Mesoscale Discussion 72

Issued

Feb 1, 2011, 3:36 PM CST (21:36 UTC)

Expired

Feb 1, 2011, 9:30 PM CST

In force

6 hr

Issued by

the Storm Prediction Center

The Lincoln radar (KILX), 107 km from the middle of the area, began a volume at 21:40 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.

766 
ACUS11 KWNS 012137
SWOMCD
SPC MCD 012136
MIZ000-INZ000-ILZ000-WIZ000-MOZ000-IAZ000-020330-

MESOSCALE DISCUSSION 0072
NWS STORM PREDICTION CENTER NORMAN OK
0336 PM CST TUE FEB 01 2011

AREAS AFFECTED...NERN MO...SERN/CNTRL IA...NRN/CNTRL IL...SRN
WI...NWRN IND...EXTREME SWRN MI

CONCERNING...BLIZZARD

VALID 012136Z - 020330Z

HEAVY SNOW AND BLIZZARD CONDITIONS WILL OVERSPREAD PORTIONS OF THE
MID-MISSISSIPPI VALLEY REGION TOWARD LAKE MICHIGAN...INCLUDING THE
CHICAGO METRO AREA...THROUGH LATE AFTERNOON INTO THE EVENING.

THE VERY POWERFUL EXTRATROPICAL CYCLONE OVER THE CENTRAL CONUS
CONTINUES SHIFTING NEWD TOWARD THE GREAT LAKES REGION. THE
WELL-DEFINED/ASCENDING WARM CONVEYOR BELT WRAPPING CYCLONICALLY
AROUND THE LOW IS TRANSPORTING DEEP MOISTURE FROM THE GULF OF MEXICO
INTO THE OHIO VALLEY AND WWD ACROSS THE MIDWEST. TO THE NORTH OF THE
IMPINGING DRY SLOT OVER THE MID-MISSISSIPPI VALLEY REGION...HEAVY
SNOW WILL CONTINUE SHIFTING N/NEWD IN THE DEFORMATION ZONE OF THE
CYCLONE ACROSS THE DISCUSSION AREA INTO THIS EVENING.

SNOWFALL RATES OF 1 TO 2 INCHES PER HOUR WILL BE WIDESPREAD ACROSS
THE REGION...AS RUC FORECAST SOUNDINGS AND SREF INDICATE VERY DEEP
AND SATURATED DENDRITIC GROWTH ZONES /AOA 150 MB THICK/ COINCIDING
WITH STRONG ASCENT. HOWEVER...RATES OF 2 TO 3 INCHES PER
HOUR...POSSIBLY HIGHER...ARE EXPECTED IN A 120-MILE-WIDE CORRIDOR
CENTERED ALONG A LINE FROM NEAR QUINCY TO CHICAGO. IN THIS
REGION...ENHANCED MESOSCALE BANDING IS EXPECTED...AND A FEW
LIGHTNING STRIKES WILL BE POSSIBLE. THIS IS SUPPORTED BY THE 18Z NAM
MODEL...WHICH INDICATES A BROAD AREA OF SLANTWISE INSTABILITY
COINCIDING WITH FRONTOGENESIS-INDUCED ASCENT THROUGH EARLY
EVENING...AS WELL AS THE DEVELOPMENT OF UPRIGHT INSTABILITY ACROSS
CNTRL IL AFTER 00Z AS 700-500-MB LAPSE RATES STEEPEN AOA 7 C/KM.
ADDITIONALLY...MESOSCALE BANDING WILL ALSO BE ENHANCED BETWEEN
CHICAGO AND THE WI BORDER DUE TO FRICTIONAL CONVERGENCE ASSOCIATED
WITH ONSHORE FLOW OFF LAKE MICHIGAN. THE TIGHT PRESSURE GRADIENT IN
THE NWRN SEMICIRCLE OF THE SFC CYCLONE MOVING NEWD ACROSS THE OH
VALLEY REGION WILL SUPPORT STRONG NELY WINDS WITH GUSTS AOA 35
MPH...RESULTING IN BLIZZARD CONDITIONS.

THE 19Z RUN OF THE HRRR HAS BEEN CAPTURING TRENDS OF THIS SYSTEM
WELL...AND INDICATES THE HEAVY SNOW AND BLIZZARD CONDITIONS
CONTINUING THROUGH MUCH OF THE EVENING. THESE CONDITIONS WILL LIKELY
SHIFT EAST OF THE MISSISSIPPI RIVER BY 06Z...ENDING LATE IN THE
NIGHT ACROSS NRN IL.

..COHEN/ROGERS.. 02/01/2011

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

ATTN...WFO...IWX...GRR...LOT...ILX...MKX...LSX...DVN...ARX...
DMX...EAX...

LAT...LON   38869268 40059447 42129353 43098927 42518602 41408621
            40238850 38719044 38869268

Mesoscale Discussions in Illinois, 2011Mesoscale Discussions in Iowa, 2011Mesoscale Discussions in Missouri, 2011Every mesoscale discussion in 2011

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.