Alert archive / Michigan / Mesoscale Discussions in 2011

Mesoscale Discussion 871

May 22, 20119 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 22, 2011, 8:09 PM EDT for 9 counties in Michigan. It was in force for 96 min.

The area

The outline as issued.

The facts

Issued: May 22, 2011, 8:09 PM EDT (00:09 UTC)
Expired: May 22, 2011, 9:45 PM EDT
In force: 96 min
Issued by: the Storm Prediction Center

Counties Antrim County, MI, Crawford County, MI, Grand Traverse County, MI, Kalkaska County, MI, Lake County, MI, Missaukee County, MI, Osceola County, MI, Otsego County, MI, Wexford County, MI

The radar

The NCL Michigan radar (KAPX), 68 km from the middle of the area, began a volume at 00:11 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 00:00Z, 0.2 hours before the alert went out and 228 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: 753 J/kg
Mixed-layer CIN: -97 J/kg
Mixed-layer LCL: 942 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 242 m²/s²
0-3 km storm-relative helicity: 325 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 7.4

Open this sounding in Storm Lab

The text

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

860 
ACUS11 KWNS 230009
SWOMCD
SPC MCD 230009 
MIZ000-230145-

MESOSCALE DISCUSSION 0871
NWS STORM PREDICTION CENTER NORMAN OK
0709 PM CDT SUN MAY 22 2011

AREAS AFFECTED...NWRN LOWER MI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 230009Z - 230145Z

A SEVERE THREAT COULD EVOLVE ACROSS NWRN PORTIONS OF LOWER MI THIS
EVENING. IT IS NOT CLEAR WHETHER A WW IS WARRANTED AT THIS TIME DUE
TO POTENTIAL LIMITING FACTORS. HOWEVER..AREA WILL CONTINUE TO BE
MONITORED...AND ANY WW ISSUANCE WILL ULTIMATELY DEPEND ON CONVECTIVE
TRENDS.

CLUSTER OF STORMS IS CROSSING LAKE MI AND APPROACHING THE COAST OF
LOWER MI. HOWEVER...DEWPOINTS ARE ONLY IN THE 50S INLAND FROM THE
COAST...AND MORE SUBSTANTIAL BOUNDARY LAYER MOISTURE RECOVERY HAS
BEEN LIMITED IN PART BY CONVECTION FARTHER SOUTH. NEVERTHELESS
OBJECTIVE ANALYSIS SHOW THE ATMOSPHERE TO BE MODERATELY UNSTABLE
WITH 1000-1500 J/KG MLCAPE. VERTICAL SHEAR IS MODEST...BUT WILL
LIKELY INCREASE LATER THIS EVENING AS THE UPPER LOW AND LLJ SHIFT
EWD. WHILE THE LOWER DEWPOINTS AND MODEST SHEAR WILL TEND TO LIMIT
TORNADO POTENTIAL...HIGH TEMPERATURE-DEWPOINTS SPREADS MAY ENHANCE
THE THREAT FOR DAMAGING WIND...BUT LOSS OF DIABATIC WARMING COULD
POTENTIALLY SERVE AS A LIMITING FACTOR.

..DIAL.. 05/23/2011

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

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

LAT...LON   43738506 43638629 44638603 45548486 45238409 43738506

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 22, 8:20 PM EDT	Mesoscale Discussion	SPC	Allegan, Barry, Berrien, Branch, Calhoun, Cass and 17 more	115 min
May 22, 8:42 PM EDT	Mesoscale Discussion	SPC	Dickinson, Iron	63 min
May 22, 10:59 PM EDT	Mesoscale Discussion	SPC	Allegan, Barry, Berrien, Branch, Calhoun, Cass and 5 more	61 min
May 23, 8:25 AM EDT	Mesoscale Discussion	SPC	Lenawee, Monroe, Washtenaw, Wayne	65 min
May 23, 12:35 PM EDT	Mesoscale Discussion	SPC	Arenac, Bay, Branch, Calhoun, Clinton, Eaton and 21 more	85 min
May 23, 2:15 PM EDT	Severe Thunderstorm Watch	SPC	Branch, Calhoun, Genesee, Hillsdale, Huron, Ingham and 13 more	8 hr
May 23, 6:40 PM EDT	Mesoscale Discussion	SPC	Hillsdale, Jackson, Lenawee, Livingston, Macomb, Monroe and 4 more	65 min

Nearby

Mesoscale Discussions in Michigan, 2011 Every mesoscale discussion in 2011

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.