Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 2248

December 28, 201248 counties in Indiana; 7 counties in Kentucky; 5 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Dec 28, 2012, 9:18 PM EST for 48 counties in Indiana; 7 counties in Kentucky; 5 counties in Ohio. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Dec 28, 2012, 9:18 PM EST (02:18 UTC)
Expired
Dec 29, 2012, 1:15 AM EST
In force
4 hr
Issued by
the Storm Prediction Center
All 60 counties

Bartholomew County, IN, Brown County, IN, Clark County, IN, Clay County, IN, Crawford County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Dubois County, IN, Fayette County, IN, Floyd County, IN, Franklin County, IN, Gibson County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Harrison County, IN, Hendricks County, IN, Henry County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Knox County, IN, Lawrence County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Morgan County, IN, Ohio County, IN, Orange County, IN, Owen County, IN, Perry County, IN, Pike County, IN, Putnam County, IN, Randolph County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Spencer County, IN, Sullivan County, IN, Switzerland County, IN, Union County, IN, Vanderburgh County, IN, Warrick County, IN, Washington County, IN, Wayne County, IN, Boone County, KY, Campbell County, KY, Carroll County, KY, Gallatin County, KY, Kenton County, KY, Oldham County, KY, Trimble County, KY, Butler County, OH, Hamilton County, OH, Montgomery County, OH, Preble County, OH, Warren County, OH

The radar

The Indianapolis radar (KIND), 85 km from the middle of the area, began a volume at 02:17 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

Cncnati-Daytn, OH (KILN), launched 00:00Z, 2.3 hours before the alert went out and 218 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-pSkew-T log-p diagram, Cncnati-Daytn, OH at 00:00Z on 2012-12-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cncnati-Daytn, OH at 00:00Z on 2012-12-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 square meters per square second.1939587897117136156Sfc1 km3 km6 km9 kmRMLM
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
746 m above ground
0-6 km bulk shear
98 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
207 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.

500 
ACUS11 KWNS 290219
SWOMCD
SPC MCD 290218
OHZ000-KYZ000-INZ000-ILZ000-290615-

MESOSCALE DISCUSSION 2248
NWS STORM PREDICTION CENTER NORMAN OK
0818 PM CST FRI DEC 28 2012

AREAS AFFECTED...SRN IND...FAR SWRN OH...EXTREME NRN KY

CONCERNING...HEAVY SNOW

VALID 290218Z - 290615Z

SUMMARY...MODERATE SNOWFALL WITH RATES APPROACHING 1 IN/HR WILL BE
POSSIBLE OVER THE SRN HALF OF IND...FAR SWRN OH AND EXTREME NRN KY
THROUGH 06Z.

DISCUSSION...LATEST WV IMAGERY AND 00Z UPPER AIR ANALYSIS SHOW A
SHORTWAVE TROUGH APPROACHING THE MID MS VALLEY REGION...WITH A
PRONOUNCED DRY SLOT ADVANCING INTO WRN KY/TN. LARGE-SCALE ASCENT
ASSOCIATED WITH THE TROUGH COMBINED WITH MODEST LOW TO MIDLEVEL
FRONTOGENESIS HAS AIDED IN THE DEVELOPMENT OF A PRECIPITATION SHIELD
LOCATED FROM SERN MO NEWD ACROSS SRN IL. IN ADDITION...MODEL CROSS
SECTIONS FROM S-N ACROSS THE LOWER OH VALLEY INDICATE THE PRESENCE
OF BOTH CI AND CSI...WHICH IS YIELDING MULTI-BANDED STRUCTURES
EMBEDDED WITHIN THE PRECIPITATION SHIELD. AS A RESULT...MODERATE
SNOWFALL WITH RATES NEAR 1 IN/HR HAVE BEEN OBSERVED OVER SRN IL
DURING THE LAST FEW HOURS.

AS THE UPSTREAM TROUGH CONTINUES ADVANCING EWD...BANDED SNOWFALL IS
FORECAST TO SPREAD ACROSS THE SRN HALF OF IND...PORTIONS OF SWRN OH
AND EXTREME NRN KY. SNOWFALL RATES APPROACHING 1 IN/HR WILL BE
POSSIBLE ACROSS THIS AREA FOR A FEW MORE HOURS. HOWEVER...SHORT TERM
MODEL GUIDANCE INDICATES LOW TO MIDLEVEL FRONTOGENESIS WILL WEAKEN
SUBSTANTIALLY DURING THE 03-06Z TIME PERIOD...WHICH WOULD REDUCE THE
POTENTIAL FOR HEAVY SNOWFALL RATES AS THE NIGHT PROGRESSES.

..GARNER.. 12/29/2012

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

ATTN...WFO...ILN...LMK...IND...PAH...ILX...

LAT...LON   37918762 38478775 39488736 40128602 40188480 39688410
            38848420 37898674 37918762

Nearby

Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Kentucky, 2012Mesoscale Discussions in Ohio, 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.