Alert archive / Iowa / Tornado Warnings in 1998

Tornado Warning 15, NWS Omaha, NE

May 15, 1998Pottawattamie County, Shelby County, Iowa

NWS Omaha, NE issued this tornado warning at May 15, 1998, 12:27 PM CDT for Pottawattamie County, Shelby County, Iowa. It was in force for 33 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
May 15, 1998, 12:27 PM CDT (17:27 UTC)
Expired
May 15, 1998, 1:00 PM CDT
In force
33 min
Issued by
NWS Omaha, NE
Area
Whole counties

Counties Pottawattamie County, IA, Shelby County, IA

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 15, 9:45 AM CDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 5.5 hours before the alert went out and 82 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 1998-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1194 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 12:00Z on 1998-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -76 square meters per square second.19395878Sfc1 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
1194 J/kg
Mixed-layer CIN
-370 J/kg
Mixed-layer LCL
1627 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
-76 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

423 
WFUS1 KOMA 151729 RRA
TOROMA
IAC155-165-151800-

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1227 PM CDT FRI MAY 15 1998

THE NATIONAL WEATHER SERVICE IN OMAHA HAS ISSUED A

* TORNADO WARNING FOR...
  SHELBY COUNTY IN SOUTHWESTERN IOWA
  EASTERN POTTAWATTAMIE COUNTY IN SOUTHWESTERN IOWA

* UNTIL 100 PM CDT

* AT 1225 PM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A POSSIBLE TORNADO 38 MILES EAST NORTHEAST OF DOWNTOWN OMAHA OR 6
  MILES SOUTH OF WALNUT MOVING NORTH AT 45 MPH.

* THE TORNADO IS EXPECTED TO BE NEAR...
  WALNUT                       AT 1225 PM CDT
  PRAIRIE ROSE STATE PARK      AT 1235 PM CDT
  ELK HORN                     AT 1235 PM CDT
  JACKSONVILLE                 AT 1240 PM CDT
  KIRKMAN                      AT 1245 PM CDT

PEOPLE IN THE WARNED AREA SHOULD MOVE TO A REINFORCED BUILDING ON
THE LOWEST FLOOR TO BE PREPARED FOR THE DESTRUCTIVE WINDS THAT
ACCOMPANY TORNADOES.  IN ADDITION TO THE THREAT OF TORNADOES...
LARGE HAIL...DANGEROUS LIGHTNING AND VERY HEAVY RAIN ARE LIKELY
WITH THIS STORM.

POLLACK

What forecasters said that day

The local office's own words before this tornado warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, May 15, 10:55 AM CDT, 1 hour 32 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-161200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1055 AM CDT FRI MAY 15 1998

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

SPOTTER ACTION...
STORM SPOTTERS CONTINUE TO BE NEEDED FOR PARTS OF NEBRASKA AND
SOUTHWEST IOWA THROUGH MID AFTERNOON.

DISCUSSION...
STRONG THUNDERSTORMS WILL CONTINUE TO LIFT OUT OF NORTHEAST NEBRASKA
AND WESTERN IOWA THROUGH MID AFTERNOON...HOWEVER ISOLATED STORMS
CONTINUE TO DEVELOP BEHIND THIS MAIN AREA.

ZAPOTOCNY
Special weather statement, May 15, 10:55 AM CDT, 1 hour 32 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-161200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1055 AM CDT FRI MAY 15 1998

...SEVERE WEATHER OUTLOOK FOR EASTERN NEBRASKA AND SOUTHWEST IOWA...

SPOTTER ACTION...
STORM SPOTTERS CONTINUE TO BE NEEDED FOR PARTS OF NEBRASKA AND
SOUTHWEST IOWA THROUGH MID AFTERNOON.

DISCUSSION...
STRONG THUNDERSTORMS WILL CONTINUE TO LIFT OUT OF NORTHEAST NEBRASKA
AND WESTERN IOWA THROUGH MID AFTERNOON...HOWEVER ISOLATED STORMS
CONTINUE TO DEVELOP BEHIND THIS MAIN AREA.

ZAPOTOCNY
Special weather statement, May 15, 12:05 PM CDT, 22 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-161700-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1205 PM CDT FRI MAY 15 1998

SEVERE THUNDERSTORM WATCH NUMBER 352 HAS BEEN ALLOWED TO EXPIRE...
HOWEVER A WATCH BOX MAY BE REISSUED FOR PARTS OF EASTERN NEBRASKA
AND WESTERN IOWA AS THUNDERSTORMS REDEVELOP.

A SEVERE THUNDERSTORM WATCH NUMBER 353 REMAINS IN EFFECT FOR PARTS
OF NORTHEAST NEBRASKA AND NORTHWEST IOWA UNTIL 3PM.

ZAPOTOCNY
Special weather statement, May 15, 12:05 PM CDT, 22 minutes before
NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-088>093-
IAZ043-055-056-069-079-080-090-091-161700-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1205 PM CDT FRI MAY 15 1998

SEVERE THUNDERSTORM WATCH NUMBER 352 HAS BEEN ALLOWED TO EXPIRE...
HOWEVER A WATCH BOX MAY BE REISSUED FOR PARTS OF EASTERN NEBRASKA
AND WESTERN IOWA AS THUNDERSTORMS REDEVELOP.

A SEVERE THUNDERSTORM WATCH NUMBER 353 REMAINS IN EFFECT FOR PARTS
OF NORTHEAST NEBRASKA AND NORTHWEST IOWA UNTIL 3PM.

ZAPOTOCNY

The office that day

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

IssuedProductOfficeCountiesLasted
May 15, 8:58 AM CDTSevere Thunderstorm WarningOAXFremont, Mills62 min
May 15, 8:58 AM CDTSevere Thunderstorm WarningOAXPage62 min
May 15, 9:10 AM CDTSevere Thunderstorm WarningOAXPottawattamie65 min
May 15, 9:16 AM CDTSevere Thunderstorm WarningOAXMontgomery64 min
May 15, 9:34 AM CDTSevere Thunderstorm WarningOAXHarrison, Shelby61 min
May 15, 9:47 AM CDTSevere Thunderstorm WarningOAXMonona63 min
May 15, 10:03 AM CDTTornado WarningOAXShelby47 min
May 15, 10:13 AM CDTSevere Thunderstorm WarningOAXPottawattamie32 min
May 15, 10:50 AM CDTSevere Thunderstorm WarningOAXMonona30 min
May 15, 11:28 AM CDTSevere Thunderstorm WarningOAXMills, Pottawattamie62 min
May 15, 2:58 PM CDTSevere Thunderstorm WarningOAXMills, Montgomery, Pottawattamie62 min
May 15, 3:01 PM CDTSevere Thunderstorm WarningOAXHarrison49 min
May 15, 3:10 PM CDTSevere Thunderstorm WarningOAXMonona50 min
May 15, 3:10 PM CDTSevere Thunderstorm WarningOAXShelby50 min

Nearby

Tornado Warnings in Iowa, 1998Every tornado warning in 1998Tornadoes in 1998

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.