Alert archive / Nebraska / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 232, NWS Omaha, NE

September 18, 2015Cass County, Nemaha County, Otoe County, Nebraska; Fremont County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Sep 18, 2015, 9:36 AM CDT for Cass County, Nemaha County, Otoe County, Nebraska; Fremont County, Iowa. It was in force for 24 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 18, 2015, 9:36 AM CDT (14:36 UTC)
Expired
Sep 18, 2015, 10:00 AM CDT
In force
24 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

Counties Fremont County, IA, Cass County, NE, Nemaha County, NE, Otoe County, NE

The radar

The Omaha radar (KOAX), 81 km from the middle of the area, began a volume at 14:39 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

Omaha, NE (KOAX), launched 12:00Z, 2.6 hours before the alert went out and 81 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, Omaha, NE at 12:00Z on 2015-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2015-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 91 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1301 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
91 m²/s²
0-3 km storm-relative helicity
227 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

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 18, 6:23 AM CDT, 3 hours 13 minutes earlier.

Area forecast discussion, Sep 18, 6:23 AM CDT, 3 hours 13 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
623 AM CDT FRI SEP 18 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 335 AM CDT FRI SEP 18 2015

THE PRIMARY FORECAST CONCERNS ARE PCPN CHANCES/COVERAGE TODAY INTO
THIS EVENING...POTENTIAL FOR LOW CLOUDS AND OR PATCHY FOG TONIGHT
AND TEMPERATURES THE NEXT FEW DAYS.

MAIN FEATURES FROM UPPER LEVEL CHARTS LAST EVENING INCLUDED THE
FOLLOWING. A JET MAX OF 80-90 KNOTS AT 300 MB WAS OVER WY AND CO
LIFTING NORTHEAST. BEST 12 HOUR HEIGHT FALLS AT 500 MB WERE OVER
THE NRN PLAINS AND LIFTING INTO CANADA...BUT THE MAIN TROUGH AXIS
WAS STILL BACK OVER THE ROCKIES. THERMAL RIDGE AT 700 MB HAD
FLATTENED A BIT...AND EXTENDED FROM SRN NM INTO CNTRL MO. 850 MB
SHOWED HIGH PRES OVER THE DKTS AND N WINDS OVER THE CNTRL PLAINS
WITH CDFNT CURVING FROM WRN WI INTO NERN KS THEN BACK INTO ERN CO.
SFC ANLYS AT 08Z SHOWED TEMPERATURES IN THE 50S ACROSS OUR NRN
ZONES AND UPPER 60S/LOWER 70S NEAR THE KS AND MO BORDERS.

SHORT RANGE MODELS ARE IN FAIRLY GOOD AGREEMENT SHOWING PCPN
COVERAGE INCREASING THIS MORNING. PCPN CHANCES ARE HIGHEST ACROSS
OUR ERN AND SRN COUNTIES INTO MID AFTN. WILL MENTION AT LEAST
ISOLD TSTMS EVEN INTO PARTS OF NERN NE WITH ELEVATED INSTABILITY
MUCH OF THE DAY. USED SPC SREF MU CAPE OF 500 J/KG OR MORE AND
FCST SOUNDINGS TO HELP DETERMINE AREA WITH THUNDER POTENTIAL.
RECENT EXPERIMENTAL HRRR RUNS SEEM REASONABLE WITH PCPN COVERAGE
AND TIMING. WILL STAY FAIRLY CLOSE TO MOS GUIDANCE FOR HIGHS
TODAY...GENERALLY MID OR UPPER 60S...BUT SOME LOWER 70S PSBL IN
THE S. MAIN AREA OF SHOWERS WILL BE MOVING EAST OUT OF OUR AREA
EARLY THIS EVENING...BUT AN AREA OF LIGHT PCPN COULD MOVE OUT OF
CNTRL NE/CNTRL SD INTO PARTS OF NERN NE BEFORE ENDING EARLY THIS
EVENING. QUESTION THEN BECOMES...HOW MUCH CLEARING WILL OCCUR.
PRESSURE GRADIENT REMAINS MODEST...SO FOG POTENTIAL DOES NOT
APPEAR OVERLY HIGH. BUT...WE MAY SEE SOME STRATUS. NAM IS THE
MOST AGGRESSIVE WITH LOW CLOUDS TONIGHT. KEPT SOME CLOUDS IN...
BUT DID NOT COMPLETELY BUY INTO THE NAM OUTPUT AT THIS POINT.

SATURDAY THROUGH SUNDAY SHOULD BE DRY...WITH HIGHS SATURDAY MAINLY
IN THE UPPER 60S AND HIGHS SUNDAY IN THE 70S.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 AM CDT FRI SEP 18 2015

TEMPERATURES SHOULD SLOWLY MODERATE THROUGH MID WEEK...THEN DROP
OFF A BIT TOWARD THURSDAY/FRIDAY. A MID LEVEL RIDGE WILL BUILD
EAST FROM THE ROCKIES...THEN EXTEND FROM MEXICO TOWARD THE GREAT
LAKES REGION BY THURSDAY. THERE WILL BE SOME LOW CHANCES FOR
SHOWERS AND THUNDERSTORMS...MAINLY FROM MONDAY NIGHT INTO TUESDAY
THEN WEDNESDAY NIGHT INTO THURSDAY NIGHT.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 614 AM CDT FRI SEP 18 2015

RA WILL BE ON THE INCREASE THIS MRNG FOR THE KOMA/KLNK TERMINALS.
THE RA WILL LIKELY STAY TO THE NORTHWEST AND SOUTH OF THE KOFK TAF
SITE...BUT WILL INCLUDE A VC MENTION. WILL INCLUDE A MENTION OF A
COUPLE HOURS OF THUNDER IN BOTH KLNK AND KOMA AS THE BEST FORCING
MOVES THROUGH THIS MRNG. WE MAY SEE SOME MVFR VISBY IN THE
TSRA...BUT OTHERWISE VFR CONDITIONS ARE EXPECTED TODAY WITH A BKN-
OVC MID LEVEL CLOUD DECK. THE RA WILL MOV OUT BY MID AFTN WITH
SOME DECREASE IN CLOUDS THIS EVENING. SOME UNCERTAINTY IN HOW
CLEAR SKIES WILL BECOME OVERNIGHT SO WILL LEAVE IN A SCT DECK FOR
NOW. NORTHEAST WINDS THIS MRNG WILL BECOME NORTHWEST THIS AFTN AS
THE STORM SYSTEM PASSES TO OUR EAST.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.

&&

SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...BOUSTEAD
Hazardous weather outlook, Sep 18, 4:10 AM CDT, 5 hours 26 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
410 AM CDT FRI SEP 18 2015

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-182315-
MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-
PAGE-KNOX-CEDAR-THURSTON-ANTELOPE-PIERCE-WAYNE-BOONE-MADISON-
STANTON-CUMING-BURT-PLATTE-COLFAX-DODGE-WASHINGTON-BUTLER-
SAUNDERS-DOUGLAS-SARPY-SEWARD-LANCASTER-CASS-OTOE-SALINE-
JEFFERSON-GAGE-JOHNSON-NEMAHA-PAWNEE-RICHARDSON-
410 AM CDT FRI SEP 18 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST
IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA...NORTHEAST
NEBRASKA AND SOUTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS WILL BE POSSIBLE OVER MOST OF THE AREA TODAY. THE
CHANCES ARE HIGHEST GENERALLY ALONG AND SOUTH OF A LINE FROM
AROUND COLUMBUS NEBRASKA TO HARLAN IOWA. STORMS NEAR THE KANSAS
AND MISSOURI BORDERS COULD APPROACH SEVERE LIMITS AND PRODUCE
LOCALLY HEAVY RAIN.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS AT LEAST A SMALL CHANCE OF THUNDERSTORMS FOR PARTS OF
EASTERN NEBRASKA AND SOUTHWEST IOWA FROM MONDAY NIGHT THROUGH
THURSDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED TO BE NEEDED TODAY OR TONIGHT.

In the hours before

Special weather statement, Sep 18, 8:51 AM CDT, 45 minutes before
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Local storm report, Sep 18, 8:54 AM CDT, 42 minutes before
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Special weather statement, Sep 18, 9:03 AM CDT, 33 minutes before
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<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 7:07 PM CDTSpecial Weather StatementOAXRichardson38 min
Sep 17, 7:21 PM CDTSpecial Weather StatementOAXNemaha24 min
Sep 17, 7:39 PM CDTSpecial Weather StatementOAXRichardson21 min
Sep 18, 8:51 AM CDTSpecial Weather StatementOAXButler24 min
Sep 18, 9:03 AM CDTSpecial Weather StatementOAXLancaster27 min
Sep 18, 9:11 AM CDTSevere Thunderstorm WarningOAXGage, Lancaster, Otoe34 min
Sep 18, 9:15 AM CDTSevere Thunderstorm WarningOAXJohnson, Otoe30 min
Sep 18, 9:45 AM CDTSpecial Weather StatementOAXLancaster45 min
Sep 18, 9:47 AM CDTSpecial Weather StatementOAXDouglas, Washington43 min
Sep 18, 9:53 AM CDTSevere Thunderstorm WarningOAXOtoe37 min
Sep 18, 9:56 AM CDTSevere Thunderstorm WarningOAXButler, Lancaster, Saunders, Seward34 min
Sep 18, 10:24 AM CDTSpecial Weather StatementOAXLancaster, Seward51 min
Sep 18, 10:31 AM CDTSevere Thunderstorm WarningOAXLancaster, Seward29 min
Sep 18, 10:38 AM CDTSevere Thunderstorm WarningOAXButler, Seward37 min
Sep 18, 10:56 AM CDTSevere Thunderstorm WarningOAXCass, Lancaster, Sarpy, Saunders34 min
Sep 18, 11:20 AM CDTSpecial Weather StatementOAXSaunders40 min
Sep 18, 11:23 AM CDTSevere Thunderstorm WarningOAXCass, Sarpy26 min
Sep 18, 11:45 AM CDTSpecial Weather StatementOAXCass30 min
Sep 18, 12:01 PM CDTSpecial Weather StatementOAXCass, Sarpy44 min
Sep 18, 10:16 AM CDTSpecial Weather StatementOAXHarrison, Pottawattamie29 min
Sep 18, 11:48 AM CDTSpecial Weather StatementOAXMills27 min

Nearby

Severe Thunderstorm Warnings in Nebraska, 2015Severe Thunderstorm Warnings in Iowa, 2015Every severe thunderstorm warning in 2015

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.