Alert archive / Iowa / Severe Thunderstorm Watches in 2000

Severe Thunderstorm Watch 709

August 26, 20008 counties in Illinois; 19 counties in Iowa; 8 counties in Missouri

The Storm Prediction Center issued this severe thunderstorm watch at Aug 26, 2000, 4:00 PM CDT for 8 counties in Illinois; 19 counties in Iowa; 8 counties in Missouri. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 26, 2000, 4:00 PM CDT (21:00 UTC)
Expired: Aug 26, 2000, 9:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 35 counties

Cedar County, IA, Davis County, IA, Des Moines County, IA, Henry County, IA, Iowa County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Keokuk County, IA, Lee County, IA, Louisa County, IA, Mahaska County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Poweshiek County, IA, Van Buren County, IA, Wapello County, IA, Washington County, IA, Adams County, IL, Brown County, IL, Hancock County, IL, Henderson County, IL, McDonough County, IL, Pike County, IL, Schuyler County, IL, Scott County, IL, Adair County, MO, Clark County, MO, Knox County, MO, Lewis County, MO, Marion County, MO, Schuyler County, MO, Scotland County, MO, Shelby County, MO

The radar

The Quad Cities radar (KDVN), 142 km from the middle of the area, began a volume at 21:04 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, 9.0 hours before the alert went out and 148 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: 2208 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 706 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

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

989 
WWUS9 KMKC 262045
SEL9  

SEL9
MKC WW 262040
IAZ000-ILZ000-MOZ000-270200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 709
STORM PREDICTION CENTER NORMAN OK
340 PM CDT SAT AUG 26 2000

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   SOUTHEAST IOWA
   WEST CENTRAL ILLINOIS
   NORTHEAST MISSOURI

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 400 PM UNTIL 900
PM CDT.

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

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 55 STATUTE MILES
EAST AND WEST OF A LINE FROM 30 MILES WEST NORTHWEST OF CEDAR
RAPIDS IOWA TO 25 MILES SOUTH SOUTHWEST OF QUINCY ILLINOIS.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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...STORMS EXPECTED TO RAPIDLY DEVELOP INTO SERN IA WHERE
AIRMASS NOW VERY UNSTABLE AND WEAK SURFACE BOUNDARY IS PUSHING SWD.
WITH UPPER TROUGH AND ASSOCIATED MID LEVEL NWLY WIND MAX CROSSING
AREA...SHEARS PROFILES WILL SUPPORT SEVERE THUNDERSTORMS POSSIBLY
EVOLVING INTO BOW ECHOES.


AVIATION...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 600.  MEAN STORM
MOTION VECTOR 33025.


...HALES

420,0911 393,0902 393,0922 420,0931

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 26, 4:00 AM CDT	Severe Thunderstorm Watch	SPC	Allamakee, Black Hawk, Bremer, Buchanan, Butler, Cerro Gordo and 11 more	4 hr
Aug 26, 5:00 PM CDT	Severe Thunderstorm Watch	SPC	Audrain, Barton, Bates, Benton, Boone, Callaway and 31 more	5 hr

Nearby

Severe Thunderstorm Watches in Iowa, 2000 Severe Thunderstorm Watches in Illinois, 2000 Severe Thunderstorm Watches in Missouri, 2000 Every severe thunderstorm watch in 2000

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.