Alert archive / Michigan / Mesoscale Discussions in 2007

Mesoscale Discussion 2017

September 25, 200712 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Sep 25, 2007, 8:03 PM EDT for 12 counties in Michigan. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued
Sep 25, 2007, 8:03 PM EDT (00:03 UTC)
Expired
Sep 25, 2007, 9:30 PM EDT
In force
87 min
Issued by
the Storm Prediction Center

Counties Genesee County, MI, Ingham County, MI, Jackson County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Oakland County, MI, Saint Clair County, MI, Sanilac County, MI, Washtenaw County, MI, Wayne County, MI

The radar

The Detroit radar (KDTX), 5 km from the middle of the area, began a volume at 00:03 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

Detroit, MI (KDTX), launched 00:00Z, 0.1 hours before the alert went out and 8 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, Detroit, MI at 00:00Z on 2007-09-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1352 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, Detroit, MI at 00:00Z on 2007-09-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 86 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
1352 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
904 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
86 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.8

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 260004
SWOMCD
SPC MCD 260003 
MIZ000-260130-

MESOSCALE DISCUSSION 2017
NWS STORM PREDICTION CENTER NORMAN OK
0703 PM CDT TUE SEP 25 2007

AREAS AFFECTED...SOUTHEAST LOWER MICHIGAN...INTO THE THUMB OF
MICHIGAN

CONCERNING...SEVERE THUNDERSTORM WATCH 689...

VALID 260003Z - 260130Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 689
CONTINUES.

AN ADDITIONAL WW IS NOT ANTICIPATED.

ALTHOUGH BOUNDARY LAYER BASED INSTABILITY IS BEGINNING TO WANE...
STORM DEVELOPMENT ACROSS LOWER MICHIGAN MAY BE SLOWEST TO WEAKEN
THIS EVENING...PERHAPS DUE TO ENHANCED FORCING FOR UPWARD VERTICAL
MOTION ASSOCIATED WITH SIGNIFICANT UPSTREAM SHORT WAVE TROUGH NOW
LIFTING INTO THE UPPER GREAT LAKES REGION.  40-50 KT SOUTHWESTERLY
500 MB FLOW TO THE SOUTHEAST OF THIS FEATURE IS CONTRIBUTING TO
STRONG DEEP LAYER SHEAR...SUPPORTIVE OF UPDRAFT ROTATION AND THE
PRODUCTION OF SMALL TO MARGINALLY SEVERE HAIL IN RELATIVELY HIGH
MOISTURE CONTENT AIR MASS WITH PRECIPITABLE WATER NEAR 1.8 INCHES
AND CAPE IN EXCESS OF 1000 J/KG.  

DESPITE NEAR SATURATED PROFILES AND WEAK TO MODERATE LOW-LEVEL FLOW
FIELDS...MELTING HAIL MAY BE ENHANCING DOWNDRAFTS...AND...IN
CONJUNCTION WITH FAST STORM MOTIONS...CONTRIBUTING TO THE DAMAGING
WIND POTENTIAL IN STRONGEST ACTIVITY.  THIS MAY CONTINUE ACROSS
SOUTHEAST LOWER MICHIGAN...INCLUDING THE THUMB AREA...POSSIBLY THE
DETROIT METROPOLITAN AREA...THROUGH 02-03Z.  THEREAFTER...SEVERE
POTENTIAL IS EXPECTED TO DIMINISH WITH FURTHER STABILIZATION...AND
PRIMARY CONVECTIVE DEVELOPMENT WILL SHIFT EASTWARD INTO ONTARIO.

..KERR.. 09/26/2007

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

ATTN...WFO...DTX...IWX...GRR...

41958334 41858421 42098495 42438501 42798432 43148380
43448329 43558275 43518218 42878196 42308264

Nearby

Mesoscale Discussions in Michigan, 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.