Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 115

February 10, 2012LaPorte County, Porter County, Starke County, Indiana; Berrien County, Michigan

The Storm Prediction Center issued this mesoscale discussion at Feb 10, 2012, 11:50 PM CST for LaPorte County, Porter County, Starke County, Indiana; Berrien County, Michigan. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Feb 10, 2012, 11:50 PM CST (05:50 UTC)
Expired: Feb 11, 2012, 3:45 AM CST
In force: 4 hr
Issued by: the Storm Prediction Center

Counties LaPorte County, IN, Porter County, IN, Starke County, IN, Berrien County, MI

The radar

The Northern Indiana radar (KIWX), 95 km from the middle of the area, began a volume at 05:51 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

Lincoln, IL (KILX), launched 00:00Z, 5.8 hours before the alert went out and 220 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: 674 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: -133 m²/s²
0-3 km storm-relative helicity: 64 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.

863 
ACUS11 KWNS 110550
SWOMCD
SPC MCD 110550 
INZ000-MIZ000-110945-

MESOSCALE DISCUSSION 0115
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM CST FRI FEB 10 2012

AREAS AFFECTED...NWRN IND...FAR SWRN LOWER MI

CONCERNING...HEAVY SNOW 

VALID 110550Z - 110945Z

A PERSISTENT AND WELL-DEFINED LAKE EFFECT SNOW BAND CONTINUES TO
PRODUCE HEAVY SNOWFALL OVER LAKE AND PORTER COUNTIES IND /PER 0545Z
RADAR REFLECTIVITY IMAGE/. VWP DATA FROM LOT/IWX SHOW NEARLY
UNIDIRECTIONAL NLY FLOW EXTENDING THROUGH AT LEAST 2 KM AGL. WITH
TIME...SLIGHT BACKING OF LOW-LEVEL FLOW OVER SRN LAKE MICHIGAN IS
FORECAST TO OCCUR /AS SUPPORTED BY 00Z WRF-NMM AND 03Z
WRF-HRRR/...WHICH WILL RESULT IN A GRADUAL EWD SHIFT OF THE LAKE
EFFECT BAND...EVENTUALLY REACHING PORTIONS OF FAR SWRN LOWER MI AND
AREAS E OF VPZ IN NWRN IND /LIKELY BY 10Z/. 

THERMODYNAMIC PROFILES OVER SRN LAKE MICHIGAN CONTINUE TO REMAIN
FAVORABLE FOR GENERATION OF HEAVY SNOWFALL GIVEN THE PRESENCE OF A
COLD ARCTIC AIR MASS...WITH RUC/NAM POINT FORECAST SOUNDINGS SHOWING
STEEP LAPSE RATES EXTENDING UP TO 2.5 KM AGL...AND EL TEMPERATURES
BELOW -20C. THESE CONDITIONS WILL CONTINUE TO SUPPORT SNOWFALL RATES
OF 1-2 INCH/HR...WITH LOCALLY HIGHER AMOUNTS OCCASIONALLY OBSERVED.
ADDITIONALLY...SUSTAINED SFC WINDS OF 20-25 MPH COULD RESULT IN
LOCALLY REDUCED VISIBILITIES.

..ROGERS.. 02/11/2012

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

ATTN...WFO...IWX...LOT...

LAT...LON   41608734 41218732 41078715 41008685 41278641 41608630
            42018631 42098644 42028653 41848670 41698696 41608734

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 10, 7:53 PM CST	Mesoscale Discussion	SPC	Jasper, Lake, LaPorte, Newton, Porter, Starke	4 hr

Nearby

Mesoscale Discussions in Indiana, 2012 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.