MESOSCALE DISCUSSION 0168
   NWS STORM PREDICTION CENTER NORMAN OK
   0622 PM CST FRI FEB 27 2009
   
   AREAS AFFECTED...ERN NEB...SWRN IA...NERN KS...NWRN MO
   
   CONCERNING...HEAVY SNOW 
   
   VALID 280022Z - 280415Z
   
   MODERATE TO HEAVY SNOWFALL IS STILL BEING OBSERVED ACROSS SERN SD
   AND ERN NEB. EXPECT SNOW TO GRADUALLY SHIFT SEWD WITH THE HEAVIEST
   SNOW SPREADING INTO SWRN IA...NERN KS...AND NWRN MO. RATES NEAR 1
   INCH AN HOUR WILL BE POSSIBLE OVER THE NEXT FEW HOURS BEFORE
   TAPERING OFF.
   
   A STRONG SHORT WAVE TROUGH THAT HAS BEEN CONTRIBUTING TO
   MODERATE/HEAVY SNOWFALL ACROSS S CNTRL SD/CNTRL NEB THIS AFTERNOON
   IS NOW CENTERED ROUGHLY OVER SWRN SD. THE LOW WILL CONTINUE TO
   PROGRESS SSEWD...BECOMING POSITIONED OVER CNTRL NEB BY 06Z.
   MEANWHILE...23Z SURFACE ANALYSIS SHOWS AN INVERTED TROUGH DEVELOPING
   FROM CNTRL MO NNWWD INTO ERN SD. PRECIPITATION HAS BEEN SLOWLY
   DEVELOPING ALONG THIS TROUGH AXIS...AND IN CONJUNCTION WITH
   FAVORABLE JET DYNAMICS/UPPER DIVERGENCE. 850/700 MB FLOW FROM THE
   S/SE IN ADDITION TO ONGOING PRECIPITATION HAS AIDED IN SATURATING
   LOW LEVELS AND PROVIDING MOISTURE FOR MODERATE/HEAVY SNOW...AND 22Z
   GOES SOUNDING ANALYSIS REFLECTS A LOCALIZED AREA OF HIGHER PWAT NEAR
   THE NEB/IA/KS/MO BORDERS...WHILE THE 00Z OAX SOUNDING REFLECTS A
   NEARLY SATURATED COLUMN FROM THE SFC THROUGH 500 MB. AN ISOTHERMAL
   LAYER REMAINS FROM 850 TO 700 MB BENEATH THE DENDRITIC GROWTH
   LAYER...SUPPORTIVE OF MDT/HVY SNOWFALL. EXPECT THIS TREND TO
   CONTINUE OVER THE OUTLINED AREA FOR THE NEXT FEW HOURS...WITH
   LOCALIZED RATES NEAR 1 INCH PER HOUR. SNOW WILL GRADUALLY TAPER OFF
   FROM NW TO SE AS THE UPPER LOW MOVES SSEWD AND LOW LEVEL FLOW VEERS
   TO THE NW...ADVECTING DRIER AIR IN.
   
   ..HURLBUT.. 02/28/2009
   
   
   ATTN...WFO...DMX...EAX...FSD...OAX...TOP...GID...LBF...
   
   LAT...LON   39899352 38489499 39169682 40659898 42229877 42749755
               41619454 39899352