Alert archive / Iowa / Severe Thunderstorm Warnings in 2008

Severe Thunderstorm Warning 270, NWS Omaha, NE

June 20, 2008Montgomery County, Pottawattamie County, Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jun 20, 2008, 6:08 PM CDT for Montgomery County, Pottawattamie County, Iowa. It was in force for 37 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: Jun 20, 2008, 6:08 PM CDT (23:08 UTC)
Expired: Jun 20, 2008, 6:45 PM CDT
In force: 37 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon

Counties Montgomery County, IA, Pottawattamie County, IA

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 11.1 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: 250 J/kg
Mixed-layer CIN: -157 J/kg
Mixed-layer LCL: 1067 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 82 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 Jun 20, 3:35 PM CDT, 2 hours 33 minutes earlier.

Area forecast discussion, Jun 20, 3:35 PM CDT, 2 hours 33 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
335 PM CDT FRI JUN 20 2008

.DISCUSSION...
FORCAST CONCERNS THROUGH THE PERIOD WILL CONTINUE TO BE UNSETTLED WX
AND TSRA.

LATEST SFC ANALYSIS HAD A WK SFC TROF FM NR CLARINDA TO WEST OF
DBQ...TSRA SEEMED TO BE FORMING IN THIS AREA OF CONVERGENCE. OTHER
TSRA WERE NR THE SFC DEWPOINT GRADIENT WEST OF ONL AND ODX...WITH
MORE SCT TSRA NR SUX. SFC DEWPOINTS WERE IN THE UPR 50S TO LOWER
60S WITH TEMPS. NW FLOW CONTINUES WITH A WEAK SHORTWAVE TROF FM MN
THROUGH NW IA AND SE SD INTO NEB. HEATING THIS AFTERNOON HAS SB
CAPE FM 1500-3000J/KG...SO THERE IS GOOD INSTABILITY...
HOWEVER...THE SHEAR PARAMETERS ARE WEAK. EXPECT ISOLD TO SCT TSRA
AGAIN THIS AFTERNOON AND THIS EVENING AND SOME ISOLD SVR WITH
LARGE HAIL AND SOME DAMAGING WINDS POSSIBLE.

SATURDAY...ANOTHER SHORTWAVE IN NW FLOW WILL BE APPROACHING AND
THIS APPEARS TO AFFECT ALL BUT THE SW PART OF THE CWA...HAVE CHC
POPS FOR THIS FEATURE DURING THE AFTERNOON AND OVERNIGHT. SFC HIGH
PRES WILL BUILD IN FOR SUNDAY AND STILL DRY FOR SUNDAY NIGHT INTO
EARLY MONDAY WITH ANOTHER SHORTWAVE MON AFTERNOON AND THE FRONTAL
PASSAGE MONDAY NIGHT AND TUESDAY...MOVING OUT TUESDAY NIGHT.
UNSETTLED PATTERN CONTINUES WITH LOW POPS WED NIGHT AND CHANCE
POPS THU INTO THU NIGHT AND FRI AS WAA AND WEAK RIPPLES IN THE NW
FLOW EXTENDS INTO THE END OF THE WEEK. HIGHS MOSTLY IN THE 80S
THROUGH THE FORECAST PD.

&&

.AVIATION...
OR TAF SITES KOMA...KLNK AND KOFK...THROUGH 21/18Z.

VFR CONDITIONS EXPECTED THROUGH THE ENTIRE PERIOD.  HAVE A CHANCE OF
SHOWERS SKIRTING KOFK FROM 20/18-21Z AND POSSIBLY SOME CONVECTION
AT KLNK FROM 20/21-01Z.  OTHERWISE...WINDS SHOULD REMAIN LIGHT
THROUGH THE DAY.

&&

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

ZAPOTOCNY/REESE

Hazardous weather outlook, Jun 20, 5:46 PM CDT, 22 minutes before

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In the hours before

Local storm report, Jun 20, 3:47 PM CDT, 2 hours 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
347 PM CDT FRI JUN 20 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0330 PM     HAIL             1 W COLON               41.30N 96.63W
06/20/2008  E0.75 INCH       SAUNDERS           NE   STORM CHASER

&&

DEWALD

Local storm report, Jun 20, 3:59 PM CDT, 2 hours 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
359 PM CDT FRI JUN 20 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0357 PM     HAIL             2 NE CASTANA            42.09N 95.88W
06/20/2008  E1.00 INCH       MONONA             IA   TRAINED SPOTTER

&&

DEWALD

Local storm report, Jun 20, 4:18 PM CDT, 1 hour 50 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
418 PM CDT FRI JUN 20 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     HAIL             SOLDIER                 41.98N 95.78W
06/20/2008  E0.75 INCH       MONONA             IA   TRAINED SPOTTER

&&

DEWALD

Local storm report, Jun 20, 4:59 PM CDT, 1 hour 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
459 PM CDT FRI JUN 20 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0445 PM     FUNNEL CLOUD     3 S OAKLAND             41.27N 95.40W
06/20/2008                   POTTAWATTAMIE      IA   TRAINED SPOTTER

            A NARROW FUNNEL REACHED DOWN ABOUT HALF WAY TO GROUND.

&&

RCHERMOK

Local storm report, Jun 20, 5:09 PM CDT, 59 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
509 PM CDT FRI JUN 20 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0440 PM     TORNADO          1 E MACEDONIA           41.19N 95.41W
06/20/2008                   POTTAWATTAMIE      IA   FIRE DEPT/RESCUE

            BRIEF TOUCHDOWN.

0447 PM     FUNNEL CLOUD     5 NW ELLIOTT            41.20N 95.23W
06/20/2008                   POTTAWATTAMIE      IA   NWS EMPLOYEE

            FUNNEL NEARING GROUND.

0448 PM     FUNNEL CLOUD     8 E TREYNOR             41.23N 95.45W
06/20/2008                   POTTAWATTAMIE      IA   TRAINED SPOTTER

            FUNNEL DESCENDED AND THEN DISSIPATED

&&

BSMITH

Local storm report, Jun 20, 5:33 PM CDT, 35 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 19, 7:12 PM CDT	Areal Flood Advisory	OAX	Douglas, Sarpy	2 hr
Jun 19, 7:16 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Otoe, Sarpy	29 min
Jun 19, 7:42 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Otoe	33 min
Jun 19, 8:07 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Nemaha	23 min
Jun 19, 8:08 PM CDT	Areal Flood Warning	OAX	Otoe	2 hr
Jun 19, 8:16 PM CDT	Severe Thunderstorm Warning	OAX	Burt, Thurston	59 min
Jun 19, 8:36 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Nemaha, Pawnee, Richardson	54 min
Jun 19, 8:42 PM CDT	Areal Flood Advisory	OAX	Nemaha	3 hr
Jun 19, 9:15 PM CDT	Areal Flood Warning	OAX	Madison	12 hr
Jun 19, 9:41 PM CDT	Severe Thunderstorm Warning	OAX	Gage, Jefferson	34 min
Jun 20, 2:50 AM CDT	River Flood Warning	OAX	Richardson	32 hr
Jun 20, 3:27 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	37 min
Jun 20, 5:40 PM CDT	Severe Thunderstorm Warning	OAX	Cass, Lancaster, Otoe	50 min
Jun 20, 6:04 PM CDT	Severe Thunderstorm Warning	OAX	Saunders	20 min
Jun 20, 6:18 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Otoe, Pawnee	27 min
Jun 20, 6:49 PM CDT	Severe Thunderstorm Warning	OAX	Johnson, Otoe, Pawnee	56 min
Jun 20, 3:11 PM CDT	Severe Thunderstorm Warning	OAX	Monona	64 min
Jun 20, 4:11 PM CDT	Severe Thunderstorm Warning	OAX	Monona	40 min
Jun 20, 4:32 PM CDT	Severe Thunderstorm Warning	OAX	Harrison, Shelby	43 min
Jun 20, 4:45 PM CDT	Tornado Warning	OAX	Montgomery, Pottawattamie	45 min
Jun 20, 5:24 PM CDT	Severe Thunderstorm Warning	OAX	Pottawattamie, Shelby	23 min
Jun 20, 5:29 PM CDT	Tornado Warning	OAX	Montgomery, Pottawattamie	29 min
Jun 20, 6:40 PM CDT	Severe Thunderstorm Warning	OAX	Montgomery	35 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2008 Every severe thunderstorm warning in 2008

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.