Alert archive / Michigan / Mesoscale Discussions in 2007

Mesoscale Discussion 2003

September 21, 20077 counties in Michigan; 5 counties in Wisconsin

The Storm Prediction Center issued this mesoscale discussion at Sep 21, 2007, 7:49 PM EDT for 7 counties in Michigan; 5 counties in Wisconsin. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Sep 21, 2007, 7:49 PM EDT (23:49 UTC)
Expired
Sep 21, 2007, 9:15 PM EDT
In force
86 min
Issued by
the Storm Prediction Center

Counties Alger County, MI, Delta County, MI, Leelanau County, MI, Luce County, MI, Mackinac County, MI, Menominee County, MI, Schoolcraft County, MI, Brown County, WI, Door County, WI, Kewaunee County, WI, Manitowoc County, WI, Sheboygan County, WI

The radar

The Marquette radar (KMQT), 143 km from the middle of the area, began a volume at 23:53 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, 11.8 hours before the alert went out and 156 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 2007-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 149 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 2007-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 194 square meters per square second.19395878Sfc1 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
149 J/kg
Mixed-layer CIN
-209 J/kg
Mixed-layer LCL
1031 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
194 m²/s²
0-3 km storm-relative helicity
167 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.

000 
ACUS11 KWNS 212349
SWOMCD
SPC MCD 212349 
MIZ000-WIZ000-220115-

MESOSCALE DISCUSSION 2003
NWS STORM PREDICTION CENTER NORMAN OK
0649 PM CDT FRI SEP 21 2007

AREAS AFFECTED...EASTERN WI/U.P. OF MI

CONCERNING...TORNADO WATCH 679...

VALID 212349Z - 220115Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 679 CONTINUES.

REMAINING PORTION OF TORNADO WATCH 679 CONTINUES UNTIL 04Z...WITH A
PRIMARY RISK OF DAMAGING WIND GUSTS. A NEW/REPLACEMENT WATCH IS
LIKELY DOWNSTREAM ACROSS THE REMAINDER OF THE U.P. OF MI WITHIN THE
HOUR.

IMMEDIATE PREFRONTAL/LEADING LINE OF STRONG/SEVERE STORMS...AND A
SMALLER/SECONDARY LINE ALONG THE COLD FRONT...CONTINUES TO ADVANCE
EASTWARD ACROSS THE WESTERN U.P. OF MI AND NORTHEAST/EAST CENTRAL WI
EARLY THIS EVENING. THE STRONG AMBIENT SHEAR/EVOLUTION OF SMALL
BOWING SEGMENTS HAS BEEN FAVORABLE FOR WIND DAMAGE SINCE MID
AFTERNOON. WHILE A COOLER AIRMASS EXISTS DOWNSTREAM ACROSS THE
CENTRAL/EASTERN U.P. OF MI...STRONG LINEAR FORCING/HEIGHT FALLS AND
PRONOUNCED LOW-MID TROPOSPHERIC WIND FIELDS SUGGEST A WIND DAMAGE
THREAT MAY CONTINUE THROUGH MID/LATE EVENING...EVEN AMIDST LIMITED
SURFACE BASED BUOYANCY. THUS...AN ADDITIONAL WATCH APPEARS LIKELY
EAST OF 679 ACROSS THE REMAINDER OF THE U.P. OF MI.

..GUYER.. 09/21/2007

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

ATTN...WFO...APX...MQT...GRB...MKX...

46578729 46778533 46238436 45558571 43948703 43698774
43998823

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 21, 7:04 AM EDTSevere Thunderstorm WatchSPCGogebic, Keweenaw, Ontonagon5 hr
Sep 21, 11:24 AM EDTMesoscale DiscussionSPCMenominee66 min
Sep 21, 2:34 PM EDTMesoscale DiscussionSPCBaraga, Gogebic, Houghton, Iron, Ontonagon116 min
Sep 21, 3:46 PM EDTTornado WatchSPCBaraga, Dickinson, Gogebic, Houghton, Iron, Keweenaw and 3 more8 hr
Sep 21, 12:09 AM EDTMesoscale DiscussionSPCBarron, Burnett, Chippewa, Clark, Dunn, Eau Claire and 9 more81 min
Sep 21, 12:13 AM EDTSevere Thunderstorm WatchSPCAshland, Bayfield, Burnett, Douglas, Iron, Price and 2 more7 hr
Sep 21, 4:08 AM EDTMesoscale DiscussionSPCAshland, Bayfield, Burnett, Douglas, Iron, Price and 2 more2 hr
Sep 21, 4:17 PM EDTMesoscale DiscussionSPCCrawford, Grant, Vernon88 min
Sep 21, 4:53 PM EDTSevere Thunderstorm WatchSPCColumbia, Crawford, Grant, Green Lake, Iowa, Lafayette and 4 more4 hr
Sep 21, 7:17 PM EDTMesoscale DiscussionSPCColumbia, Dane, Dodge, Grant, Green, Iowa and 7 more88 min

Nearby

Mesoscale Discussions in Michigan, 2007Mesoscale Discussions in Wisconsin, 2007Every mesoscale discussion in 2007

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.