Alert archive / Wisconsin / Mesoscale Discussions in 2012
Mesoscale Discussion 1870
The Storm Prediction Center issued this mesoscale discussion at Sep 3, 2012, 1:43 PM EDT for 9 counties in Michigan; 20 counties in Wisconsin. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 3, 2012, 1:43 PM EDT (17:43 UTC)
- Expired
- Sep 3, 2012, 3:45 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 29 counties
Alger County, MI, Charlevoix County, MI, Chippewa County, MI, Delta County, MI, Dickinson County, MI, Luce County, MI, Mackinac County, MI, Menominee County, MI, Schoolcraft County, MI, Adams County, WI, Brown County, WI, Calumet County, WI, Door County, WI, Florence County, WI, Forest County, WI, Kewaunee County, WI, Langlade County, WI, Lincoln County, WI, Marathon County, WI, Marinette County, WI, Menominee County, WI, Oconto County, WI, Outagamie County, WI, Portage County, WI, Shawano County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI, Wood County, WI
The radar
The Marquette radar (KMQT), 135 km from the middle of the area, began a volume at 17:42 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
Green Bay/Straub, WI (KGRB), launched 12:00Z, 5.7 hours before the alert went out and 144 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
- 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
The text
As transmitted, in the capitals the NWS used until 2016.
492
ACUS11 KWNS 031744
SWOMCD
SPC MCD 031743
MIZ000-WIZ000-031945-
MESOSCALE DISCUSSION 1870
NWS STORM PREDICTION CENTER NORMAN OK
1243 PM CDT MON SEP 03 2012
AREAS AFFECTED...WI INTO UPPER MI
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 031743Z - 031945Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...STORMS SHOULD GRADUALLY INCREASE INTO THE AFTERNOON WITH
SEVERE HAIL AND WIND POSSIBLE.
DISCUSSION...STORMS ARE NOW INCREASING NEAR A WEAK SFC PRESSURE
TROUGH FROM CNTRL UPPER MI INTO NRN WI...AND ALSO WITHIN THE
INSTABILITY AXIS WHERE DEWPOINTS HAVE RISEN INTO THE 65-70 F RANGE.
WITH CONTINUED COOLING ALOFT AND HEIGHT FALLS WITH THE UPPER
TROUGH...AND SFC HEATING...A GENERAL INCREASE IN STORM INTENSITY IS
LIKELY. ALTHOUGH LOW LEVEL WINDS ARE WEAK...MID TO UPPER LEVEL SHEAR
IS ROBUST AND SHOULD FAVOR A FEW SUPERCELLS OR SMALL BOWS CAPABLE OF
BOTH LARGE HAIL AND DAMAGING WIND GUSTS.
..JEWELL/CORFIDI.. 09/03/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...APX...MQT...GRB...MKX...ARX...
LAT...LON 44438735 43958800 43798883 43949002 44809050 45498994
46198799 46548664 46798502 46688443 46588410 46268390
45988384 45808502 45028658 44438735SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 3, 4:01 PM EDT | Severe Thunderstorm Watch | SPC | Alger, Chippewa, Delta, Dickinson, Iron, Luce and 4 more | 5 hr |
| Sep 3, 7:59 PM EDT | Mesoscale Discussion | SPC | Door, Marinette, Menominee, Oconto | 61 min |
Nearby
Mesoscale Discussions in Wisconsin, 2012Mesoscale Discussions in Michigan, 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.