Alert archive / Iowa / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 9, NWS Sioux Falls, SD

April 12, 1998Plymouth County, Iowa; Union County, South Dakota

NWS Sioux Falls, SD issued this severe thunderstorm warning at Apr 12, 1998, 5:13 PM CDT for Plymouth County, Iowa; Union County, South Dakota. It was in force for 32 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Apr 12, 1998, 5:13 PM CDT (22:13 UTC)
Expired: Apr 12, 1998, 5:45 PM CDT
In force: 32 min
Issued by: NWS Sioux Falls, SD
Area: Whole counties

Counties Plymouth County, IA, Union County, SD

The radar

The Sioux Falls radar (KFSD), 92 km from the middle of the area, began a volume at 22:16 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.

What was reported inside it

Time	Report	Where	Remark
Apr 12, 5:17 PM CDT	Hail 0.75	Elk Pt, SD

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 12, 3:30 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.2 hours before the alert went out and 163 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1568 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 487 m²/s²
0-3 km storm-relative helicity: 522 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KFSD 122213 RRA
SVRFSD
IAC149-SDC127-122245-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
513 PM CDT SUN APR 12 1998

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN UNION COUNTY IN SOUTHEASTERN SOUTH DAKOTA
  WESTERN PLYMOUTH COUNTY IN NORTHWESTERN IOWA

* UNTIL 545 PM CDT

* SOME AREAS AFFECTED
  RICHLAND                 AROUND 506 PM CDT
  WESTFIELD                AROUND 507 PM CDT
  AKRON                    AROUND 515 PM CDT
  RUBLE                    AROUND 520 PM CDT
  MERRILL                  AROUND 525 PM CDT

* AT 509 PM CDT... NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORM 17 MILES NORTHWEST OF SIOUX CITY  OR 6
  MILES SOUTH OF WESTFIELD MOVING NORTHEAST AT 40 MPH.

AT 500 PM DIME SIZE HAIL WAS REPORTED AT PONCA.

WHEN THUNDERSTORMS ARE OCCURRING...PEOPLE SHOULD MOVE INSIDE A
STRONG BUILDINGj.  DO NOT STAND BY WINDOWS.  DO NOT USE TELEPHONES OR
ELECTRICAL APPLIANCES UNTIL THE STORM HAS PASSED UNLESS IN AN
EMERGENCY.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER CROSSINGS.

&

BLOOM

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 Sioux Falls, SD wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 12, 10:20 AM CDT, 6 hours 53 minutes earlier.

Area forecast discussion, Apr 12, 10:20 AM CDT, 6 hours 53 minutes before

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1020 AM CDT SUN APR 12 1998

WILL HAVE TO WATCH AC TYPE CONVECTION MOVING NE OUT OF NE.

.FSD...WIND ADVISORIES HAVE BEEN ISSUED IN FAR EASTERN SOUTH DAKOTA INTO
THIS AFTERNOON.  ADVISORIES IN NORTHWEST IA AND PARTS OF SW MN GO ALL
DAY.
    MILLSAPPS

In the hours before

Special weather statement, Apr 12, 11:32 AM CDT, 5 hours 41 minutes before

SIGNIFICANT WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1132 AM CDT SUN APR 12 1998

*** SIGNIFICANT WEATHER PERTAINS TO WEATHER ELEMENTS ASSOCIATED WITH
THUNDERSTORMS. ***

.SYNOPSIS...A STRONG LOW PRESSURE AREA CENTERED OVER CENTRAL SOUTH
DAKOTA WILL MOVE NORTHEAST THIS AFTERNOON. A FRONT WILL SWING ACROSS
THE AREA LATE THIS AFTERNOON AND EVENING.  THUNDERSTORMS COULD
DEVELOP AHEAD OR NEAR THIS FRONT... AND GUSTS FROM THESE
THUNDERSTORMS COULD COMBINE WITH THE ALREADY STRONG WINDS ASSOCIATED
WITH THE LOW AND PRODUCE SEVERE DAMAGING WINDS.  THERE WILL ALSO BE A
SLIGHT RISK OF HAIL... BUT ANY HEAVY RAINS SHOULD BE OF SHORT
DURATION.

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-IAZ001>003-
012>014-020>022-031-032-NEZ013-014-130500-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-CHARLES MIX-CLAY-DAVISON-
DOUGLAS-GREGORY-HANSON-HUTCHINSON-JERAULD-KINGSBURY-LAKE-LINCOLN-
MC COOK-MINER-MINNEHAHA-MOODY-SANBORN-TURNER-UNION-YANKTON-COTTONWOOD-
JACKSON-LINCOLN-LYON-MURRAY-NOBLES-PIPESTONE-ROCK-BUENA VISTA-
CHEROKEE-CLAY-DICKINSON-IDA-LYON-OBRIEN-OSCEOLA-PLYMOUTH-SIOUX-
WOODBURY-DAKOTA-DIXON-
INCLUDING THE CITIES OF...BROOKINGS...CHAMBERLAIN...HURON...MITCHELL...
SIOUX FALLS...YANKTON...LUVERNE...PIPESTONE...SLAYTON...WORTHINGTON...
LE MARS...ROCK RAPIDS...SIOUX CENTER...SIOUX CITY...SPENCER...
SPIRIT LAKE...STORM LAKE
1132 AM CDT SUN APR 12 1998

FORECAST THROUGH MIDNIGHT:
A SLIGHT CHANCE FOR SEVERE WEATHER EXISTS FOR MID AFTERNOON INTO THIS
EVENING.

* SIGNIFICANT WEATHER:
  SEVERE WINDS (GUSTS EQUAL TO OR GREATER THAN 58 MPH)

* SPOTTER ACTIVATION:
  SPOTTER ACTIVATION MAY BE NEEDED AFTER 2PM.

MILLSAPPS

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 12, 5:45 PM CDT	Severe Thunderstorm Warning	FSD	Plymouth, Sioux	30 min
Apr 12, 6:11 PM CDT	Severe Thunderstorm Warning	FSD	Cherokee, O'Brien	44 min
Apr 12, 6:32 PM CDT	Severe Thunderstorm Warning	FSD	Clay, Dickinson	28 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1998 Severe Thunderstorm Warnings in South Dakota, 1998 Every severe thunderstorm warning 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.