12:00Z, 4.2 hours before the alert went out and 164 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: 1545 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 658 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 140 m²/s²
0-3 km storm-relative helicity: 141 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.1

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 Omaha, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 7, 2:25 AM CDT, 8 hours 48 minutes earlier.

Area forecast discussion, Sep 7, 2:25 AM CDT, 8 hours 48 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
225 AM CDT FRI SEP 7 2001

FORECAST CHALLENGES -- PRECIPITATION CHANCES

SYNOPSIS -- LATEST 88D Z MOSAIC INDICATED CONVECTIVE LINE EXTENDING
FROM FSD TO W OF OFK TO GRI MOVING EWD.  ALTHOUGH DEEP LAYERED SHEAR
REMAINS WEAK AHEAD OF THIS LINE, MODERATE INSTABILITY EXISTS (CAPES
AOA 1000-1500 J/KG), SO IT APPEARS SOME SEVERE WEATHER THREAT WILL
CONTINUE FOR THE NEXT FEW HOURS.  EARLY MORNING MOISTURE CHANNEL
IMAGERY DEPICTED A POTENT CLOSED, CIRCULATION OVER NWRN CO, DIVING
SEWD, WITH ANOTHER STRONG SYSTEM ASSOCIATED WITH A +140KT JET OVER
ERN B.C. CANADA.

FORECAST -- ONLY TIME FOR A BRIEF DISCUSSION THIS MORNING WITH THE
ONGOING SEVERE WEATHER.  OVERALL, WE FAVOR A BLEND OF THE ETA AND
AVN HANDLING OF THESE UPPER-LEVEL SYSTEMS FORECAST TO IMPACT THE
CWFA THROUGH THE WEEKEND.  IN THE SHORT TERM, THE SURFACE FRONTAL
BOUNDARY, NEARLY COINCIDENT WITH THE CONVECTIVE LINE, WILL CONTINUE
TO PUSH SEWD TODAY, REACHING THE FAR SERN ZONES BY 08/00Z.  THUS,
SCATTERED PRECIPITATION IS LIKELY TO CONTINUE TODAY ALONG AND
IMMEDIATELY BEHIND FRONTAL BOUNDARY...WITH AN ADDITIONAL AFTERNOON
SEVERE WEATHER THREAT OVER FAR SERN NEB.

ALTHOUGH SURFACE FRONTAL ZONE WILL CONTINUE TO PUSH SOUTH OF THE
AREA TONIGHT THROUGH SATURDAY, THE AFOREMENTIONED MID-LEVEL
DISTURBANCES WILL STEEPEN LAPSE RATES AND GENERATE ENOUGH
LARGE-SCALE ASCENT FOR POST-FRONTAL SHOWER ACTIVITY THROUGH THE DAY
SUNDAY.  CONDITIONS WILL BEGIN TO DRY ON SUNDAY NIGHT AS THE DEEP,
MID-LEVEL TROUGH AXIS BEGINS TO SHIFT E OF THE CWFA.  FOR
TEMPERATURES, THE AVN LOOKS TO BE TOO COOL ON SATURDAY AND WE HAVE
GONE CLOSER TO THE FWC DATA.

IN THE EXTENDED, WE WILL TAKE A QUICK LOOK AT THE NEW MRF WHEN IT
ARRIVES AND MAKE ANY CHANGES IF NECESSARY.

.OMA...NONE.
MEAD

In the hours before

Special weather statement, Sep 7, 5:46 AM CDT, 5 hours 27 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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Special weather statement, Sep 7, 6:05 AM CDT, 5 hours 8 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.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 7, 12:51 AM CDT	Severe Thunderstorm Warning	OAX	Knox	54 min
Sep 7, 1:09 AM CDT	Severe Thunderstorm Warning	OAX	Antelope	46 min
Sep 7, 1:48 AM CDT	Severe Thunderstorm Warning	OAX	Knox, Pierce	42 min
Sep 7, 1:55 AM CDT	Severe Thunderstorm Warning	OAX	Antelope, Boone	35 min
Sep 7, 3:13 AM CDT	Severe Thunderstorm Warning	OAX	Cuming	32 min
Sep 7, 3:18 AM CDT	Severe Thunderstorm Warning	OAX	Colfax	27 min
Sep 7, 3:24 AM CDT	Severe Thunderstorm Warning	OAX	Dodge	36 min
Sep 7, 3:51 AM CDT	Severe Thunderstorm Warning	OAX	Burt, Cuming, Thurston	24 min
Sep 7, 4:43 PM CDT	Severe Thunderstorm Warning	OAX	Jefferson, Saline	32 min
Sep 7, 4:53 PM CDT	Severe Thunderstorm Warning	OAX	Lancaster, Seward	52 min
Sep 7, 5:12 PM CDT	Tornado Warning	OAX	Saline	33 min
Sep 7, 5:31 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Lancaster	59 min
Sep 7, 5:35 PM CDT	Severe Thunderstorm Warning	OAX	Pawnee	40 min
Sep 7, 6:31 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Jefferson	44 min
Sep 7, 6:38 PM CDT	Flash Flood Warning	OAX	Pawnee	6 hr
Sep 7, 6:46 PM CDT	Severe Thunderstorm Warning	OAX	Richardson	44 min
Sep 7, 6:59 PM CDT	Tornado Warning	OAX	Gage	46 min
Sep 7, 6:53 PM CDT	Severe Thunderstorm Warning	OAX	Fremont, Page	52 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2001 Every severe thunderstorm warning in 2001

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.