Alert archive / Indiana / Mesoscale Discussions in 2015

Mesoscale Discussion 49

February 1, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Feb 1, 2015, 7:43 AM CST for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Feb 1, 2015, 7:43 AM CST (13:43 UTC)
Expired
Feb 1, 2015, 1:15 PM CST
In force
6 hr
Issued by
the Storm Prediction Center
All 42 counties

Cook County, IL, DuPage County, IL, Ford County, IL, Grundy County, IL, Iroquois County, IL, Kankakee County, IL, Kendall County, IL, LaSalle County, IL, Livingston County, IL, Will County, IL, Allen County, IN, Benton County, IN, Cass County, IN, DeKalb County, IN, Elkhart County, IN, Fulton County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Wabash County, IN, White County, IN, Whitley County, IN, Berrien County, MI, Branch County, MI, Cass County, MI, Saint Joseph County, MI, Defiance County, OH, Henry County, OH, Paulding County, OH, Williams County, OH

The radar

The Northern Indiana radar (KIWX), 86 km from the middle of the area, began a volume at 13:45 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 12:00Z, 1.7 hours before the alert went out and 204 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, Lincoln, IL at 12:00Z on 2015-02-01Temperature 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, Lincoln, IL at 12:00Z on 2015-02-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 387 square meters per square second.1939587897Sfc1 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
461 m above ground
0-6 km bulk shear
67 kt
0-1 km storm-relative helicity
387 m²/s²
0-3 km storm-relative helicity
516 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.

313 
ACUS11 KWNS 011343
SWOMCD
SPC MCD 011343 
OHZ000-MIZ000-INZ000-ILZ000-011915-

MESOSCALE DISCUSSION 0049
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CST SUN FEB 01 2015

AREAS AFFECTED...PORTIONS OF NRN ILLINOIS...NRN INDIANA...SRN LOWER
MICHIGAN...NWRN OHIO

CONCERNING...HEAVY SNOW 

VALID 011343Z - 011915Z

SUMMARY...AREAS OF HEAVY SNOW WITH RATES TO 1 INCH PER HOUR WILL
SPREAD ACROSS THE REGION THROUGH THE DAY.

DISCUSSION...SFC PRESSURE FALLS OF 2-3 MB PER 2 HOURS ARE ANALYZED
ACROSS THE MID-MS VALLEY TO PORTIONS OF NRN IL/INDIANA...REFLECTING
THE LOW-LEVEL WAA REGIME IN PLACE AHEAD OF SFC LOW PRESSURE ANALYZED
NEAR KANSAS CITY. RELATED ISENTROPIC ASCENT IS SUPPORTING WIDESPREAD
PRECIPITATION IN THIS REGIME...WITH MODERATE TO OCCASIONALLY HEAVY
SNOW BEING REPORTED ACROSS PARTS OF NRN IL. AS THE SFC LOW DEVELOPS
EWD/ENEWD WHILE DEEPENING AND LOW-LEVEL FRONTOGENESIS
CORRESPONDINGLY BECOMES ENHANCED...PRECIPITATION WILL FURTHER
INCREASE IN COVERAGE AND INTENSITY ACROSS THE DISCUSSION
AREA...WHERE WET-BULB ZERO HEIGHTS WILL REMAIN SUFFICIENTLY LOW/AT
THE GROUND IN SUPPORT OF SNOW PER THE 12Z ILX RAOB AND RAP FORECAST
SOUNDINGS. THE STRONGER WAA AND ASSOCIATED LLJ-ENHANCED ASCENT WILL
SHIFT EWD THROUGH THE DAY. AS SUCH...SNOWFALL RATES TO 1 INCH PER
HOUR WILL GRADUALLY SPREAD EWD AS WELL -- REACHING NWRN OHIO
AROUND/AFTER 18Z. ALSO OF NOTE...STRENGTHENING NELY WINDS TO THE NW
OF THE SFC CYCLONE WILL COMBINE WITH LINGERING LIGHT TO MODERATE
SNOW ACROSS NERN IL TO ENCOURAGE BLOWING/DRIFTING OF SNOW AND VERY
LOW VISIBILITIES BY THIS AFTERNOON. THIS INCLUDES THE CHICAGO AREA
AND SURROUNDING COMMUNITIES.

..COHEN/CARLAW.. 02/01/2015

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

ATTN...WFO...CLE...DTX...IWX...IND...LOT...ILX...DVN...

LAT...LON   41988761 41538935 40778913 40438808 40588673 40838506
            41118383 41828431 42068552 41988761

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 31, 10:13 PM CSTMesoscale DiscussionSPCBureau, Hancock, Henderson, Henry, Knox, LaSalle and 11 more6 hr
Feb 1, 1:35 PM CSTMesoscale DiscussionSPCAllen, DeKalb, LaGrange, Noble, Steuben, Whitley6 hr

Nearby

Mesoscale Discussions in Indiana, 2015Mesoscale Discussions in Illinois, 2015Mesoscale Discussions in Michigan, 2015Every mesoscale discussion in 2015

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.