Alert archive / Iowa / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 80, NWS Quad Cities, IA

June 11, 1999Des Moines County, Iowa; Henderson County, Illinois

NWS Quad Cities, IA issued this severe thunderstorm warning at Jun 11, 1999, 4:43 PM CDT for Des Moines County, Iowa; Henderson County, Illinois. It was in force for 62 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: Jun 11, 1999, 4:43 PM CDT (21:43 UTC)
Expired: Jun 11, 1999, 5:45 PM CDT
In force: 62 min
Issued by: NWS Quad Cities, IA
Area: Whole counties

Counties Des Moines County, IA, Henderson County, IL

The radar

The Quad Cities radar (KDVN), 91 km from the middle of the area, began a volume at 21:43 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
Jun 11, 4:45 PM CDT	Thunderstorm Wind 52	Rozetta, IL	Winds gusting to 60 mph downed a tree.

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 nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 9.7 hours before the alert went out and 222 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: 380 J/kg
Mixed-layer CIN: -95 J/kg
Mixed-layer LCL: 1398 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

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 Quad Cities, IA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jun 11, 2:35 PM CDT, 2 hours 8 minutes earlier.

Area forecast discussion, Jun 11, 2:35 PM CDT, 2 hours 8 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
235 PM CDT FRI JUN 11 1999

WILL KEEP THIS SHORT AS RUNNING BEHIND.  KEY QUESTION TODAY IS
MOVEMENT OF SURFACE FRONT...WHICH IS CURRENTLY PROGRESSING ACROSS
CENTRAL IOWA AT ABOUT THE SAME PACE AS A PERSON CAN WALK.  WITH MOIST
AIR STREAMING NORTH FROM GULF AND UPPER SUPPORT AT 250 MB...RIGHT
REAR QUAD...WILL HAVE GOOD SHOT AT HEAVY RAIN TONIGHT...AND SATURDAY
ALSO ESPECIALLY IN ILLINOIS.  DIFFLUENT 850-300 MB THICKNESSES BEGIN
POINTING EAST INTO EAST CENTRAL ILLINOIS ON SATURDAY...AND UPPER
SUPPORT SHIFTS A LITTLE NORTH..BUT TOTAL-TOTALS...K INDICES...ETC...
STILL GOOD FOR PRECIP ACROSS FORECAST AREA SATURDAY.  SURFACE
FRONT...SUCH AS IT IS...SHOULD BE NEAR CID AT 12Z SAT...MOVING SLOWLY
TO PIA AT 12Z SUN.

WILL KEEP FLASH FLOOD WATCH IN PLACE FOR TONIGHT...AND EXTEND FOR
SATURDAY IN ILLINOIS AND ALONG MISSISSIPPI RIVER.  PRIMARY THREAT
SATURDAY LOOKS TO BE ON THE ILLINOIS SIDE.

WILL KEEP WITH CURRENT FORECAST FOR THE MOST PART...RAISING POPS A
BIT TONIGHT AND SATURDAY.  TEMPS ON TRACK ALTHOUGH MAY SHADE LOWER
SATURDAY A CATEGORY DUE TO CLOUDS/PRECIP.  TRANSITION TO LOWER POPS
WILL BE SATURDAY NIGHT IN IOWA AND SUNDAY IN ILLINOIS...ALTHOUGH WILL
NOT BE TOTALLY OUT OF WOODS...VIS-A-VIS CLOUDS... TIL SUNDAY NIGHT OR
MONDAY.

COORDINATED WITH ARX AND LOT...THANX.

.DVN...
IA...FLASH FLOOD WATCH FOR ALL OF EASTERN IOWA TONIGHT AND ALONG THE
MISSISSIPPI RIVER SATURDAY.
IL...FLASH FLOOD WATCH FOR ALL OF NORTHWEST AND WEST CENTRAL ILLINOIS
FOR TONIGHT AND SATURDAY.

ARKELL

In the hours before

Local storm report, Jun 11, 3:21 PM CDT, 1 hour 22 minutes before

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Local storm report, Jun 11, 3:21 PM CDT, 1 hour 22 minutes before

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Local storm report, Jun 11, 3:55 PM CDT, 48 minutes before

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Local storm report, Jun 11, 3:55 PM CDT, 48 minutes before

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      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
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The office that day

Everything else NWS Quad Cities, IA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 11, 6:49 PM CDT	Severe Thunderstorm Warning	DVN	Cedar	61 min
Jun 11, 5:22 PM CDT	Severe Thunderstorm Warning	DVN	Mercer	48 min
Jun 11, 5:24 PM CDT	Severe Thunderstorm Warning	DVN	Bureau	36 min
Jun 11, 5:45 PM CDT	Severe Thunderstorm Warning	DVN	Whiteside	50 min

Nearby

Severe Thunderstorm Warnings in Iowa, 1999 Severe Thunderstorm Warnings in Illinois, 1999 Every severe thunderstorm warning in 1999

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.