000
ACUS11 KWNS 120453
SWOMCD
SPC MCD 120452
INZ000-MIZ000-ILZ000-IAZ000-MOZ000-121045-

MESOSCALE DISCUSSION 0175
NWS STORM PREDICTION CENTER NORMAN OK
1152 PM CDT TUE MAR 11 2014

AREAS AFFECTED...NERN MO/SERN IA/NRN IL/NRN IND/FAR SWRN LOWER MI

CONCERNING...HEAVY SNOW

VALID 120452Z - 121045Z

SUMMARY...THE PRECIP TYPE WILL CONTINUE TO TRANSITION FROM RAIN TO
SNOW FROM WEST TO EAST ACROSS THE DISCUSSION AREA.  SNOWFALL RATES
ARE EXPECTED TO INCREASE TO 1 INCH/HR /LOCALLY 2 INCH/HR POSSIBLE/
OVER NERN MO AND SERN IA THROUGH 09Z...WITH THESE SNOWFALL RATES
DEVELOPING OVER NRN IL /INCLUDING THE CHICAGO METRO AREA/ INTO NWRN
IND AND FAR SWRN LOWER MI BETWEEN 06-09Z.  GIVEN THE EWD TRANSITION
OF THIS STORM SYSTEM...THE HEAVY SNOWFALL RATES SHOULD DIMINISH OVER
NERN MO/SERN IA AFTER 09Z.

DISCUSSION...AT 04Z...A SURFACE LOW WAS LOCATED JUST EAST OF STL
WITH THIS LOW ATTENDANT TO A PROGRESSIVE SHORTWAVE TROUGH...
CURRENTLY MOVING EWD ACROSS NRN MO.  WHILE EACH OF THESE SYNOPTIC
FEATURES WILL TRACK EWD OVERNIGHT...WITH THE SURFACE LOW DEEPENING
AND REACHING SWRN IND BY 09Z...A LARGER-SCALE TROUGH WILL AMPLIFY
SEWD ACROSS THE UPPER MS VALLEY.  90-120 METER 500-MB HEIGHT FALLS
ARE EXPECTED INTO LOWER MI AND THE LOWER OH VALLEY THROUGH 12Z.
STRENGTHENING NLY LOW LEVEL WINDS ACROSS THE DISCUSSION AREA WILL
SUPPORT COLD AIR ADVECTION TO AID IN RAIN CHANGING TO SNOW FROM WEST
TO EAST AS THE SURFACE LOW AND ATTENDANT MID LEVEL TROUGH TRACK EWD.
STRONG FORCING FOR ASCENT ATTENDANT TO THE TWO MID-LEVEL TROUGHS AND
FURTHER ENHANCED BY STRENGTHENING FRONTOGENETIC FORCING IN THE
850-700 MB LAYER FROM SERN IA/NERN MO TO SWRN LOWER MI/NRN IND
THROUGH 06-09Z WILL SUPPORT A BAND OF HEAVY SNOWFALL RATES.

..PETERS.. 03/12/2014

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

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

LAT...LON   42228605 41828586 40968676 40668726 40388794 39988916
            39879021 39629150 39539290 39639349 40349329 40809263
            41099150 41359060 41558960 41988785 42228605