Alert archive / Wisconsin / Mesoscale Discussions in 2012

Mesoscale Discussion 1876

September 3, 20124 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 3, 2012, 6:59 PM CDT for 4 counties in Wisconsin. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
Sep 3, 2012, 6:59 PM CDT (23:59 UTC)
Expired
Sep 3, 2012, 8:00 PM CDT
In force
61 min
Issued by
the Storm Prediction Center

Counties Door County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI

The radar

The Green Bay radar (KGRB), 78 km from the middle of the area, began a volume at 00:00 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 12.0 hours before the alert went out and 79 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, Green Bay/Straub, WI at 12:00Z on 2012-09-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 556 joules per kilogram.LCLLFCEL10008507005003002001001 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, Green Bay/Straub, WI at 12:00Z on 2012-09-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 square meters per square second.193958Sfc1 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
556 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
677 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

951 
ACUS11 KWNS 040000
SWOMCD
SPC MCD 032359
MIZ000-WIZ000-040100-

MESOSCALE DISCUSSION 1876
NWS STORM PREDICTION CENTER NORMAN OK
0659 PM CDT MON SEP 03 2012

AREAS AFFECTED...NERN WI

CONCERNING...SEVERE THUNDERSTORM WATCH 611...

VALID 032359Z - 040100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 611
CONTINUES.

SUMMARY...WHILE AN ISOLATED STRONG WIND GUST OR TWO AND MARGINALLY
SEVERE HAIL IS STILL POSSIBLE...OVERALL SEVERE THREAT APPEARS
MARGINAL ACROSS THE REMAINING PARTS OF WW 611.

DISCUSSION...STORMS HAVE ALIGNED THEMSELVES PARALLEL TO MEAN DEEP
LAYER FLOW FROM NERN WI INTO NRN LAKE MI AND ARE TRAINING EWD WITH
SLIGHT BACKBUILDING ALONG THE WRN FLANK. PARAMETER SPACE IN THIS
REGION HAS BECOME MARGINAL FOR SEVERE STORMS. FLOW IN THE SFC-3 KM
LAYER IS WEAK...AND THE ATMOSPHERE IS NOT PARTICULARLY UNSTABLE.
PRIMARY THREAT APPEARS TO HAVE TRANSITIONED TO HEAVY RAIN...AND
SEVERE POTENTIAL IS EXPECTED TO BECOME INCREASINGLY MARGINAL WITH
ONSET OF NOCTURNAL COOLING.

..DIAL.. 09/03/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MQT...GRB...

LAT...LON   44918710 44628780 44868880 45548902 45488752 45628654
            44918710

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 3, 12:43 PM CDTMesoscale DiscussionSPCAdams, Brown, Calumet, Door, Florence, Forest and 14 more2 hr
Sep 3, 3:01 PM CDTSevere Thunderstorm WatchSPCDoor, Florence, Forest, Langlade, Lincoln, Marathon and 9 more5 hr

Nearby

Mesoscale Discussions in Wisconsin, 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.