Alert archive / Wisconsin / Mesoscale Discussions in 2012
Mesoscale Discussion 820
The Storm Prediction Center issued this mesoscale discussion at May 15, 2012, 4:58 PM CDT for 7 counties in Illinois; 5 counties in Iowa; 9 counties in Wisconsin. It was in force for 62 min.
The area
The outline as issued.
The facts
- Issued
- May 15, 2012, 4:58 PM CDT (21:58 UTC)
- Expired
- May 15, 2012, 6:00 PM CDT
- In force
- 62 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 21 counties
Cedar County, IA, Clinton County, IA, Jackson County, IA, Jones County, IA, Linn County, IA, Boone County, IL, Carroll County, IL, Jo Daviess County, IL, McHenry County, IL, Ogle County, IL, Stephenson County, IL, Winnebago County, IL, Green County, WI, Jefferson County, WI, Kenosha County, WI, Lafayette County, WI, Milwaukee County, WI, Racine County, WI, Rock County, WI, Walworth County, WI, Waukesha County, WI
The radar
The Quad Cities radar (KDVN), 108 km from the middle of the area, began a volume at 21:59 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, 10.0 hours before the alert went out and 103 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
- 2205 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- -8 m²/s²
- 0-3 km storm-relative helicity
- 25 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
854 ACUS11 KWNS 152159 SWOMCD SPC MCD 152158 ILZ000-WIZ000-IAZ000-152300- MESOSCALE DISCUSSION 0820 NWS STORM PREDICTION CENTER NORMAN OK 0458 PM CDT TUE MAY 15 2012 AREAS AFFECTED...ECNTRL IA...NRN IL...SERN WI CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 152158Z - 152300Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...GUSTY WINDS MAY BE NOTED WITH STRONGER TSTM CORES THIS EVENING FROM SRN WI...ACROSS NRN IL INTO SERN IA. DISCUSSION...STRONG SUNSHINE HAS CONTRIBUTED TO VERY STEEP LAPSE RATES AHEAD OF COLD FRONT FROM SERN IA INTO SRN WI. SFC TEMPERATURES HAVE WARMED INTO THE MID-UPPER 80S ACROSS THIS REGION BUT DEW POINTS HAVE DROPPED AS BOUNDARY LAYER HAS DEEPENED. MODEL FORECAST DEW POINTS ACROSS THIS REGION ARE AT LEAST 10 DEG F TOO HIGH BUT NEAR DRY ADIABATIC LAPSE RATES ARE CONTRIBUTING TO HIGH BASED CONVECTION WITH BASES LIKELY NEAR 700 MB. ALTHOUGH INSTABILITY IS FAIRLY WEAK...GIVEN THE DRY SUB-CLOUD LAYER IT WOULD SEEM PLAUSIBLE THAT GUSTY WINDS MAY BE NOTED WITH STRONGER CORES. AT THIS TIME IT APPEARS DOWNBURST WINDS SHOULD REMAIN MOSTLY SUB-SEVERE AND A WATCH IS NOT ANTICIPATED. ..DARROW/CORFIDI.. 05/15/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...LOT...MKX...DVN...ARX... LAT...LON 42099176 43318870 43008741 42258795 41569118 42099176
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 2:51 PM CDT | Mesoscale Discussion | SPC | Boone, Carroll, DeKalb, DuPage, Jo Daviess, Kane and 7 more | 54 min |
Nearby
Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Illinois, 2012Mesoscale Discussions in Iowa, 2012Every mesoscale discussion in 2012
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.