Alert archive / Iowa / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 115, NWS Omaha, NE

June 9, 20187 counties in Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Jun 9, 2018, 4:15 AM CDT for 7 counties in Iowa. 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
Jun 9, 2018, 4:15 AM CDT (09:15 UTC)
Expired
Jun 9, 2018, 4:45 AM CDT
In force
30 min
Issued by
NWS Omaha, NE
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Fremont County, IA, Harrison County, IA, Mills County, IA, Montgomery County, IA, Page County, IA, Pottawattamie County, IA, Shelby County, IA

The radar

The Omaha radar (KOAX), 78 km from the middle of the area, began a volume at 09:16 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 00:00Z, 9.3 hours before the alert went out and 78 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 00:00Z on 2018-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2133 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2018-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 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
2133 J/kg
Mixed-layer CIN
-79 J/kg
Mixed-layer LCL
1659 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

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 9, 3:49 AM CDT, 26 minutes earlier.

Area forecast discussion, Jun 9, 3:49 AM CDT, 26 minutes before
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Hazardous weather outlook, Jun 8, 4:37 PM CDT, 11 hours 38 minutes before
Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
437 PM CDT Fri Jun 8 2018

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-091145-
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-
437 PM CDT Fri Jun 8 2018

This Hazardous Weather Outlook is for portions of southwest
Iowa...west central Iowa...east central Nebraska...northeast
Nebraska and southeast Nebraska.

.DAY ONE...Tonight and Saturday

A few isolated thunderstorms may try to develop this evening in
southwest Iowa. Should they develop, isolated severe storms with
large hail and gusty winds are possible. Later tonight, strong to
severe thunderstorms are possible for parts of eastern Nebraska
and southwest Iowa overnight. Depending on how the storms hold
together, there is a risk of severe storms containing damaging
winds, large hail and locally heavy rain late tonight and early
Saturday morning.

The overnight storms may lay out a boundary where additional
isolated severe storms could focus Saturday afternoon and
evening.

High temperatures in the 90s and muggy conditions will produce
heat index values from 95 to 100 degrees.

.DAYS TWO THROUGH SEVEN...Saturday night through Friday

Isolated thunderstorms may develop north of the warm front Sunday.

Hot and humid conditions are forecast Sunday when highs in the 90s
and high humidity will push heat index values near or above 100.

More thunderstorms are possible Sunday night and Monday as a cold
front sweeps through the area, with a chance for severe
thunderstorms. Then off-and-on thunderstorm chances remain in the
forecast through Thursday.

.SPOTTER INFORMATION STATEMENT...

Storm spotter activation later tonight or Saturday may be needed on
a localized basis.

Zapotocny

In the hours before

Special weather statement, Jun 9, 1:37 AM CDT, 2 hours 38 minutes before
Special Weather Statement
National Weather Service Omaha/Valley Nebraska
137 AM CDT SAT JUN 9 2018

NEZ016-030>032-042-090715-
Stanton NE-Madison NE-Platte NE-Boone NE-Antelope NE-
137 AM CDT SAT JUN 9 2018

...SIGNIFICANT WEATHER ADVISORY FOR MADISON...WESTERN PLATTE...
SOUTHEASTERN ANTELOPE...EASTERN BOONE AND NORTHWESTERN STANTON
COUNTIES UNTIL 215 AM CDT...

At 137 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 3 miles west of Meadow Grove to 3 miles
southwest of Albion to 3 miles north of St. Paul. Movement was east
at 40 mph.

Wind gusts up to 50 mph will be possible with these storms.

Locations impacted include...
Norfolk, Madison, Albion, Battle Creek, Newman Grove, St. Edward,
Cedar Rapids, Meadow Grove, Lindsay, Tilden, Humphrey, Tarnov,
Cornlea and The Highway 14 And 56 Junction.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4163 9812 4209 9785 4209 9715 4165 9744
      4140 9770 4152 9771 4153 9788 4151 9789
      4151 9804 4150 9804 4150 9809 4148 9810
      4148 9829
TIME...MOT...LOC 0637Z 265DEG 33KT 4205 9779 4164 9803 4126 9846

FOBERT
Local storm report, Jun 9, 3:25 AM CDT, 50 minutes before
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Special weather statement, Jun 9, 3:53 AM CDT, 22 minutes before
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Special weather statement, Jun 9, 4:05 AM CDT, 10 minutes before
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Local storm report, Jun 9, 4:06 AM CDT, 9 minutes before
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Local storm report, Jun 9, 4:14 AM CDT, 1 minute before
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The office that day

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

IssuedProductOfficeCountiesLasted
Jun 8, 11:32 PM CDTSpecial Weather StatementOAXKnox28 min
Jun 9, 12:15 AM CDTSpecial Weather StatementOAXAntelope45 min
Jun 9, 12:55 AM CDTSevere Thunderstorm WarningOAXAntelope, Boone, Madison, Platte35 min
Jun 9, 1:01 AM CDTSpecial Weather StatementOAXCedar, Pierce, Wayne44 min
Jun 9, 1:37 AM CDTSpecial Weather StatementOAXBoone, Madison38 min
Jun 9, 1:47 AM CDTSevere Thunderstorm WarningOAXBoone, Madison, Platte28 min
Jun 9, 2:04 AM CDTSevere Thunderstorm WarningOAXMadison, Pierce, Stanton41 min
Jun 9, 2:13 AM CDTSevere Thunderstorm WarningOAXColfax, Madison, Platte, Stanton32 min
Jun 9, 2:38 AM CDTSevere Thunderstorm WarningOAXButler, Colfax, Platte, Seward52 min
Jun 9, 2:45 AM CDTSevere Thunderstorm WarningOAXCuming, Stanton45 min
Jun 9, 2:53 AM CDTSevere Thunderstorm WarningOAXButler, Jefferson, Lancaster, Saline, Saunders, Seward37 min
Jun 9, 3:00 AM CDTSevere Thunderstorm WarningOAXButler, Colfax, Dodge, Saunders30 min
Jun 9, 3:25 AM CDTSevere Thunderstorm WarningOAXBurt, Cass, Dodge, Douglas, Gage, Jefferson and 7 more50 min
Jun 9, 3:53 AM CDTSpecial Weather StatementOAXBurt, Thurston37 min
Jun 9, 4:05 AM CDTSpecial Weather StatementOAXJohnson, Nemaha, Otoe, Pawnee25 min
Jun 9, 6:35 PM CDTSpecial Weather StatementOAXRichardson40 min
Jun 9, 6:45 PM CDTSpecial Weather StatementOAXRichardson45 min
Jun 9, 6:49 PM CDTSevere Thunderstorm WarningOAXRichardson41 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2018Every severe thunderstorm warning in 2018

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.