Alert archive / Michigan / Mesoscale Discussions in 2012

Mesoscale Discussion 947

May 28, 201215 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at May 28, 2012, 8:42 PM EDT for 15 counties in Michigan. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued: May 28, 2012, 8:42 PM EDT (00:42 UTC)
Expired: May 28, 2012, 10:15 PM EDT
In force: 93 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Barry County, MI, Calhoun County, MI, Clare County, MI, Clinton County, MI, Eaton County, MI, Gratiot County, MI, Ionia County, MI, Isabella County, MI, Kalamazoo County, MI, Kent County, MI, Lake County, MI, Mecosta County, MI, Montcalm County, MI, Newaygo County, MI, Osceola County, MI

The radar

The Grand Rapids radar (KGRR), 19 km from the middle of the area, began a volume at 00:41 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, 0.7 hours before the alert went out and 172 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: 455 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 2268 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 179 m²/s²
0-3 km storm-relative helicity: 297 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.2

Open this sounding in Storm Lab

The text

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

029 
ACUS11 KWNS 290042
SWOMCD
SPC MCD 290042 
MIZ000-290215-

MESOSCALE DISCUSSION 0947
NWS STORM PREDICTION CENTER NORMAN OK
0742 PM CDT MON MAY 28 2012

AREAS AFFECTED...CNTRL AND SRN LOWER MI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 290042Z - 290215Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...STORMS MAY POSE SOME RISK FOR ISOLATED DAMAGING WIND AND
HAIL AS THEY CROSS LAKE MI AND MOVE ONTO THE WRN LOWER MI COAST.
OVERALL MAGNITUDE OF THREAT IS SOMEWHAT UNCERTAIN...SO WW ISSUANCE
WILL ULTIMATELY DEPEND ON CONVECTIVE TRENDS.

DISCUSSION...STORMS DEVELOPING ALONG A CONSOLIDATED OUTFLOW BOUNDARY
APPEAR TO BE MAINTAINING THEIR INTENSITY AS THEY CROSS LAKE MI. THE
STORMS ARE DEVELOPING WITHIN A ZONE OF MODEST HEIGHT FALLS
ASSOCIATED WITH AN IMPULSE EJECTING NEWD WITHIN THE ERN PERIPHERY OF
SYNOPTIC UPPER TROUGH. ACTIVITY IS ALSO EMBEDDED WITHIN 35-40 KT
EFFECTIVE UNIDIRECTIONAL SHEAR. HOWEVER...THE DOWNSTREAM
THERMODYNAMIC ENVIRONMENT OVER LOWER MI IS SOMEWHAT MARGINAL. BOTH
THE DETROIT AND ALPENA 00Z RAOB DATA INDICATED ONLY AROUND 500 J/KG
MLCAPE...AND SURFACE BASED INSTABILITY WILL DECREASE FURTHER AS THE
BOUNDARY LAYER STABILIZES. THIS RAISES UNCERTAINTY REGARDING
LONGEVITY AND EXTENT OF SEVERE THREAT. NEVERTHELESS...GIVEN THE
FAVORABLE KINEMATIC ENVIRONMENT POTENTIAL WILL EXIST FOR ORGANIZED
STORMS INCLUDING BOWING SEGMENTS WITH A THREAT FOR ISOLATED WIND
DAMAGE AND POSSIBLY SOME HAIL AS STORMS APPROACH THE LOWER MI COAST.

..DIAL/HART.. 05/29/2012

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

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

LAT...LON   43038614 44118622 44228496 43548438 42248446 42098541
            42218622 43038614

Nearby

Mesoscale Discussions in Michigan, 2012 Every 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.