Alert archive / Michigan / Mesoscale Discussions in 2007

Mesoscale Discussion 1221

June 20, 200710 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Jun 20, 2007, 7:57 PM EDT for 10 counties in Michigan. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued: Jun 20, 2007, 7:57 PM EDT (23:57 UTC)
Expired: Jun 20, 2007, 9:00 PM EDT
In force: 63 min
Issued by: the Storm Prediction Center

Counties Antrim County, MI, Benzie County, MI, Grand Traverse County, MI, Kalkaska County, MI, Lake County, MI, Manistee County, MI, Mason County, MI, Missaukee County, MI, Osceola County, MI, Wexford County, MI

The radar

The NCL Michigan radar (KAPX), 97 km from the middle of the area, began a volume at 23:59 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

Green Bay/Straub, WI (KGRB), launched 12:00Z, 12.0 hours before the alert went out and 182 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1326 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 110 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
ACUS11 KWNS 202357
SWOMCD
SPC MCD 202357 
MIZ000-210100-

MESOSCALE DISCUSSION 1221
NWS STORM PREDICTION CENTER NORMAN OK
0657 PM CDT WED JUN 20 2007

AREAS AFFECTED...NWRN LOWER MI

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 202357Z - 210100Z

POTENTIAL FOR ISOLATED SEVERE HAIL AND/OR LOCALLY STRONG WIND GUSTS
WILL BE POSSIBLE WITH ONGOING STORMS THROUGH 21/03Z.  A WW IS NOT
ANTICIPATED.

AS OF 2345Z...REGIONAL RADAR IMAGERY INDICATED A BROKEN LINE OF
TSTMS FROM CHARLEVOIX/ANTRIM SWWD TO BENZIE COUNTIES IN NRN LOWER MI
MOVING 310/35 KT. THE MOST INTENSE STORM WAS LOCATED ALONG THE ERN
SHORE OF LAKE MI APPROXIMATELY 30N MBL AT THIS TIME.  RUC FORECAST
SOUNDINGS INDICATE THAT AMBIENT THERMODYNAMIC ENVIRONMENT REMAINS
MARGINALLY UNSTABLE /SBCAPES OF AROUND 300 J PER KG/ LARGELY DUE TO
THE PRESENCE OF STEEP LOW LEVEL LAPSE RATES.

WHILE DEEP LAYER VERTICAL SHEAR WILL REMAIN QUITE SUPPORTIVE FOR
ORGANIZED...SEVERE STORMS FOR THE NEXT SEVERAL HOURS...INSTABILITY
WILL LIKELY BEGIN TO DIMINISH WITH THE LOSS OF DAYTIME HEATING.  AS
SUCH...ONGOING STORMS SHOULD TEND TO WEAKEN BY 20/02-03Z AS THEY
CONTINUE SEWD ACROSS REGION.

..MEAD.. 06/20/2007

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

ATTN...WFO...APX...GRR...

44628660 44878631 45078578 45088528 44848494 44408487
43938536 43798589 43818645

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 20, 2:52 PM EDT	Mesoscale Discussion	SPC	Alger, Baraga, Delta, Dickinson, Gogebic, Iron and 2 more	23 min
Jun 20, 3:10 PM EDT	Severe Thunderstorm Watch	SPC	Alger, Baraga, Delta, Dickinson, Gogebic, Iron and 5 more	8 hr

Nearby

Mesoscale Discussions in Michigan, 2007 Every 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.