MESOSCALE DISCUSSION 0024
   NWS STORM PREDICTION CENTER NORMAN OK
   0635 AM CST MON JAN 17 2011
   
   AREAS AFFECTED...SERN IA...EXTREME NERN MO AND PART OF NWRN IL
   
   CONCERNING...WINTER MIXED PRECIPITATION 
   
   VALID 171235Z - 171700Z
   
   A TRANSITION FROM LIGHT SNOW TO SLEET AND LIGHT FREEZING RAIN IS
   EXPECTED TO OCCUR FROM W-E THIS MORNING.  THIS TRANSITION IN
   PRECIPITATION TYPE IS EXPECTED OVER SERN IA AND EXTREME NERN MO
   THROUGH 15Z...AND THEN INTO PART OF NWRN IL BETWEEN 15-18Z. 
   PRECIPITATION RATES HAVE BEEN GENERALLY AOB 0.05 IN/3HR...THUS
   FAR...ACROSS SRN IA...WITH LOCALIZED TOTAL AMOUNTS UP TO 0.1 INCH. 
   GIVEN THE LACK OF GREATER MOISTURE ADVECTION INTO THE MID-UPPER MS
   VALLEY...SIMILAR RATES SHOULD OCCUR THIS MORNING ACROSS THE
   DISCUSSION AREA. 
   
   EARLY MORNING WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH LOCATED
   ACROSS SRN MN INTO CENTRAL IA...WITH THIS FEATURE EXPECTED TO TRACK
   ENEWD INTO WI/FAR NRN IL BY MID DAY.  40-50 KT SWLY LLJ EXTENDING
   FROM CENTRAL KS TO CENTRAL IA PER 11Z WIND PROFILERS/WSR-88D VAD
   WILL SHIFT EWD THIS MORNING AND SHOULD EXTEND FROM NERN MO TO NRN
   IL/SERN WI AND LAKE MI BY 18Z.  DEEP LAYER ASCENT ATTENDANT TO THE
   SHORTWAVE TROUGH AND STRONG LOW LEVEL WAA ALONG THE LLJ WILL SUPPORT
   THE PRECIPITATION SHIELD SPREADING ENEWD ALONG THE TRACK OF THIS
   SYSTEM. 
   
   10Z RUC REMAINS CONSISTENT WITH EARLIER MODELS SUGGESTING THE
   PORTION OF THE 850 MB 0 C LINE IN IA/IL WILL MOVE NEWD CONCURRENT TO
   THE EWD SHIFT OF THE LLJ THIS MORNING...AND SHOULD EXTEND FROM 30 W
   CID-5 NNE MLI-10 WNW DEC BY 18Z.  THE LOCATION OF THE LLJ THROUGH
   THE MORNING IS EXPECTED TO DELINEATE THE AREA RECEIVING THE GREATEST
   POTENTIAL FOR SLEET AND LIGHT FREEZING RAIN...AS THE CONTINUED
   INCREASE IN TEMPERATURES IN THE 850-900 MB LAYER ATOP SUB-FREEZING
   SURFACE TEMPERATURES SUPPORT AN INITIAL TRANSITION TO SLEET AND THEN
   MAINLY LIGHT FREEZING RAIN.
   
   ..PETERS.. 01/17/2011
   
   
   ATTN...WFO...LOT...ILX...DVN...DMX...EAX...
   
   LAT...LON   40429325 41339308 41519241 41609135 41828979 41438913
               40599016 40419137 40429325