Alert archive / Iowa / Mesoscale Discussions in 2016
Mesoscale Discussion 1721
The Storm Prediction Center issued this mesoscale discussion at Sep 19, 2016, 5:07 PM CDT for 4 states. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Sep 19, 2016, 5:07 PM CDT (22:07 UTC)
- Expired
- Sep 19, 2016, 7:00 PM CDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
All 77 counties
Allamakee County, IA, Appanoose County, IA, Benton County, IA, Black Hawk County, IA, Buchanan County, IA, Cedar County, IA, Clarke County, IA, Clayton County, IA, Clinton County, IA, Davis County, IA, Decatur County, IA, Delaware County, IA, Des Moines County, IA, Dubuque County, IA, Fayette County, IA, Henry County, IA, Iowa County, IA, Jackson County, IA, Jasper County, IA, Jefferson County, IA, Johnson County, IA, Jones County, IA, Keokuk County, IA, Lee County, IA, Linn County, IA, Louisa County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Muscatine County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Scott County, IA, Tama County, IA, Van Buren County, IA, Wapello County, IA, Warren County, IA, Washington County, IA, Wayne County, IA, Carroll County, IL, Henderson County, IL, Henry County, IL, Jo Daviess County, IL, Mercer County, IL, Rock Island County, IL, Stephenson County, IL, Warren County, IL, Whiteside County, IL, Winnebago County, IL, Harrison County, MO, Mercer County, MO, Putnam County, MO, Schuyler County, MO, Columbia County, WI, Crawford County, WI, Dane County, WI, Dodge County, WI, Grant County, WI, Green County, WI, Iowa County, WI, Jefferson County, WI, Lafayette County, WI, Milwaukee County, WI, Ozaukee County, WI, Racine County, WI, Richland County, WI, Rock County, WI, Sauk County, WI, Sheboygan County, WI, Vernon County, WI, Walworth County, WI, Washington County, WI, Waukesha County, WI
The radar
The Quad Cities radar (KDVN), 55 km from the middle of the area, began a volume at 22:07 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Davenport, (KDVN), launched 12:00Z, 10.1 hours before the alert went out and 60 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1974 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 117 m²/s²
- 0-3 km storm-relative helicity
- 125 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
992
ACUS11 KWNS 192208
SWOMCD
SPC MCD 192207
WIZ000-ILZ000-IAZ000-MOZ000-200000-
MESOSCALE DISCUSSION 1721
NWS STORM PREDICTION CENTER NORMAN OK
0507 PM CDT MON SEP 19 2016
AREAS AFFECTED...ERN IA...SRN WI...NRN IL
CONCERNING...SEVERE THUNDERSTORM WATCH 483...
VALID 192207Z - 200000Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 483
CONTINUES.
SUMMARY...SCATTERED STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE TO
THREATEN PARTS OF SOUTHERN WI...EASTERN IA...AND NORTHERN IL THIS
EVENING. HOWEVER...A GENERAL WEAKENING TREND WITH TIME IS LIKELY.
DISCUSSION...LATEST RADAR LOOPS SHOW MULTIPLE BROKEN LINES OF
INTENSE THUNDERSTORMS. ONE LINE IS AFFECTING PARTS OF
SOUTHERN/SOUTHEASTERN WI AND WILL APPROACH THE MKE AREA WITHIN THE
HOUR. ANOTHER SHORT LINE OF STORMS IS OVER POWESHIEK/
JASPER/MARION/LUCAS COUNTIES IA. AND FINALLY...CONVECTION HAS
RE-DEVELOPED WEST OF THE INITIAL STORMS ALONG A LINE FROM CENTRAL WI
INTO EXTREME NORTHEAST IA. ALL OF THIS ACTIVITY IS TRACKING
EAST-SOUTHEASTWARD AT 30-35 KNOTS.
THE STORMS ARE IN A RELATIVELY NARROW INSTABILITY AXIS...WHICH
SUGGESTS A SLOW WEAKENING TREND WILL OCCUR AS ACTIVITY MOVES INTO
MORE STABLE AIR OVER NORTHERN IL. NEVERTHELESS...THE STRONGEST
CELLS WILL POSE A RISK OF DAMAGING WIND GUSTS AND LARGE HAIL.
OVER IA...FAVORABLE VERTICAL SHEAR AND STEEP MID LEVEL LAPSE RATES
WILL MAINTAIN SOME RISK OF INTENSIFICATION OF ONGOING STORMS TO THE
EAST OF DSM. MORE PROMINENT SUPERCELL CHARACTERISTICS IN THESE
STORMS SUGGEST SOME RISK OF AN ISOLATED TORNADO...ALONG WITH LARGE
HAIL AND DAMAGING WINDS.
..HART/DIAL.. 09/19/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LOT...ILX...MKX...DVN...ARX...DMX...EAX...
LAT...LON 41819368 43599098 43818743 42748712 42448866 42198936
40819056 40359270 40299397 40669450 41819368SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 19, 2:02 PM CDT | Mesoscale Discussion | SPC | Carroll, Jo Daviess, Stephenson | 58 min |
| Sep 19, 2:55 PM CDT | Tornado Watch | SPC | Jo Daviess, Rock Island | 4 hr |
| Sep 19, 2:31 PM CDT | Severe Thunderstorm Watch | SPC | Clayton | 3 hr |
| Sep 19, 5:47 PM CDT | Mesoscale Discussion | SPC | Appanoose, Davis, Wayne | 118 min |
| Sep 19, 6:27 PM CDT | Tornado Watch | SPC | Caldwell, Daviess, Grundy, Harrison, Linn, Livingston and 4 more | 4 hr |
| Sep 19, 2:19 PM CDT | Mesoscale Discussion | SPC | Columbia, Dane, Dodge, Fond du Lac, Green Lake, Iowa and 7 more | 26 min |
Nearby
Mesoscale Discussions in Iowa, 2016Mesoscale Discussions in Wisconsin, 2016Mesoscale Discussions in Illinois, 2016Every mesoscale discussion in 2016
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.