Alert archive / Nebraska / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 257, NWS Omaha, NE

July 24, 2011Jefferson County, Nebraska

NWS Omaha, NE issued this severe thunderstorm warning at Jul 24, 2011, 7:15 PM CDT for Jefferson County, Nebraska. It was in force for 15 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: Jul 24, 2011, 7:15 PM CDT (00:15 UTC)
Expired: Jul 24, 2011, 7:30 PM CDT
In force: 15 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 0.75 in
Wind: 65.0 mph

County Jefferson County, NE

The radar

The Grand Island radar (KUEX), 111 km from the middle of the area, began a volume at 00:17 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 00:00Z, 0.3 hours before the alert went out and 184 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: 2665 J/kg
Mixed-layer CIN: -157 J/kg
Mixed-layer LCL: 1367 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -5 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

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 Jul 24, 2:53 PM CDT, 4 hours 22 minutes earlier.

Area forecast discussion, Jul 24, 2:53 PM CDT, 4 hours 22 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
253 PM CDT SUN JUL 24 2011

.DISCUSSION...TONIGHT THROUGH SUNDAY.

LATEST DETERMINISTIC MODELS SUGGESTING GOING FCST IS IN PRETTY GOOD
SHAPE THRU DAY 7. NAM/GFS/ECM/CMC ALL BASICALLY ADVERTISING SEVERAL
SHORTWAVE TROFS MIGRATING ALONG THE U.S./CAN BORDER WILL HELP KEEP
THE HIGH PRESSURE DOME THAT DOMINATES THE LOWER 48 FROM AMPLIFYING
TOO MUCH UNTIL NEXT SATURDAY. FOR TONIGHT HAVE FOCUSED POPS SOUTH IN
RELATION TO CLOSE PROXIMITY OF MOIST BNDRY LYR/INSTABILITY AXIS. AM
RATHER IMPRESSED HOW YESTERDAY AFTN HRRR3 PROGS CAUGHT THE
CONVECTION...AND LATEST RUN IS AGAIN POINTING DEVELOPMENT SOUTH THIS
EVENING. CONFIDENCE WITH THIS OCCURRING SOMEWHAT HIGHER GIVEN LAMP-
GFS CONVECTION PROBABILITY AND 12Z 4KM WRF-NMM COMPLIMENTING HRRR3.
ON MONDAY NIGHT...PROBABLE THAT MCS WILL TRACK ACROSS THE DAKOTAS
WHERE BEST UPGLIDE FORCING/MOISTURE WILL BE LOCATED. MUCINS THOUGH
AROUND -125J/KG AS WELL AS HIGH LID STRENGTH VALUES SUGGEST CAP WILL
BE QUITE STRONG OVER THE NRN CWA AND HINDER ANY ACTIVITY FROM MOVING
IN.

NRN SHORTWAVE AND SFC REFLECTION WEDNESDAY NIGHT DRAGS A COLD FRONT
INTO THE CNTRL PLAINS...WHICH EVENTUALLY STALLS...AND BECOMES THE
FOCUS FOR PCPN CHANCES OVER THE REGION. THE STALLED FRONT IS THEN
ADVERTISED TO BEGIN LIFTING NORTH BY SATURDAY WHEN MODEST
AMPLIFICATION OF CONUS HIGH PRESSURE DOME TAKES PLACE. UNTIL TILL
THEN...APPEARS THAT AFTN HIGHS WILL BE CLOSE TO NEAR NORMAL UNTIL THE
CWA ONCE AGAIN FALLS UNDER MOIST WAA REGIME ON SUNDAY. GFS EVEN
SUGGESTING SULTRY CONDITIONS RETURN SUNDAY AFTN BY PUSHING HEAT
INDICES TO AROUND 100-105 DEG.

DEE

&&

.AVIATION...
TAF SITES KOFK/KOMA/KLNK

18Z TAFS

VFR CONDITIONS INITIALLY AT ALL TAF SITES...HOWEVER AM EXPECTING
MVFR CONDITIONS TO DEVELOP OVERNIGHT BY AROUND 06Z...EVENTUALLY
DROPPING DOWN TO IFR CONDITIONS FOR CEILINGS AND FOG BY 09-10Z.
COULD TEMPORARILY SEE LIFR CONDITIONS AT KOMA 11-14Z. WHILE THERE IS
A SMALL CHANCE OF THUNDERSTORMS THROUGH THE EVENING AT  KLNK/KOMA...
WAS NOT CONFIDENT ENOUGH TO MENTION AT ANY SPECIFIC TIME JUST YET
AND DECIDED TO WAIT UNTIL THEY DEVELOP TO GET A BETTER HANDLE OF
WHEN AND WHERE THEY MIGHT BE NEEDED.

&&

DEWALD

.OAX WATCHES/WARNINGS/ADVISORIES...

NE...NONE.
IA...NONE.

&&

Hazardous weather outlook, Jul 24, 6:33 PM CDT, 42 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
633 PM CDT SUN JUL 24 2011

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-251100-
ANTELOPE-BOONE-BURT-BUTLER-CASS-CEDAR-COLFAX-CUMING-DODGE-DOUGLAS-
FREMONT IA-GAGE-HARRISON IA-JEFFERSON-JOHNSON-KNOX-LANCASTER-MADISON-
MILLS IA-MONONA IA-MONTGOMERY IA-NEMAHA-OTOE-PAGE IA-PAWNEE-PIERCE-
PLATTE-POTTAWATTAMIE IA-RICHARDSON-SALINE-SARPY-SAUNDERS-SEWARD-
SHELBY IA-STANTON-THURSTON-WASHINGTON-WAYNE-
633 PM CDT SUN JUL 24 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MOST OF EASTERN NEBRASKA AND
PARTS OF SOUTHWEST IOWA.

.DAY ONE...TONIGHT AND MONDAY

ISOLATED TO SCATTERED THUNDERSTORMS WILL AFFECT PARTS OF SOUTHEAST
NEBRASKA TONIGHT AND MAY ALSO MAY MOVE INTO SOUTHWEST IOWA. THESE
WOULD MAINLY OCCUR BEFORE 2 AM CDT. THESE STORMS COULD PRODUCE
DAMAGING WINDS...HAIL AND LOCALLY HEAVY RAIN MAINLY SOUTHWEST OF
A LINE FROM SEWARD TO PAWNEE CITY THIS EVENING.

MODERATE TO MAJOR FLOODING WILL CONTINUE ALONG THE MISSOURI RIVER.

.DAYS TWO THROUGH SEVEN...MONDAY NIGHT THROUGH SATURDAY

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS FOR PARTS OF THE AREA
FROM MONDAY NIGHT INTO TUESDAY...THEN AGAIN FROM WEDNESDAY INTO
SATURDAY. LATER OUTLOOKS WILL ADDRESS THE POTENTIAL FOR SEVERE
WEATHER IN THOSE PERIODS.

MODERATE TO MAJOR FLOODING WILL CONTINUE ALONG THE MISSOURI RIVER
FOR THE NEXT SEVERAL WEEKS.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT OR MONDAY.

MILLER

In the hours before

Local storm report, Jul 24, 7:04 PM CDT, 11 minutes before

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Nearby

Severe Thunderstorm Warnings in Nebraska, 2011 Every severe thunderstorm warning in 2011

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.