MESOSCALE DISCUSSION 0120
   NWS STORM PREDICTION CENTER NORMAN OK
   1030 AM CST WED FEB 23 2011
   
   AREAS AFFECTED...PORTIONS OF NWRN WA INVOF THE PUGET SOUND
   
   CONCERNING...HEAVY SNOW 
   
   VALID 231630Z - 232030Z
   
   SNOWFALL RATES REACHING OR EXCEEDING 1" PER HOUR LOCALLY CAN BE
   EXPECTED INTO THIS AFTERNOON.
   
   LATEST RADAR IMAGERY SHOWS A CONCENTRATED AREA OF HEAVIER
   PRECIPITATION OVER ERN PORTIONS OF THE STRAIT OF JUAN DE FUCA AND
   FAR NRN PORTIONS OF PUGET SOUND -- WITH IR LOOP CONFIRMING THE
   INCREASING ASCENT WITH SUBSTANTIAL CLOUD-TOP COOLING.
   
   THE ASCENT IS BEING FOCUSED ON THE MESOSCALE BY A VERY SMALL LOW IN
   ERN PORTIONS OF THE STRAIT...WITH A CLEAR CIRCULATION EVIDENT IN
   LATEST SURFACE MESOANALYSIS ACROSS THIS AREA.  AS THE LARGER-SCALE
   UPPER TROUGH SHIFTS SLOWLY SWD/SSEWD...A CORRESPONDING SWD SHIFT OF
   THIS MESOLOW APPEARS POSSIBLE -- WHICH SHOULD ALLOW HEAVIER SNOWFALL
   RATES TO SPREAD ACROSS NRN AND INTO CENTRAL PORTIONS OF THE PUGET
   SOUND OVER THE NEXT FEW HOURS.  WHILE ATTM IT APPEARS THAT SNOW MAY
   REMAIN NORTH OF DOWNTOWN SEATTLE OVER THE NEXT FEW HOURS...STEADIER
   SNOWFALL COULD POSSIBLY REACH SEATTLE THIS AFTERNOON.
   
   ..GOSS.. 02/23/2011
   
   
   ATTN...WFO...SEW...
   
   LAT...LON   47852316 48032338 48262368 48662351 48652271 47942214
               47552229 47512292 47852316