Alert archive / Iowa / Tornado Watches in 1998

Tornado Watch 253

April 25, 1998Adams County, Hancock County, Illinois; 41 counties in Iowa; 12 counties in Missouri

The Storm Prediction Center issued this tornado watch at Apr 25, 1998, 5:30 PM CDT for Adams County, Hancock County, Illinois; 41 counties in Iowa; 12 counties in Missouri. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 25, 1998, 5:30 PM CDT (22:30 UTC)
Expired
Apr 25, 1998, 11:00 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
All 55 counties

Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Boone County, IA, Buchanan County, IA, Calhoun County, IA, Clarke County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Story County, IA, Tama County, IA, Union County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Webster County, IA, Adams County, IL, Hancock County, IL, Adair County, MO, Clark County, MO, Daviess County, MO, Grundy County, MO, Harrison County, MO, Knox County, MO, Lewis County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Scotland County, MO, Sullivan County, MO

The radar

The Des Moines radar (KDMX), 96 km from the middle of the area, began a volume at 22:26 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 25, 5:45 PM CDTSevere Thunderstorm WarningDMXClarke35 min
Apr 25, 5:56 PM CDTSevere Thunderstorm WarningDMXMadison34 min
Apr 25, 6:02 PM CDTSevere Thunderstorm WarningDMXDallas33 min
Apr 25, 6:20 PM CDTSevere Thunderstorm WarningDMXWarren35 min
Apr 25, 6:21 PM CDTSevere Thunderstorm WarningDMXDallas34 min
Apr 25, 7:26 PM CDTSevere Thunderstorm WarningDMXGreene34 min
Apr 25, 7:39 PM CDTSevere Thunderstorm WarningDMXCalhoun36 min
Apr 25, 8:10 PM CDTSevere Thunderstorm WarningDMXGreene, Webster35 min

The nearest sounding before it

Davenport, (KDVN), launched 12:00Z, 10.5 hours before the alert went out and 177 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, Davenport, at 12:00Z on 1998-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Davenport, at 12:00Z on 1998-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2075 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
113 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.

799 
WWUS9 KMKC 252158
SEL3  
MKC WW 252158
IAZ000-MOZ000-260400-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 253
STORM PREDICTION CENTER NORMAN OK
458 PM CDT SAT APR 25 1998

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   IOWA                               
   NORTHERN MISSOURI                           

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 530 PM UNTIL
1100 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 80 STATUTE MILES EAST AND WEST
OF A LINE FROM 40 MILES WEST OF WATERLOO IOWA TO 15 MILES SOUTH OF
KIRKSVILLE MISSOURI.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. 
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.


DISCUSSION...THUNDERSTORMS ARE EXPECTED TO DEVELOP RAPIDLY ALONG
DRYLINE BULGE OVER NRN MO/SRN IA. SHEAR PROFILES WILL SUPPORT
SUPERCELL DEVELOPMENT...WITH GREATEST TORNADO POTENTIAL WHERE
DRYLINE INTERSECTS WARM FRONT. 


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 25030.


...VESCIO

423,0913 395,0910 395,0940 423,0944

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 25, 6:30 PM CDTSevere Thunderstorm WatchSPCAudubon, Buena Vista, Calhoun, Carroll, Cherokee, Crawford and 10 more5 hr
Apr 25, 6:00 PM CDTSevere Thunderstorm WatchSPCBates, Benton, Caldwell, Carroll, Cass, Chariton and 19 more5 hr

Nearby

Tornado Watches in Iowa, 1998Tornado Watches in Missouri, 1998Tornado Watches in Illinois, 1998Every tornado watch 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; radar from the NEXRAD Level II archive.