Alert archive / Iowa / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 6, NWS Des Moines, IA

April 30, 1997Appanoose County, Monroe County, Iowa

NWS Des Moines, IA issued this severe thunderstorm warning at Apr 30, 1997, 11:45 AM CDT for Appanoose County, Monroe County, 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
Apr 30, 1997, 11:45 AM CDT (16:45 UTC)
Expired
Apr 30, 1997, 12:15 PM CDT
In force
30 min
Issued by
NWS Des Moines, IA
Area
Whole counties

Counties Appanoose County, IA, Monroe County, IA

The radar

The Des Moines radar (KDMX), 118 km from the middle of the area, began a volume at 16:46 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

Davenport, (KDVN), launched 12:00Z, 4.8 hours before the alert went out and 214 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 1997-04-30Temperature 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 1997-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 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
1366 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
180 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 KDSM 301644 RRA
SVRDSM
IAC007-135-301715-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE DES MOINES IA
1145 AM CDT WED APR 30 1997

* SEVERE THUNDERSTORM WARNING FOR
  NORTHEASTERN APPANOOSE COUNTY - SOUTH CENTRAL IOWA
  EASTERN MONROE COUNTY - SOUTH CENTRAL IOWA

* UNTIL 1215 PM CDT
 
* SOME AREAS AFFECTED
    AVERY
    UNIONVILLE

* AT 1143 AM CDT RADAR INDICATED A SEVERE THUNDERSTORM FROM ALBIA TO
  JUST NORTH OF CENTERVILLE OR 25 MILES SOUTHWEST OF OTTUMWA MOVING
  NORTHEAST AT 30 MPH.

* THE STORM WILL BE NEAR AVERY AND UNIONVILLE BY NOON CDT.

THIS IS A DANGEROUS STORM.  DO NOT GO OUTDOORS.

WINDS TO 60 MPH AND HAIL TO 3/4 INCH CAN BE EXPECTED WITH THIS STORM.


JUNGBLUTH

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.

In the hours before

Special weather statement, Apr 30, 5:45 AM CDT, 6 hours before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-021200-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
545 AM CDT WED APR 30 1997

HAZARD...ALTHOUGH AN ISOLATED THUNDERSTORM IS POSSIBLE TONIGHT...NO
SEVERE WEATHER IS EXPECTED ACROSS THE AREA.

AREA OF CONCERN...THE ENTIRE COUNTY WARNING AREA.

METEOROLOGICAL COMMENTS...ALTHOUGH SHOWERS RECENTLY ENDED ACROSS
IOWA...ANOTHER LOW PRESSURE SYSTEM DEVELOPING OVER THE CENTRAL PLAINS
WILL AGAIN SPREAD SHOWERS ACROSS THE STATE TONIGHT. WHILE ONLY AN
ISOLATED THUNDERSTORM IS POSSIBLE TONIGHT...THERE IS LITTLE INSTABILITY
AND NOT MUCH MOISTURE...AND NO SEVERE WEATHER IS EXPECTED.

THERE WILL BE A GREATER CHANCE FOR THUNDERSTORMS ALONG WITH HEAVIER
AMOUNTS OF RAIN ON FRIDAY HOWEVER AS THE SYSTEM MOVES JUST TO THE SOUTH
OF IOWA AND MORE MOISTURE WORKS INTO THE AREA. ALTHOUGH MUCH OF IOWA
RECEIVED OVER AN INCH OF PRECIPITATION WITH THE LAST SYSTEM OF LOW
PRESSURE...TOTAL PRECIPITATION AMOUNTS FROM 1/2 TO 1 INCH ARE POSSIBLE
THROUGH FRIDAY...HOWEVER THE GREATEST AMOUNTS OF RAIN ARE EXPECTED
FURTHER SOUTH OVER MISSOURI AND ILLINOIS...AND WITH AN INCH OR LESS OF
PRECIPITATION WIDESPREAD FLOODING IS NOT EXPECTED IN THE COUNTY
WARNING AREA.

PRECAUTIONS...AS THIS IS STILL A DEVELOPING SITUATION WITH THE MAIN
THREAT FOR THUNDERSTORMS AND HEAVIER RAIN AMOUNTS 36 TO 48 HOURS
OUT...THOSE INTERESTED SHOULD STAY TUNED FOR LATER FORECASTS AND
STATEMENTS.

S2
Special weather statement, Apr 30, 10:14 AM CDT, 1 hour 31 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-012100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1015 AM CDT WED APR 30 1997

HAZARD...WIDELY SCATTERED THUNDERSTORMS PRODUCING HAIL OVER 1/2 INCH
DIAMETER.

AREA OF CONCERN...SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS ARE
POSSIBLE OVER THE ENTIRE COUNTY WARNING AREA...WITH ISOLATED
THUNDERSTORMS NEAR SEVERE LEVELS OVER THE SOUTHEAST THIRD OF THE
STATE.

TIMING DETAILS...FROM LATE MORNING THROUGH THIS AFTERNOON.

METEOROLOGICAL COMMENTS...A LARGE AREA OF RAIN MOVED THROUGH FROM
SOUTHWEST TO NORTHEAST IOWA THROUGH THE MORNING HOURS.  THERE WAS A
BRIEF BREAK IN THE PRECIPITATION OVER THE SOUTHWEST AND SOUTH CENTRAL
HOWEVER...SHOWERS QUICKLY FILLED IN THIS AREA BY MID MORNING.  ANOTHER
AREA OF SHOWERS AND THUNDERSTORMS WAS MOVING THROUGH NORTHEAST KANSAS
AND NORTHWEST MISSOURI.  HAIL GREATER THAN 1 INCH IN DIAMETER ARE
POSSIBLE WITH THESE STORMS AS THEY MOVE INTO SOUTH CENTRAL IOWA.
LATER THIS AFTERNOON THE THREAT OF SEVERE WEATHER WILL SHIFT FURTHER
INTO SOUTHEAST IOWA.  A BIT OF SUNSHINE WILL FURTHER DESTABILIZE THE
ATMOSPHERE IN THIS AREA.

PRECAUTIONS...ISOLATED SEVERE STORMS ARE POSSIBLE INTO EARLY AFTERNOON
OVER SOUTH CENTRAL IOWA AND INTO SOUTHEAST IOWA THROUGHOUT THE
AFTERNOON HOURS.  EMERGENCY MANAGERS AND SPOTTERS SHOULD KEEP ABREAST
OF THE LATEST FORECASTS.

STARK
Special weather statement, Apr 30, 10:15 AM CDT, 1 hour 30 minutes before
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097-012100-

CENTRAL IOWA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
1015 AM CDT WED APR 30 1997

HAZARD...WIDELY SCATTERED THUNDERSTORMS PRODUCING HAIL OVER 1/2 INCH
DIAMETER.

AREA OF CONCERN...SCATTERED SHOWERS AND EMBEDDED THUNDERSTORMS ARE
POSSIBLE OVER THE ENTIRE COUNTY WARNING AREA...WITH ISOLATED
THUNDERSTORMS NEAR SEVERE LEVELS OVER THE SOUTHEAST THIRD OF THE
STATE.

TIMING DETAILS...FROM LATE MORNING THROUGH THIS AFTERNOON.

METEOROLOGICAL COMMENTS...A LARGE AREA OF RAIN MOVED THROUGH FROM
SOUTHWEST TO NORTHEAST IOWA THROUGH THE MORNING HOURS.  THERE WAS A
BRIEF BREAK IN THE PRECIPITATION OVER THE SOUTHWEST AND SOUTH CENTRAL
HOWEVER...SHOWERS QUICKLY FILLED IN THIS AREA BY MID MORNING.  ANOTHER
AREA OF SHOWERS AND THUNDERSTORMS WAS MOVING THROUGH NORTHEAST KANSAS
AND NORTHWEST MISSOURI.  HAIL GREATER THAN 1 INCH IN DIAMETER ARE
POSSIBLE WITH THESE STORMS AS THEY MOVE INTO SOUTH CENTRAL IOWA.
LATER THIS AFTERNOON THE THREAT OF SEVERE WEATHER WILL SHIFT FURTHER
INTO SOUTHEAST IOWA.  A BIT OF SUNSHINE WILL FURTHER DESTABILIZE THE
ATMOSPHERE IN THIS AREA.

PRECAUTIONS...ISOLATED SEVERE STORMS ARE POSSIBLE INTO EARLY AFTERNOON
OVER SOUTH CENTRAL IOWA AND INTO SOUTHEAST IOWA THROUGHOUT THE
AFTERNOON HOURS.  EMERGENCY MANAGERS AND SPOTTERS SHOULD KEEP ABREAST
OF THE LATEST FORECASTS.

STARK

The office that day

Everything else NWS Des Moines, IA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 30, 10:26 AM CDTSevere Thunderstorm WarningDMXWayne29 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1997Every severe thunderstorm warning in 1997

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.