Snow Update: Winter Storm Watch Warns of Potential for Heavy Snow Wednesday

Forecasting snow in the Puget Sound can be more an art form than science, but the National Weather Service issued a Winter Storm Warning Tuesday morning for "heavy snow" accumulation in the Seattle Metro area.

"Snowfall accumulations of up to 6 inches are possible" read the statement. It warned that severe winter weather conditions were likely

Forecasters say scattered rain and snow showers will begin falling Monday night and continue into Tuesday. Snow accumulations are predicted to reach at least 2 inches by Wednesday, and possibly more snowfall overnight as temperatures drop below freezing. On Thursday, cold air from Canada will keep temperatures in the 30s. 

The following is a Winter Storm Watch bulletin from the NWS: 

429 AM PST TUE FEB 22 2011

SNOW WILL CONTINUE OVER THE MOUNTAIN TODAY AND TONIGHT AS COLD AIR ALOFT AND STRONG NORTHWEST FLOW MOVES INTO WESTERN WASHINGTON. NEW SNOWFALL ACCUMULATIONS BY EARLY WEDNESDAY MORNING COULD BE AS HIGH AS 16 INCHES IN THE CASCADES AND 8 INCHES IN THE OLYMPICS.

IN THE LOWLANDS...EXPECT BRIEF AND LOCAL ACCUMULATIONS OF SLUSHY SNOW TO OCCUR THROUGH EARLY WEDNESDAY MORNING. THIS IS MOST LIKELY TO OCCUR ON HILLS ABOVE ABOUT 500 FEET THIS MORNING AND ABOVE 300 FEET TONIGHT AND EARLY WEDNESDAY MORNING...AND MAINLY WHERE CONVERGENCE ZONES SET UP IN THE NORTH INTERIOR AND NORTHERN PORTIONS OF THE EAST PUGET SOUND LOWLANDS.

AN ARCTIC AIR MASS DROPPING SOUTH FROM BRITISH COLUMBIA... COMBINED WITH DEVELOPING LOW PRESSURE OFF THE WASHINGTON COAST WILL GIVE THE POTENTIAL FOR HEAVY SNOW OVER ALL OF THE LOWLANDS OF WESTERN WASHINGTON BEGINNING WEDNESDAY AND CONTINUING INTO THURSDAY MORNING. SNOWFALL IN WESTERN WHATCOM COUNTY AND THE SAN JUAN ISLANDS WILL LIKELY BE ACCOMPANIED BY STRONG NORTHEASTERLY WINDS OF 25 TO 35 MPH AND GUSTS TO 50 MPH BY THURSDAY MORNING.

WAZ504-508-509-511-512-516-517-230015-/O.EXA.KSEW.WS.A.0004.110223T1500Z-110224T2000Z/SOUTHWEST INTERIOR-SEATTLE/BREMERTON AREA-TACOMA AREA-HOOD CANAL AREA-LOWER CHEHALIS VALLEY AREA-NORTH COAST-CENTRAL COAST-

429 AM PST TUE FEB 22 2011

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH THURSDAY MORNING FOR THE SEATTLE AREA...HOOD CANAL...SOUTHWEST INTERIOR...LOWER CHEHALIS VALLEY AND THE NORTH AND CENTRAL COAST...

* SOME AFFECTED LOCATIONS...SEATTLE...TACOMA...OLYMPIA...CHEHALIS...SHELTON...HOQUIAM AND FORKS.

* ACCUMULATIONS...SNOWFALL ACCUMULATIONS OF UP TO 6 INCHES ARE POSSIBLE.

* TIMING...WHILE BRIEF SLUSHY ACCUMULATIONS ARE POSSIBLE IN SHOWERS THROUGH EARLY WEDNESDAY MORNINGS...THE MAIN PERIOD OF SIGNIFICANT ACCUMULATING SNOW IS EXPECTED TO BEGIN OVER THE CENTRAL PUGET SOUND AREA...SOUTHWEST INTERIOR...HOOD CANAL...LOWER CHEHALIS VALLEY AND THE COAST LATE WEDNESDAY MORNING INTO WEDNESDAY AFTERNOON. THE SNOW MAY CONTINUE WEDNESDAY NIGHT INTO THURSDAY MORNING FOR FURTHER ACCUMULATIONS.

PRECAUTIONARY/PREPAREDNESS ACTIONS... 

A WINTER STORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE WINTER WEATHER. IF YOU MUST TRAVEL IN THE WATCH AREA...CARRY AN EXTRA FLASHLIGHT...FOOD...WATER...AND BLANKETS IN CASE OF EMERGENCY.