Alert archive / Michigan / Mesoscale Discussions in 2012
Mesoscale Discussion 2196
The Storm Prediction Center issued this mesoscale discussion at Dec 20, 2012, 3:34 PM EST for 13 counties in Michigan. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 20, 2012, 3:34 PM EST (20:34 UTC)
- Expired
- Dec 20, 2012, 8:30 PM EST
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
Counties Antrim County, MI, Charlevoix County, MI, Cheboygan County, MI, Chippewa County, MI, Delta County, MI, Emmet County, MI, Grand Traverse County, MI, Kalkaska County, MI, Luce County, MI, Mackinac County, MI, Montmorency County, MI, Otsego County, MI, Schoolcraft County, MI
The radar
The NCL Michigan radar (KAPX), 89 km from the middle of the area, began a volume at 20:33 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
Alpena, MI (KAPX), launched 12:00Z, 8.6 hours before the alert went out and 231 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 469 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 332 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
746
ACUS11 KWNS 202034
SWOMCD
SPC MCD 202034
MIZ000-210130-
MESOSCALE DISCUSSION 2196
NWS STORM PREDICTION CENTER NORMAN OK
0234 PM CST THU DEC 20 2012
AREAS AFFECTED...NRN LOWER MI...CNTRL/ERN UPPER MI
CONCERNING...HEAVY SNOW
VALID 202034Z - 210130Z
SUMMARY...HEAVY SNOW WITH RATES OF 1-1.5 IN/HR ALONG WITH LOCALIZED
BLIZZARD CONDITIONS ARE EXPECTED TO DEVELOP BY 2200Z AND CONTINUE
INTO THE EVENING HOURS.
DISCUSSION...WATER VAPOR LOOPS DEPICT A WELL-DEFINED BAROCLINIC LEAF
STRUCTURE EVOLVING DOWNSTREAM OF A DEEP CYCLONE APPROACHING THE
CHICAGO AREA FROM THE SW. ACCOMPANYING STRONG DIVERGENCE WITHIN A
COUPLED UPPER JET STRUCTURE ATOP LOW/MID-LEVEL FRONTOGENESIS WILL
SUPPORT AN INCREASE IN SNOW RATES DURING THE NEXT FEW HOURS. DEEP
ASCENT THROUGH DENDRITIC GROWTH ZONES WITHIN THE 700-500-MB LAYER
WILL SUPPORT EFFICIENT SNOW GROWTH...WITH ISOTHERMAL PROFILES IN THE
850-700-MB LAYER YIELDING EFFICIENT SNOW AGGREGATION. SNOWFALL RATES
OF 1-1.5 INCHES WILL LIKELY BECOME COMMON BY 2200Z...AS ONE OR MORE
NE/SW-ORIENTED SNOW BANDS DEVELOP WHILE THE SFC LOW APPROACHES. THE
ENHANCED SFC PRESSURE GRADIENT WILL SUPPORT NNELY TO ENELY WINDS OF
20-25 MPH WITH GUSTS REACHING 30 TO OCCASIONALLY 35 MPH. THIS WILL
SUPPORT REDUCED VISIBILITIES TO ONE-HALF MILE IN BLOWING SNOW...AND
LOCALIZED BLIZZARD CONDITIONS MAY OCCUR. THE AREAS OF GREATEST
CONCERN FOR BLIZZARD CONDITIONS WILL BE LAKESHORE LOCATIONS IN THE
IMMEDIATE LEE OF THE GREAT LAKES...WHERE REDUCED FRICTIONAL EFFECTS
OVER THE WATER WILL BE MANIFESTED. HOWEVER...THE ABSENCE OF A
TIGHTER SFC PRESSURE GRADIENT WILL LIKELY PREVENT THE DEVELOPMENT OF
MORE WIDESPREAD BLIZZARD CONDITIONS.
..COHEN.. 12/20/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...APX...MQT...
LAT...LON 45958396 45778427 45598412 45508384 45348345 45058363
44748436 44568524 44428608 44918604 45228572 45498561
45738592 45548687 45728770 46128756 46448690 46688616
46748494 46348411 45958396Nearby
Mesoscale Discussions in Michigan, 2012Every 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.