Moderately major

Here's the Western USA NWS mosaic of various warnings, watches and what not. Most of the Pacific NW and what some people call tine "Inland Northwest" is blanketed by winter storm warnings and watches. Snow is progged to start today over most of this area and then gain momentum during the night and on Christmas Day. Idaho Falls is progged to get anywhere from 4-8 inches total during that 36-hour time frame.

Meanwhile, there's some ominous chunks of water vapor gathering steam out in the Pacific. They are moving this way pretty fast, too. It's a long read but check out the 3 am Portland NWS Discussion for 24DEC.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...AVAILABLE GUIDANCE ALL SEEMS TO POINT TO A VERY WET AND ACTIVE EXTENDED FORECAST. STRATIFORM RAIN WILL SPREAD ACROSS THE AREA ON FRIDAY AFTERNOON AND EVENING AS A PACIFIC SYSTEM MAKES LANDFALL NORTH OF VANCOUVER ISLAND. THIS SYSTEM OPENS UP ZONAL FLOW THAT STRETCHES INTO THE PACIFIC NORTHWEST FROM WELL PAST THE ALEUTIAN CHAIN. WITH SUCH A FAST FLOW ACROSS THE PACIFIC...AND SEVERAL EMBEDDED SYSTEMS FORECAST TO MOVE THROUGH THE DISTRICT FROM SATURDAY ONWARD...KEPT LIKELY POPS IN THE LOWLANDS AND CATEGORICAL POPS ALONG THE COAST AND COAST RANGE AS WELL AS IN THE CASCADES FOR THE ENTIRE EXTENDED TIME FRAME. ADDITIONALLY...WESTERLY H85 FLOW OF +30KT IS FORECAST FROM SATURDAY MORNING ONWARD...WITH FREEZING LEVELS BETWEEN 3500-5000 FEET. WITH SUCH FAVORABLE OROGRAPHIC FLOW AND MODEL QPF VALUES OF 2-3 INCHES DURING THIS TIME PERIOD...A SIGNIFICANT AND PROLONGED PERIOD OF MOUNTAIN SNOW SEEMS LIKELY...LIKELY IN EXCESS OF 3 FT IF FREEZING LEVELS STAY AROUND OR BELOW PASS LEVELS. DALTON